WO2022096024A1 - Construction method for super-long small-diameter hole bored pile - Google Patents

Construction method for super-long small-diameter hole bored pile Download PDF

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Publication number
WO2022096024A1
WO2022096024A1 PCT/CN2021/138914 CN2021138914W WO2022096024A1 WO 2022096024 A1 WO2022096024 A1 WO 2022096024A1 CN 2021138914 W CN2021138914 W CN 2021138914W WO 2022096024 A1 WO2022096024 A1 WO 2022096024A1
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WIPO (PCT)
Prior art keywords
hole
reinforcement
pile
mud
casing
Prior art date
Application number
PCT/CN2021/138914
Other languages
French (fr)
Chinese (zh)
Inventor
柯书豪
尹苏江
杨红磊
杨礼铭
费继为
丁列
王佳博
李辉
张野
郭云鹏
Original Assignee
中铁九局集团第四工程有限公司
中铁九局集团有限公司
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Application filed by 中铁九局集团第四工程有限公司, 中铁九局集团有限公司 filed Critical 中铁九局集团第四工程有限公司
Priority to JP2022534479A priority Critical patent/JP7266228B2/en
Publication of WO2022096024A1 publication Critical patent/WO2022096024A1/en

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
    • E02D5/38—Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D15/00—Handling building or like materials for hydraulic engineering or foundations
    • E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
    • E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/02—Determining slope or direction
    • E21B47/022—Determining slope or direction of the borehole, e.g. using geomagnetism
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/04—Measuring depth or liquid level
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/08—Measuring diameters or related dimensions at the borehole
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B7/00—Special methods or apparatus for drilling
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2250/00—Production methods
    • E02D2250/0023—Cast, i.e. in situ or in a mold or other formwork

Definitions

  • the invention belongs to the technical field of drilling of soil layers or rocks, and particularly relates to a construction method of an ultra-long and small-diameter bored cast-in-place pile.
  • Bored piles are the most common construction method, which can improve the overall quality of the project.
  • the design of the station building of Gaochuan Station on the Chenglan Railway is a pile foundation, with an average pile length of 45m and a pile diameter of 800mm. It is located above the Longmenshan fault zone, with complex underground rock formations and topography. Changeable, the existing bored pile construction structure is not stable, easy to collapse holes, the drill bit wears a lot, and the drill bit needs to be replaced frequently, which wastes time and increases the construction cost.
  • the purpose of the present invention is to provide a construction method for super-long and small-diameter bored cast-in-place piles, so as to at least solve the problems of poor structural stability, easy hole collapse, serious drill bit wear and high construction cost in the current bored cast-in-place pile construction process.
  • the present invention provides the following technical solutions:
  • a construction method for super-long and small-diameter bored cast-in-place piles comprising the following steps:
  • Step S100 leveling the site, so that the site of the pile hole reaches the height required by the design
  • Step S101 measuring and positioning, using a total station to locate the position of the pile hole, using the "+" cross method to embed and fix four positioning piles outside the pile hole, and determine the outline of the cast-in-place pile based on the positioning pile;
  • Step S102 burying the casing, burying the casing according to the outline of the cast-in-situ pile, the inner diameter of the casing is larger than the diameter of the cast-in-place pile, and the casing of the casing is vertical and backfilled with clay;
  • Step S103 the drill bit is improved and corrected, the drill bit is improved to improve the hole forming effect during the drilling process, the positioning piles embedded around the casing are diagonally connected with thin lines, and the check ensures the improved drill bit center and casing center On the same vertical line as the center of the cast-in-place pile;
  • the drill bit includes a drill rod and a blade, a steel plate is set on the drill rod, and a plurality of blades evenly distributed along the circumferential direction are arranged on the lower part of the drill rod.
  • the thickness of the steel plate is the same as the thickness of the blade protruding from the drill pipe;
  • the steel plate is curved in an arc shape, the bending curvature of the steel plate is consistent with the blade, and the steel plate and the blade form a closed ring when looking up;
  • Step S104 mud preparation, excavating a mud pool and a sedimentation tank within the range of the pile hole, the sedimentation tank is connected with the mud pool through a drainage ditch, the sedimentation tank is connected with the casing through a mud ditch, and the mud in the mud pool is prepared by using water, clay and additives ;
  • Step S105 drill a hole, use a wire rope to hoist the drilling rig so that the center of the drilling rig is aligned with the center of step S103, and the drill bit of the drilling rig first uses a low hammer to close the hole until the depth of the hole reaches 3-4m below the casing, and then begins to increase the stroke and increase the hammer height. Switch to normal continuous impact, and inject the prepared mud into the pile hole when drilling;
  • Step S106 check the verticality, check the verticality of the pile hole
  • Two observation points are set on the ground, and the two observation points are perpendicular to the line connecting the center of the pile hole, and a verticality measuring device is installed at the observation point.
  • the verticality measuring device is used to measure the verticality here.
  • the verticality at each observation point is compared with the verticality of the wire rope of the pulling drill bit, and the verticality of the pile hole body is monitored;
  • the verticality measuring device includes a support frame on which a wire pendant is hung.
  • the wire pendant includes a wire rope and a drop body. One end of the wire rope is connected to the drop body, and the other end is fixed on the support frame.
  • the drop body depends on its own gravity to hang freely. The direction of the rope determines the verticality of the observation point;
  • Step S107 cleaning the hole for the first time, using a slag scavenging bucket with a valve at the bottom, repeatedly scavenging the slag, removing the mud and sediment at the bottom of the hole, and replacing the mud with high density with water by a water pump to form the end hole of the pile hole;
  • Step S108 check the hole formation, check the final hole of the pile hole, check the hole diameter with a cage, check the hole depth with a measuring rope, check the verticality with a caliper, and enter the next process after meeting the requirements;
  • step S109 the reinforcement cage is fabricated and installed.
  • the reinforcement cage is made of steel bars in sections, and the reinforcement cage is hoisted into the pile hole with a crane, and the end of the reinforcement cage that is hoisted into the pile hole is temporarily supported at the mouth of the casing, and then the other cage is hoisted.
  • a section of steel cage is welded, and then sent into the pile hole, repeat the above steps, and all the steel cages are hoisted into the pile hole in turn;
  • the reinforcement cage includes the main reinforcement and the reinforcement hoop, the reinforcement hoop is fixed on the main reinforcement horizontally, and along the length of the main reinforcement, a reinforcement hoop is arranged every 2m;
  • the reinforcement cage is provided with grinding wheel protection pads, each section of the reinforcement cage is provided with at least two sets of grinding wheel protection pads, and each group is evenly arranged with at least four grinding wheel protection pads along the circumferential direction of the reinforcement cage; the reinforcement cage is also provided with reinforcement
  • the adjacent main bars are cross-connected by steel bars to form reinforcements. In the same section, a reinforcement is arranged every other space. Along the length of the main reinforcement, the center distance of the reinforcements in the adjacent reinforcement areas is 3m;
  • the length of the reinforcement cage reinforced by the reinforcement is 1m, and the reinforcement used for the reinforcement is HRB400E ⁇ 16 reinforcement;
  • Step S110 the conduit is installed, the conduit is hoisted into the pile hole by a crane, the conduit is connected with a screw thread, and a sealing ring is added at the interface;
  • Step S111 cleaning the hole for the second time, using a water pump to press the mud into the conduit, and then replacing the sediment along the outside of the conduit from the bottom of the hole;
  • Step S112 pouring concrete, and pouring concrete into the pile hole through the conduit.
  • the construction method of the super-long and small-diameter bored cast-in-place piles of the present invention is suitable for the cast-in-place piles with long length and small diameter.
  • the construction method of the present invention has simple equipment, convenient operation, and wide application range;
  • the wall is solid and stable, and there are few collapse holes.
  • the drill bit is improved, and the steel plate is welded on the drill bit, which greatly reduces the wear amount of the drill bit, reduces the frequency of replacing the drill bit, saves time, and reduces the construction cost.
  • the machinery used in the construction process can be driven by itself, without the need for large-scale machinery to transport and assemble, saving energy and reducing emissions.
  • Fig. 1 is the construction process flow chart of bored piles
  • Figure 2 is a front view of the improved drill bit
  • Figure 3 is a bottom view of the improved drill bit
  • Fig. 4 is the front view of observation point arrangement
  • Fig. 5 is the top view of observation point arrangement
  • Fig. 6 is the structural schematic diagram of observation point
  • Fig. 7 is the structural schematic diagram of the arrangement of wheeled mortar protection pads on the reinforcement cage
  • FIG. 8 is a schematic structural diagram of arranging reinforcements on the reinforcement cage.
  • a construction method for an ultra-long small-diameter bored cast-in-place pile is provided.
  • 800mm cast-in-place pile construction It is used in loess, cohesive or silty clay and artificial miscellaneous fills in engineering, as well as in bored pile engineering of gravel layer, boulder layer, hard soil layer and rock foundation containing boulders.
  • the working principle of percussion drilling pile Squeeze into the hole wall to form a retaining wall. After the hole is formed, use a slag bucket to remove excess slag or mud for the first hole cleaning. After the hole depth and the reinforcement cage 8 have passed the inspection and acceptance, the reinforcement cage 8 is put into the hole. After the installation of the conduit is completed, the mud deposited at the bottom of the hole is circulated through the conduit with a mud pump to achieve the second hole cleaning. After two times of hole cleaning, the thickness of the sediment meets the specification requirements, and finally the concrete is poured into the pile.
  • the super-long small-diameter bored pile construction method of the present invention mainly comprises the following steps:
  • Step S100 leveling the site so that the site of the pile hole reaches the height required by the design.
  • the site shall be leveled according to the elevation required by the design, and all obstacles on the ground and underground at the pile position shall be removed, and the low-lying areas of the site shall be backfilled and compacted.
  • Step S101 measuring and positioning, using a total station to locate the position of the pile hole, using the "+" cross method to embed and fix four positioning piles outside the pile hole, and determine the outline of the cast-in-place pile based on the positioning pile.
  • Step S102 bury the casing 5, embed the casing 5 according to the outline of the cast-in-place pile, the inner diameter of the casing 5 is larger than the diameter of the cast-in-place pile, the casing of the casing 5 is vertical and backfilled with clay to fix the casing.
  • the protective tube 5 has the functions of protecting the orifice, positioning and guiding, isolating the surface water, maintaining the height of the water head in the hole, preventing landslides, and fixing the steel cage 8.
  • the casing 5 is generally made of 4-8mm steel plate, its inner diameter should be larger than the design pile diameter of 200mm, and 1-2 overflow holes are set on the upper part; the casing 5 should be buried accurately and stably, and the deviation between the center of the casing 5 and the center of the pile position It should not be greater than 20mm, the inclination of the protective tube 5 should not be greater than 1% and the top end should be 300mm higher than the ground.
  • the positioning pile is made of ⁇ 20 steel bar, which is buried at a position of 1-2m on the 5th side of the casing.
  • the top of the positioning pile is 20mm higher than the top of the casing 5, and the buried depth is not less than 300mm.
  • Circular concrete with a thickness of 200mm and a radius of 200mm is poured. Fix and mark well, and do a good job in the protection of positioning piles during construction.
  • Step S103 the drill bit 1 is improved and corrected, the drill bit 1 is improved to improve the hole forming effect during the drilling process, the positioning piles embedded around the casing 5 are connected diagonally with thin lines, and the center of the drill bit 1 after the improvement is checked and guaranteed. , the center of the casing 5 and the center of the cast-in-place pile are on the same vertical line.
  • the improvement to the drill bit 1 is mainly reflected in that the drill rod 11 of the drill bit 1 is provided with a steel plate 2, the drill bit 1 includes a drill rod 11 and a blade 12, and the lower part of the drill rod 11 is provided with a plurality of uniform circumferential
  • the blades 12 are distributed, the blades 12 protrude outward from the drill rod 11, and the steel plate 2 is located at the groove formed between the adjacent blades 12 after extending upward, that is, the steel plate 2 is located at the upper part of the blade 12, and the steel plate 2 and the blade 12 are located in the upper part of the blade 12.
  • the circumferential direction is staggered from each other; the thickness of the steel plate 2 is the same as the thickness of the blade 12 protruding from the drill rod 11 .
  • the steel plate 2 is curved in an arc shape, the bending curvature of the steel plate 2 is consistent with the blade 12, the steel plate 2 and the blade 12 are closed rings when viewed from above, and the steel plate is welded on the drill bit 1 because the shape of the drill bit 1 is different from the hole diameter of the designed pile , after welding the steel plate, it becomes a closed ring in bottom view, which can improve the quality of the hole and ensure that the hole diameter meets the requirements.
  • the improved drill bit 1 of the present invention greatly reduces the wear amount of the drill bit 1, reduces the number of times of replacing the drill bit 1, saves time and reduces construction costs.
  • Step S104 mud preparation, excavating a mud pool and a sedimentation tank within the range of the pile hole, the sedimentation tank and the mud pool are connected through the drainage ditch, the sedimentation tank is communicated with the casing 5 through the mud ditch, and the mud is prepared in the mud pond for the casing.
  • the mud and sand mixture overflowing from the casing 5 during the drilling process is discharged into the sedimentation tank.
  • the upper mud is returned to the mud tank again, and the mud can be recycled.
  • the mud in the mud pit is prepared with water, high viscosity clay and additives.
  • the additives include bentonite and soda ash solution.
  • the additives can be added to the mud pool, or the inner wall of the casing 5 can be smeared with bentonite and soda ash solution before hammering. If the mud is too thin to hang on the wall of the casing 5, it can be added if necessary. Viscosity-increasing and fluid-loss reducing agent, use barite powder to increase the specific gravity of the slurry, or sawdust to prevent slurry leakage.
  • the mud pool is set on the outside of the site, which does not affect the normal drilling work and does not disturb the undisturbed soil of the foundation.
  • the capacity of the mud tank should be set at 1.5 times the total amount of mud produced by the simultaneous drilling, and the capacity of the sedimentation tank is slightly smaller than that of the mud tank.
  • the sedimentation tank and mud tank are excavated manually with excavators, and the excavated earth is piled up and transported to the designated location for subsequent backfilling. After the pile hole is filled, the waste slurry in the mud pool and sedimentation tank is pumped into the mud transport vehicle in time by the mud pump, and transported out of the construction site. The truck is transported out of the construction site, and the mud tank and sedimentation tank are backfilled in time after the transfer of the sediment is completed. The drilling slag and waste slurry shall be discarded and transported in time.
  • Step S105 drill a hole, use the wire rope 4 to hoist the drilling rig 3 so that the center of the drilling rig 3 is aligned with the center of the step S103 , the drill bit 1 of the drilling rig 3 first uses a low hammer to close the hole until the depth of the hole reaches 3-4m below the casing 5 and then begins to increase. Stroke, increase the hammer height, switch to normal continuous impact, and inject the prepared mud into the pile hole when drilling.
  • the hammer height is 0.4-0.6m during low-hammer compact impact, and clay mud is added to protect the wall in time to compact the hole wall; the hammer height during normal continuous impact is 1.5-2.0m.
  • the drilling process for the variable layer and the parts that are prone to deflection, use a low hammer to lightly strike and pass through intermittent impact to maintain a good hole shape; when deflection occurs, stop drilling and use The gravel is backfilled to the point where the hole body is offset, and the drilling is re-drilled.
  • the change of the mud level should be paid attention to by visual inspection.
  • the slurry should be replenished in time to prevent the hole from collapsing due to insufficient mud.
  • step S106 the verticality of the hole is checked, and the verticality of the pile hole is checked.
  • two observation points that are perpendicular to each other from the center of the pile hole are set on the ground, as shown in FIG.
  • the verticality measuring device is used to measure the verticality here.
  • the verticality at the two observation points is compared with the verticality of the wire rope 4 of the traction drill bit 1, and it is observed whether the verticality of the three coincides, and the coincidence is the hole. If the body is vertical, if the hole body is not coincident, the hole body will be deflected, so as to monitor the verticality of the hole body of the pile hole.
  • the verticality measuring device includes a support frame 6 on which a wire weight 7 is hung.
  • the wire weight 7 includes a wire rope 71 and a drop body 72.
  • One end of the wire rope 71 is connected to the drop body 72, and the other end is fixed on the support frame 6 , the verticality of the observation point is judged by the direction of the wire 71 of the wire weight 7 .
  • the support frame 6 uses four steel bars to form a pyramid, and the steel bars are HRB400E ⁇ 20 steel bars.
  • Step S107 cleaning the hole for the first time, using a slag scavenging bucket with a valve at the bottom (that is, a check valve at the bottom of the slag scavenging bucket to prevent the leakage of sediment), repeatedly digging out the slag, and removing the mud and sediment at the bottom of the hole.
  • the large mud is replaced by water pump with clean water, so that the density is controlled between 1.15-1.25, and the final hole of the pile hole is formed.
  • Step S108 check the hole formation, check the final hole of the pile hole, check the hole diameter with a probe cage, check the hole depth with a measuring rope, check the verticality with a caliper, and enter the next process after meeting the requirements.
  • Step S109 the reinforcement cage 8 is fabricated and installed, the reinforcement cage 8 is made of steel bars in sections, the reinforcement cage 8 is hoisted into the pile hole with a crane, and the end of the reinforcement cage 8 that is hoisted into the pile hole is temporarily supported on the casing 5. Then, another section of reinforcement cage 8 is hoisted for welding, and then sent into the pile hole, and the above steps are repeated to sequentially hoist all the reinforcement cages 8 into the pile hole.
  • the reinforcement cage 8 includes a main reinforcement 81 and a reinforcing hoop 82.
  • the reinforcement hoop 82 is laterally fixed on the main reinforcement 81.
  • a reinforcement hoop 82 is arranged every 2m; 81 is fixed by staggered spot welding and binding, and the dislocation overlap length of the joint position of the main bar 81 during cutting is not less than 35d (d is the diameter of the main bar).
  • the number of joints in the same section does not exceed 50% of the total number of reinforcement bars; the joints of the main reinforcement 81 are welded on one side, and the welding length is 10d (d is the diameter of the main reinforcement).
  • a wheeled mortar protection block 83 is provided on the reinforcement cage 8 , and its function is to prevent the reinforcement cage 8 from rubbing against the hole wall when the reinforcement cage 8 is lowered, so as to ensure the smooth installation of the reinforcement cage 8 .
  • At least two groups of wheeled mortar protection blocks 83 are arranged on each section of the reinforcement cage 8 , and at least four wheeled mortar protection cushions 83 are evenly arranged in each group along the circumferential direction of the reinforcement cage 8 .
  • the reinforcement cage 8 Before the reinforcement cage 8 enters the hole, in order to ensure the integrity of the reinforcement cage 8, strengthen measures are taken to the skeleton of the reinforcement cage 8 before lifting.
  • the reinforcement cage 8 is provided with a reinforcement 84, and the adjacent main bars 81 are crossed by reinforcement.
  • a reinforcement 84 is arranged every other space in the same section, along the length direction of the main reinforcement 81, the center distance of reinforcements 84 in adjacent reinforcement areas is 3m; preferably, the reinforcement cage reinforced by reinforcements 84
  • the length of 8 is 1m, and the reinforcement used for the reinforcement 84 is HRB400E ⁇ 16 reinforcement.
  • the steel cage 8 When the steel cage 8 enters the hole, it is hoisted by a crane.
  • two-point lifting is adopted.
  • the first hanging point is set at the lower part of the frame (the steel cage 8 frame), and the second hanging point is set between the midpoint and one-third of the length of the frame.
  • lift the first lifting point When lifting, lift the first lifting point first to lift the frame slightly, and then lift at the same time with the second lifting point. After the frame leaves the ground, the first lifting point stops lifting and continues to lift the second lifting point.
  • the second lifting point continues to rise, slowly loosen the first lifting point until the skeleton is perpendicular to the ground and stop lifting. Check that the skeleton is straight.
  • the skeleton When the skeleton enters the hole, it should be lowered slowly, and it is strictly forbidden to touch the hole wall. When it is lowered to the end of the skeleton, temporarily support the skeleton on the 5 openings of the protective tube, and then lift the skeleton of the second steel cage 8, so that the upper and lower skeletons are located on the same straight line for welding. After welding, it should be firmly positioned at the orifice to avoid the floating cage phenomenon during the pouring of concrete.
  • the length of the positioning rib must be calculated by measuring the elevation of the orifice.
  • the center of the reinforcement cage 8 should be aligned with the center of the design pile. It is welded and fixed on the steel casing 5 to complete the installation of the reinforcement cage 8 .
  • connection with the upper reinforcement shall be single-sided welding. After welding, it is forbidden to put it into the hole immediately, and the reinforcement shall be cooled for 1 minute before being put into the hole.
  • Step S110 the conduit is installed, the conduit is hoisted into the pile hole by a crane, the conduit is connected with a screw thread, and a sealing ring is added at the interface to prevent mud from entering the conduit when concrete is poured.
  • step S111 the second hole is cleaned, and the mud is pressed into the pipe by a water pump, and then the sediment is replaced along the outside of the pipe from the bottom of the hole.
  • the second hole cleaning method is adopted to achieve the purpose of secondary hole cleaning.
  • swing the guide tube frequently to change the position of the guide tube at the bottom of the hole to ensure complete replacement of the sediment.
  • the specific gravity of the mud is less than or equal to 1.1
  • the sand content is less than or equal to 8%
  • the viscosity is 18-28Pa.s
  • the thickness of the sediment at the bottom of the hole is less than or equal to 50mm.
  • Step S112 pouring concrete, and pouring concrete into the pile hole through the conduit.
  • the concrete After the slag at the bottom of the hole has passed the acceptance, the concrete must be initially poured within half an hour, and the concrete pouring should be carried out continuously without leaving construction joints. The time to complete the concrete pouring of the whole pile should be controlled within 2-4 hours.
  • the back-to-top pouring method is used. First, pour concrete at the bottom of the conduit to form a water-insulating layer, and then enter the concrete into the water-insulating layer through the bottom of the conduit. The poured concrete solidifies into a complete pile body.
  • the bottom of the conduit should be 300-500mm away from the bottom of the hole, so that the aquifer and concrete can be discharged smoothly. , to prevent mud water from pouring into the conduit.
  • the position of the concrete surface must be measured frequently to ensure that the buried depth of the conduit is within the range of 2-6 meters.
  • the catheter is often inserted up and down to ensure the compactness of the pile body. After pouring, the protective tube 5 is slowly and vertically pulled up to ensure the quality of the concrete at the top of the pile.
  • the station building and corridor foundation of the newly built Chengdu-Lanzhou Railway Chengdu-Chuanzhusi Section Station Building Project CLZF-1 bid section is designed as end-bearing piles.
  • the situation (from top to bottom) is: mixed fill, pebble soil, silty clay, pebble soil, strongly weathered rock, weakly weathered rock (dolomitic limestone), the situation is changeable and the structure is complex. good.
  • this construction method is simple to operate, less restrictive, and has a wide range of applications; during construction, the noise and vibration are small and do not disturb the people; the hole wall is solid, stable and not easy to collapse, which ensures the construction quality of the pile foundation and improves the structure. security.

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Abstract

The present invention provides a construction method for a super-long small-diameter hole bored pile, the construction method comprising the following steps: measurement and positioning, casing burial, drill bit improvement and correction, slurry preparation, drilling, hole verticality checking, primary hole clearing, hole completion acceptance checking, steel reinforcement cage manufacturing and installation, pipe installation, secondary hole clearing and concrete pouring. The present construction method is suitable for bored piles having a longer length and a smaller diameter, and by means of improving the drill bit, the amount of wear on the drill bit is greatly reduced, the number of times the drill bit is replaced is reduced, and time is saved. Multiple reinforcing modes are used in manufacturing the steel reinforcement cage, and thus overall structural stability is stronger, and strength and safety are better. The invention features convenient construction operations and a broad range of use, is not limited by sites, and produces holes that are sturdy and stable, with few collapses. The invention also features little dust pollution and meets requirements for green construction.

Description

一种超长小直径钻孔灌注桩施工方法A construction method of super-long and small-diameter bored cast-in-place piles 技术领域technical field
本发明属于土层或岩石的钻进技术领域，具体涉及一种超长小直径钻孔灌注桩施工方法。The invention belongs to the technical field of drilling of soil layers or rocks, and particularly relates to a construction method of an ultra-long and small-diameter bored cast-in-place pile.
背景技术Background technique
随着建筑行业的高速发展，对建筑地基的要求标准也越来越高。不同的地质条件采用不同的基础形式，尤其是铁路桥梁、公路桥梁以及地下结构极其复杂的地区，钻孔灌注桩是最为常见施工方法，能够提高工程整体质量。针对超长小直径的灌注桩，施工难度大，比如成兰铁路高川站站房设计形式为桩基础，平均桩长45m，桩径800mm，且位于龙门山断裂带之上，地下岩层复杂，地形多变，现有的钻孔灌注桩施工结构稳定性不佳，易塌孔，钻头磨损大，需要经常更换钻头，浪费时间，增加施工成本。With the rapid development of the construction industry, the requirements for building foundations are also getting higher and higher. Different geological conditions use different foundation forms, especially for railway bridges, highway bridges and areas with extremely complex underground structures. Bored piles are the most common construction method, which can improve the overall quality of the project. For super-long and small-diameter cast-in-place piles, the construction is difficult. For example, the design of the station building of Gaochuan Station on the Chenglan Railway is a pile foundation, with an average pile length of 45m and a pile diameter of 800mm. It is located above the Longmenshan fault zone, with complex underground rock formations and topography. Changeable, the existing bored pile construction structure is not stable, easy to collapse holes, the drill bit wears a lot, and the drill bit needs to be replaced frequently, which wastes time and increases the construction cost.
发明内容SUMMARY OF THE INVENTION
本发明的目的在于提供一种超长小直径钻孔灌注桩施工方法，以至少解决目前钻孔灌注桩施工过程中结构稳定性差，易塌孔，钻头磨损严重，施工成本高的问题。The purpose of the present invention is to provide a construction method for super-long and small-diameter bored cast-in-place piles, so as to at least solve the problems of poor structural stability, easy hole collapse, serious drill bit wear and high construction cost in the current bored cast-in-place pile construction process.
为了实现上述目的，本发明提供如下技术方案：In order to achieve the above object, the present invention provides the following technical solutions:
一种超长小直径钻孔灌注桩施工方法，施工方法包括如下步骤：A construction method for super-long and small-diameter bored cast-in-place piles, comprising the following steps:
步骤S100，平整场地，使桩孔的场地达到设计要求的高度；Step S100, leveling the site, so that the site of the pile hole reaches the height required by the design;
步骤S101，测量定位，采用全站仪定位桩孔的位置，采用“+”字交叉法在桩孔外部埋设固定四个定位桩，以定位桩为基准确定灌注桩轮廓线；Step S101, measuring and positioning, using a total station to locate the position of the pile hole, using the "+" cross method to embed and fix four positioning piles outside the pile hole, and determine the outline of the cast-in-place pile based on the positioning pile;
步骤S102，埋设护筒，根据灌注桩轮廓线埋设护筒，护筒内径大于灌注桩的直径，护筒的筒身竖直后用黏土回填；Step S102, burying the casing, burying the casing according to the outline of the cast-in-situ pile, the inner diameter of the casing is larger than the diameter of the cast-in-place pile, and the casing of the casing is vertical and backfilled with clay;
步骤S103，钻头改进和校正，对钻头进行改进以提高钻进过程中成孔效果，用细线将埋设在护筒周围的定位桩对角连接，校核确保改进后的钻头中心、护筒中心和灌注桩中心在同一竖直线上；Step S103, the drill bit is improved and corrected, the drill bit is improved to improve the hole forming effect during the drilling process, the positioning piles embedded around the casing are diagonally connected with thin lines, and the check ensures the improved drill bit center and casing center On the same vertical line as the center of the cast-in-place pile;
钻头包括钻杆与刀片，在钻杆上设置有钢板，钻杆下部设置有多个沿周 向均匀分布的刀片，刀片向外凸出于钻杆，钢板位于相邻刀片向上延伸后之间形成的凹槽处，钢板的厚度与刀片凸出于钻杆的厚度相同；The drill bit includes a drill rod and a blade, a steel plate is set on the drill rod, and a plurality of blades evenly distributed along the circumferential direction are arranged on the lower part of the drill rod. At the groove, the thickness of the steel plate is the same as the thickness of the blade protruding from the drill pipe;
钢板呈弧形弯曲，钢板的弯曲曲率与刀片一致，钢板与刀片在仰视时呈闭合圆环；The steel plate is curved in an arc shape, the bending curvature of the steel plate is consistent with the blade, and the steel plate and the blade form a closed ring when looking up;
刀片有四个，钢板也设置有四个，钢板焊接在钻杆上；There are four blades and four steel plates, and the steel plates are welded on the drill pipe;
步骤S104，泥浆制备，在桩孔范围内挖设泥浆池和沉淀池，沉淀池与泥浆池通过排水沟相连通，沉淀池通过泥浆沟与护筒连通，泥浆池内泥浆采用水、黏土和添加剂制备；Step S104, mud preparation, excavating a mud pool and a sedimentation tank within the range of the pile hole, the sedimentation tank is connected with the mud pool through a drainage ditch, the sedimentation tank is connected with the casing through a mud ditch, and the mud in the mud pool is prepared by using water, clay and additives ;
步骤S105，钻孔，使用钢丝绳吊装钻机使钻机中心对准步骤S103的中心，钻机的钻头先使用低锤密击，直至孔深达到护筒下方3-4m后开始加大冲程，提高锤高，转入正常连续冲击，在钻孔时将制备的泥浆注入桩孔内；Step S105, drill a hole, use a wire rope to hoist the drilling rig so that the center of the drilling rig is aligned with the center of step S103, and the drill bit of the drilling rig first uses a low hammer to close the hole until the depth of the hole reaches 3-4m below the casing, and then begins to increase the stroke and increase the hammer height. Switch to normal continuous impact, and inject the prepared mud into the pile hole when drilling;
步骤S106，垂直度检查，检查桩孔的垂直度；Step S106, check the verticality, check the verticality of the pile hole;
在地面上设置两个观测点，两个观测点分别与桩孔中心的连线相互垂直，观测点处均设置有垂直度测量装置，垂直度测量装置用于测量此处的垂直度，通过两个观测点处的垂直度与牵引钻头的钢丝绳的垂直度进行比较，监控桩孔孔身的垂直度；Two observation points are set on the ground, and the two observation points are perpendicular to the line connecting the center of the pile hole, and a verticality measuring device is installed at the observation point. The verticality measuring device is used to measure the verticality here. The verticality at each observation point is compared with the verticality of the wire rope of the pulling drill bit, and the verticality of the pile hole body is monitored;
垂直度测量装置包括支撑架，支撑架上挂设有线坠，线坠包括线绳和坠体，线绳的一端连接坠体，另一端固定在支撑架上，坠体依靠自身重力自由垂落，通过线绳方向判断该观测点的垂直度；The verticality measuring device includes a support frame on which a wire pendant is hung. The wire pendant includes a wire rope and a drop body. One end of the wire rope is connected to the drop body, and the other end is fixed on the support frame. The drop body depends on its own gravity to hang freely. The direction of the rope determines the verticality of the observation point;
步骤S107，第一次清孔，使用底部带活门的掏渣桶，反复掏渣，将孔底淤泥、沉渣清除干净，对于密度大的泥浆采用水泵用清水置换，形成桩孔终孔；Step S107, cleaning the hole for the first time, using a slag scavenging bucket with a valve at the bottom, repeatedly scavenging the slag, removing the mud and sediment at the bottom of the hole, and replacing the mud with high density with water by a water pump to form the end hole of the pile hole;
步骤S108，成孔验收，对桩孔终孔进行验收，采用探笼检查孔径，用测绳检查孔深，用井径仪检查垂直度，符合要求后进入下一道工序；Step S108 , check the hole formation, check the final hole of the pile hole, check the hole diameter with a cage, check the hole depth with a measuring rope, check the verticality with a caliper, and enter the next process after meeting the requirements;
步骤S109，钢筋笼制作与安装，钢筋笼由钢筋分节制作，用吊车将钢筋笼吊入桩孔内，并将吊入进桩孔的钢筋笼的末端临时支撑于护筒口，再吊起另一节钢筋笼进行焊接，然后送入桩孔，重复上述步骤，依次将全部钢筋笼全部吊入桩孔内；In step S109, the reinforcement cage is fabricated and installed. The reinforcement cage is made of steel bars in sections, and the reinforcement cage is hoisted into the pile hole with a crane, and the end of the reinforcement cage that is hoisted into the pile hole is temporarily supported at the mouth of the casing, and then the other cage is hoisted. A section of steel cage is welded, and then sent into the pile hole, repeat the above steps, and all the steel cages are hoisted into the pile hole in turn;
钢筋笼包括主筋和加强箍，加强箍横向固定在主筋上，沿主筋长度方向上，每隔2m设置一道加强箍；The reinforcement cage includes the main reinforcement and the reinforcement hoop, the reinforcement hoop is fixed on the main reinforcement horizontally, and along the length of the main reinforcement, a reinforcement hoop is arranged every 2m;
钢筋笼上设置有砂轮保护垫块，每节钢筋笼上设置有至少两组砂轮保护垫块，每组沿钢筋笼的环向均匀布置有至少四个砂轮保护垫块；钢筋笼还设置有加强件，相邻的主筋之间采用钢筋交叉连接，形成加强件，同一截面中每隔一空布置一道加强件，沿主筋长度方向上，相邻加强区域的加强件的中心距为3m；The reinforcement cage is provided with grinding wheel protection pads, each section of the reinforcement cage is provided with at least two sets of grinding wheel protection pads, and each group is evenly arranged with at least four grinding wheel protection pads along the circumferential direction of the reinforcement cage; the reinforcement cage is also provided with reinforcement The adjacent main bars are cross-connected by steel bars to form reinforcements. In the same section, a reinforcement is arranged every other space. Along the length of the main reinforcement, the center distance of the reinforcements in the adjacent reinforcement areas is 3m;
加强件加强的钢筋笼长度为1m，加强件采用的钢筋为HRB400EΦ16钢筋；The length of the reinforcement cage reinforced by the reinforcement is 1m, and the reinforcement used for the reinforcement is HRB400EΦ16 reinforcement;
步骤S110，导管安装，采用吊车将导管吊入桩孔内，导管采用丝扣连接，且在接口处加密封圈；Step S110, the conduit is installed, the conduit is hoisted into the pile hole by a crane, the conduit is connected with a screw thread, and a sealing ring is added at the interface;
步骤S111，第二次清孔，采用水泵将泥浆压入导管内，再从孔底沿着导管外置换沉渣；Step S111, cleaning the hole for the second time, using a water pump to press the mud into the conduit, and then replacing the sediment along the outside of the conduit from the bottom of the hole;
步骤S112，灌注混凝土，通过导管向桩孔内灌注混凝土。Step S112, pouring concrete, and pouring concrete into the pile hole through the conduit.
有益效果：Beneficial effects:
本发明超长小直径钻孔灌注桩施工方法适用于长度较长，直径较小的灌注桩，本发明的施工方法所用设备简单，操作方便，使用范围广泛；且不受场地限制，所成孔壁坚实、稳定，塌孔少。The construction method of the super-long and small-diameter bored cast-in-place piles of the present invention is suitable for the cast-in-place piles with long length and small diameter. The construction method of the present invention has simple equipment, convenient operation, and wide application range; The wall is solid and stable, and there are few collapse holes.
施工过程中无噪声和振动影响，不扰民，施工过程中产生的扬尘少，降低了粉尘污染，符合绿色施工的要求。There is no noise and vibration in the construction process, no disturbance to the people, less dust is generated during the construction process, dust pollution is reduced, and it meets the requirements of green construction.
钢筋笼制作采用多种加固方式，整体结构稳定性更强，强度和安全性更高，能够顺利下放至桩孔中，对孔壁影响较小，不仅提高工程质量，还有效提升了结构的整体性。Various reinforcement methods are used in the production of the steel cage, which has stronger overall structural stability, higher strength and safety, and can be smoothly lowered into the pile hole with little impact on the hole wall, which not only improves the quality of the project, but also effectively improves the overall structure of the structure. sex.
本施工方法中对钻头进行了改进，钻头上焊接了钢板，大大降低了钻头的磨损量，减少更换钻头次数，节约时间，降低施工成本。In this construction method, the drill bit is improved, and the steel plate is welded on the drill bit, which greatly reduces the wear amount of the drill bit, reduces the frequency of replacing the drill bit, saves time, and reduces the construction cost.
施工过程中使用的机械自身可以驾驶，无需大型机械调运组装，节能减排。The machinery used in the construction process can be driven by itself, without the need for large-scale machinery to transport and assemble, saving energy and reducing emissions.
附图说明Description of drawings
图1为钻孔灌注桩施工工艺流程图；Fig. 1 is the construction process flow chart of bored piles;
图2为改进后钻头的正视图；Figure 2 is a front view of the improved drill bit;
图3为改进后钻头的仰视图；Figure 3 is a bottom view of the improved drill bit;
图4为观测点布置的正视图；Fig. 4 is the front view of observation point arrangement;
图5为观测点布置的俯视图；Fig. 5 is the top view of observation point arrangement;
图6为观测点的结构示意图；Fig. 6 is the structural schematic diagram of observation point;
图7为钢筋笼上布置轮式砂浆保护垫块的结构示意图；Fig. 7 is the structural schematic diagram of the arrangement of wheeled mortar protection pads on the reinforcement cage;
图8为钢筋笼上布置加强件的结构示意图。FIG. 8 is a schematic structural diagram of arranging reinforcements on the reinforcement cage.
图中：1、钻头；11、钻杆；12、刀片；2、钢板；3、钻机；4、钢丝绳；5、护筒；6、支撑架；7、线坠；71、线绳；72、坠体；8、钢筋笼；81、主筋；82、加强箍；83、轮式砂浆保护垫块；84、加强件。In the picture: 1. Drill bit; 11. Drill pipe; 12. Blade; 2. Steel plate; 3. Drilling rig; 4. Steel wire rope; Falling body; 8. Reinforcement cage; 81. Main reinforcement; 82. Reinforcing hoop; 83. Wheeled mortar protection pad; 84. Reinforcing piece.
具体实施方式Detailed ways
如图1至图8所示，根据本发明的实施例，提供了一种超长小直径钻孔灌注桩施工方法，本发明中的施工方法适用于桩长40-80m，桩径为600-800mm的灌注桩施工。用于工程中的黄土、粘性土或粉质粘土和人工杂填土以及含有孤石的砂砾石层、漂石层、坚硬土层、岩石地基的钻孔灌注桩工程中。As shown in FIGS. 1 to 8 , according to an embodiment of the present invention, a construction method for an ultra-long small-diameter bored cast-in-place pile is provided. 800mm cast-in-place pile construction. It is used in loess, cohesive or silty clay and artificial miscellaneous fills in engineering, as well as in bored pile engineering of gravel layer, boulder layer, hard soil layer and rock foundation containing boulders.
冲击钻钻孔灌注桩的工作原理：用冲击形式钻机3或卷扬机悬吊冲锤利用自身重力上下往复冲击，将卵石土、岩石层或者人工杂填土中的碎石破碎，部分碎渣或泥浆挤入孔壁中，形成护壁。成孔后，第一次清孔用掏渣桶捞取多余碎渣或泥浆，孔深及钢筋笼8经过验收合格后，将钢筋笼8放入孔中。导管安装完成后，通过导管用泥浆泵循环清理沉积在孔底部的泥浆，实现第二次清孔。经过两次清孔使得沉渣厚度满足规范要求，最终灌注混凝土成桩。The working principle of percussion drilling pile Squeeze into the hole wall to form a retaining wall. After the hole is formed, use a slag bucket to remove excess slag or mud for the first hole cleaning. After the hole depth and the reinforcement cage 8 have passed the inspection and acceptance, the reinforcement cage 8 is put into the hole. After the installation of the conduit is completed, the mud deposited at the bottom of the hole is circulated through the conduit with a mud pump to achieve the second hole cleaning. After two times of hole cleaning, the thickness of the sediment meets the specification requirements, and finally the concrete is poured into the pile.
本发明的超长小直径钻孔灌注桩施工方法主要包括如下步骤：The super-long small-diameter bored pile construction method of the present invention mainly comprises the following steps:
步骤S100，平整场地，使桩孔的场地达到设计要求的高度。场地先按设计要求的标高进行平整，清除桩位处地上、地下的一切障碍物，场地低洼处需回填夯实。Step S100, leveling the site so that the site of the pile hole reaches the height required by the design. The site shall be leveled according to the elevation required by the design, and all obstacles on the ground and underground at the pile position shall be removed, and the low-lying areas of the site shall be backfilled and compacted.
步骤S101，测量定位，采用全站仪定位桩孔的位置，采用“+”字交叉法在桩孔外部埋设固定四个定位桩，以定位桩为基准确定灌注桩轮廓线。Step S101, measuring and positioning, using a total station to locate the position of the pile hole, using the "+" cross method to embed and fix four positioning piles outside the pile hole, and determine the outline of the cast-in-place pile based on the positioning pile.
步骤S102，埋设护筒5，根据灌注桩轮廓线埋设护筒5，护筒5内径大于灌注桩的直径，护筒5的筒身竖直后用黏土回填以固定筒身。Step S102, bury the casing 5, embed the casing 5 according to the outline of the cast-in-place pile, the inner diameter of the casing 5 is larger than the diameter of the cast-in-place pile, the casing of the casing 5 is vertical and backfilled with clay to fix the casing.
护筒5作用有保护孔口、定位导向、隔离地表水、保持孔内水头高度、防止塌方、固定钢筋笼8等。护筒5一般用4-8mm钢板制作，其内径应大于设计桩径200mm，其上部开设1-2个溢浆孔；护筒5埋设应准确、稳定，护 筒5中心与桩位中心的偏差不得大于20mm，护筒5的倾斜度不得大于1％且顶端高于地面300mm。The protective tube 5 has the functions of protecting the orifice, positioning and guiding, isolating the surface water, maintaining the height of the water head in the hole, preventing landslides, and fixing the steel cage 8. The casing 5 is generally made of 4-8mm steel plate, its inner diameter should be larger than the design pile diameter of 200mm, and 1-2 overflow holes are set on the upper part; the casing 5 should be buried accurately and stably, and the deviation between the center of the casing 5 and the center of the pile position It should not be greater than 20mm, the inclination of the protective tube 5 should not be greater than 1% and the top end should be 300mm higher than the ground.
定位桩采用Φ20的钢筋，在位于护筒5边1-2m位置进行埋设，定位桩顶高于护筒5顶20mm，且埋入地下不小于300mm，并浇筑200mm厚半径200mm的圆形混凝土进行固定，并做好标识，施工中做好定位桩的保护工作。The positioning pile is made of Φ20 steel bar, which is buried at a position of 1-2m on the 5th side of the casing. The top of the positioning pile is 20mm higher than the top of the casing 5, and the buried depth is not less than 300mm. Circular concrete with a thickness of 200mm and a radius of 200mm is poured. Fix and mark well, and do a good job in the protection of positioning piles during construction.
步骤S103，钻头1改进和校正，对钻头1进行改进以提高钻进过程中成孔效果，用细线将埋设在护筒5周围的定位桩对角连接，校核确保改进后的钻头1中心、护筒5中心和灌注桩中心在同一竖直线上。Step S103, the drill bit 1 is improved and corrected, the drill bit 1 is improved to improve the hole forming effect during the drilling process, the positioning piles embedded around the casing 5 are connected diagonally with thin lines, and the center of the drill bit 1 after the improvement is checked and guaranteed. , the center of the casing 5 and the center of the cast-in-place pile are on the same vertical line.
本发明的具体实施例中，对钻头1的改进主要体现在钻头1的钻杆11上设置有钢板2，钻头1包括钻杆11和刀片12，钻杆11下部设置有多个沿周向均匀分布的刀片12，刀片12向外凸出于钻杆11，钢板2位于相邻刀片12向上延伸后之间形成的凹槽处，也即钢板2位于刀片12的上部，钢板2与刀片12在周向上相互错开布置；钢板2的厚度与刀片12凸出于钻杆11的厚度相同。In the specific embodiment of the present invention, the improvement to the drill bit 1 is mainly reflected in that the drill rod 11 of the drill bit 1 is provided with a steel plate 2, the drill bit 1 includes a drill rod 11 and a blade 12, and the lower part of the drill rod 11 is provided with a plurality of uniform circumferential The blades 12 are distributed, the blades 12 protrude outward from the drill rod 11, and the steel plate 2 is located at the groove formed between the adjacent blades 12 after extending upward, that is, the steel plate 2 is located at the upper part of the blade 12, and the steel plate 2 and the blade 12 are located in the upper part of the blade 12. The circumferential direction is staggered from each other; the thickness of the steel plate 2 is the same as the thickness of the blade 12 protruding from the drill rod 11 .
优选地，钢板2呈弧形弯曲，钢板2的弯曲曲率与刀片12一致，钢板2与刀片12俯视时呈闭合圆环，在钻头1上焊接钢板是因为钻头1外形与设计桩的孔径有差别，焊接钢板后在仰视图中成为一个闭合环，能够提高成孔质量，确保孔径符合要求；再优选地，刀片12有四个，钢板也设置有四个，钢板焊接在钻杆11上。本发明的改进后的钻头1大大降低了钻头1的磨损量，减少更换钻头1次数，节约时间，降低施工成本。Preferably, the steel plate 2 is curved in an arc shape, the bending curvature of the steel plate 2 is consistent with the blade 12, the steel plate 2 and the blade 12 are closed rings when viewed from above, and the steel plate is welded on the drill bit 1 because the shape of the drill bit 1 is different from the hole diameter of the designed pile , after welding the steel plate, it becomes a closed ring in bottom view, which can improve the quality of the hole and ensure that the hole diameter meets the requirements. The improved drill bit 1 of the present invention greatly reduces the wear amount of the drill bit 1, reduces the number of times of replacing the drill bit 1, saves time and reduces construction costs.
步骤S104，泥浆制备，在桩孔范围内挖设泥浆池和沉淀池，沉淀池与泥浆池通过排水沟相连通，沉淀池通过泥浆沟与护筒5连通，泥浆池内制备泥浆，用于护筒5中，在钻进过程中从护筒5中溢出的泥浆和砂子混合物排入沉淀池内，经过沉淀池的沉淀，上层泥浆再次返回至泥浆池内，泥浆可实现循环利用。泥浆池内的泥浆采用水、高粘度黏土和添加剂制备。添加剂包括膨润土和纯碱溶液，添加剂可以加入至泥浆池内，也可以在开锤前，护筒5内壁上涂抹上膨润土和纯碱溶液，若泥浆过稀无法挂到护筒5壁面上，必要时可以加增黏降失水剂，使用重晶石粉增大泥浆比重，或者锯末防止漏浆。Step S104, mud preparation, excavating a mud pool and a sedimentation tank within the range of the pile hole, the sedimentation tank and the mud pool are connected through the drainage ditch, the sedimentation tank is communicated with the casing 5 through the mud ditch, and the mud is prepared in the mud pond for the casing. In 5, the mud and sand mixture overflowing from the casing 5 during the drilling process is discharged into the sedimentation tank. After the sedimentation in the sedimentation tank, the upper mud is returned to the mud tank again, and the mud can be recycled. The mud in the mud pit is prepared with water, high viscosity clay and additives. The additives include bentonite and soda ash solution. The additives can be added to the mud pool, or the inner wall of the casing 5 can be smeared with bentonite and soda ash solution before hammering. If the mud is too thin to hang on the wall of the casing 5, it can be added if necessary. Viscosity-increasing and fluid-loss reducing agent, use barite powder to increase the specific gravity of the slurry, or sawdust to prevent slurry leakage.
泥浆池设置于场地外侧，不影响正常钻进工作，不扰动地基原状土。泥浆池容量应按照同时钻进所产生的泥浆总量的1.5倍设置，沉淀池容量略小 于泥浆池。沉淀池、泥浆池采用人工配合挖掘机进行挖掘，挖出的土方集中堆放，并运至指定地点，以便后续回填使用。桩孔完成灌注后，泥浆池及沉淀池内的废浆采用泥浆泵及时抽到泥浆运输车内，运出工地，沉淀池及泥浆池底的沉渣晾干后，用挖掘机挖出并用密闭式运输车运出工地，泥浆池及沉淀池待沉渣转运完毕后及时回填。钻渣、废浆及时弃运。The mud pool is set on the outside of the site, which does not affect the normal drilling work and does not disturb the undisturbed soil of the foundation. The capacity of the mud tank should be set at 1.5 times the total amount of mud produced by the simultaneous drilling, and the capacity of the sedimentation tank is slightly smaller than that of the mud tank. The sedimentation tank and mud tank are excavated manually with excavators, and the excavated earth is piled up and transported to the designated location for subsequent backfilling. After the pile hole is filled, the waste slurry in the mud pool and sedimentation tank is pumped into the mud transport vehicle in time by the mud pump, and transported out of the construction site. The truck is transported out of the construction site, and the mud tank and sedimentation tank are backfilled in time after the transfer of the sediment is completed. The drilling slag and waste slurry shall be discarded and transported in time.
步骤S105，钻孔，使用钢丝绳4吊装钻机3使钻机3中心对准步骤S103的中心，钻机3的钻头1先使用低锤密击，直至孔深达到护筒5下方3-4m后开始加大冲程，提高锤高，转入正常连续冲击，在钻孔时将制备的泥浆注入桩孔内。Step S105 , drill a hole, use the wire rope 4 to hoist the drilling rig 3 so that the center of the drilling rig 3 is aligned with the center of the step S103 , the drill bit 1 of the drilling rig 3 first uses a low hammer to close the hole until the depth of the hole reaches 3-4m below the casing 5 and then begins to increase. Stroke, increase the hammer height, switch to normal continuous impact, and inject the prepared mud into the pile hole when drilling.
本发明的具体实施例中，低锤密击时的锤高为0.4-0.6m，并及时加粘土泥浆护壁，使孔壁挤压密实；正常连续冲击时的锤高为1.5-2.0m。在钻进过程中，对于变层处和易于发生偏斜的部位，采用低锤轻击，间断冲击的方式穿过，以保持孔形的良好；在发生偏斜时，应停止钻进，使用碎石回填至孔身发生偏移处，重新进行钻孔。In a specific embodiment of the present invention, the hammer height is 0.4-0.6m during low-hammer compact impact, and clay mud is added to protect the wall in time to compact the hole wall; the hammer height during normal continuous impact is 1.5-2.0m. During the drilling process, for the variable layer and the parts that are prone to deflection, use a low hammer to lightly strike and pass through intermittent impact to maintain a good hole shape; when deflection occurs, stop drilling and use The gravel is backfilled to the point where the hole body is offset, and the drilling is re-drilled.
在钻进过程中，用目测法关注泥浆液面变化情况，当桩孔内的泥浆液面低于水面时及时进行补浆，防止由于泥浆不足造成塌孔。每天钻进结束后做好孔口防护，用木盖帘将孔口封死，防止人员发生意外。During the drilling process, the change of the mud level should be paid attention to by visual inspection. When the mud level in the pile hole is lower than the water level, the slurry should be replenished in time to prevent the hole from collapsing due to insufficient mud. After drilling every day, do a good job of hole protection, and use a wooden cover to seal the hole to prevent accidents.
步骤S106，垂直度检孔，检查桩孔的垂直度。In step S106, the verticality of the hole is checked, and the verticality of the pile hole is checked.
本发明的具体实施例中，在地面上设置距离桩孔中心相互垂直的两个观测点，如图5中所示为观测点1和观测点2，两个观测点处均设置有垂直度测量装置，垂直度测量装置用于测量此处的垂直度，通过两个观测点处的垂直度与牵引钻头1的钢丝绳4的垂直度进行比较，观测三者的垂直度是否重合，重合则为孔身垂直，不重合则孔身偏斜，从而监控桩孔孔身的垂直度。In a specific embodiment of the present invention, two observation points that are perpendicular to each other from the center of the pile hole are set on the ground, as shown in FIG. The verticality measuring device is used to measure the verticality here. The verticality at the two observation points is compared with the verticality of the wire rope 4 of the traction drill bit 1, and it is observed whether the verticality of the three coincides, and the coincidence is the hole. If the body is vertical, if the hole body is not coincident, the hole body will be deflected, so as to monitor the verticality of the hole body of the pile hole.
优选地，垂直度测量装置包括支撑架6，支撑架6上挂设有线坠7，线坠7包括线绳71和坠体72，线绳71的一端连接坠体72，另一端固定在支撑架6上，通过线坠7的线绳71方向判断该观测点的垂直度。本发明的具体实施例中，支撑架6使用四根钢筋组成棱锥体，钢筋为HRB400EΦ20钢筋，在椎体的顶端固定有线坠7的线绳71，坠体72呈自由下垂状态。Preferably, the verticality measuring device includes a support frame 6 on which a wire weight 7 is hung. The wire weight 7 includes a wire rope 71 and a drop body 72. One end of the wire rope 71 is connected to the drop body 72, and the other end is fixed on the support frame 6 , the verticality of the observation point is judged by the direction of the wire 71 of the wire weight 7 . In the specific embodiment of the present invention, the support frame 6 uses four steel bars to form a pyramid, and the steel bars are HRB400EΦ20 steel bars.
步骤S107，第一次清孔，使用底部带活门的掏渣桶(即掏渣桶底部带有逆止阀，防止沉渣外漏)，反复掏渣，将孔底淤泥、沉渣清除干净，对于密度 大的泥浆采用水泵用清水置换，使密度控制在1.15-1.25之间，形成桩孔终孔。Step S107, cleaning the hole for the first time, using a slag scavenging bucket with a valve at the bottom (that is, a check valve at the bottom of the slag scavenging bucket to prevent the leakage of sediment), repeatedly digging out the slag, and removing the mud and sediment at the bottom of the hole. The large mud is replaced by water pump with clean water, so that the density is controlled between 1.15-1.25, and the final hole of the pile hole is formed.
步骤S108，成孔验收，对桩孔终孔进行验收，采用探笼检查孔径，用测绳检查孔深，用井径仪检查垂直度，符合要求后进入下一道工序。Step S108 , check the hole formation, check the final hole of the pile hole, check the hole diameter with a probe cage, check the hole depth with a measuring rope, check the verticality with a caliper, and enter the next process after meeting the requirements.
步骤S109，钢筋笼8制作与安装，钢筋笼8由钢筋分节制作，用吊车将钢筋笼8吊入桩孔内，并将吊入进桩孔的钢筋笼8的末端临时支撑于护筒5口，再吊起另一节钢筋笼8进行焊接，然后送入桩孔，重复上述步骤，依次将全部钢筋笼8全部吊入桩孔内。Step S109, the reinforcement cage 8 is fabricated and installed, the reinforcement cage 8 is made of steel bars in sections, the reinforcement cage 8 is hoisted into the pile hole with a crane, and the end of the reinforcement cage 8 that is hoisted into the pile hole is temporarily supported on the casing 5. Then, another section of reinforcement cage 8 is hoisted for welding, and then sent into the pile hole, and the above steps are repeated to sequentially hoist all the reinforcement cages 8 into the pile hole.
本发明的具体实施例中，钢筋笼8包括主筋81和加强箍82，加强箍82横向固定在主筋81上，沿主筋81长度方向上，每隔2m设置一道加强箍82；加强箍82与主筋81采用交错点焊和绑扎方式进行固定，下料时主筋81接头位置的错位搭接长度不少于35d(d为主筋直径)。同一截面内接头数量不超过钢筋总数的50％；主筋81的接头采用单面焊接，焊接长度为10d(d为主筋的直径)。In the specific embodiment of the present invention, the reinforcement cage 8 includes a main reinforcement 81 and a reinforcing hoop 82. The reinforcement hoop 82 is laterally fixed on the main reinforcement 81. Along the length of the main reinforcement 81, a reinforcement hoop 82 is arranged every 2m; 81 is fixed by staggered spot welding and binding, and the dislocation overlap length of the joint position of the main bar 81 during cutting is not less than 35d (d is the diameter of the main bar). The number of joints in the same section does not exceed 50% of the total number of reinforcement bars; the joints of the main reinforcement 81 are welded on one side, and the welding length is 10d (d is the diameter of the main reinforcement).
优选地，钢筋笼8上设置有轮式砂浆保护垫块83，其作用是防止在下钢筋笼8时与孔壁发生剐蹭，保证钢筋笼8安装顺利。每节钢筋笼8上设置有至少两组轮式砂浆保护垫块83，每组沿钢筋笼8的环向均匀布置有至少四个轮式砂浆保护垫块83。Preferably, a wheeled mortar protection block 83 is provided on the reinforcement cage 8 , and its function is to prevent the reinforcement cage 8 from rubbing against the hole wall when the reinforcement cage 8 is lowered, so as to ensure the smooth installation of the reinforcement cage 8 . At least two groups of wheeled mortar protection blocks 83 are arranged on each section of the reinforcement cage 8 , and at least four wheeled mortar protection cushions 83 are evenly arranged in each group along the circumferential direction of the reinforcement cage 8 .
钢筋笼8的具体安装步骤：The specific installation steps of the reinforcement cage 8:
1)钢筋笼8入孔前，为保证钢筋笼8的整体性，在起吊之前对钢筋笼8骨架采取加强措施，钢筋笼8上设置有加强件84，相邻的主筋81之间采用钢筋交叉连接，形成加强件84，同一截面中每隔一空布置一道加强件84，沿主筋81长度方向上，相邻加强区域的加强件84的中心距为3m；优选地，加强件84加强的钢筋笼8长度为1m，加强件84采用的钢筋为HRB400EΦ16钢筋。1) Before the reinforcement cage 8 enters the hole, in order to ensure the integrity of the reinforcement cage 8, strengthen measures are taken to the skeleton of the reinforcement cage 8 before lifting. The reinforcement cage 8 is provided with a reinforcement 84, and the adjacent main bars 81 are crossed by reinforcement. Connected to form reinforcements 84, a reinforcement 84 is arranged every other space in the same section, along the length direction of the main reinforcement 81, the center distance of reinforcements 84 in adjacent reinforcement areas is 3m; preferably, the reinforcement cage reinforced by reinforcements 84 The length of 8 is 1m, and the reinforcement used for the reinforcement 84 is HRB400EΦ16 reinforcement.
2)钢筋笼8入孔时，由吊车吊装。在安装钢筋笼8时，采用两点起吊。第一吊点设在骨架(钢筋笼8骨架)的下部，第二吊点设在骨架长度的中点到三分之一点之间。起吊时先起提第一吊点，使骨架稍稍提起，再与第二吊点同时起吊，待骨架离开地面后，第一吊点停止起吊，继续提升第二吊点。随着第二吊点不断提升，慢慢放松第一吊点，直到骨架与地面垂直，停止起吊。检查骨架是否顺直。骨架入孔时应慢慢下放，严禁触碰孔壁。下放至骨 架的末端时，将骨架临时支撑于护筒5口，再起吊第二节钢筋笼8骨架，使上下两节骨架位于同一条直线上进行焊接。焊接好后在孔口牢固定位，以免在灌注混凝土过程中发生浮笼现象。2) When the steel cage 8 enters the hole, it is hoisted by a crane. When installing the reinforcement cage 8, two-point lifting is adopted. The first hanging point is set at the lower part of the frame (the steel cage 8 frame), and the second hanging point is set between the midpoint and one-third of the length of the frame. When lifting, lift the first lifting point first to lift the frame slightly, and then lift at the same time with the second lifting point. After the frame leaves the ground, the first lifting point stops lifting and continues to lift the second lifting point. As the second lifting point continues to rise, slowly loosen the first lifting point until the skeleton is perpendicular to the ground and stop lifting. Check that the skeleton is straight. When the skeleton enters the hole, it should be lowered slowly, and it is strictly forbidden to touch the hole wall. When it is lowered to the end of the skeleton, temporarily support the skeleton on the 5 openings of the protective tube, and then lift the skeleton of the second steel cage 8, so that the upper and lower skeletons are located on the same straight line for welding. After welding, it should be firmly positioned at the orifice to avoid the floating cage phenomenon during the pouring of concrete.
3)骨架最上端的定位，必须由测定孔口标高来计算定位筋的长度，为防止钢筋笼8掉笼或在灌注过程中上浮，钢筋笼8中心与设计桩中心位置对正，核对无误后再焊接固定于钢护筒5上，完成钢筋笼8的安装。3) For the positioning of the uppermost end of the skeleton, the length of the positioning rib must be calculated by measuring the elevation of the orifice. In order to prevent the reinforcement cage 8 from falling out of the cage or floating during the pouring process, the center of the reinforcement cage 8 should be aligned with the center of the design pile. It is welded and fixed on the steel casing 5 to complete the installation of the reinforcement cage 8 .
4)钢筋笼8在入孔后，与上部钢筋连接采用单面焊、焊接好后禁止马上放入孔中，等钢筋冷却1分钟后再放入孔中。4) After the reinforcement cage 8 is inserted into the hole, the connection with the upper reinforcement shall be single-sided welding. After welding, it is forbidden to put it into the hole immediately, and the reinforcement shall be cooled for 1 minute before being put into the hole.
步骤S110，导管安装，采用吊车将导管吊入桩孔内，导管采用丝扣连接，且在接口处加密封圈，防止灌注混凝土时泥浆进入导管中。Step S110, the conduit is installed, the conduit is hoisted into the pile hole by a crane, the conduit is connected with a screw thread, and a sealing ring is added at the interface to prevent mud from entering the conduit when concrete is poured.
步骤S111，第二次清孔，采用水泵将泥浆压入导管内，再从孔底沿着导管外置换沉渣。In step S111 , the second hole is cleaned, and the mud is pressed into the pipe by a water pump, and then the sediment is replaced along the outside of the pipe from the bottom of the hole.
由于安放钢筋笼8及导管时间较长，孔底产生新的沉渣，待安放钢筋笼8及导管就位后，采用换浆法二次清孔，以达到二次清孔的目的。施工中勤摆动导管，改变导管在孔底的位置，保证沉渣置换彻底。待孔底往上500mm以内泥浆各项指标均达到以下标准，泥浆比重≤1.1，含砂率≤8％，粘度18-28Pa.s，复测孔底沉渣厚度≤50mm后，清孔完成，清孔完成后立即进行水下混凝土灌注。Due to the long time for placing the steel cage 8 and the guide pipe, new sediment is generated at the bottom of the hole. After the steel cage 8 and the guide pipe are placed in place, the second hole cleaning method is adopted to achieve the purpose of secondary hole cleaning. During construction, swing the guide tube frequently to change the position of the guide tube at the bottom of the hole to ensure complete replacement of the sediment. When the mud indicators within 500mm from the bottom of the hole meet the following standards, the specific gravity of the mud is less than or equal to 1.1, the sand content is less than or equal to 8%, the viscosity is 18-28Pa.s, and the thickness of the sediment at the bottom of the hole is less than or equal to 50mm. Immediately after the hole is completed, underwater concrete pouring is carried out.
步骤S112，灌注混凝土，通过导管向桩孔内灌注混凝土。Step S112, pouring concrete, and pouring concrete into the pile hole through the conduit.
孔底沉渣验收合格后，必须在半个小时内初灌混凝土，混凝土浇灌时应连续进行，不得留有施工缝。完成整根桩混凝土灌注时间应控制在2-4小时之内。After the slag at the bottom of the hole has passed the acceptance, the concrete must be initially poured within half an hour, and the concrete pouring should be carried out continuously without leaving construction joints. The time to complete the concrete pouring of the whole pile should be controlled within 2-4 hours.
灌注混凝土时采用回顶灌注法，先在导管底部灌注混凝土形成隔水层，然后将混凝土通过导管底口进入到隔水层，从下面顶出初期浇筑的混凝土及其上面的泥浆，从而使后面灌入的混凝土凝结成为完整的桩身。When pouring concrete, the back-to-top pouring method is used. First, pour concrete at the bottom of the conduit to form a water-insulating layer, and then enter the concrete into the water-insulating layer through the bottom of the conduit. The poured concrete solidifies into a complete pile body.
灌注首批隔水层的混凝土时，导管下口离孔底300-500mm，使隔水层及混凝土能顺利排出，混凝土灌入量应确定导管底口至少埋入浇筑的混凝土中1.0-1.3m，严防泥浆水涌入导管。在灌注过程中，必须经常测量混凝土面位置，保证导管埋深在2-6米范围内。经常上下窜插导管，以保证桩身密实，灌注完后缓慢、垂直拔起护筒5，保证桩顶砼质量。When pouring the concrete of the first batch of aquifers, the bottom of the conduit should be 300-500mm away from the bottom of the hole, so that the aquifer and concrete can be discharged smoothly. , to prevent mud water from pouring into the conduit. During the pouring process, the position of the concrete surface must be measured frequently to ensure that the buried depth of the conduit is within the range of 2-6 meters. The catheter is often inserted up and down to ensure the compactness of the pile body. After pouring, the protective tube 5 is slowly and vertically pulled up to ensure the quality of the concrete at the top of the pile.
应用例Application example
新建成都至兰州铁路成都至川主寺段站房工程CLZF-1标段高川站站房及连廊基础设计形式为端承桩，要求桩底入岩1米，平均桩长41-44m，地质情况(从上到下)为：杂填土、卵石土、粉质粘土、卵石土、强风化岩、弱风化岩(白云质灰岩)，情况多变结构复杂，应用此工法进行施工，效果良好。与其它方法相比，此工法操作简单，受限性小，应用范围广；施工过程中噪音及振动小，不扰民；孔壁坚实、稳定不易塌孔，保证了桩基施工质量，进而提高结构的安全性。经各方面综合评定优势明显。The station building and corridor foundation of the newly built Chengdu-Lanzhou Railway Chengdu-Chuanzhusi Section Station Building Project CLZF-1 bid section is designed as end-bearing piles. The situation (from top to bottom) is: mixed fill, pebble soil, silty clay, pebble soil, strongly weathered rock, weakly weathered rock (dolomitic limestone), the situation is changeable and the structure is complex. good. Compared with other methods, this construction method is simple to operate, less restrictive, and has a wide range of applications; during construction, the noise and vibration are small and do not disturb the people; the hole wall is solid, stable and not easy to collapse, which ensures the construction quality of the pile foundation and improves the structure. security. After comprehensive evaluation in all aspects, the advantages are obvious.

Claims (5)

  1. 一种超长小直径钻孔灌注桩施工方法，其特征在于，所述施工方法包括如下步骤：A construction method for super-long and small-diameter bored cast-in-place piles, characterized in that the construction method comprises the following steps:
    步骤S100，平整场地，使桩孔的场地达到设计要求的高度；Step S100, leveling the site, so that the site of the pile hole reaches the height required by the design;
    步骤S101，测量定位，采用全站仪定位桩孔的位置，采用“+”字交叉法在桩孔外部埋设固定四个定位桩，以定位桩为基准确定灌注桩轮廓线；Step S101, measuring and positioning, using a total station to locate the position of the pile hole, using the "+" cross method to embed and fix four positioning piles outside the pile hole, and determine the outline of the cast-in-place pile based on the positioning pile;
    步骤S102，埋设护筒，根据灌注桩轮廓线埋设护筒，所述护筒内径大于灌注桩的直径，护筒的筒身竖直后用黏土回填；Step S102, burying the casing, burying the casing according to the outline of the cast-in-situ pile, the inner diameter of the casing is larger than the diameter of the cast-in-situ pile, and the casing of the casing is vertical and backfilled with clay;
    步骤S103，钻头改进和校正，对钻头进行改进以提高钻进过程中成孔效果，用细线将埋设在护筒周围的定位桩对角连接，校核确保改进后的钻头中心、护筒中心和灌注桩中心在同一竖直线上；Step S103, the drill bit is improved and corrected, the drill bit is improved to improve the hole forming effect during the drilling process, the positioning piles embedded around the casing are diagonally connected with thin lines, and the check ensures the improved drill bit center and casing center On the same vertical line as the center of the cast-in-place pile;
    所述钻头包括钻杆与刀片，在所述钻杆上设置有钢板，所述钻杆下部设置有多个沿周向均匀分布的刀片，所述刀片向外凸出于所述钻杆，所述钢板位于相邻刀片向上延伸后之间形成的凹槽处，所述钢板的厚度与刀片凸出于钻杆的厚度相同；The drill bit includes a drill rod and a blade, a steel plate is arranged on the drill rod, and a plurality of blades evenly distributed along the circumferential direction are arranged on the lower part of the drill rod, and the blades protrude outward from the drill rod, so The steel plate is located at the groove formed between adjacent blades extending upward, and the thickness of the steel plate is the same as the thickness of the blade protruding from the drill rod;
    所述钢板呈弧形弯曲，所述钢板的弯曲曲率与所述刀片一致，所述钢板与所述刀片在仰视时呈闭合圆环；The steel plate is curved in an arc shape, the bending curvature of the steel plate is consistent with the blade, and the steel plate and the blade form a closed ring when viewed from above;
    所述刀片有四个，所述钢板也设置有四个，所述钢板焊接在所述钻杆上；There are four said blades, four said steel plates are also provided, and said steel plates are welded on said drill pipe;
    步骤S104，泥浆制备，在桩孔范围内挖设泥浆池和沉淀池，沉淀池与泥浆池通过排水沟相连通，沉淀池通过泥浆沟与护筒连通，泥浆池内泥浆采用水、黏土和添加剂制备；Step S104, mud preparation, excavating a mud pool and a sedimentation tank within the range of the pile hole, the sedimentation tank is connected with the mud pool through the drainage ditch, the sedimentation tank is connected with the casing through the mud ditch, and the mud in the mud pool is prepared by using water, clay and additives ;
    步骤S105，钻孔，使用钢丝绳吊装钻机使钻机中心对准步骤S103的中心，钻机的钻头先使用低锤密击，直至孔深达到护筒下方3-4m后开始加大冲程，提高锤高，转入正常连续冲击，在钻孔时将制备的泥浆注入桩孔内；Step S105, drill a hole, use a wire rope to hoist the drilling rig so that the center of the drilling rig is aligned with the center of step S103, and the drill bit of the drilling rig first uses a low hammer to close the drill until the depth of the hole reaches 3-4m below the casing, and then begins to increase the stroke and increase the hammer height, Switch to normal continuous impact, and inject the prepared mud into the pile hole when drilling;
    步骤S106，垂直度检查，检查桩孔的垂直度；Step S106, check the verticality, check the verticality of the pile hole;
    在地面上设置两个观测点，两个观测点分别与桩孔中心的连线相互垂直，观测点处均设置有垂直度测量装置，所述垂直度测量装置用于测量此处的垂直度，通过两个观测点处的垂直度与牵引钻头的钢丝绳的垂直度进行比较，监控桩孔孔身的垂直度；Two observation points are set on the ground, the two observation points are respectively perpendicular to the line connecting the center of the pile hole, and a perpendicularity measuring device is arranged at the observation point, and the perpendicularity measuring device is used to measure the perpendicularity here, Monitor the verticality of the pile hole body by comparing the verticality at the two observation points with the verticality of the wire rope pulling the drill bit;
    所述垂直度测量装置包括支撑架，所述支撑架上挂设有线坠，所述线坠 包括线绳和坠体，线绳的一端连接坠体，另一端固定在支撑架上，坠体依靠自身重力自由垂落，通过线绳方向判断该观测点的垂直度；The verticality measuring device includes a support frame on which a wire weight is hung, the wire weight includes a wire rope and a drop body, one end of the wire rope is connected to the drop body, the other end is fixed on the support frame, and the drop body relies on the drop body. Its own gravity is free to fall, and the verticality of the observation point is judged by the direction of the rope;
    步骤S107，第一次清孔，使用底部带活门的掏渣桶，反复掏渣，将孔底淤泥、沉渣清除干净，对于密度大的泥浆采用水泵用清水置换，形成桩孔终孔；Step S107, cleaning the hole for the first time, using a slag scavenging bucket with a valve at the bottom, repeatedly scavenging the slag, removing the mud and sediment at the bottom of the hole, and replacing the mud with high density with water by a water pump to form the end hole of the pile hole;
    步骤S108，成孔验收，对桩孔终孔进行验收，采用探笼检查孔径，用测绳检查孔深，用井径仪检查垂直度，符合要求后进入下一道工序；Step S108 , check the hole formation, check the final hole of the pile hole, check the hole diameter with a cage, check the hole depth with a measuring rope, check the verticality with a caliper, and enter the next process after meeting the requirements;
    步骤S109，钢筋笼制作与安装，钢筋笼由钢筋分节制作，用吊车将钢筋笼吊入桩孔内，并将吊入进桩孔的钢筋笼的末端临时支撑于护筒口，再吊起另一节钢筋笼进行焊接，然后送入桩孔，重复上述步骤，依次将全部钢筋笼全部吊入桩孔内；In step S109, the reinforcement cage is fabricated and installed. The reinforcement cage is made of steel bars in sections, and the reinforcement cage is hoisted into the pile hole with a crane, and the end of the reinforcement cage that is hoisted into the pile hole is temporarily supported at the mouth of the casing, and then the other cage is hoisted. A section of steel cage is welded, and then sent into the pile hole, repeat the above steps, and all the steel cages are hoisted into the pile hole in turn;
    钢筋笼包括主筋和加强箍，加强箍横向固定在主筋上，沿主筋长度方向上，每隔2m设置一道加强箍；The reinforcement cage includes the main reinforcement and the reinforcement hoop, the reinforcement hoop is fixed on the main reinforcement horizontally, and along the length of the main reinforcement, a reinforcement hoop is arranged every 2m;
    所述钢筋笼上设置有砂轮保护垫块，每节钢筋笼上设置有至少两组所述砂轮保护垫块，每组沿钢筋笼的环向均匀布置有至少四个砂轮保护垫块；The reinforcement cage is provided with grinding wheel protection pads, each section of the reinforcement cage is provided with at least two groups of the grinding wheel protection pads, and each group is evenly arranged with at least four grinding wheel protection pads along the circumferential direction of the reinforcement cage;
    所述钢筋笼还设置有加强件，相邻的主筋之间采用钢筋交叉连接，形成加强件，同一截面中每隔一空布置一道加强件，沿主筋长度方向上，相邻加强区域的加强件的中心距为3m；The reinforcement cage is also provided with reinforcements. The adjacent main reinforcements are cross-connected by reinforcement to form reinforcements. In the same section, a reinforcement is arranged every other space. The center distance is 3m;
    所述加强件加强的钢筋笼长度为1m，所述加强件采用的钢筋为HRB400EΦ16钢筋；The length of the reinforcement cage reinforced by the reinforcement is 1m, and the reinforcement used in the reinforcement is HRB400EΦ16 reinforcement;
    步骤S110，导管安装，采用吊车将导管吊入桩孔内，导管采用丝扣连接，且在接口处加密封圈；Step S110, the conduit is installed, the conduit is hoisted into the pile hole by a crane, the conduit is connected with a screw thread, and a sealing ring is added at the interface;
    步骤S111，第二次清孔，采用水泵将泥浆压入所述导管内，再从孔底沿着导管外置换沉渣；Step S111, cleaning the hole for the second time, using a water pump to press the mud into the conduit, and then replacing the sediment along the outside of the conduit from the bottom of the hole;
    步骤S112，灌注混凝土，通过导管向桩孔内灌注混凝土。Step S112, pouring concrete, and pouring concrete into the pile hole through the conduit.
  2. 如权利要求1所述的超长小直径钻孔灌注桩施工方法，其特征在于，所述步骤S105中，低锤密击时的锤高为0.4-0.6m，正常连续冲击时的锤高为1.5-2.0m。The construction method of super-long and small-diameter bored piles according to claim 1, characterized in that, in the step S105, the hammer height during low hammer close impact is 0.4-0.6 m, and the hammer height during normal continuous impact is 0.4-0.6 m. 1.5-2.0m.
  3. 如权利要求1或2所述的超长小直径钻孔灌注桩施工方法，其特征在于，所述步骤S105中，在钻进过程中，对于变层处和易于发生偏斜的部位， 采用低锤轻击，间断冲击的方式穿过；在发生偏斜时，停止钻进，使用碎石回填至孔身发生偏移处，重新进行钻孔。The construction method for super-long and small-diameter bored cast-in-place piles according to claim 1 or 2, characterized in that, in the step S105, during the drilling process, low The hammer hits lightly and penetrates through intermittent impact; when deflection occurs, stop drilling, use gravel to backfill to the deviation of the hole body, and drill again.
  4. 如权利要求3所述的超长小直径钻孔灌注桩施工方法，其特征在于，所述步骤S105中，在钻进过程中，用目测法关注泥浆液面变化情况，当桩孔内的泥浆液面低于水面时及时进行补浆。The construction method for super-long and small-diameter bored cast-in-place piles as claimed in claim 3, characterized in that, in the step S105, during the drilling process, visual observation is used to pay attention to the change of the mud level. When the liquid level is lower than the water level, replenish the slurry in time.
  5. 如权利要求1所述的超长小直径钻孔灌注桩施工方法，其特征在于，所述步骤S112中，灌注混凝土时采用回顶灌注法，先在导管底部灌注混凝土形成隔水层，然后将混凝土通过导管底口进入到隔水层，从下面顶出初期浇筑的混凝土及其上面的泥浆，从而使后面灌入的混凝土凝结成为完整的桩身，混凝土灌注量应满足导管底口至少埋入浇筑的混凝土中1.0-1.3m。The method for constructing super-long and small-diameter bored piles according to claim 1, characterized in that, in the step S112, when pouring concrete, a top-return pouring method is used, first pouring concrete at the bottom of the conduit to form a water barrier, and then pouring concrete The concrete enters the water-insulating layer through the bottom of the conduit, and the initially poured concrete and the mud above it are ejected from below, so that the concrete poured in later is condensed into a complete pile body. 1.0-1.3m in poured concrete.
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