CN115162425B - Rock mass bearing capacity testing method and system under geological conditions of large burial depth and high water level - Google Patents
Rock mass bearing capacity testing method and system under geological conditions of large burial depth and high water level Download PDFInfo
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- CN115162425B CN115162425B CN202210764064.3A CN202210764064A CN115162425B CN 115162425 B CN115162425 B CN 115162425B CN 202210764064 A CN202210764064 A CN 202210764064A CN 115162425 B CN115162425 B CN 115162425B
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- 238000012360 testing method Methods 0.000 title claims abstract description 48
- 239000011435 rock Substances 0.000 title claims abstract description 40
- 238000009933 burial Methods 0.000 title claims abstract description 26
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 25
- 238000012544 monitoring process Methods 0.000 claims abstract description 25
- 238000011068 loading method Methods 0.000 claims abstract description 24
- 230000005540 biological transmission Effects 0.000 claims abstract description 20
- 238000006073 displacement reaction Methods 0.000 claims abstract description 20
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 3
- 230000002787 reinforcement Effects 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 25
- 230000001681 protective effect Effects 0.000 claims description 19
- 238000004062 sedimentation Methods 0.000 claims description 16
- 238000005553 drilling Methods 0.000 claims description 14
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 13
- 229910000831 Steel Inorganic materials 0.000 claims description 13
- 239000010959 steel Substances 0.000 claims description 13
- 238000001514 detection method Methods 0.000 claims description 10
- 239000000945 filler Substances 0.000 claims description 9
- 238000004140 cleaning Methods 0.000 claims description 6
- 238000010276 construction Methods 0.000 claims description 5
- 239000013049 sediment Substances 0.000 claims description 5
- 239000011229 interlayer Substances 0.000 claims description 4
- 238000012806 monitoring device Methods 0.000 claims description 3
- 238000005429 filling process Methods 0.000 claims description 2
- 238000009527 percussion Methods 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 238000003466 welding Methods 0.000 claims description 2
- 238000004891 communication Methods 0.000 claims 1
- 239000010410 layer Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 8
- 239000002689 soil Substances 0.000 description 7
- 230000014759 maintenance of location Effects 0.000 description 5
- 230000003014 reinforcing effect Effects 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 239000002893 slag Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006353 environmental stress Effects 0.000 description 1
- 229920001903 high density polyethylene Polymers 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D13/00—Accessories for placing or removing piles or bulkheads, e.g. noise attenuating chambers
- E02D13/04—Guide devices; Guide frames
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D13/00—Accessories for placing or removing piles or bulkheads, e.g. noise attenuating chambers
- E02D13/08—Removing obstacles
-
- 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
- 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
-
- 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
- E02D5/66—Mould-pipes or other moulds
- E02D5/68—Mould-pipes or other moulds for making bulkheads or elements thereof
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/10—Miscellaneous comprising sensor means
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The invention discloses a rock mass bearing capacity testing method and system under geological conditions of large burial depth and high water level, the system comprises a force transmission module used for transmitting force to a rock mass, a loading module used for providing power counter force for the force transmission module, a monitoring module used for monitoring settlement displacement and loading force data, and a fixing module for stabilizing the modules.
Description
Technical Field
The invention relates to the field of geotechnical engineering test, in particular to a method and a system for testing the bearing capacity of a rock mass under geological conditions of large burial depth and high water level.
Background
The choice of the elevation of the anchorage substrate of the suspension bridge needs to consider both the bearing capacity characteristic of the bearing stratum and the foundation pit excavation economy, and the traditional deep load plate test based on the manual hole digging process is mostly adopted to determine the bearing capacity of the deep rock and soil layer, but the safety risk and the high cost of the deep load plate test method provided by the existing standard are high for the bearing stratum under the geological conditions of large burial depth and high water level, and the difficulty of rock mass bearing capacity test is how to ensure the force transmission stability of the cast-in-place pile and improve the load proportion transferred to the end part.
In order to solve the problems, patent document CN 202020826092-a loading counterforce device for load test-utility model, a first retention plate and a retention counterforce steel beam are arranged on the upper end cover of a counterweight, steel bars are connected with two sides of the retention counterforce steel beam and a lower anchor pile, counterforce of the anchor pile is transferred to the retention counterforce steel beam when load test is carried out, the anchor pile and the counterweight are ensured to bear force simultaneously when the test is carried out, coordination and systematicness of the anchor pile and the counterweight are improved, and meanwhile, the counterweight is fixed by applying pressure through the first retention plate, so that the damage to a construction site or a worker caused by dumping of the counterweight is prevented.
The prior art has several disadvantages: (1) Under the condition of deeper stratum or weak soil environment stability, the loading process of the cast-in-place pile is easy to generate larger side friction with the soil body at the pile side, so that the load actually transferred to the pile end is reduced, and the loading load of the pile end bearing layer is insufficient; (2) For proposing to adopt double-walled bellows to keep apart pile foundation and pore wall to reduce the side friction scheme, the pile side confining pressure tends to be reduced, but because the pile foundation is longer, the pile foundation has self stability problem.
Disclosure of Invention
According to the method, through testing the load and sedimentation values of the bored pile end, the characteristic value of the bearing capacity of the deep rock mass of the pile end bearing layer is analyzed and obtained, when the bored pile is manufactured, an inner layer reinforcement cage is wrapped with a double-wall corrugated pipe to serve as an inner side retaining wall, the pile side friction resistance is reduced, the load proportion transferred to the pile end is improved, a steel retaining cylinder is adopted as the bored retaining wall for the outer layer, filling materials are filled between the inner wall and the outer wall, the stability of the pile foundation and the hole wall is ensured, the problems of high resistance and poor stability of the bearing capacity test side of the deep rock mass of the bored pile are solved, and the problems of poor bearing capacity test stability of the deep rock mass of the bored pile and insufficient load transfer to the end are solved.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for testing bearing capacity of a rock mass under geological conditions of large burial depth and high water level, comprising:
S100, drilling and clearing holes, namely, driving a steel pile casing in the plane position of a pile foundation, centering, adopting a rotary drilling drill or a percussion drill to finish hole forming operation, and adopting a reverse circulation process to carry out hole clearing work;
S200, binding a reinforcement cage, welding and fixing a reinforcement meter on the reinforcement cage, and embedding a protective sleeve for pile end settlement monitoring and a long reinforcement in the pipe;
S300, lowering the reinforcement cage and the inner protective cylinder, binding the sound measuring tube with the reinforcement cage, sealing the bottom of the sound measuring tube, wrapping the inner sleeve on the outer side of the reinforcement cage, hanging the inner sleeve and the reinforcement cage to a drilling hole for lowering, and filling a filler between the inner sleeve and the outer protective cylinder after lowering in place, wherein the periphery is uniformly filled in the filler filling process, and the perpendicularity of the reinforcement cage is ensured;
s400, pile foundation pouring and integrity detection, wherein before concrete pouring, a gas lift reverse circulation hole cleaning process is adopted to continuously clean holes of drilled holes, then pile body concrete pouring work is completed, and after the pile foundation strength meets the requirement, an ultrasonic non-damage method is used to detect the pile body quality;
S500, arranging a counter-force pile-up system, arranging the counter-force pile-up system after pile body concrete reaches an age, erecting a counter-force beam at the top of the pile body, arranging pile-up blocks at the top of the counter-force beam, respectively contacting the top of the pile body and the bottom of the counter-force beam at two ends of a jack, installing displacement sensors for pile top and pile end settlement monitoring on the counter-force beam, connecting a reinforcing steel bar meter and an acquisition instrument shaft force monitoring device, and completing rock mass bearing capacity test construction.
Further, the S100 includes: after the hole cleaning work is completed, the center deviation of the hole site, the hole diameter, the hole depth, the verticality of the drilled hole and the thickness of sediment at the bottom of the hole are checked.
Further, the S400 includes: and after the pile foundation detection is finished, filling concrete into the sounding pipe.
According to another aspect of the invention there is provided a rock mass bearing capacity testing system under high burial depth and high water level geological conditions, comprising:
The device comprises a force transmission module, a loading module, a sedimentation monitoring module and a fixing module, wherein the force transmission module is used for transmitting force to a rock mass, the loading module is used for providing counter force for the force transmission module, the sedimentation monitoring module is used for monitoring sedimentation displacement and loading force data, and the fixing module is used for stabilizing the modules;
The fixing module comprises a stacking block, a counter-force beam and a buttress, wherein the buttress is fixed on the ground, the counter-force beam is horizontally fixed on the buttress, and the stacking block is fixed on the counter-force beam;
The force transmission module comprises a filling pile, an inner sleeve, an outer protective cylinder and a filler, wherein the inner sleeve is sleeved outside the filling pile and used for reducing side friction force of the filling pile, the outer protective cylinder is arranged in a preset drilling hole, an interlayer is arranged between the inner sleeve and the outer protective cylinder, the filler is filled in the interlayer, the settlement monitoring module is arranged on the force transmission module, and the loading module is connected with the fixing module and the force transmission module.
Further, subside monitoring module includes displacement sensor, bar gauge, long reinforcing bar and outer tube, the bar gauge pre-buried be fixed in the bored concrete pile for detect the bearing capacity value, long reinforcing bar runs through the bottom and the top of bored concrete pile, the outer tube parcel is located on the long reinforcing bar, displacement sensor is fixed in the counter-force roof beam bottom.
Further, the loading module comprises a jack and an oil pump, wherein two ends of the jack are respectively fixed at the top end of the cast-in-place pile and the bottom of the counter-force beam, and the oil pump is communicated with an oil path of the jack.
Further, the pile foundation detection device comprises a sound tube, wherein the sound tube is fixed in the cast-in-place pile, the bottom of the sound tube is sealed, and concrete is filled in the sound tube after pile foundation detection is completed
In general, the above technical solutions conceived by the present invention, compared with the prior art, enable the following beneficial effects to be obtained:
1. The invention provides a rock mass bearing capacity testing system under geological conditions of large burial depth and high water level, which is characterized in that the bearing capacity characteristic value of deep rock mass of a pile end bearing layer is analyzed and obtained by testing the load and settlement values of a bored pile end, an inner layer reinforcement cage is wrapped with a double-wall corrugated pipe to serve as an inner side retaining wall when the bored pile is applied, the friction resistance of the pile side is reduced, the load proportion transferred to the pile end is improved, a steel retaining cylinder is adopted as the bored retaining wall at the outer layer, a filling material is filled between the inner wall and the outer wall, the stability of the pile foundation and the hole wall is ensured, the problems of high side resistance and poor stability of the bearing capacity testing of the deep rock mass bearing capacity of the bored pile under geological conditions of large burial depth and high water level are solved, and the problems of poor bearing capacity testing stability of the deep rock mass of the bored pile and insufficient load proportion transferred to the end are solved.
2. The invention provides a rock mass bearing capacity test method under geological conditions of large burial depth and high water level, which adopts a mode of embedding a protective sleeve in a cast-in-place pile in a monitoring sedimentation system, meanwhile, through-length steel bars are arranged in the pipe, the steel bars are completely separated from the protective sleeve and extend out from the top end of the cast-in-place pile, sedimentation data of the end of the cast-in-place pile can be obtained by monitoring sedimentation of the steel bars by using a displacement sensor, and accuracy of displacement data is ensured.
3. The invention provides a rock mass bearing capacity testing method under geological conditions of large burial depth and high water level, which is characterized in that slag is removed from a preset drilling hole before concrete is poured, so that the slag at the bottom end of a poured pile is ensured to be clean, compression of sediments in the loading process is avoided, and rock mass settlement deformation monitoring data of a pile end bearing layer are influenced.
Drawings
FIG. 1 is a front view of a rock mass bearing capacity testing system under high burial depth and high water level geological conditions in accordance with an embodiment of the present invention;
FIG. 2 is a partial enlarged view A of a rock mass bearing capacity test system under geological conditions of large burial depth and high water level according to an embodiment of the invention;
FIG. 3 is a diagram of a method for testing bearing capacity of a rock mass under geological conditions of large burial depth and high water level according to an embodiment of the invention;
Fig. 4 is a graph of pile stress versus time for a rock mass bearing capacity test of a double-walled cast-in-place pile according to an embodiment of the present invention.
Like reference numerals denote like technical features throughout the drawings, in particular: 1-pile loading block, 2-counterforce beam, 3-buttress, 4-jack, 5-displacement sensor, 6-oil pump, 7-filling pile, 8-inner casing, 9-outer casing, 10-filler and 11-reinforcing steel bar meter.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The foundation bearing capacity of the anchorage substrate has important significance for reasonably determining the plane scale of the anchorage, the foundation and the reference can be provided for design, the pile loading method deep rock mass bearing capacity test is carried out on the basis of considering test rationality, the reasonable characteristic value of the foundation bearing capacity of the anchorage substrate is determined, the soil shallow layer of the area is provided with sludge with the depth of about forty meters, the water level is relatively deep, and after the construction of the cast-in-place pile is completed, the friction resistance of the sludge and clay to the pile body in the test process is easy to cause inaccurate bearing capacity test result.
As shown in fig. 1 to 3, the invention provides a rock mass bearing capacity test system under geological conditions of large burial depth and high water level, which comprises a force transmission module, a loading module, a settlement monitoring module and a fixing module, wherein the force transmission module is used for transmitting force to a rock mass, the loading module is used for providing counter force for the force transmission module, the settlement monitoring module is used for monitoring settlement displacement and loading force data, the fixing module is used for fixing the modules, the fixing module comprises a pile block 1, a counter force beam 2 and a buttress 3, the force transmission module comprises a filling pile 7, an inner sleeve 8, an outer protective sleeve 9 and a filling material 10, the loading module comprises a jack 4 and an oil pump 6, the jack 4 and the buttress 3 are arranged around the filling pile 7, the buttress is horizontally fixed on the ground, the upper surface is flush, the counter force beam 2 is used for mounting the counter force beam 2, the pile block 1 is fixedly piled on the upper surface of the counter force beam 2, the pile block 1 can be made of concrete, the device is used for compacting the counter-force beam 2 on the buttress 3 and providing counter force for loading the cast-in-place pile 7, further, the inner protective cylinder 8 is sleeved outside the reinforcement cage to serve as an inner protective wall, concrete is cast into the reinforcement cage to form the cast-in-place pile 7, the cast-in-place pile 7 is cast to serve as a force transmission column after reaching an age, the cast-in-place pile 7 is vertically arranged in a preset drilling hole, the drilling hole is positioned at the bottom of the counter-force beam 2, preferably, the inner protective cylinder 8 is made of double-wall corrugated pipe, the double-wall corrugated pipe is made of high-density polyethylene, the device has excellent ageing resistance and environmental stress cracking resistance, the double-wall corrugated pipe with thinner pipe wall is sleeved outside the reinforcement cage, the side body of the cast-in-place pile 7 can be prevented from being rubbed with broken stone directly, and the load proportion transferred to the end part of the cast-in-place pile 7 is improved. Further, an outer casing 9 is arranged on the outer side of the inner casing 8, the sleeve is made of a steel casing, a certain space is formed between the sleeve and the inner casing 8, and a filling material 10 is filled in the space, preferably, the filling material 10 can be made of gravels, and the filling material is supported between the inner casing 8 and the outer casing 9 through uniformly filling the gravels, so that stability of the filling pile 7 and the hole wall when force is transferred under the conditions of soft soil and large burial depth is ensured.
Further, the test system comprises a jack 4 and an oil pump 6, wherein two ends of the jack 4 are respectively fixed at the bottom of the counter-force beam 2 and the top of the filling pile 7, the jack 4 is vertically arranged, the oil pump 6 is externally connected with the jack 4, downward load is applied to the filling pile 7 by increasing oil pressure, and the counter-force beam 2 is pressed on the jack 4 to provide counter force for the filling pile 7.
Further, the test system comprises a displacement sensor 5, a reinforcing steel bar meter 11 and long reinforcing steel bars, wherein the reinforcing steel bar meter 11 is fixed in a bored pile 7 and used for detecting the bearing capacity, the long reinforcing steel bars penetrate through the top and the bottom of the bored pile 7, preferably, an outer sleeve is arranged on the long reinforcing steel bars, the bored pile 7 concrete is isolated from the long reinforcing steel bars, displacement data are obtained by detecting the sedimentation capacity of the long reinforcing steel bars through the displacement sensor 5, the displacement sensor 5 is fixed at the bottom of a counter-force beam 2, the sedimentation capacity of the bored pile 7 is recorded through the displacement sensor 5 and the reinforcing steel bar meter 11 in the pressurizing process of a jack 4, pile end load is obtained through the reinforcing steel bar meter 11, and finally, a pile end load-pile end sedimentation curve graph is obtained through the displacement data and the pile end load data.
1-3, According to another aspect of the present invention, the present invention provides a method for testing bearing capacity of a rock mass under geological conditions of large burial depth and high water level, which specifically includes:
s100, drilling and cleaning holes;
Specifically, determining the plane position of a pile foundation, driving a steel pile casing to a designed depth, then pulling a cross line for centering, adopting a rotary drilling or impact drilling to complete hole forming operation, carrying out hole cleaning work based on a reverse circulation process, and checking the deviation of the center of a hole site, the aperture, the depth of the hole, the verticality of the drilled hole and the thickness of sediment at the bottom of the hole, wherein the requirements of relevant indexes of the technical Specification of highway bridge and culvert construction (JTG/T3650-2020) are met;
s200, binding a reinforcement cage;
Specifically, a reinforcement meter is welded on a designed section position of a reinforcement cage in advance, a protective sleeve and an in-pipe long reinforcement for pile end settlement monitoring are embedded in advance, the in-pipe long reinforcement is completely isolated from a pile body by the protective sleeve, the settlement of the in-pipe long reinforcement at the pile top is monitored to be the pile end settlement value, the sleeve is ensured to be communicated when the reinforcement cage is put down and connected with the cage, the inner diameter of the pipe is preferably larger than the diameter of the long reinforcement, the in-pipe long reinforcement is in a free state, the deviation of the perpendicularity of the protective sleeve is not larger than 1%, and otherwise, the adjustment is required to be reinstalled;
s300, lowering the reinforcement cage and the inner casing;
Specifically, the reinforcement cage is sleeved into the double-wall corrugated pipe and bound with the double-wall corrugated pipe, the double-wall corrugated pipe mainly plays a role in reducing friction force between a pile body and a peripheral soil body, the double-wall corrugated pipe is used as a separating medium, even if crushed, the separating effect is not affected, finally, bearing capacity of a bearing layer is calculated based on the axial force actually monitored by a pile end, enough gaps are reserved between the reinforcement cage and the corrugated pipe to ensure thickness of a concrete protective layer, the reinforcement cage and the acoustic pipe are lowered to the bottom of a hole by a crane, then filling materials 10 are filled between the double-wall corrugated pipe and an outer protective cylinder, and the periphery of the double-wall corrugated pipe is uniformly filled in the process of filling the filling materials 10, so that the influence of bias voltage on the perpendicularity of the double-wall corrugated pipe is avoided;
S400, pile foundation pouring and integrity detection;
specifically, before concrete pouring, continuously clearing holes of a drilled hole by adopting a gas lift reverse circulation hole clearing process, pouring concrete can be started when the thickness of sediment at the pile end is not more than 1cm, pile body concrete pouring work is completed, after the strength of a pile foundation meets the requirement, the quality of the pile body is detected by adopting an ultrasonic non-breakage method, the integrity of the pile body is required to be a type I pile, and after the pile foundation detection is completed, grouting filling treatment is timely carried out on a sound detection pipe;
s500, arranging a counter-force stacking system;
Specifically, after pile body concrete reaches an age, a counter-force pile-up system is arranged, a counter-force beam is erected at the top of the pile body, pile-up blocks are arranged at the top of the counter-force beam, two ends of a jack are respectively contacted with the top of the pile body and the bottom of the counter-force beam, displacement sensors for monitoring pile top and pile end settlement are arranged on a reference beam, a reinforcing steel bar meter and an acquisition instrument shaft force monitoring device are connected, rock mass bearing capacity testing is started, a pile end bearing layer load-settlement relation curve is drawn by monitoring pile end settlement and pile end shaft force, and bearing capacity characteristic values of the bearing layer are analyzed according to the pile end bearing capacity curve;
S501, judging a bearing capacity characteristic value: the relative sedimentation control method is adopted, a load value corresponding to s/d=0.01-0.015 is selected as a bearing stratum characteristic value through a load-sedimentation (p-s) curve, but the value is not larger than 1/2 of the maximum loading capacity, if the range of measured values of three test points of the same stratum is not more than 30% of the average value, the average value is taken as a foundation bearing capacity characteristic value fak (kPa) of the soil layer, foundation bearing capacity correction of foundation burial is not carried out during use according to a foundation bearing capacity characteristic value fak determined by a deep load test, namely, the bearing capacity characteristic value of the bearing stratum obtained according to the method is taken as 0, s is pile end sedimentation, d is pile diameter, and the units are cm.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (7)
1. The rock mass bearing capacity testing method under the geological condition of large burial depth and high water level is characterized by comprising the following steps:
S100, drilling and clearing holes, namely, driving a steel pile casing in the plane position of a pile foundation, centering, adopting a rotary drilling drill or a percussion drill to finish hole forming operation, and adopting a reverse circulation process to carry out hole clearing work;
S200, binding a reinforcement cage, welding and fixing a reinforcement meter on the reinforcement cage, and embedding a protective sleeve for pile end settlement monitoring and a long reinforcement in the pipe;
S300, lowering the reinforcement cage and the inner protective cylinder, binding the sound measuring tube with the reinforcement cage, sealing the bottom of the sound measuring tube, wrapping the inner sleeve on the outer side of the reinforcement cage, hanging the inner sleeve and the reinforcement cage to a drilling hole for lowering, filling filler between the inner sleeve and the outer protective cylinder after lowering in place, ensuring uniform filling around in the filler filling process, and adjusting the verticality of the reinforcement cage;
s400, pile foundation pouring and integrity detection, wherein before concrete pouring, a gas lift reverse circulation hole cleaning process is adopted to continuously clean holes of drilled holes, then pile body concrete pouring work is completed, and after the pile foundation strength meets the requirement, an ultrasonic non-damage method is used to detect the pile body quality;
S500, arranging a counter-force pile-up system, arranging the counter-force pile-up system after pile body concrete reaches an age, erecting a counter-force beam at the top of the pile body, arranging pile-up blocks at the top of the counter-force beam, respectively contacting the top of the pile body and the bottom of the counter-force beam at two ends of a jack, installing displacement sensors for pile top and pile end settlement monitoring on the counter-force beam, connecting a reinforcing steel bar meter and an acquisition instrument shaft force monitoring device, and completing rock mass bearing capacity test construction.
2. The method for testing the bearing capacity of a rock mass under geological conditions of large burial depth and high water level according to claim 1, wherein said S100 comprises: after the hole cleaning work is completed, the center deviation of the hole site, the hole diameter, the hole depth, the verticality of the drilled hole and the thickness of sediment at the bottom of the hole are checked.
3. The method for testing the bearing capacity of a rock mass under geological conditions of large burial depth and high water level according to claim 1, wherein said S400 comprises: and after the pile foundation detection is finished, filling concrete into the sounding pipe.
4. A system for testing the bearing capacity of a rock mass under geological conditions of large burial depth and high water level, which is used for realizing the method for testing the bearing capacity of the rock mass under geological conditions of large burial depth and high water level according to any one of claims 1 to 3, comprising:
The device comprises a force transmission module, a loading module, a sedimentation monitoring module and a fixing module, wherein the force transmission module is used for transmitting force to a rock mass, the loading module is used for providing counter force for the force transmission module, the sedimentation monitoring module is used for monitoring sedimentation displacement and loading force data, and the fixing module is used for stabilizing the modules;
The fixing module comprises a stacking block (1), a counter-force beam (2) and a buttress (3), wherein the buttress (3) is fixed on the ground, the counter-force beam (2) is horizontally fixed on the buttress (3), and the stacking block (1) is fixed on the counter-force beam (2);
The power transmission module comprises a filling pile (7), an inner sleeve (8), an outer protection cylinder (9) and a filler (10), wherein the inner sleeve (8) is sleeved outside the filling pile (7) and used for reducing side friction force of the filling pile (7), the outer protection cylinder (9) is arranged in a preset drilling hole, an interlayer is arranged between the inner sleeve (8) and the outer protection cylinder (9), the filler (10) is filled in the interlayer, the settlement monitoring module is arranged on the power transmission module, and the loading module is connected with the fixing module and the power transmission module.
5. The rock mass bearing capacity testing system under the geological condition with large burial depth and high water level according to claim 4, wherein the settlement monitoring module comprises a displacement sensor (5), a rebar meter (11), long rebar and an outer sleeve, wherein the rebar meter (11) is pre-buried and fixed in the bored concrete pile (7) and used for detecting bearing capacity values, the long rebar penetrates through the bottom and the top of the bored concrete pile (7), the outer sleeve is wrapped on the long rebar, and the displacement sensor (5) is fixed at the bottom of the counter-force beam (2).
6. The rock mass bearing capacity testing system under the geological condition with large burial depth and high water level according to claim 4, wherein the loading module comprises a jack (4) and an oil pump (6), two ends of the jack (4) are respectively fixed at the top end of the bored concrete pile (7) and the bottom of the counter-force beam (2), and the oil pump (6) is in oil way communication with the jack (4).
7. The rock mass bearing capacity test system under the geological condition of large burial depth and high water level according to claim 4 is characterized by comprising a sound test tube, wherein the sound test tube is fixed in the cast-in-place pile (7), the bottom of the sound test tube is sealed, and concrete is filled in the sound test tube after pile foundation detection is completed.
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