CN209816867U - A supporting construction for peripheral foundation ditch of existing building - Google Patents
A supporting construction for peripheral foundation ditch of existing building Download PDFInfo
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- CN209816867U CN209816867U CN201920113673.6U CN201920113673U CN209816867U CN 209816867 U CN209816867 U CN 209816867U CN 201920113673 U CN201920113673 U CN 201920113673U CN 209816867 U CN209816867 U CN 209816867U
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Abstract
A supporting structure for foundation pits around an existing building comprises a group of high-pressure jet grouting piles between the existing building and a foundation pit slope and cast-in-place piles on the foundation pit slope, wherein the tops of the cast-in-place piles are provided with crown beams, and gaps between adjacent cast-in-place pile bodies are filled with concrete; the cast-in-place pile is provided with stay cable anchors at intervals, and the cable anchors are positioned at the lower part of the high-pressure jet grouting pile and extend to the lower part of the existing building. The utility model uses the cast-in-place pile to reinforce and support the foundation pit slope, and uses the characteristics of the cast-in-place pile and the slightly dense soil layer to dually reinforce the cast-in-place pile; the arranged waist beam and the arranged crown beam increase the lateral anti-overturning capability of the cast-in-place pile; the high-pressure jet grouting pile is used for reinforcing, and a steel core is erected inside the high-pressure jet grouting pile close to one side of the foundation pit, so that the lateral anti-overturning capability of the high-pressure jet grouting pile is guaranteed. The utility model discloses can the segmentation construction when the construction, and relate to the easy operation of technology, can be very big save construction cost and man-hour.
Description
Technical Field
The utility model belongs to the excavation supporting field, in particular to a supporting construction for peripheral foundation ditch of existing building.
Background
The foundation pit support is a retaining, reinforcing and protecting measure adopted for the side wall of the foundation pit and the surrounding environment in order to ensure the safety of the construction of an underground structure and the surrounding environment of the foundation pit. When soil bodies around a foundation pit are reinforced, cement fly ash gravel piles (commonly called CFG piles) or precast pile composite foundations are generally adopted for reinforcement in the traditional method, but the traditional method is only suitable for pile forming with a soft soil layer as the surface layer, in the actual construction process, fewer construction sites meeting the construction conditions are needed, the surface layers of most sites are filled with miscellaneous soil layers, and the stratum of other sites contain soft stone layers or existing buildings exist around the sites, so that the construction cost is high during foundation pit supporting construction, the construction process is relatively complicated, time and labor are wasted, the construction efficiency is low, and the construction period is seriously influenced. Therefore, aiming at the construction site of the existing building, a pointed supporting structure is required to be provided to protect the normal operation of the foundation pit engineering.
SUMMERY OF THE UTILITY MODEL
The utility model provides a supporting construction for peripheral foundation ditch of existing building for solve the peripheral foundation ditch reinforcement problem of existing building, concrete technical scheme is as follows:
the utility model provides a supporting construction for peripheral foundation ditch of existing building contains a set of high pressure jet grouting pile between existing building and foundation ditch slope to and the bored concrete pile on the foundation ditch slope, high pressure jet grouting pile contains one row of outside high pressure jet grouting pile that is close to existing building one side, one row of inboard high pressure jet grouting pile that is close to foundation ditch hole limit one side, and the middle part high pressure jet grouting pile between outside high pressure jet grouting pile and the inboard jet grouting pile.
The pile bodies of the adjacent high-pressure jet grouting piles in the outer high-pressure jet grouting pile and the inner high-pressure jet grouting pile are tightly attached; the middle high-pressure rotary jet grouting piles are arranged in a quincunx shape or a row shape; and a steel core is inserted into the pile body of the inner high-pressure jet grouting pile.
The outer high-pressure jet grouting pile is arranged along the existing building sideline, a gap is reserved between the outer high-pressure jet grouting pile and the existing building sideline on the horizontal plane, and the gap is correspondingly provided with a fence.
The bottom of the cast-in-place pile extends into the position below the elevation of the pit bottom of the foundation pit, a crown beam is arranged at the top of the pile, and gaps between adjacent cast-in-place pile bodies are filled with concrete.
The cast-in-place pile is provided with stay cable anchors at intervals, and the cable anchors are positioned at the lower part of the high-pressure jet grouting pile and extend to the lower part of the existing building.
A waist beam is arranged between the cast-in-place pile and the cable anchor anchorage; the cross section of the waist beam is a right-angled trapezoid cross section, wherein the inclined edge on the right-angled trapezoid cross section corresponds to the anchor, and the inclination angle of the inclined edge corresponds to the installation angle of the anchor cable; the anchorage device is a square anchorage device and is correspondingly attached to the bevel edge of the waist rail.
The anchor cable is provided with an anchor on the cast-in-place pile, the anchor is a right-angled triangle anchor, the long right-angled edge of the right-angled triangle anchor is attached to the pile body of the cast-in-place pile, and the size of two acute angles of the right-angled triangle anchor is suitable for the installation angle of the anchor cable.
The utility model discloses following beneficial effect has:
the utility model uses the cast-in-place pile to reinforce and support the side slope of the pit edge of the foundation pit, and uses the cast-in-place pile to reinforce the soil body and to drive the cast-in-place pile into the slightly dense soil layer for double reinforcement; the waist beams and the crown beams are arranged among the cast-in-place piles and at the tops of the cast-in-place piles, so that the integrity of the cast-in-place piles is ensured, the bearing capacity and the lateral anti-overturning capacity of the cast-in-place piles are increased, and the bearing capacity, the lateral anti-overturning capacity and the anchoring range of the cast-in-place piles are further improved by arranging the anchor cables on the cast-in-place piles; the high-pressure jet grouting pile is used for reinforcing a soil layer from a foundation pit to an existing building, laying side lines of the building, closely arranging the high-pressure jet grouting pile on the inner side and the outer side, arranging residual high-pressure jet grouting piles between the inner high-pressure jet grouting pile and the outer high-pressure jet grouting pile, guaranteeing effectiveness of soil body reinforcement, erecting a steel core inside the high-pressure jet grouting pile close to one side of the foundation pit, and guaranteeing lateral anti-overturning capacity of the high-pressure jet grouting pile. The utility model discloses construction simultaneously in the construction time segmentable, and relate to the simple and convenient easy operation of construction process, can be when guaranteeing foundation ditch engineering construction, very big saving construction cost and man-hour.
Drawings
FIG. 1 is a plan arrangement view of a foundation pit supporting structure around an existing building;
FIG. 2 is a sectional view of a-a of a foundation pit supporting structure around an existing building;
FIG. 3 is a schematic vertical view of an injection pile;
FIG. 4 is a schematic view of the connection of a square anchor to a wale;
FIG. 5 is a schematic view of a right angle triangular anchor attachment.
Reference numerals: 1-filling a pile; 2-a crown beam; 3-inner high-pressure jet grouting pile; 4-high-pressure jet grouting pile on the outer side; 5-high-pressure jet grouting pile in the middle; 6-a steel core; 7-enclosure; 8-existing building; 9-anchor cable; 10-right triangle anchorage; 11-a square anchorage; 12-raft foundation; 13-drainage ditch; 14-wale.
Detailed Description
As shown in fig. 1, the engineering foundation is in the form of a raft foundation 12 and an independent column foundation, and the main strata of the field are distributed into a filling soil layer, a clay layer, a silty clay layer, a silt clay layer and a silty clay layer at the upper part and a mud stratum at the lower part; the foundation pit depth is great, reaches 15 meters, and the raft foundation 12 avris at foundation pit bottom is provided with escape canal 13, and foundation pit side slope fender pile is nearer apart from peripheral building. Therefore, the supporting structure for the foundation pit around the existing building 8 comprises a group of high-pressure jet grouting piles between the existing building 8 and the foundation pit slope and concrete cast-in-place piles 1 on the foundation pit slope, wherein the high-pressure jet grouting piles comprise a row of outer high-pressure jet grouting piles 4 close to one side of the existing building 8, a row of inner high-pressure jet grouting piles 3 close to one side of the foundation pit slope and a middle high-pressure jet grouting pile 5 between the outer high-pressure jet grouting piles 4 and the inner high-pressure jet grouting piles; the high-pressure jet grouting piles are all 0.5m in diameter, 6 m in length and slightly dense pebble layers in a supporting layer.
In this embodiment, the pile bodies of the adjacent high-pressure jet grouting piles in the outer high-pressure jet grouting pile 4 and the inner high-pressure jet grouting pile 3 are both tightly attached to each other; the middle high-pressure rotary jet grouting piles 5 are arranged in a quincunx shape at a large space and in a row shape at a small and narrow space; a steel core 6 of I-shaped steel is inserted into the pile body of the inner side high-pressure jet grouting pile 3; the outer high-pressure jet grouting pile 4 is arranged along the side line of the existing building 8, a gap is reserved between the outer high-pressure jet grouting pile and the side line of the existing building 8 on the horizontal plane, and the gap is correspondingly provided with an enclosure 7.
As shown in fig. 2 to 3, the bottom of the cast-in-place pile 1 extends to a position below the elevation of the pit bottom of the foundation pit, a concrete crown beam 2 is arranged at the top of the pile, and a gap between pile bodies of adjacent cast-in-place piles 1 is filled with concrete; inclined cable anchors are arranged on the cast-in-place pile 1 at intervals, are positioned at the lower part of the high-pressure jet grouting pile and extend to the lower part of the existing building 8; a waist beam 14 is arranged between the cast-in-place pile 1 and the cable anchor anchorage; as shown in fig. 4, the wale 14 is made of cast-in-place concrete, and the cross section of the wale 14 is a right trapezoid section, wherein an oblique side of the right trapezoid section corresponds to an anchor, and an inclination angle of the oblique side corresponds to an installation angle of the anchor cable 9; the anchorage device is a square anchorage device 11 and is correspondingly attached to the inclined edge of the waist rail 14.
As shown in fig. 5, an anchor is arranged on the cast-in-place pile 1 of the anchor cable 9, the anchor is a steel right-angled triangular anchor 10, a long right-angled side of the right-angled triangular anchor 10 is attached to a pile body of the cast-in-place pile 1 through a bolt, and two acute angles of the right-angled triangular anchor 10 are adapted to the installation angle of the anchor cable 9.
With reference to fig. 1 and 2, a construction method of a high-pressure jet grouting pile in a supporting structure of a foundation pit around an existing building is further described, which specifically comprises the following steps:
firstly, defining the range of soil mass to be reinforced according to a point position plane layout diagram of the high-pressure jet grouting piles, using a theodolite to discharge the specific central point position of each high-pressure jet grouting pile, and rechecking the pile position at any time in the construction process to ensure that the pile position is accurate.
Drilling a guide hole in the sand and pebble through a drilling machine to penetrate through the horizontal medium sand, the loose pebble and the slightly dense pebble layer to a designed depth, and ensuring that the rotary spray pipe reaches the slightly dense pebble layer; after the drilling machine is used for guiding the hole, a 30 cm-length PVC pipe with the diameter of 15cm is placed at the top of the pile hole.
And step three, placing the rotary spray pipe into the formed hole, checking and debugging whether the air nozzle and the guniting nozzle are intact and unblocked before the lower spray pipe is arranged, vertically aligning the lower spray pipe to the hole center to ensure that the spray pipe is lifted and rotated, sealing a grouting pipe connecting joint well, and ensuring that the spray nozzle is not blocked and a drill rod joint is not loosened in the process of arranging the rotary spray pipe.
Step four, adopting common Portland cement, and stirring the cement slurry by using a stirrer according to the water cement ratio of 0.8-1.0, wherein the cement slurry is required to be uniformly stirred; the high-speed stirring time is not less than 60 seconds, the ordinary stirring time is not less than 90 seconds, and the temperature of the slurry is preferably controlled to be 5-40 ℃. The time from preparation to completion is less than 4 hours, and the time is discarded; after the cement slurry is manufactured, feeding the slurry into a high-pressure pump, and pressurizing the cement slurry by using the high-pressure pump; after pressurization is completed, the slurry is sent to the drilling machine by the high-pressure pump to prepare for rotary spraying operation.
After the rotary spraying pipe is placed at the designed depth, the pressure of a double pipe is controlled to be more than or equal to 25MPa, the rotating speed is controlled to be 18-22 rpm, the lifting speed is controlled to be 180mm/min in the rotary spraying process, and the rotary spraying pipe is lifted at a low speed to the pile top at the position which is 1.0m close to the pile top and is close to the sand layer section; and (5) timely using cement paste for filling until the grout surface of the orifice does not sink any more, and then carrying out construction for inserting I-shaped steel into the inner high-pressure jet grouting pile 3.
In addition, according to the rotary leading hole of a positioning point drilling machine, attention is paid to the perpendicularity of a drill rod constantly, the I-shaped steel is inserted immediately after the double-pipe high-pressure jet grouting pile is formed, the time between inches is not more than 3 hours, the insertion positioning error of the section steel is not more than 10mm in the direction vertical to the foundation pit, the force direction parallel to the foundation pit is not more than 20mm, the bottom elevation error is not more than 30cm, the perpendicularity deviation is not more than 0.5%, dirt and iron rust on the surface of the I-shaped steel need to be eliminated before the antifriction agent is coated, the thickness is uniform during coating, the position where the hole opening sinks due to the water separation effect is filled after injection grouting is completed, the drilling.
With reference to fig. 1 to 5, a construction method of a cast-in-place pile 1 in a supporting structure of a foundation pit around an existing building is further described, which specifically includes the following steps:
firstly, carefully checking relevant data such as coordinates, elevations and the like provided by a design drawing, adopting a total station to perform pile position lofting, drawing a cross line to be more than 1.5m along the center of a pile, marking a pile protection pile, and performing hole opening, steel pile casing embedding and anchor cable embedding 9 after pile foundation hole positioning of a cast-in-place pile 1 is completed; and (3) arranging a mud pit on the site according to the construction process requirement, wherein the size of the mud pit is 1.2-1.5 times of the volume of the drilled hole, and the position of the mud pit is about 10m outside the position of the pile hole.
Secondly, adopting a wet type drilling bucket (rotary bucket) for rotary drilling hole forming construction in a sand gravel stratum, and enlarging a feed inlet and a tooth angle of the wet type drilling bucket so as to be beneficial to cutting in and entering a soil body; before drilling construction, firstly, the wall protection slurry is injected into the protection cylinder, and simultaneously, the slurry is injected in time along with the soil taking during the construction process, so that the liquid level of the slurry in the hole is always kept to avoid the collapse of the hole wall.
Thirdly, hoisting the reinforcement cage and preparing concrete pouring, wherein before the concrete pouring, the thickness of the sediment is rechecked by using a measuring rope, and the sediment is emptied for the second time until the thickness of the sediment is not more than 50mm when the thickness exceeds the acceptance standard; the steel reinforcement cage is manufactured by field processing, the steel reinforcement adopts a continuous reinforcement allocation method, the concrete pouring adopts a conduit method, the concrete pouring is finished after the steel reinforcement cage is hoisted, all detection data are qualified, the pouring amount of the primary pouring is calculated before the bored pile is poured, and the success of primary pouring and pipe burying is ensured.
And step four, in the pouring process, detecting the rising height of the concrete surface by using a measuring hammer frequently, and lifting and detaching the guide pipe timely to keep the reasonable burial depth of the guide pipe. The buried depth of the conduit should be not less than 2m, but the maximum buried depth should not exceed 4 m; the guide pipes need to be dismantled section by section along with the ascending of the concrete in the holes, and the dismantled guide pipes need to be washed clean immediately; when the position close to the pile top is poured, the required amount of concrete is calculated in order to strictly control the elevation of the pile top, and the concrete pouring amount of the last time is strictly controlled.
Fifthly, the concrete surface of the cast-in-place pile 1 is higher than the design by 0.3m so as to remove the laitance and the pile head and ensure the concrete quality of the pile body; after concrete pouring is completed for 5 days, foundation pit bearing platform excavation is carried out, the part of redundant concrete higher than the designed pile top is cut off, and the surface of the steel bar at the upper part of the pile top is cleaned; the rotary-excavated bored concrete pile 1 is required to be subjected to pile body integrity and single-pile vertical bearing capacity detection; the vertical bearing capacity of the single pile is preferably detected by selecting a representative pile according to the integrity detection result after the integrity of the pile body is detected; and pouring the waist beam 14, the square anchorage 11 on the waist beam 14, the right-angled triangle anchorage 10 on the cast-in-place pile 1 and the crown beam 2, tensioning the anchor cable at the embedded anchor cable point, and filling concrete between the cast-in-place piles 1 to meet the stress.
It is to be understood that the foregoing examples are illustrative only for the purpose of clearly illustrating the salient features of the present invention, and are not intended to limit the embodiments of the present invention; it will be apparent to those skilled in the art that various changes and modifications can be made in the above-described embodiments without departing from the spirit and scope of the invention.
Claims (7)
1. The utility model provides a supporting construction for peripheral foundation ditch of existing building which characterized in that: contain a set of high pressure jet grouting pile between existing building (8) and foundation ditch slope to and bored concrete pile (1) on the foundation ditch slope, high pressure jet grouting pile contains one row of outside high pressure jet grouting pile (4) that is close to existing building (8) one side, one row of inboard high pressure jet grouting pile (3) that is close to foundation ditch hole slope one side, and middle part high pressure jet grouting pile (5) between outside high pressure jet grouting pile (4) and inboard jet grouting pile.
2. A supporting construction for an existing building perimeter foundation pit according to claim 1, wherein: the pile bodies of the adjacent high-pressure jet grouting piles in the outer high-pressure jet grouting pile (4) and the inner high-pressure jet grouting pile (3) are tightly attached; the middle high-pressure rotary jet grouting piles (5) are arranged in a quincunx or row shape; and a steel core (6) is inserted into the pile body of the inner high-pressure jet grouting pile (3).
3. A supporting construction for an existing building perimeter foundation pit according to claim 2, wherein: the outer high-pressure jet grouting pile (4) is arranged along the side line of the existing building (8), a gap is reserved between the outer high-pressure jet grouting pile and the side line of the existing building (8) on the horizontal plane, and the gap is correspondingly provided with the enclosure (7).
4. A supporting construction for an existing building perimeter foundation pit according to claim 1, wherein: the bottom of the cast-in-place pile (1) extends to a position below the elevation of the pit bottom of the foundation pit, a crown beam (2) is arranged at the top of the pile, and gaps between pile bodies of adjacent cast-in-place piles (1) are filled with concrete.
5. A supporting construction for foundation pits around an existing building according to claim 4, characterized in that: inclined stay cable anchors are arranged on the cast-in-place pile (1) at intervals, are positioned on the lower portion of the high-pressure jet grouting pile and extend to the lower portion of the existing building (8).
6. A supporting construction for foundation pits around an existing building according to claim 5, characterized in that: a waist beam (14) is arranged between the cast-in-place pile (1) and the cable anchor anchorage; the cross section of the waist beam (14) is a right-angled trapezoid section, wherein the oblique edge on the right-angled trapezoid section corresponds to an anchor, and the inclination angle of the oblique edge corresponds to the installation angle of the anchor cable (9); the anchorage device is a square anchorage device (11) and is correspondingly attached to the oblique edge of the waist beam (14).
7. A supporting construction for an existing building perimeter foundation pit according to claim 6, wherein: anchor devices are arranged on the cast-in-place piles (1) of the anchor cables (9), the anchor devices are right-angled triangle anchor devices (10), long right-angled edges of the right-angled triangle anchor devices (10) are attached to the pile bodies of the cast-in-place piles (1), and the size of two acute angles of the right-angled triangle anchor devices (10) is adapted to the installation angle of the anchor cables (9).
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| CN201920113673.6U CN209816867U (en) | 2019-01-23 | 2019-01-23 | A supporting construction for peripheral foundation ditch of existing building |
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| CN201920113673.6U CN209816867U (en) | 2019-01-23 | 2019-01-23 | A supporting construction for peripheral foundation ditch of existing building |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111236310A (en) * | 2020-03-03 | 2020-06-05 | 福建工程学院 | Construction method of connecting channel of existing underground structure in weak water-rich stratum |
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2019
- 2019-01-23 CN CN201920113673.6U patent/CN209816867U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111236310A (en) * | 2020-03-03 | 2020-06-05 | 福建工程学院 | Construction method of connecting channel of existing underground structure in weak water-rich stratum |
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