CN110409510B - Water stopping structure at joint of engagement pile and ground continuous wall - Google Patents

Water stopping structure at joint of engagement pile and ground continuous wall Download PDF

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CN110409510B
CN110409510B CN201910669417.XA CN201910669417A CN110409510B CN 110409510 B CN110409510 B CN 110409510B CN 201910669417 A CN201910669417 A CN 201910669417A CN 110409510 B CN110409510 B CN 110409510B
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pile
wall
piles
grouting
secant
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CN110409510A (en
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韩超
郭海涛
宁凯飞
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Fourth Engineering Co Ltd of China Railway 20th Bureau Group Co Ltd
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Fourth Engineering Co Ltd of China Railway 20th Bureau Group Co Ltd
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D17/00Excavations; Bordering of excavations; Making embankments
    • E02D17/02Foundation pits
    • E02D17/04Bordering surfacing or stiffening the sides of foundation pits
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00Independent underground or underwater structures; Retaining walls
    • E02D29/16Arrangement or construction of joints in foundation structures
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D31/00Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
    • E02D31/02Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against ground humidity or ground water

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
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  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Environmental & Geological Engineering (AREA)
  • Hydrology & Water Resources (AREA)
  • Bulkheads Adapted To Foundation Construction (AREA)
  • Piles And Underground Anchors (AREA)

Abstract

The invention belongs to the technical field of constructional engineering, and relates to a water stopping structure at a joint of a secant pile and an underground diaphragm wall, wherein the secant pile concrete pile and the secant pile element pile are arranged at intervals and are mutually occluded to form the secant pile, the underground diaphragm wall is occluded with the adjacent secant pile element pile, a steel pipe is welded on a reinforcement cage at the adjacent side of the underground diaphragm wall and the adjacent secant pile element pile, a grouting pipe is buried at the outer side of the joint of the secant pile element pile and the underground diaphragm wall, a jet grouting pile is arranged at the outer side of the joint of the secant pile element pile and the underground diaphragm wall, the steel pipe is buried between the underground diaphragm wall and the secant pile through the occlusion of the ground diaphragm wall and the adjacent pile body, double-row grouting pipes are arranged at the outer sides of the joint of the ground diaphragm wall and the secant pile, and the outer side of the ground diaphragm wall are subjected to jet grouting pile reinforcement and the like.

Description

Water stopping structure at joint of engagement pile and ground continuous wall
Technical field:
The invention belongs to the technical field of constructional engineering, and relates to a water stopping structure at a joint of a secant pile of a foundation pit supporting structure and an underground continuous wall.
The background technology is as follows:
Along with the increasing number of subway projects in China, various buildings around the subway foundation pit in the city are dense, the surrounding environment and the water and soil geological conditions are complex, the construction difficulty is high, and a new foundation pit supporting mode needs to be explored.
Currently, foundation pit supporting forms commonly used in subway engineering include a snap pile, an underground continuous wall and the like. The engagement piles are foundation pit supporting structures formed by mutually engaging reinforced concrete piles and plain piles, wherein the adjacent piles between the row piles are arranged in a plane manner, and the foundation pit supporting structures are used as foundation pit supporting structures of subway engineering. The engaged piles have lower reinforcement ratio than the underground continuous wall, and the reinforcement ratio of the supporting structure can be greatly reduced and the fund can be saved by adopting the construction mode of the spaced arrangement of the reinforced concrete columns and the plain concrete piles. The impervious capacity of the secant pile is strong, because the secant pile is continuously constructed, no construction cold joint exists between the columns and is not mixed with soil, and the construction cold joint at the framing joint of the underground diaphragm wall is often a weak link for seepage prevention, and if the wall brushing effect of the underground diaphragm wall is not in place, the hidden danger of seepage can be left. The construction of the secant pile is flexible, and the secant pile can turn the transformation line according to the requirement, so the secant pile is more suitable for the foundation pit support with changeable foundation pit side walls.
The underground diaphragm wall is characterized in that various grooving machines are utilized, grooves with certain dimensions are dug at designed positions by means of the wall protection effect of slurry, then a reinforcement cage is lifted and lowered, and concrete is poured, so that a continuous underground wall with seepage prevention, soil retaining and bearing effects is formed. The underground diaphragm wall has small vibration and noise during construction, has small influence on the periphery and is suitable for urban construction. The underground diaphragm wall has high rigidity, can bear larger soil pressure after the foundation pit is excavated, rarely has foundation settlement or collapse accidents in engineering application, has better seepage prevention performance, and has better water stop and seepage prevention effect if the joint form and the construction method are proper. The underground continuous wall is suitable for various geological conditions and has wide application range.
If the occluding piles are combined with the underground continuous wall, two supporting structures are used simultaneously in the same engineering according to geological conditions, and the advantages of the two supporting structures can be fully utilized. However, the water stop problem at the joint of the engagement pile and the underground continuous wall is a serious difficulty, and once the water leakage condition occurs at the joint of the engagement pile and the underground continuous wall, the leakage blocking work is very difficult, and the safety of the foundation pit and the surrounding environment can be influenced. At present, an effective system construction method does not exist. Therefore, it is urgent to design a water stopping structure at the joint of the engagement pile and the ground connecting wall.
The invention comprises the following steps:
The invention aims to overcome the defects in the prior art, and aims at the problem of water leakage at the joint of the occluding pile and the underground continuous wall, and the water stop structure at the joint of the occluding pile and the underground continuous wall is designed, so that the water resistance and the leakage resistance of the joint are improved, and the stability and the safety of a foundation pit are enhanced.
In order to achieve the purpose, the main structure of the water stopping structure at the joint of the secant pile and the underground continuous wall comprises an underground continuous wall, a secant pile element pile, a secant pile concrete pile, a jet grouting pile, a steel flower pipe and a grouting pipe; the occlusion pile concrete piles and the occlusion pile element piles are arranged at intervals and are occluded with each other to form occlusion piles, the ground continuous wall is occluded with the adjacent occlusion pile element piles, and the burying depth of the underground continuous wall is the same as that of the adjacent occlusion pile element piles; the steel flower pipe is welded on a reinforcement cage on the adjacent side of the underground continuous wall and the adjacent meshed pile element pile, and the embedded depth is the same as that of the underground continuous wall; the grouting pipe is buried outside the joint of the secant pile element pile and the ground connecting wall, and the buried depth is determined according to the geological conditions of specific engineering; the jet grouting piles are arranged on the outer sides of joints of the engaged pile element piles and the underground continuous wall, and the embedded depth is the same as that of the underground continuous wall.
The thickness, the width and the depth of the underground diaphragm wall are determined according to the geological condition of a specific engineering and the size of the occluding pile, the width of the underground diaphragm wall is not more than 6m, the depth of the underground diaphragm wall is 10m to 50m, the thickness is 0.5m to 1.2m, and the thickness is smaller than the diameter of an adjacent occluding pile by at least 200mm, so that the underground diaphragm wall and the occluding pile are tightly connected; the diameter and the burial depth of the engaged pile element piles are determined according to engineering geological conditions, the diameter is not smaller than 1000mm, at least C25 super-retarding concrete is used for pouring, and the engagement between the engaged pile element piles and adjacent piles is not smaller than 300mm; the diameter and the burial depth of the pile of the occluding pile are determined according to engineering geological conditions, the diameter is not smaller than 1000mm, at least C45 underwater concrete is used for pouring, and the occlusion between the pile and the adjacent pile is not smaller than 300mm; the diameter of the jet grouting pile is the same as that of the secant pile, and at least common silicate cement with the reference number of 42.5 is used for being tangent with the pile of the secant pile, the pile element pile of the secant pile and the pile of the ground continuous wall, and the reinforcement depth is the elevation from the ground to the pile bottom of the secant pile; the diameter of the steel floral tube is determined according to the concrete engineering geological condition, generally, an A42 steel floral tube is adopted, and the steel tubes are connected by welding; the diameter and the burial depth of the grouting pipe are determined according to the concrete engineering geological conditions, and the steel pipes are connected by screw threads.
The concrete process for realizing water stop at the joint of the occluding pile and the ground connecting wall comprises the following steps:
Step 1: constructing an occlusion pile, namely occluding pile element piles which are occluded with a ground continuous wall, paying out and positioning, positioning by a drilling machine, taking soil and forming holes until the elevation of the bottom of a designed hole is reached, if the occlusion pile element piles are occlusion pile elements, hoisting a reinforcement cage after the hole forming inspection is qualified, and pouring concrete to draw out pipes to form piles;
Step 2: preparing the construction of the diaphragm wall, carrying out paying-off positioning guide wall construction of the diaphragm wall by adopting the existing process, preparing slurry, and then testing into a groove;
step 3: the conventional grooving of the diaphragm wall, determining the position of the diaphragm wall according to the design requirement and the guide wall, performing excavation operation by a grooving machine, adopting slurry to protect the wall when grooving until the depth is the same as the embedded depth of the adjacent secant piles, and checking and accepting the slotted holes;
Step 4: when the diaphragm wall forms a groove, the side close to the element pile of the engaged pile is enlarged into the groove wall with the width of at least 200mm by adopting a rotary drilling drill, so that the concrete can flow around the back of the channel steel when pouring the concrete, and is tightly combined with the element pile of the engaged pile, so that the element pile of the engaged pile is firmly connected with the diaphragm wall;
Step 5: adopting a rotary drilling drill to drill out part of engaged pile element piles at the joint so that the ground continuous wall is engaged with the adjacent engaged pile element piles by at least 300mm, and controlling the specific gravity of slurry to be 1.1g/cm 3~1.25g/cm3 in the construction process until the elevation of the wall bottom is reached;
Step 6: the bottom cleaning and hole cleaning operation is carried out after the groove is formed, the bottom cleaning adopts a grabbing and fishing method, the hole cleaning operation can adopt positive circulation hole cleaning operation, and the bottom cleaning is stopped after the slurry in the groove is replaced;
Step 7: repeatedly cleaning the side walls of adjacent occluding piles by adopting a steel wire brush after grooving, ensuring that the side walls are not sticky with mud, ensuring that the side walls are tightly connected with a ground continuous wall, repeatedly brushing the wall brushing device up and down for at least 20 times, timely cleaning mud skin on the wall brushing device after brushing the wall, and checking the condition of the steel wire, if loss exists, timely repairing;
step 8: manufacturing a reinforcement cage, namely derusting reinforcement before manufacturing, manufacturing the reinforcement cage by adopting a mould method forming process, strictly controlling welding quality during welding, and determining the manufacturing width of the reinforcement cage according to the position of the engaged pile element pile;
Step 9: two steel flower pipes are buried between the wall body of the underground continuous wall and the adjacent secant pile element piles, the two steel flower pipes are welded and then bound on the steel reinforcement cages at the sides of the secant pile element piles, the two steel flower pipes are arranged in parallel and buried to the design height of the wall bottom of the underground continuous wall, grouting water stop reinforcement is conveniently carried out by pouring concrete, and the positions of the grouting pipes are properly close to the seam channel steel;
Step 10: hoisting the reinforcement cage, wherein the position of the section of reinforcement cage channel steel is controlled to be as close as possible to the pile-formed occluding pile element pile during hoisting, so that the gap between the pile-formed occluding pile element pile and the ground continuous wall is reduced, and the pile-formed occluding pile element pile is firmly connected;
step 11: pouring the wall body concrete, wherein the better fluidity of the underwater concrete is ensured during pouring, the quality of the concrete wall body is ensured, the concrete is required to be ensured to be continuously poured after pouring, and a grouting pipe is enabled to move up and down by 30cm in the pouring of a joint part, so that the pouring quality is ensured;
Step 12: double rows of grouting pipes are arranged along the outer sides of joints of the diaphragm wall and the engaged pile element piles in a driving mode, the number and the distance between the grouting pipes are determined according to the geological hydrologic conditions of specific engineering, grouting construction is conducted, and water stop reinforcement of the joints is guaranteed;
Step 13: after the construction of the diaphragm wall is finished for 3 days, water is injected into the embedded steel flowtube to ensure the smoothness of the grouting pipeline and the splitting of the annular tube, so that preparation is made for cement injection, the lowering position of the water surface and the output pressure of the grouting pump are noticed at any time during water injection, the pressurized water is not too much or too little, the cement injection is reinforced after the steel flowtube 5 is injected with water, and the water stop quality of the joint is ensured;
Step 14: reinforcing the outer sides of the engaged pile element piles and the underground continuous wall by adopting double rows of jet grouting piles, wherein the diameters and the number of the jet grouting piles are determined according to the geological hydrologic conditions of specific engineering, the engaged piles are at least 200mm, double rows of grouting embedded outside the joint of the engaged piles and the underground continuous wall are avoided during paying-off and positioning, slurry retaining wall rotary drilling is adopted during drilling, the stability of the wall of the hole is maintained, at least ordinary Portland cement with the reference number of 42.5 is adopted, and the reinforcing depth is the designed elevation from the ground to the bottom of the underground continuous wall;
Step 15: if seepage occurs in the later-stage joint, chiseling and cleaning the wall surface, and then plugging with double quick cement; when the method is serious, the chisel is used for cleaning the water leakage point, the honeycomb duct is inserted, the plugging material (plugging agent, quick hardening cement and the like) is smeared for plugging the honeycomb duct, finally, grouting treatment is carried out on the outer side of the enclosure structure or below the water leakage point, the grouting is supplemented and reinforced, and the excavation can be continued after the water leakage plugging is completed.
The grouting material for grouting adopts 425# sulfate-resistant cement (sulfate erosion resistance), the water-cement ratio is 0.5, and 0.2% basalt fiber is added into the slurry to improve the crack resistance (fiber filament diameter is 12=3um, density is 2.65kg/m < 3 >, average length is 6mm, tensile strength is 2000MPa, elastic modulus is 90GPa, and ultimate elongation is 3.5%).
The proportion (%) of the slurry for the wall protection is water, bentonite, carboxymethyl cellulose and barite=100:10:0.3:0.02, wherein the elevation of the liquid level in the control tank is 1m higher than the underground water level; the specific gravity of the slurry is controlled between 1.05 and 1.15; the viscosity of the slurry is controlled to be 20-22 s; the PH value of the slurry is not more than 10.5, and the slurry has the functions of suspending drill slag, cooling a drill bit and lubricating a drilling tool, can increase hydrostatic pressure, forms mud skin on the wall of the tank, cuts off seepage inside and outside the tank, and prevents the protection wall from collapsing.
Compared with the prior art, the invention provides an effective water stopping structure and method at the joint of the secant pile and the underground diaphragm wall, the secant wall is engaged with the adjacent pile body, the steel pipe is buried between the secant wall body and the secant pile, double rows of grouting pipes are arranged at the outer sides of the joint of the secant wall and the secant pile, and jet grouting pile reinforcement is carried out at the outer sides of the secant pile and the secant wall, so that the water stopping problem at the joint of the secant pile and the underground diaphragm wall is solved, the water resistance and leakage resistance at the joint are improved, and the stability and safety of a foundation pit are enhanced.
Description of the drawings:
FIG. 1 is a schematic overall plan view of a water stop structure at a joint between a pile and an underground diaphragm wall in the present invention.
Fig. 2 is a 1-1 cross-sectional view of a water stopping structure at a joint of a secant pile and an underground diaphragm wall, wherein 1 is the underground diaphragm wall, 2 is a secant pile element pile, 3 is a secant pile meat pile, 4 is a jet grouting pile, 5 is a steel pipe, 6 is a grouting pipe, H1 is the depth from the ground to the bottom of the underground diaphragm wall, and H2 is the embedded depth of the grouting pipe.
The specific embodiment is as follows:
The invention will now be described in further detail by way of specific examples with reference to the accompanying drawings. It should not be understood that the scope of the above subject matter of the present invention is limited to the following examples, and all techniques implemented based on the present disclosure fall within the scope of the present invention.
Example 1:
The main structure of the water stopping structure at the joint of the secant pile and the underground continuous wall comprises an underground continuous wall 1, a secant pile element pile 2, a secant pile concrete pile 3, a jet grouting pile 4, a steel flower pipe 5 and a grouting pipe 6; the occlusion pile concrete piles 3 and the occlusion pile element piles 2 are arranged at intervals and are occluded with each other to form occlusion piles, the underground continuous wall 1 is occluded with the adjacent occlusion pile element piles 2, and the burial depth of the underground continuous wall 1 is the same as that of the adjacent occlusion pile element piles 2; the steel pipe 5 is welded on the reinforcement cage on the adjacent side of the underground continuous wall 1 and the adjacent meshed pile element pile 2, and the embedded depth is the same as that of the underground continuous wall 1; the grouting pipe 6 is buried outside the joint of the secant pile element 2 and the underground diaphragm wall 1, and the buried depth is determined according to the geological conditions of specific engineering; the jet grouting piles 4 are arranged on the outer side of the joint of the engaged pile element piles 2 and the underground continuous wall 1, and the embedded depth is the same as that of the underground continuous wall 1.
The thickness, width and depth of the underground diaphragm wall 1 are determined according to the geological condition of a specific engineering and the size of the occluding pile, the width of the underground diaphragm wall is not more than 6m, the depth of the embedded diaphragm wall is 10m to 50m, the thickness is 0.5m to 1.2m, and the thickness is smaller than the diameter of the adjacent occluding pile element pile 2 by at least 200mm, so that the underground diaphragm wall and the occluding pile element pile are tightly connected; the diameter and the burial depth of the engaged pile element piles 2 are determined according to engineering geological conditions, the diameter is not smaller than 1000mm, at least C25 ultra-retarding concrete is used for pouring, and the engagement between the engaged pile element piles and adjacent piles is not smaller than 300mm; the diameter and the burial depth of the secant pile 3 are determined according to engineering geological conditions, the diameter is not smaller than 1000mm, at least C45 underwater concrete is used for pouring, and the secant between the secant pile and the adjacent pile is not smaller than 300mm; the diameter of the jet grouting pile 4 is the same as that of the secant pile, and at least common silicate cement with the reference number of 42.5 is used for tangential connection with the secant pile concrete pile 3, the secant pile element pile 2 and the underground continuous wall 1, and the reinforcement depth is the elevation from the ground to the pile bottom of the secant pile; the diameter of the steel floral tube 5 is determined according to the concrete engineering geological conditions, generally, an A42 steel floral tube is adopted, and the steel tubes are connected by welding; the diameter and the burial depth of the grouting pipe 6 are determined according to the concrete engineering geological conditions, and the steel pipes are connected by screw threads.
Example 2:
The water stopping structure at the joint of the secant pile and the underground continuous wall in the embodiment is applied to the joint of the secant pile and the underground continuous wall of a certain subway station, and the main structure of the water stopping structure at the joint of the secant pile and the underground continuous wall comprises a ground continuous wall 1, the wall thickness is 800mm, the width is 6.0m, the burial depth is 26m, and C45 underwater concrete pouring is adopted; the diameter of the engaged pile element pile 2 is 1000mm, the pile distance between the engaged pile element pile and the adjacent pile is 700mm, the engaged pile element pile is 300mm, the embedded depth is 26m, and C25 super-retarding concrete is adopted for pouring; pile 3 of the occluding pile, wherein the diameter of the occluding pile is 1000mm, the pile distance between the occluding pile and the adjacent pile is 700mm, the occluding pile is 300mm, the embedded depth is 26m, and C45 underwater concrete casting is adopted; the jet grouting piles 4 are 1000mm in diameter and 26m in embedded depth, the jet grouting piles 4 are meshed with each other for 300mm and tangent to the ground continuous wall 1, the meshed pile element piles 2 and the meshed pile element piles 3, and the pile element piles are poured by using ordinary Portland cement with the reference number of 42.5; the steel floral tube 5 is made of an A42 steel floral tube, the thickness of the tube wall is 3mm, grouting holes with the thickness of 8mm are formed in the periphery of the tube wall, welding is adopted among the steel floral tubes, and the burial depth is 26m; the grouting pipe 6 is an A42 grouting pipe, the pipe wall thickness is 3mm, grouting holes with the pipe wall circumference being 8mm are formed in the periphery of the pipe wall, the grouting pipes are connected by screw threads, and the embedded depth is 26m; the pile spacing between the secant pile element piles 2 and the secant pile 3 is 700mm, the secant pile is 300mm, and the secant pile element piles 2 are adjacent to the ground continuous wall 1 and are convenient to be engaged with the ground continuous wall 1; two A42 steel floral tubes 5 are bound on a reinforcement cage at the joint side of the underground continuous wall 1, and the burial depth is 26m. Constructing the diaphragm wall 1, and enabling the diaphragm wall 1 to be meshed with adjacent meshed piles for 200mm; double rows of A42 grouting pipes 6 are arranged on the outer sides of the ground connecting wall 1 and the occluding piles in a driving mode, the distance is 1m, 8 grouting pipes are arranged in total, and the burying depth is 12m; the outer sides of the underground diaphragm wall 1 and the occlusion piles are additionally provided with 9 double-row jet grouting piles 4 with the diameter of 1000mm, the mutual occlusion among the jet grouting piles 4 is 300mm, and the total of 9 piles are tangent to the underground diaphragm wall 1, the occlusion pile plain piles 2 and the occlusion pile meat piles 3.
The specific implementation method of the embodiment is as follows:
Step 1: when the phi 1000@700mm sleeve pipe occluding piles are adopted for constructing the occluding piles, the occluding piles adjacent to the ground connecting wall 1 are plain piles 2, so that the ground connecting wall 1 can be conveniently occluded with the adjacent occluding piles 2; after paying off and positioning, a drilling machine is positioned, soil is taken for pore forming until the elevation of the bottom of a designed hole is reached, if the pile is a secant pile, the reinforcement cage is hung after the pore forming inspection is qualified, and then concrete is poured for pipe drawing to form the pile;
Step 2: preparing the diaphragm wall for grooving, carrying out paying-off positioning and wall guiding construction of the diaphragm wall 1, preparing slurry, then performing grooving test, wherein the concrete construction process of the grooving test is the same as that of normal grooving construction;
step 3: the conventional grooving of the diaphragm wall, the position of the diaphragm wall 1 is determined according to a design drawing and a guide wall, the grooving machine performs excavation operation, a Xu Gong hydraulic grab grooving machine is used for grooving in the example, slurry is used for protecting the wall during grooving until the depth is the same as the embedded depth of the adjacent secant piles, and then slotted hole acceptance is performed;
Step 4: when the diaphragm wall 1 forms a groove, the side close to the secant pile element pile 2 is enlarged into the width of the groove wall body to 1000mm by adopting a rotary drilling drill, so that when concrete is poured, the concrete can flow around the back of the channel steel and be tightly combined with the secant pile element pile 2, and the connection between the secant pile element pile 2 and the diaphragm wall 1 is firmer;
Step 5: the pile is formed by drilling part of the engaged pile element piles 2 at the joint by rotary drilling, so that the earth continuous wall 1 is engaged with the adjacent engaged pile element piles 2 by at least 300mm, the specific gravity of slurry is controlled to be 1.1g/cm 3~1.25g/cm3 in the process, the wall of the hole is ensured not to collapse until the elevation of the wall bottom, and the slurry adopts bentonite, calcined soda, CMC, barite, a leakage-proof agent and tap water as raw materials, wherein the raw material ratio is 100:4:1:1:2:1000, by flushing with clear slurry, mixing, stirring, and secondary mixing;
Step 6: the bottom and hole cleaning operation is carried out after the diaphragm wall 1 is formed into a groove, and the bottom cleaning operation is carried out by adopting a rotary drilling, fishing and grabbing method in the example. After the fishing is completed, adopting positive circulation to carry out hole cleaning operation, ensuring that sediment at the bottom of the hole is not more than 50mm, and ensuring that the specific gravity of mud at the bottom of the hole is not more than 1.15 after hole cleaning;
Step 7: repeatedly cleaning the side walls of the adjacent finished pile element piles 2 by adopting a steel wire brush after grooving, ensuring that the side walls are not sticky with mud, ensuring that the wall bodies are tightly connected, repeatedly brushing the wall brushing device up and down for at least 20 times, timely cleaning mud skin on the wall brushing device after brushing the wall, and checking the condition of the steel wire, wherein if loss occurs, the repairing should be timely carried out; .
Step 8: manufacturing a reinforcement cage, namely derusting reinforcement before manufacturing, manufacturing the reinforcement cage by adopting a mould method forming process, strictly controlling welding quality during welding, and determining the manufacturing width of the reinforcement cage according to the position and the diameter of the element piles 2 of the interlocking piles so as to facilitate the interlocking of the ground continuous wall 1 and the adjacent interlocking piles 2;
Step 9: 2 steel flower pipes 5 are buried between the wall body 1 of the ground continuous wall and the adjacent secant pile element piles 2, the two steel flower pipes 5 are connected by welding and bound on a joint side steel reinforcement cage, the two steel flower pipes 5 are arranged in parallel and have a spacing of 400mm and buried to the design height of the wall bottom of the ground continuous wall, so that concrete pouring is facilitated, grouting water stop reinforcement is carried out, and the position of a guide pipe is properly close to a joint channel steel;
Step 10: hoisting the reinforcement cage, wherein the position of the section of reinforcement cage channel steel is controlled to be as close as possible to the pile body 2 of the formed pile occluding pile during hoisting, so that gaps are reduced, and the ground connecting wall 1 and the adjacent occluding pile element pile 2 are firmly connected after concrete is poured;
Step 11: c45 underwater concrete is adopted to pour the wall body concrete, the better fluidity of the underwater concrete is ensured during pouring, the quality of the concrete wall body is ensured, the concrete is required to be ensured to be continuously poured after pouring is started, and in the pouring of the joint part, the guide pipe is made to move up and down by 30cm, so that the pouring quality is ensured;
Step 12: double rows of grouting pipes 6 are arranged along the outer side of the joint for grouting construction, the water stop reinforcement of the joint is guaranteed, after the concrete pouring of the underground continuous wall 1 is completed, double rows of A42 grouting pipes are arranged on the outer side of the joint of the occluding pile 2 and the underground continuous wall 1 at a spacing of 1m, 8 steel pipes are connected by screw threads, the pipe wall thickness is 3mm, the reinforcement depth of the engineering reaches 12m below the ground, and the engineering extends into a powdery clay layer of 1m; forming holes on the outer sides of the joints of the diaphragm wall and the secant piles by using a drilling machine, and then vertically driving the grouting pipe into the holes by manpower; when grouting operation is carried out, the grouting pressure is controlled to be 2-4 Mpa, the cement used for preparing the slurry is 42.5 ordinary Portland cement, and the weight ratio is 1:1, cement paste is injected into two holes in trial, for example, the injectability is good, and the water-cement ratio is adjusted to be 0.5-0.6;
Step 13: after the construction of the diaphragm wall 1 is completed for 3 days, the embedded steel flowtube 5 is injected with water to ensure the smoothness of a grouting pipeline and the splitting of an annular tube, so that preparation is made for grouting in the future, the descending position of the water surface and the output pressure of a grouting pump are noticed at any time during the water injection, the pressurized water is not too much or too little, the grouting pump with a pressure gauge is used for grouting after dredging, the grouting is prepared by using ordinary Portland cement with the mark number of 42.5, the grouting pressure is 2-4 Mpa, and the weight ratio is 1:1, cement paste is injected into two holes in trial, and the water-cement ratio can be adjusted to 0.5-0.6 when the gap is larger;
step 14: the outer sides of the occluding pile element piles 2 and the underground continuous wall 1 are reinforced by adopting double rows of jet grouting piles 4, in the embodiment, 9 jet grouting piles 4 are arranged in total, the occluding piles are occluded by 300mm, double rows of grouting pipes buried outside joints of the occluding piles and the underground continuous wall are avoided during paying-off positioning, slurry retaining wall rotary drilling is adopted during drilling, the stability of the wall of the hole is maintained, ordinary Portland cement with the reference number of 42.5 is adopted, and the reinforcing depth is the design elevation of the bottom of the underground continuous wall 1;
Step 15: if seepage occurs in the later-stage joint, the wall surface can be chiseled and cleaned, and then blocked by using double quick cement; when the leakage point is seriously cleaned by chiseling, a flow guide pipe is inserted, a plugging material (plugging agent, quick hardening cement and the like) is smeared, the flow guide pipe is plugged, finally grouting treatment is carried out on the outer side of the enclosure structure or below the leakage point, the grouting is supplemented and reinforced, and the excavation is continued after the leakage blocking is finished.
The grouting material for grouting in the embodiment adopts 425# sulfate-resistant cement (sulfate erosion resistance), the water cement ratio is 0.5, and 0.2% basalt fiber is added into the slurry to improve the crack resistance (fiber filament diameter is 12=3um, density is 2.65kg/m < 3 >, average length is 6mm, tensile strength is 2000MPa, elastic modulus is 90GPa, and ultimate elongation is 3.5%).
The proportion (%) of the slurry for wall protection in the embodiment is water, bentonite, carboxymethyl cellulose and barite=100:10:0.3:0.02, wherein the elevation of the liquid level in the control tank is higher than the ground water level by 1m; the specific gravity of the slurry is controlled between 1.05 and 1.15; the viscosity of the slurry is controlled to be 20-22 s; the PH value of the slurry is not more than 10.5, and the slurry has the functions of suspending drill slag, cooling a drill bit and lubricating a drilling tool, can increase hydrostatic pressure, forms mud skin on the wall of the tank, cuts off seepage inside and outside the tank, and prevents the protection wall from collapsing.

Claims (2)

1. A water stopping structure at the joint of a secant pile and a ground continuous wall is characterized in that the main structure comprises the ground continuous wall, a secant pile element pile, a secant pile meat pile, a jet grouting pile, a steel pipe and a grouting pipe; the meat piles and the vegetable piles of the interlocking piles are arranged at intervals and mutually meshed to form the interlocking piles, the ground continuous wall is meshed with the adjacent vegetable piles of the interlocking piles, and the buried depth of the underground continuous wall is the same as the buried depth of the adjacent vegetable piles of the interlocking piles; the steel flower pipe is welded on a reinforcement cage on the adjacent side of the underground continuous wall and the adjacent meshed pile element pile, and the embedded depth is the same as that of the underground continuous wall; the grouting pipe is buried outside the joint of the secant pile element pile and the ground connecting wall, and the buried depth is determined according to the geological conditions of specific engineering; the jet grouting piles are arranged on the outer sides of joints of the engaged pile element piles and the underground continuous wall, and the embedded depth is the same as that of the underground continuous wall; the concrete process for realizing water stop at the joint of the occluding pile and the diaphragm wall comprises the following steps:
Step 1: constructing an occlusion pile, namely an occlusion pile element pile which is occluded with a ground continuous wall, paying off and positioning, positioning by a drilling machine, taking soil and forming holes until the bottom elevation of a designed hole is reached, and pouring concrete to pull out a pipe to form a pile after a reinforcement cage is hung after the pore forming inspection of the occlusion pile meat pile is qualified, wherein the occlusion pile meat pile and the occlusion pile element pile are arranged at intervals and are occluded with each other to form an occlusion pile;
Step 2: preparing the construction of the diaphragm wall, carrying out paying-off positioning guide wall construction of the diaphragm wall by adopting the existing process, preparing slurry, and then testing into a groove;
step 3: the conventional grooving of the diaphragm wall, determining the position of the diaphragm wall according to the design requirement and the guide wall, performing excavation operation by a grooving machine, adopting slurry to protect the wall when grooving until the depth is the same as the embedded depth of the adjacent secant piles, and checking and accepting the slotted holes;
Step 4: when the diaphragm wall forms a groove, a rotary drilling bit is adopted to enlarge one side close to the element pile of the engaged pile into a groove wall body with the width of at least 200 mm, so that when concrete is poured, the concrete can flow around the back surface of the channel steel and be tightly combined with the element pile of the engaged pile, and the element pile of the engaged pile is firmly connected with the diaphragm wall;
step 5: adopting a rotary drilling drill to drill out part of the engaged pile element piles at the joint so that the ground continuous wall is engaged with the adjacent engaged pile element piles by at least 300mm, and controlling the specific gravity of slurry to be 1.1 g/cm 3~1.25 g/cm3 in the construction process until the elevation of the wall bottom;
Step 6: after the groove is formed, bottom cleaning and hole cleaning operations are carried out, a grabbing and fishing method is adopted for bottom cleaning, positive circulation hole cleaning operation is adopted for hole cleaning, and bottom cleaning is stopped after slurry replacement in the groove is completed;
Step 7: repeatedly cleaning the side walls of adjacent occluding piles by adopting a steel wire brush after grooving, ensuring that the side walls are not sticky with mud, ensuring that the side walls are tightly connected with a ground continuous wall, repeatedly brushing the wall brushing device up and down for at least 20 times, timely cleaning mud skin on the wall brushing device after brushing the wall, and checking the condition of the steel wire, if loss exists, timely repairing;
step 8: manufacturing a reinforcement cage, namely derusting reinforcement before manufacturing, manufacturing the reinforcement cage by adopting a mould method forming process, strictly controlling welding quality during welding, and determining the manufacturing width of the reinforcement cage according to the position of the engaged pile element pile;
Step 9: two steel flower pipes are buried between the wall body of the underground continuous wall and the adjacent secant pile element piles, the two steel flower pipes are welded and then bound on the reinforcement cages on the adjacent sides of the wall body of the underground continuous wall and the adjacent secant pile element piles, the two steel flower pipes are arranged in parallel and buried to the designed height of the wall bottom of the wall body of the underground continuous wall, so that concrete is convenient to pour for grouting, water stopping and reinforcement, and the positions of the grouting pipes are properly close to the seam channel steel;
Step 10: hoisting the reinforcement cage, wherein the position of the channel steel of the reinforcement cage is controlled to be as close as possible to the position of the pile of the formed occlusion pile when the reinforcement cage is hoisted, so that gaps between the pile of the occlusion pile and the ground continuous wall are reduced, and the pile of the occlusion pile is firmly connected;
Step 11: pouring wall concrete, wherein the good fluidity of the underwater concrete is ensured during pouring, the quality of the concrete wall is ensured, the concrete is required to be continuously poured after pouring is started, and in the pouring of the joint part, a grouting pipe is enabled to move up and down by 30 cm, so that the pouring quality is ensured;
Step 12: double rows of grouting pipes are arranged along the outer sides of joints of the diaphragm wall and the engaged pile element piles in a driving mode, the number and the distance between the grouting pipes are determined according to the geological hydrologic conditions of specific engineering, grouting construction is conducted, and water stop reinforcement of the joints is guaranteed;
Step 13: after the construction of the diaphragm wall is finished for 3 days, water is injected into the embedded steel flowtube to ensure smoothness of a grouting pipeline and splitting of the steel flowtube, preparation is made for grouting cement, the descending position of the water surface and the output pressure of a grouting pump are noted at any time during water injection, the pressurized water is not too much or too little, the grouting cement is reinforced after the grouting of the steel flowtube, and the water stop quality of joints is ensured;
Step 14: reinforcing the outer sides of the engaged pile element piles and the underground continuous wall by adopting double rows of jet grouting piles, wherein the diameters and the number of the jet grouting piles are determined according to the geological hydrologic conditions of specific engineering, at least 200 mm are engaged among the jet grouting piles, double rows of grouting embedded outside the engaged pile and the underground continuous wall joint are avoided during paying-off positioning, slurry retaining wall rotary drilling is adopted during drilling, the stability of the wall is maintained, at least the ordinary Portland cement with the reference number of 42.5 is adopted, and the reinforcing depth is the designed elevation from the ground to the bottom of the underground continuous wall;
Step 15: if seepage occurs in the later-stage joint, chiseling and cleaning the wall surface, and then plugging with double quick cement; when the method is serious, the chisel is used for cleaning the water leakage point, the honeycomb duct is inserted, the plugging material is smeared for plugging the honeycomb duct, finally, grouting treatment is carried out on the outer side of the enclosure structure or below the water leakage point, grouting is supplemented and reinforced, and the excavation can be continued after the water leakage plugging is completed.
2. The water stopping structure at the joint of the secant pile and the underground continuous wall according to claim 1, wherein the thickness, the width and the depth of the underground continuous wall are determined according to the geological condition of specific engineering and the size of the secant pile, the width of the underground continuous wall is not more than 6m, the depth of the secant pile is 10m to 50m, the thickness is 0.5 m to 1.2m, and the diameter of the secant pile is at least 200 mm which is smaller than that of the adjacent secant pile so as to be tightly connected; the diameter and the burial depth of the engaged pile element piles are determined according to engineering geological conditions, the diameter is not smaller than 1000 mm, at least C25 ultra-retarding concrete is used for pouring, and the engagement between the engaged pile element piles and adjacent piles is not smaller than 300 mm; the diameter and the burial depth of the pile are determined according to engineering geological conditions, the diameter is not less than 1000 mm, at least C45 underwater concrete is used for pouring, and the occlusion between the pile and the adjacent pile is not less than 300 mm; the diameter of the jet grouting pile is the same as that of the secant pile, and the jet grouting pile is tangent to the meat pile of the secant pile, the vegetable pile of the secant pile and the wall pile of the ground, and the reinforcement depth is the elevation from the ground to the pile bottom of the secant pile by using at least the ordinary Portland cement with the reference number of 42.5; the steel flower pipes are A42 steel flower pipes, and the steel flower pipes are connected by welding; the diameter and the burial depth of the grouting pipes are determined according to the concrete engineering geological conditions, and the grouting pipes are connected by screw threads.
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CN112095582B (en) * 2020-09-24 2021-12-31 山东中能杆塔有限公司 Impervious concrete precast pile based on acid soil
CN113174992B (en) * 2021-04-29 2022-08-30 福建永强岩土股份有限公司 Comprehensive treatment and reinforcement method for collapse of stratum around marine deep-water inclined pile
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CN114232668A (en) * 2021-11-30 2022-03-25 中交路桥华南工程有限公司 Water sealing structure for anchorage support
CN115262651B (en) * 2022-08-08 2023-11-07 上海建工集团股份有限公司 Underground diaphragm wall local self-collapsing type water stopping method

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