Large-diameter meat-vegetable occluding pile anchor supporting structure and construction method thereof
Technical Field
The invention relates to the technical field of foundation pit engineering construction, in particular to a large-diameter meat-vegetable occluding pile anchor supporting structure and a construction method thereof, which are mainly applied to the situation that occluding piles are designed with multiple rows of anchor cables (rods).
Background
The pile is a foundation pit supporting structure for supporting foundation pit of underground structure, which is formed by partially embedding piles (plain concrete piles) with reinforcement cages into piles (plain concrete piles) without reinforcement cages. The plain concrete pile mainly has the functions of water stopping, seepage prevention and soil blocking between piles; the reinforced concrete pile has good bending moment resisting effect due to the arrangement of the reinforcement cage, can effectively support water and soil pressure in an active area, ensures stability of a foundation pit, organically combines meat and vegetable concrete piles, can effectively exert retaining, water stopping and seepage-proofing foundation pit supporting and retaining effects, and has the advantages of quick construction, good water stopping effect and the like, and is widely used in foundation pit engineering.
When some foundation pit engineering adopts a secant pile supporting structure, a plurality of rows of anchor cables (rods) are also arranged, namely a meat-vegetable concrete pile anchor system, and the conventional construction flow of the supporting system is as follows: the construction of plain concrete piles, reinforced concrete piles, first layer earth excavation, pile head rupture, first layer anchor cable (rod) construction, crown beam construction, second layer earth excavation, pile body anchor cable (rod) hole drilling, second layer anchor cable (rod) and waist beam construction........., by adopting the method, pile walls are formed due to mutual embedding among engaged piles, inclined holes are required to be drilled on the pile bodies with large diameter after maintenance molding in the later stage, the drilling of the inclined holes is easy to damage the pile bodies, so that a support system is invalid, the construction work efficiency is low, the period is long, foundation pits are easy to be exposed for a long time, and the safety and stability of the foundation pits are influenced; meanwhile, the produced concrete construction waste also causes pollution to the environment, and also causes the waste of concrete materials, thereby increasing the labor and material cost.
Disclosure of Invention
The invention aims to design a large-diameter meat-vegetable occluding pile anchor supporting structure and a construction method thereof, wherein anchor rope (rod) inclined holes are not required to be drilled on an occluding pile wall again, the risk of damage to a pile body is avoided, the integrity of the pile body is ensured, the engineering quality of a pile anchor supporting system is improved, the construction efficiency of a foundation pit can be greatly improved, meanwhile, the cost of man-machine materials is effectively saved, and the environment is protected.
In order to achieve the technical aim, the invention provides a large-diameter meat-vegetable occluding pile anchor supporting structure, which comprises a reinforced concrete pile and a plain concrete pile which are occluded with each other, wherein the pile diameter of the plain concrete pile is 500-1000 mm, the pile diameter of the reinforced concrete pile is more than or equal to 800mm, and the diameter of the plain concrete pile is 200-400 mm smaller than that of the reinforced concrete pile; the plain concrete pile comprises an anchor rope mounting frame pre-buried in a pile hole, pile body concrete poured in the pile hole and a plurality of layers of anchor ropes or anchor rods arranged in the plain concrete pile through the anchor rope mounting frame; the anchor cable installation rack comprises two vertical embedded plates and at least two anchor cable installation pipes fixed between the two vertical embedded plates, wherein the at least two anchor cable installation pipes are distributed at positions of different heights of the vertical embedded plates from bottom to top in a dispersed manner, each anchor cable installation pipe is inclined, and pipe caps are arranged at two ends of each anchor cable installation pipe; the anchor cable installation frame is installed in the pile hole through a horizontal positioning plate fixed at the pile hole opening of the plain concrete pile, a concrete pouring hole is formed in the horizontal positioning plate, the horizontal positioning plate is clamped with two vertical embedded plates, and the plain concrete pile and the anchor cable or the anchor rod are removed after construction is completed; the plain concrete pile body is formed by pouring plain concrete into pile holes through concrete pouring holes on the horizontal positioning plates after the anchor cable mounting frame is pre-buried into the pile holes; and the anchor cable or the anchor rod is installed in the plain concrete pile through the anchor cable installation pipe after the pile body concrete is poured and maintenance is completed.
The invention has the preferable technical scheme that: the reinforced concrete pile and the plain concrete pile are mutually engaged by 100-200 mm, the pile bottom of the plain concrete pile exceeds 2-3 m below the excavation surface of the foundation pit, and the pile length of the reinforced concrete pile is greater than that of the plain concrete pile.
The invention has the preferable technical scheme that: the anchor cable installation pipes are PVC pipes, the anchor cable installation pipes obliquely penetrate through the vertical embedded plates on the other side from the vertical embedded plates on one side, the inclination angle of the anchor cable installation pipes is 15-30 degrees, and the inner diameter of each anchor cable installation pipe is 140-160 mm; the inclination angles of the at least two anchor cable installation pipes are the same, and the arrangement position of each anchor cable installation pipe corresponds to the anchor cable installation position designed by the pile anchor supporting structure; the distance between two adjacent anchor cable installation pipes is equal.
The invention has the preferable technical scheme that: the horizontal positioning plate is made of steel plates, the length of the horizontal positioning plate is larger than the diameter of a pile hole of the plain concrete pile, the width of the horizontal positioning plate is smaller than the diameter of the pile hole of the plain concrete pile, vertical embedded plate mounting grooves matched with the diameter of the pile hole of the plain concrete pile are formed in the length direction of the horizontal positioning plate, the concrete pouring holes are formed in the width direction of the horizontal positioning plate, and the aperture of the concrete pouring holes is 280-320 mm; two sides of the inner wall of the mounting groove are correspondingly provided with embedded plate clamping grooves, and two vertical embedded plates are correspondingly inserted into the mounting groove along the clamping grooves respectively.
The invention has the preferable technical scheme that: the vertical embedded plates are PP plates, and hanging rings are arranged at the top of each vertical embedded plate; the vertical embedded plate close to the foundation pit outside sets up the split type, including two sections plate bodies and the regulating plate of connecting two sections plate bodies, the anchor rope installation tube is located same plate body, has reserved the bolted connection hole respectively at the junction part of two sections plate bodies, correspond on the regulating plate and offer the regulation screw, connect two sections plate bodies through regulating plate and locking bolt to adjust the length of the vertical embedded plate close to the foundation pit outside, thereby adjust the inclination of anchor rope installation tube.
In order to achieve the technical aim, the invention also provides a construction method of the large-diameter meat-vegetable occluding pile anchor supporting structure, which is characterized by comprising the following specific steps:
(1) Manufacturing a guide wall, accurately measuring and positioning the pile center position of each occlusion pile according to the drawing coordinates, wherein the error is not more than 20mm; constructing a reinforced concrete guide wall of the secant pile, wherein the inner width of the guide wall is at least 100mm larger than the two sides of the pile diameter, the thickness is 200-300 mm, and the widths of the two sides are 800-1200 mm respectively;
(2) Forming holes on the plain concrete piles, drilling by adopting a rotary drilling machine or full-rotation full-sleeve equipment, and sequentially drilling holes by adopting a mode of drilling one jump one pile at intervals to finish the plain concrete pile holes, wherein the plane error of the holes is not more than 50mm; the pile hole diameter of the plain concrete pile is 500 mm-1000 mm;
(3) Installing an anchor cable installation rack: after a single plain concrete pile hole is formed, installing an anchor rope installation frame in the plain concrete pile hole, firstly, longitudinally placing a horizontal positioning plate at the opening of the plain concrete pile hole, and adjusting the plane position by the installation groove and the concrete pouring hole on the horizontal positioning plate to be opposite to the plain concrete pile hole, wherein the center line of a vertical embedded plate reserved by the positioning plate and the center line of the plain concrete pile hole are on the same straight line; then vertically inserting the anchor cable installation frame manufactured according to the design drawing into the plain concrete pile hole through the installation groove on the horizontal positioning plate by using the hoisting equipment;
(4) Pouring plain concrete piles: after the installation of the anchor cable installation frame is completed, hoisting concrete pouring guide pipes from the concrete pouring holes on the horizontal positioning plates to positions 300-500 mm away from the bottoms of the pile holes one by one, and after the installation of the guide pipes is completed, pouring concrete of the plain concrete pile underwater;
(5) Dismantling the positioning plate: after the concrete pouring of the plain concrete piles is finished, dismantling the locating plates to finish the construction of the first plain concrete pile, and then repeating the steps (2) to (4) to construct the next plain concrete pile;
(6) Construction of reinforced concrete piles: after 2-3 plain concrete piles are constructed, constructing reinforced concrete piles with the pile diameter of 1600mm between two plain concrete piles, wherein the construction of the reinforced concrete piles sequentially comprises pore forming, steel reinforcement cage descending and concrete pouring, the depth of the reinforced concrete piles is greater than that of the plain concrete piles, and the reinforced concrete piles and the two adjacent plain concrete piles are respectively engaged with each other by 200mm;
(7) Repeating the steps (5) and (6) to finish the construction of the meat-vegetable occlusion pile wall, then excavating a first layer of earthwork, and constructing a first layer of anchor cables or anchor rods and crown beams at the positions of the first layer of anchor cable mounting holes;
(8) Then, continuously excavating a second layer of earthwork, excavating the second layer of earthwork to a position 300-500 mm below the design elevation of the second layer of anchor cable or anchor rod, directly constructing a second layer of construction anchor cable or anchor rod at the reserved second layer of anchor cable installation hole position, and then completing the construction of the waist beam to form a supporting system;
(9) And (3) repeating the step (8) after the maintenance of the second layer of anchor cables or anchor rods and the waist beam is completed, continuing earth excavation, gradually constructing according to the design drawing or the construction of the lower layer of anchor cables or anchor rods and the waist beam or reaching the bottom elevation of the designed foundation pit, and finally completing the foundation pit construction and entering the foundation construction stage.
The invention has the preferable technical scheme that: the anchor cable installation frame manufacturing process according to the design drawing in the step (3) is to determine the length of a vertical embedded plate and the elevations of the holes of the anchor cable or the anchor rod in the pit and the outer elevations of the pit according to the elevation of the holes of the anchor cable or the anchor rod on the design drawing, wherein the upper end of the vertical embedded plate is 300-500 mm higher than the horizontal positioning plate, the lower end of the vertical embedded plate is 300-500 mm longer than the central elevation of the anchor hole at the bottommost layer, the middle length and the position of the anchor cable installation pipe are determined according to the design drawing, then installing holes matched with the anchor cable installation pipe are formed in the corresponding positions on the vertical embedded plate, and the anchor cable installation pipe is fixedly embedded in the installing holes on the vertical embedded plate; after the installation holes are designed, the inclination angle of the anchor holes can be adjusted and regulated by adjusting the length of the vertical embedded plates adjacent to the outer side of the foundation pit, and the inclination angle is ensured to be 15-30 degrees.
The invention has the preferable technical scheme that: and (3) hoisting the anchor cable installation frame by adopting a 25T crane, vertically placing the assembled vertical embedded plate and the anchor cable installation pipe into a pile hole preset position integrally, measuring and controlling the direction and elevation of the device, wherein the error is not more than 20mm.
The invention has the preferable technical scheme that: the diameter of the catheter in the step (4) is 180-220 mm.
The invention has the preferable technical scheme that: and (3) during the construction of the anchor cable or the anchor rod in the step (6) and the step (7), directly removing the pipe cap of the anchor cable installation pipe close to the inner side end part of the foundation pit, rechecking the position of the reserved anchor hole, positioning the drilling machine, adjusting the angle of the drill rod, directly drilling the anchor cable drilling machine towards the outer side of the foundation pit through the anchor cable installation hole to construct the anchor rod or the anchor cable hole, and after the hole forming reaches the designed depth, sequentially carrying out the installation and grouting construction of the anchor cable or the anchor rod.
The invention has the beneficial effects that:
(1) According to the invention, the step of drilling the inclined hole on the large-diameter pile body after the later earth excavation of the foundation pit and the anchor cable construction are required, so that the risk of damage to the pile body is avoided, the integrity of the pile body is ensured, the engineering quality of a pile anchor supporting system is improved, and the construction efficiency of the foundation pit can be greatly improved.
(2) According to the invention, the anchor cable installation pipe frame is pre-buried in the pile hole, and then concrete pouring is carried out, so that the waste of concrete materials caused by pouring concrete and then drilling is avoided, and the anchor cable installation pipe frame is buried in the pile hole to play a certain supporting role, so that the waste of concrete materials is further reduced, and the construction cost is reduced.
(3) The invention reduces the investment of later-stage perforating equipment and saves the labor; the whole construction process does not generate redundant construction waste and does not cause environmental pollution.
(4) The anchor cable installation frame designed in the invention comprises the support frame and the anchor cable installation reserved pipe, the device can be manufactured in advance and integrally installed in the pile hole in the construction process, multiple rows of embedded pipes with different heights can be installed at one time, and the installation process of the embedded pipes is saved.
(5) According to the invention, the inclination angles of the multiple rows of embedded pipes of the anchor rope mounting frame can be adjusted, and the inclination angles of the anchor rope embedded pipes can be adjusted according to construction design, so that different construction requirements can be met.
(6) The anchor cable mounting frame is provided with the locating plate and the grouting holes, so that locating and mounting of the anchor cable mounting frame can be guaranteed, and after the anchor cable mounting frame is mounted, concrete pouring is carried out on the whole pile hole through the grouting holes, and construction is simple and convenient.
Drawings
FIG. 1 is a schematic plan view of a meat-vegetable bite pile according to the present invention;
FIG. 2 is a schematic elevational view of a pile anchor support structure according to the present invention;
FIG. 3 is a plan view of a horizontal positioning plate of the present invention;
figure 4 is a perspective view of the present invention in a fixed anchor cable mount;
fig. 5 is a schematic view of the structure of the adjustable anchor cable mount of the present invention;
FIG. 6 is a schematic view of the anchor line mount of FIG. 5 in an adjusted position;
FIG. 7 is an elevation of the vertical embedment plate of the present invention away from the outside of the foundation pit;
fig. 8 is an elevation view of the vertical embedment plate adjacent the outside of the foundation pit of the present invention.
In the figure: 1-reinforced concrete pile, 2-plain concrete pile, 3-anchor cable installation frame, 300-vertical pre-buried plate, 301-horizontal positioning plate, 302-anchor cable installation pipe, 303-concrete pouring hole, 304-pipe cap, 305-installation groove, 306-pre-buried plate clamping groove, 307-hanging ring, 308-bolt connection hole, 309-adjusting plate, 310-adjusting screw hole, 311-locking bolt, 4-pile body concrete, 5-anchor cable or anchor rod.
Detailed Description
The invention is further described below with reference to the accompanying drawings. Fig. 1 to 5 are drawings of embodiments, which are drawn in a simplified manner, for the purpose of clearly and concisely illustrating embodiments of the present invention. The following technical solutions presented in the drawings are specific to embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, or the directions or positional relationships conventionally put in place when the inventive product is used, or the directions or positional relationships conventionally understood by those skilled in the art are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific direction, be configured and operated in a specific direction, and therefore should not be construed as limiting the present invention.
The embodiment provides a large-diameter meat-vegetable secant pile anchor supporting structure, which is shown in fig. 1 and 2, and comprises a reinforced concrete pile 1 and a plain concrete pile 2 which are mutually occluded, wherein the pile diameter of the plain concrete pile 2 is 500-1000 mm, the pile diameter of the reinforced concrete pile 1 is more than or equal to 800mm, and the diameter of the plain concrete pile 2 is 200-400 mm smaller than the diameter of the reinforced concrete pile 1; the reinforced concrete pile 1 and the plain concrete pile 2 are mutually meshed for 100-200 mm, the pile bottom of the plain concrete pile 2 exceeds the position below the excavation surface of the foundation pit by 2-3 m, and the pile length of the reinforced concrete pile 1 is greater than that of the plain concrete pile 2. The plain concrete pile 2 comprises an anchor cable installation frame 3 pre-buried in a pile hole, pile body concrete 4 poured in the pile hole and a plurality of layers of anchor cables or anchor rods 5 distributed in the plain concrete pile 2 through the anchor cable installation frame 3. The anchor cable mounting frame 3 is arranged in a pile hole through a horizontal positioning plate 301 fixed at the pile hole opening of the plain concrete pile, and is removed after the construction of the plain concrete pile 2 and the anchor cable or anchor rod 5 is completed; the plain concrete pile body 4 is formed by pouring plain concrete into pile holes through concrete pouring holes 303 on a horizontal positioning plate 301 after the anchor cable mounting frame 3 is pre-buried into the pile holes; the anchor cable or the anchor rod 5 is installed in the plain concrete pile 2 through the anchor cable installation pipe 302 after the pile body concrete is poured and the maintenance is completed.
As shown in fig. 4 to 6, the anchor cable installation rack 3 includes two vertical pre-buried plates 300 and two anchor cable installation pipes 302 fixed between the two vertical pre-buried plates 300, the two anchor cable installation pipes 302 are distributed at different height positions of the vertical pre-buried plates 300 from bottom to top, each anchor cable installation pipe 302 is inclined, and pipe caps 304 are arranged at two ends; the vertical embedded plates 300 are PP plates, and hanging rings 307 are arranged at the top of each vertical embedded plate 300; the cable bolt installation tube 302 is a PVC tube. Through holes are correspondingly formed in the vertical embedded plates 300, the anchor cable mounting pipes 302 obliquely penetrate through the vertical embedded plates on the other side from the vertical embedded plates on one side, the inclination angle of the anchor cable mounting pipes is 15-30 degrees, and the inner diameter of each anchor cable mounting pipe 302 is 140-160 mm. The inclination angles of the at least two anchor cable installation pipes 302 are the same, and the arrangement position of each anchor cable installation pipe 302 corresponds to the anchor cable installation position of the pile anchor supporting structure design; the spacing between adjacent anchor line installation tubes 302 is equal.
In the drawings, two anchor cable installation frames are shown, wherein the anchor cable installation frame 3 in fig. 4 is fixed, the lengths of the vertical embedded plates 300 on two sides are not adjustable, and the anchor cable installation frame 3 determines the position of an anchor cable installation tube 302 according to the design position of an anchor cable or an anchor rod, and is fixedly connected. The anchor cable installation frame 3 shown in fig. 5 and 6 is adjustable, the vertical embedded plate 300 adjacent to the outer side of the foundation pit is arranged to be split, the anchor cable installation frame comprises two sections of plate bodies and an adjusting plate 309 for connecting the two sections of plate bodies, the anchor cable installation pipes 302 are all positioned on the plate bodies at the lower side, bolt connecting holes 308 are reserved at the connecting positions of the two sections of plate bodies respectively, adjusting screw holes 310 are correspondingly formed in the adjusting plate 309, the two sections of plate bodies are connected through the adjusting plate 309 and the locking bolt 311, when the adjustment is needed, the position of the upper plate body is not moved, the two locking bolts 311 are loosened, the position of the lower plate body is adjusted, the adjusting screw holes 310 on the adjusting plate 310 are corresponding to the bolt connecting holes 308 of the two sections of plate body trusses, and then the length of the vertical embedded plate adjacent to the outer side of the foundation pit can be adjusted by locking, so that the inclination angle of the anchor cable installation pipes 302 is adjusted.
As shown in fig. 3, the horizontal positioning plate 301 is made of steel plates, the length of the horizontal positioning plate is greater than the diameter of the pile hole of the plain concrete pile 2, the width of the horizontal positioning plate is smaller than the diameter of the pile hole of the plain concrete pile 2, vertical embedded plate mounting grooves 305 matched with the diameter of the pile hole of the plain concrete pile 2 are formed in the length direction of the horizontal positioning plate 301, concrete pouring holes 303 are formed in the horizontal positioning plate 301, and the apertures of the concrete pouring holes 303 are 280-320 mm in the width direction of the horizontal positioning plate 301; two sides of the inner wall of the mounting groove 305 are correspondingly provided with embedded board clamping grooves 306, and two vertical embedded boards 300 are correspondingly inserted into the mounting groove 305 along the clamping grooves 306 respectively. As shown in fig. 4, the horizontal positioning plate 301 is clamped with two vertical pre-buried plates 300,
the invention is further described below by referring to the examples, the method of the invention is used for a foundation pit project, the foundation pit project is positioned in coastal beach areas, the excavation depth is about 10m, a meat-vegetable occlusion pile anchor supporting system is adopted on one side of the foundation pit, and the pile spacing is 1600mm; the pile diameter of the plain reinforced concrete pile is 1000mm, the pile length is 13.4m, the concrete strength grade is C20, the pile diameter of the reinforced concrete pile is 1200mm, the pile length is 27.4m, and the concrete strength grade is C35; 3 layers of prestressed anchor cables are arranged, the aperture of each anchor cable is 150mm, one anchor is arranged on one pile, and the row distance of each anchor cable is 2.2m. The construction method of the large-diameter meat-vegetable occluding pile anchor supporting system comprises the following steps:
(1) Manufacturing a guide wall, accurately measuring and positioning the pile center position of each occlusion pile according to the drawing coordinates, wherein the error is not more than 20mm; and constructing the reinforced concrete guide wall of the occluding pile, wherein the inner width of the guide wall is 100mm larger than that of each of two sides of the pile diameter, the thickness is 300mm, and the width of each of two sides is 1200mm.
(2) Forming holes on the plain concrete piles, wherein the holes can be formed by adopting a 360-bit rotary drilling machine, the drilling sequence adopts a drilling one-jump-one mode, and the holes are formed at intervals by one pile, so that plain concrete pile holes are formed, and the plane error of the holes is not more than 50mm; the pile hole diameter of the plain concrete pile is 1000mm.
(3) Installing an anchor cable installation rack: after the single plain concrete pile hole is formed, installing an anchor cable installation frame in the plain concrete pile hole: a. firstly, longitudinally placing a horizontal positioning plate in a plain concrete pile hole opening, wherein a mounting groove and a concrete pouring hole on the horizontal positioning plate are opposite to the plain concrete pile hole, and the plane position is adjusted, and the center line of a vertical embedded plate reserved by the positioning plate and the center line of the plain concrete pile hole are on the same straight line; the positioning plate 301 is made of a steel plate with the thickness of 3mm, the length of 1400mm and the width of 900mm, a plain concrete pile body concrete pouring hole is formed in the positioning plate 301, and the diameter of the hole is 300mm;
b. manufacturing an anchor cable installation frame according to a design drawing, specifically determining the length of a vertical embedded plate and the elevations of the inside and outside of a pit of an anchor cable installation pipe according to the elevations of an orifice of the anchor cable or an anchor rod on the design drawing, wherein the vertical embedded plate 300 is a PP plate with the thickness of 2mm, the length of the vertical embedded plate is 7m, an installation hole of the anchor cable installation pipe is formed in the position of the elevation of the anchor cable (rod) according to the inclination angle of the anchor cable by 15 degrees, the diameter of the hole is 165mm, the center of a first hole of the vertical embedded plate in the pit is 4m to the end of the plate, and the center of a second hole of the vertical embedded plate in the pit is 6.2m to the end of the plate; the center of a first hole of the out-pit vertical embedded plate is 4.25m to the plate end, and the center of a second hole of the out-pit vertical embedded plate 2 is 6.45m to the plate end; the width of the vertical embedded plate is 400mm above the horizontal positioning plate by 300mm, and the width of the vertical embedded plate at the lower part is 300mm; the anchor cable installation tube adopts a PVC tube, the inner diameter of the tube is 150mm, the length is 1200mm, and both ends of the tube are plugged by tube caps;
c. and vertically placing the assembled embedded plate and embedded pipe integrated device into a pile hole preset position by adopting a 25T crane, measuring and controlling the direction and elevation of the device, wherein the error is not more than 20mm.
(4) Pouring plain concrete piles: after the installation of the anchor cable installation frame is completed, hoisting concrete pouring guide pipes from the concrete pouring holes on the horizontal positioning plates to positions 300-500 mm away from the bottoms of the pile holes one by one, and after the installation of the guide pipes is completed, pouring concrete of the plain concrete pile underwater, wherein the diameter of each concrete pouring guide pipe is 200mm.
(5) Dismantling the positioning plate: after the concrete pouring of the plain concrete piles is finished, dismantling the locating plates to finish the construction of the first plain concrete pile, and then repeating the steps (2) to (4) to construct the next plain concrete pile;
(6) Construction of reinforced concrete piles: after 2-3 plain concrete piles are constructed, constructing reinforced concrete piles with the pile diameter being more than or equal to 800mm between the two plain concrete piles, wherein the diameter of each plain concrete pile is 200-400 mm smaller than that of each reinforced concrete pile; the construction of the reinforced concrete pile sequentially comprises pore-forming, steel bar cage descending and concrete pouring, wherein the depth of the reinforced concrete pile is greater than that of the plain concrete pile, and the reinforced concrete pile and two adjacent plain concrete piles are respectively meshed with each other by 100-200 mm;
(7) Repeating the steps (5) and (6) to finish the construction of the meat-vegetable occlusion pile wall, then excavating a first layer of earthwork, and constructing a first layer of anchor cables or anchor rods and crown beams at the positions of the first layer of anchor cable mounting holes; and (3) during the construction of the anchor cable or the anchor rod in the step (6) and the step (7), directly removing the pipe cap of the anchor cable installation pipe close to the inner side end part of the foundation pit, rechecking the position of the reserved anchor hole, positioning the drilling machine, adjusting the angle of the drill rod, directly drilling the anchor cable drilling machine towards the outer side of the foundation pit through the anchor cable installation hole to construct the anchor rod or the anchor cable hole, and after the hole forming reaches the designed depth, sequentially carrying out the installation and grouting construction of the anchor cable or the anchor rod.
(8) Then, continuously excavating a second layer of earthwork, excavating the second layer of earthwork to a position 300-500 mm below the design elevation of the second layer of anchor cable or anchor rod, directly constructing a second layer of construction anchor cable or anchor rod at the reserved second layer of anchor cable installation hole position, and then completing the construction of the waist beam to form a supporting system;
(9) And (3) repeating the step (8) after the maintenance of the second layer of anchor cables or anchor rods and the waist beam is completed, continuing earth excavation, gradually constructing according to the design drawing or the construction of the lower layer of anchor cables or anchor rods and the waist beam or reaching the bottom elevation of the designed foundation pit, and finally completing the foundation pit construction and entering the foundation construction stage.
The foregoing description is of one embodiment of the invention and is thus not to be taken as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of the invention should be assessed as that of the appended claims.