Fabricated precast pile foundation retaining wall structure and construction method

Abstract

The invention discloses an assembly type precast pile foundation retaining wall structure and a construction method, and the method comprises the following steps: S100, carrying out site cleaning and leveling work before construction, and arranging temporary facilities including a construction fence and a temporary road; s200, according to a design drawing and specifications, the distance between the hollow square piles is controlled according to the width of the retaining wall plate, and the hollow square piles are constructed; s300, earth excavation is conducted after the installation area of the retaining wall plate is determined, the retaining wall plate is installed in the installation area, and the joint of the retaining wall plate and the installation area is connected with the prestressed concrete hollow square pile through connecting mortar; s400, a circular cavity of the hollow square pile is filled with core filling materials so as to block the hollow square pile, holes of the retaining wall plate are filled with extruded sheet fragments for blocking, and the retaining wall plate and the top beam are connected through anchoring steel bars; s500, after construction of the main body structure is completed, functional tests including a hydraulic test are carried out to determine that the stability and the safety of the structure meet the requirements; and S600, backfilling operation is conducted according to the design scheme.

Description

Technical Field

[0001] The present invention belongs to the technical field of building construction, and more specifically, relates to an assembled prefabricated pile foundation retaining wall structure and a construction method. Background Art

[0002] In recent years, due to the advantages of prefabricated construction technology such as high mechanized construction efficiency, good construction quality, safety and environmental protection, with the strong support and promotion of our country, prefabricated construction technology has developed rapidly in the construction industry. In terms of retaining walls, the traditional cantilever reinforced concrete retaining wall construction method is on-site casting, and the main construction process is mainly completed by manual labor. Mechanized means cannot be applied, and the construction quality and production efficiency are low. In addition, the retaining wall is an open-air on-site operation and is greatly affected by natural conditions. At present, attempts to assemble retaining walls are mainly based on the structure of traditional gravity, counterweight or cantilever retaining walls.

[0003] The Chinese patent with publication number CN111364504A discloses an assembled prefabricated pile foundation retaining wall structure and construction method, specifically: the retaining wall body and the bottom plate are prefabricated components respectively, a row of holes are opened on the bottom plate, the retaining wall body is set on the holes, the two sides of the holes are expanded to the two sides of the thickness of the retaining wall body, the vertical main reinforcement of the retaining wall body corresponding to the holes is inserted into the holes, and fine stone concrete is poured on site in the holes to connect and fix the root of the retaining wall body and the bottom plate. This assembled prefabricated concrete retaining wall explores new ideas for the design and construction of prefabricated and assembled retaining walls. By prefabricating the retaining wall body and the bottom plate separately and assembling them on site, the maximum retaining height of the retaining wall can be increased to about 5m, which increases the scope of application of the assembled retaining wall. At the same time, multiple rows of cavities are set in the retaining wall body and the bottom plate respectively, saving the amount of concrete.

[0004] However, the Chinese patent with publication number CN111364504A mainly connects by insertion, which has weaknesses. In addition, the scope of application is limited by the transportation and hoisting conditions of prefabricated components. Therefore, a prefabricated pile foundation retaining wall structure and construction method are needed to simplify the component structure under the premise of reasonable structural force and convenient construction, so as to achieve the purpose of high mechanization, simple process and wide application range. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides an assembled prefabricated pile foundation retaining wall structure and a construction method. A simply supported structure is formed by arranging prefabricated piles and prefabricated panels to resist lateral earth pressure. Hollow square piles serve as the main supporting members of the structure, and retaining wall panels serve as members that directly bear and transmit the lateral earth pressure. They are connected and reinforced by pressing the top, anchoring steel bars, mortar, etc.

[0006] To achieve the above objectives, according to a first aspect of an embodiment of the present invention, a construction method of an assembled prefabricated pile foundation retaining wall structure is provided, comprising:

[0007] S100. Carry out site cleaning and leveling work before construction, and set up temporary facilities including construction fences and temporary roads;

[0008] S200, determining the specifications of the hollow square piles and the retaining wall panels according to the design drawings and specifications, controlling the distance between the hollow square piles according to the width of the retaining wall panels, and constructing the hollow square piles;

[0009] S300, according to the position of the hollow square pile after the construction is completed, determine the installation area of ​​the retaining wall plate, and then perform earth excavation, install the retaining wall plate in the installation area, and connect the two to the prestressed concrete hollow square pile through a connecting mortar, and the mortar thickness is controlled between 10 and 20 mm;

[0010] S400, filling the circular cavity of the hollow square pile with a core filling material to seal it, filling the hole of the retaining wall plate with extruded board fragments to seal it, and connecting the retaining wall plate and the crown beam with anchor steel bars;

[0011] S500. After the main structure is completed, a comprehensive quality inspection is carried out to confirm that all joints are firm, the crown beams are installed in place, and the mortar connections are dense. Functional tests including water pressure tests are carried out to ensure that the stability and safety of the structure meet the requirements;

[0012] S600. Perform backfilling operation according to the design plan.

[0013] Furthermore, step S200 specifically includes:

[0014] S201. Select appropriate specifications of prestressed concrete hollow square piles according to the design drawings, ensure that they meet the design requirements including technical indicators such as bearing capacity, prepare mechanical equipment required for construction, inspect the construction site, remove obstacles, and ensure that the construction site is flat for mechanical operation;

[0015] S202. According to the instructions of the design drawings, accurately measure and mark the positions of the prestressed concrete hollow square piles, and use a pile driver to drive the prestressed concrete hollow square piles into the soil until the depth required by the design is reached;

[0016] S203, controlling the distance between the square piles to ensure that the distance between the square piles matches the width of the precast slab, and the distance between the square piles is determined according to the width of the precast slab;

[0017] S204. After the piling is completed, the piles are visually inspected to ensure that there are no cracks or damage. After the piling is completed, necessary static load tests are carried out to verify whether the bearing capacity of the pile foundation meets the design requirements.

[0018] Further, in step S203, two prestressed concrete hollow square piles and a prefabricated slab form a simply supported structure, and the spacing of the square piles needs to be adjusted according to specific design requirements and site conditions to avoid affecting the overall bearing performance of the retaining wall;

[0019] The square pile spacing d p for:

[0020]

[0021] Among them, w b is the width of the baffle,

[0022] k s is the safety factor, take 0.9-1.05,

[0023] c l is the earth pressure distribution coefficient, which indicates the distribution of earth pressure at different depths.

[0024] Furthermore, in step S204, the static load test is specifically to test the single pile ultimate bearing capacity Q of the hollow square pile. u , the ultimate bearing capacity of the single pile is Q u :

[0025]

[0026] Among them, F max is the maximum loading load of hollow square piles,

[0027] F c is the initial load of the hollow square pile,

[0028] K is the safety factor, which is 1.05.

[0029] η f is the bearing capacity correction factor, which is determined by the soil conditions and the situation of the pile end entering the bearing layer.

[0030] η d It is the depth correction coefficient, which indicates the influence of burial depth on bearing capacity.

[0031] Furthermore, step S300 specifically includes:

[0032] S301. Determine the installation location of the prefabricated panels according to the design drawings, mark the boundary line of the excavation area on the ground, prepare the required construction equipment, clean the construction area, and ensure that there are no obstacles that hinder the construction;

[0033] S302. Use excavators and other mechanical equipment to excavate according to the design requirements. The excavation depth should ensure that the prefabricated panels can reach the design elevation after installation. During the excavation process, pay attention to monitoring the stability of the slope and take reinforcement measures to prevent landslides. After the excavation is completed, use measuring tools to check whether the plane size and depth of the excavation area meet the design requirements;

[0034] S303. Use a crane or other lifting equipment to stably hoist the retaining wall panel to the designated location. The side of the retaining wall panel is connected to the hollow square pile through mortar. The thickness of the mortar should be controlled between 10 and 20 mm.

[0035] S304. During the installation process, check the verticality and flatness of the prefabricated panels at any time to ensure that the joints with adjacent panels are tight. The gaps in the middle need to be filled with fine stone concrete to enhance the rigidity of the overall structure.

[0036] Furthermore, in step S302, the stability of the slope is monitored by determining the safety factor F of the slope. s , specifically:

[0037]

[0038] Where R is the anti-sliding force of the slope,

[0039] T is the sliding force of the slope.

[0040] Furthermore, the anti-sliding force R of the slope is specifically:

[0041] R=∑(γ i ·A i ·sin(α i )+c i ·L i +tan(φ i )·N i );

[0042] Among them, γ i is the dry density of the i-th soil layer,

[0043] A i is the area of ​​the i-th soil layer,

[0044] α i is the inclination angle of the i-th soil layer,

[0045] c i is the cohesion of the i-th soil layer,

[0046] L i is the length of the i-th soil layer along the sliding surface,

[0047] φ i is the internal friction angle of the i-th soil layer,

[0048] N i is the normal force of the i-th soil layer;

[0049] The sliding force T of the slope is:

[0050] T=∑(γ i ·V i )·sin(β);

[0051] Among them, V i is the volume of the i-th soil layer,

[0052] β is the average inclination of the slope.

[0053] Furthermore, step S400 specifically includes:

[0054] S401, filling the circular cavity of the hollow square pile with a core filling material to seal it, and filling the holes of the retaining wall panels with extruded board fragments to seal them, and the extruded board fragments in the holes at both ends of each retaining wall panel are located 500 mm below the hole;

[0055] S402. Accurately place the crown beam on the top of the prefabricated component according to the design drawings and mark it with ink lines. Tie the steel bar skeleton of the crown beam according to the design requirements to ensure that the number, diameter and spacing of the steel bars meet the design specifications;

[0056] S403. Install the formwork to form the shape of the crown beam. The formwork should be stable to prevent deformation when pouring concrete. Pour the concrete evenly into the formwork and vibrate it to make it dense and free of voids.

[0057] Furthermore, in step S400, the gap of the retaining wall plate needs to be monitored, specifically: a certain water pressure or air pressure is applied inside the template, and the test is started after the pressure is stable, and a flow meter is used to record the volume V of liquid or gas leaking through the joint per unit time. leak , record the test time t, and calculate the leakage pressure P at the joint leak , the leakage pressure P at the calculated joint leak for:

[0058]

[0059] Among them, P leak is the leakage pressure at the joint,

[0060] V leak is the volume of liquid or gas leaking through the joint per unit time,

[0061] A seam is the total area of ​​the joint,

[0062] t is the test time, s.

[0063] According to a second aspect of an embodiment of the present invention, there is provided an assembled prefabricated pile foundation retaining wall structure, comprising a hollow square pile and a retaining wall plate arranged on one side of the hollow square pile;

[0064] There are multiple retaining wall panels, which are arranged in a row to form a retaining wall surface. The gap between two adjacent retaining wall panels is filled with fine stone concrete to achieve connection. The fine stone concrete is poured after the retaining wall panels are spliced ​​on site;

[0065] The hollow square piles are arranged at equal distances on the rear side of the retaining wall surface and at the connection between two adjacent hollow square piles, and the two are connected by setting connecting mortar, wherein the connecting mortar;

[0066] Anchor steel bars are arranged in the middle of the retaining wall plate, and the anchor steel bars leak out from the top of the retaining wall plate;

[0067] The retaining wall plate is a porous hollow structure, and the holes on the top thereof are provided with extruded board fragments, which are used to block the holes, and the holes at both ends of each retaining wall plate are provided with anchoring steel bars, which extend upward, and the extended part is bent toward the side close to the hollow square pile;

[0068] The hollow square pile is flush with the top of the retaining wall plate, and a crown beam is provided on the top of both. The bent portion of the anchor steel bar extending out of the retaining wall plate is anchored in the crown beam, so that it is fixedly connected with the hollow square pile and the retaining wall plate;

[0069] The hollow square pile is a columnar structure with a square cross-section as a whole, with a circular cavity in the middle and a core filling material arranged in the cavity.

[0070] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0071] 1. An assembled prefabricated pile foundation retaining wall structure and construction method of the present invention, a simply supported structure formed by arranging prefabricated piles and prefabricated panels to resist lateral soil pressure, hollow square piles as the main supporting members of the structure, retaining wall panels as components that directly bear and transmit lateral soil pressure, connected and reinforced by pressing tops, anchoring steel bars, mortar, etc.

[0072] 2. The assembled prefabricated pile foundation retaining wall structure and construction method of the present invention break through the reliance of the prior art on the structural frame of the cast-in-place concrete retaining wall, give full play to the advantages of the strong plasticity of the prefabricated components from the perspective of the simple force form, and expand the scope of use of the prefabricated retaining wall under the condition of a reasonable force structure.

[0073] 3. The assembled prefabricated pile foundation retaining wall structure and construction method of the present invention simplifies the process, improves the degree of mechanization in the construction process, saves the construction time of the load-bearing structure, greatly improves the construction efficiency, and saves construction period by adopting prefabricated hollow square piles as supporting structures and prefabricated panels as components that directly bear and transmit lateral earth pressure.

[0074] 4. The present invention provides an assembled prefabricated pile foundation retaining wall structure and construction method. By selecting common prefabricated components and materials as the structural materials of the retaining wall, on the one hand, the cost of obtaining materials is reduced, and on the other hand, relevant specifications can be used as a basis during the acceptance and construction of prefabricated components, thereby improving the construction quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 A schematic diagram of a method for using an assembled prefabricated pile foundation retaining wall structure according to an embodiment of the present invention;

[0076] Figure 2 This is a flow chart of step S200 of a method for using an assembled prefabricated pile foundation retaining wall structure according to an embodiment of the present invention;

[0077] Figure 3 This is a flow chart of step S300 of a method for using an assembled prefabricated pile foundation retaining wall structure according to an embodiment of the present invention;

[0078] Figure 4 This is a flow chart of step S400 of a method for using an assembled prefabricated pile foundation retaining wall structure according to an embodiment of the present invention;

[0079] Figure 5 A top view of a prefabricated pile foundation retaining wall structure according to an embodiment of the present invention;

[0080] Figure 6 The present invention is a structural side view of an assembled prefabricated pile foundation retaining wall structure according to an embodiment of the present invention.

[0081] In all the drawings, the same reference numerals represent the same technical features, specifically: 1-hollow square piles, 2-retaining wall panels, 3-anchor steel bars, 4-connecting mortar, 5-fine stone concrete, 6-extruded board fragments, 7-crown beams, and 8-core fillings. DETAILED DESCRIPTION

[0082] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0083] Example 1

[0084] like Figure 5 , 6 As shown, an embodiment of the present invention provides an assembled prefabricated pile foundation retaining wall structure, including a hollow square pile 1 and a retaining wall plate 2 arranged on one side of the hollow square pile 1. There are multiple retaining wall plates 2, which are arranged in a row to form a retaining wall surface. The gap between two adjacent retaining wall plates 2 is filled with fine stone concrete 5 to achieve connection. The fine stone concrete 5 is cast after the retaining wall plates 2 are spliced ​​on site. The hollow square piles 1 are equidistantly arranged on the rear side of the retaining wall surface, and are arranged at the connection between two adjacent hollow square piles 1. The two are connected by setting a connecting mortar 4. Anchor steel bars 3 are provided in the middle of the retaining wall plate 2, and the anchor steel bars 3 leak out from the top of the retaining wall plate 2. The retaining wall plate 2 is a porous hollow structure, and the holes at the top thereof are provided with extruded board fragments 6, which are sealed by the extruded board fragments 6, and the holes at both ends of each retaining wall plate 2 are provided with anchoring steel bars 3, which extend upward, and the extended part is bent toward the side close to the hollow square pile 1. The extruded board fragments 6 in the holes at both ends of the retaining wall plate 2 are not filled, and the distance between the top surface and the hole is greater than 500mm. The hollow square pile 1 is flush with the top of the retaining wall plate 2, and a crown beam 7 is also provided on the top of both. The bent part of the anchoring steel bar 3 extending out of the retaining wall plate 2 is anchored in the crown beam 7, so that it is fixedly connected to the hollow square pile 1 and the retaining wall plate 2. The hollow square pile 1 is a columnar structure with a square cross-section as a whole, with a circular cavity in the middle, and a core filling material 8 is provided in the cavity.

[0085] Preferably, the hollow square piles 1 serve as the main supporting members of the retaining wall structure, and the retaining wall panels 2 serve as the members that directly bear and transmit the lateral earth pressure, and are connected and reinforced by anchoring steel bars 3, connecting mortar 4 and fine stone concrete 5 to resist the lateral earth pressure.

[0086] Example 2

[0087] like Figure 1 As shown, an embodiment of the present invention provides a construction method for an assembled prefabricated pile foundation retaining wall structure, which specifically includes the following steps:

[0088] S100. Carry out site cleaning and leveling work before construction, and set up temporary facilities including construction fences and temporary roads;

[0089] S200, determining the specifications of the hollow square piles 1 and the retaining wall 2 according to the design drawings and specifications, controlling the distance between the hollow square piles 1 according to the width of the retaining wall 2, and constructing the hollow square piles 1;

[0090] S300, according to the position of the hollow square pile 1 after the construction is completed, determine the installation area of ​​the retaining wall 2 and then perform earth excavation, install the retaining wall 2 in the installation area, and connect the two to the prestressed concrete hollow square pile through a connecting mortar 4, and the mortar thickness is controlled between 10 and 20 mm;

[0091] S400, filling the circular cavity of the hollow square pile 1 with a core filler 8 to seal it, filling the hole of the retaining wall plate 2 with extruded board fragments 6 to seal it, and connecting the retaining wall plate 2 and the crown beam 7 with the anchor steel bar 3;

[0092] S500. After the main structure is constructed, a comprehensive quality inspection is conducted to confirm that all joints are firm, the crown beam 7 is installed in place, and the mortar connection is dense. Functional tests including water pressure tests are conducted to ensure that the stability and safety of the structure meet the requirements;

[0093] S600. Perform backfilling operation according to the design plan.

[0094] like Figure 2 As shown, step S200 specifically includes:

[0095] S201. Select appropriate specifications of prestressed concrete hollow square piles according to the design drawings, ensure that they meet the design requirements including technical indicators such as bearing capacity, prepare mechanical equipment required for construction, inspect the construction site, remove obstacles, and ensure that the construction site is flat for mechanical operation;

[0096] S202. According to the instructions of the design drawings, accurately measure and mark the positions of the prestressed concrete hollow square piles, and use a pile driver to drive the prestressed concrete hollow square piles into the soil until the depth required by the design is reached;

[0097] S203, controlling the distance between the square piles to ensure that the distance between the square piles matches the width of the precast slab, and the distance between the square piles is determined according to the width of the precast slab;

[0098] S204. After the piling is completed, the piles are visually inspected to ensure that there are no cracks or damage. After the piling is completed, necessary static load tests are carried out to verify whether the bearing capacity of the pile foundation meets the design requirements.

[0099] In step S201, the mechanical equipment shown includes a pile driver and a measuring instrument.

[0100] In step S202, during the piling process, the verticality of the hollow square pile 1 is continuously monitored to ensure that its vertical error does not exceed a specified value. After the piling is completed, the pile head is immediately processed, including cleaning the surface of the pile head to prepare for subsequent construction.

[0101] The verticality of the hollow square pile 1 is:

[0102]

[0103] D v is the verticality deviation percentage of the hollow square pile,

[0104] H h is the design height of the hollow square pile,

[0105] H t is the actual measured height,

[0106] E r is the measurement error correction factor.

[0107] In step S203, two prestressed concrete hollow square piles and a prefabricated board form a simply supported structure. The spacing of the square piles needs to be adjusted according to the specific design requirements and site conditions to avoid affecting the overall stress performance of the retaining wall. During the piling process, attention should be paid to monitoring the sinking speed of the hollow square pile 1 to prevent damage to the pile body due to excessive speed or slowness. During the construction process, the construction data of each hollow square pile 1, including the number, driving depth, and verticality, should be recorded.

[0108] In step S203, the square pile spacing d p for:

[0109]

[0110] Among them, w b is the width of the baffle,

[0111] k s is the safety factor, take 0.9-1.05,

[0112] c l is the earth pressure distribution coefficient, which indicates the distribution of earth pressure at different depths.

[0113] In step 204, the static load test is specifically to test the single pile ultimate bearing capacity Q of the hollow square pile 1. u , the ultimate bearing capacity of the single pile is Q u :

[0114]

[0115] Among them, F max is the maximum loading load of hollow square piles,

[0116] F c is the initial load of the hollow square pile,

[0117] K is the safety factor, which is 1.05.

[0118] η fis the bearing capacity correction factor, which is determined by the soil conditions and the situation of the pile end entering the bearing layer.

[0119] η d It is the depth correction coefficient, which indicates the influence of burial depth on bearing capacity.

[0120] like Figure 3 As shown, step S300 specifically includes:

[0121] S301. Determine the installation location of the prefabricated panels according to the design drawings, mark the boundary line of the excavation area on the ground, prepare the required construction equipment, clean the construction area, and ensure that there are no obstacles that hinder the construction;

[0122] S302. Use excavators and other mechanical equipment to excavate according to the design requirements. The excavation depth should ensure that the prefabricated panels can reach the design elevation after installation. During the excavation process, pay attention to monitoring the stability of the slope and take reinforcement measures to prevent landslides. After the excavation is completed, use measuring tools to check whether the plane size and depth of the excavation area meet the design requirements;

[0123] S303, using a crane or other lifting equipment to stably hoist the retaining wall panel 2 to a designated position, the side of the retaining wall panel 2 is connected to the hollow square pile 1 by mortar, and the thickness of the mortar should be controlled between 10 and 20 mm;

[0124] S304. During the installation process, check the verticality and flatness of the prefabricated panels at any time to ensure that the joints with adjacent panels are tight. The gaps in the middle need to be filled with fine stone concrete to enhance the rigidity of the overall structure.

[0125] In step S302, the stability of the slope is monitored and the safety factor F of the slope needs to be determined. s , specifically:

[0126]

[0127] Where R is the anti-sliding force of the slope,

[0128] T is the sliding force of the slope.

[0129] The anti-sliding force R of the slope is specifically:

[0130] R=∑(γ i ·A i ·sin(α i )+c i ·L i +tan(φ i )·N i );

[0131] Among them, γ i is the dry density of the i-th soil layer,

[0132] A i is the area of ​​the i-th soil layer,

[0133] α i is the inclination angle of the i-th soil layer,

[0134] c i is the cohesion of the i-th soil layer,

[0135] L i is the length of the i-th soil layer along the sliding surface,

[0136] φ i is the internal friction angle of the i-th soil layer,

[0137] N i is the normal force of the i-th soil layer.

[0138] The sliding force T of the slope is:

[0139] T=∑(γ i ·V i )·sin(β);

[0140] Among them, V i is the volume of the i-th soil layer,

[0141] β is the average inclination of the slope.

[0142] like Figure 4 As shown, step S400 specifically includes:

[0143] S401, filling the circular cavity of the hollow square pile 1 with a core filler 8 to seal it, and filling the holes of the retaining wall 2 with extruded board fragments 6 to seal them, and the extruded board fragments 6 in the holes at both ends of each retaining wall 2 are located 500 mm below the hole;

[0144] S402. Accurately place the crown beam on the top of the prefabricated component according to the design drawings and mark it with ink lines. Tie the steel bar skeleton of the crown beam according to the design requirements to ensure that the number, diameter and spacing of the steel bars meet the design specifications;

[0145] S403. Install the formwork to form the shape of the crown beam. The formwork should be stable to prevent deformation when pouring concrete. Pour the concrete evenly into the formwork and vibrate it to make it dense and free of voids.

[0146] In step S400, the gap of the baffle plate 2 needs to be monitored, specifically: a certain water pressure or air pressure is applied inside the template, and the test is started after the pressure is stable, and a flow meter is used to record the volume V of liquid or gas leaking through the joint per unit time. leak , record the test time t, and calculate the leakage pressure P at the joint leak, the leakage pressure P at the calculated joint leak for:

[0147]

[0148] Among them, P leak is the leakage pressure at the joint,

[0149] V leak is the volume of liquid or gas leaking through the joint per unit time,

[0150] A seam is the total area of ​​the joint,

[0151] t is the test time, s.

[0152] Step S500 specifically includes:

[0153] S501. Check that there are no obvious gaps or unevenness at the template joints. Use a feeler gauge to check the maximum opening width of the template joints to ensure that it does not exceed the specified allowable value.

[0154] S502. Use a level ruler or theodolite to check the levelness of the template to ensure that the plane position of the template meets the design requirements;

[0155] S503. Use a theodolite or total station to check the verticality of the template to ensure that the verticality of the template meets the design requirements;

[0156] S504. Check the stability of the formwork to ensure that it will not deform or move during the pouring process. Check the mix ratio and slump of the concrete to ensure that it meets the construction requirements.

[0157] In step S500, the thickness of the connecting mortar 4 needs to be detected, specifically:

[0158]

[0159] Among them, t m is the mortar thickness,

[0160] M m is the measured value,

[0161] T b is the thickness of the retaining wall,

[0162] s c Mortar shrinkage.

[0163] Step S600 is specifically as follows:

[0164] S601. Determine the boundary and elevation of the backfill area, prepare the necessary construction equipment, and ensure that the backfill materials meet the design requirements;

[0165] S602. Backfill in layers according to design requirements. The thickness of each backfill layer should not exceed 30 cm. After each backfill layer is completed, compact it with a compactor to ensure that the density of the backfill soil meets the design requirements.

[0166] S603. For the slope area, reinforcement measures such as laying mesh cloth and planting turf are taken to ensure the stability of the slope;

[0167] S604. During the backfilling process, ensure that the original drainage facilities are unobstructed and add drainage ditches or water collection wells to prevent water accumulation.

[0168] Step S300 also includes:

[0169] S700. If there is no excavation condition on site, the retaining wall 2 is made of high-strength prefabricated panels and is directly pressed into the soil by static pressure. In this case, no mortar connection is required between the retaining wall 2 and the hollow square pile 1.

[0170] In step S700, the static pressure of the retaining wall 2 into the soil is p for:

[0171]

[0172] Among them, W b is the weight of the baffle,

[0173] F a For the pressure applied,

[0174] A b is the bottom area of ​​the retaining wall,

[0175] τ s is the shear strength of soil.

[0176] In step S700, the bearing capacity of the foundation needs to be determined, specifically:

[0177] q u =c+σ′·tan(φ′);

[0178] q u is the ultimate bearing capacity of the foundation,

[0179] c is the cohesion of soil,

[0180] σ′ is the effective vertical stress,

[0181] φ′ is the effective internal friction angle of soil.

[0182] If, in frozen soil areas, the temperature of the frozen soil layer should also be predicted, specifically:

[0183]

[0184] Where T(z, t) is the temperature at depth z at time t,

[0185] T ∞ is the ambient temperature,

[0186] ΔT is the initial temperature difference,

[0187] L is the heat diffusion depth,

[0188] P is the period, recorded as 1 year.

[0189] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A construction method for an assembled prefabricated pile foundation retaining wall structure, characterized in that: include: S100. Carry out site cleaning and leveling work before construction, and set up temporary facilities including construction fences and temporary roads; S200, determining the specifications of the hollow square piles (1) and the retaining wall panels (2) according to the design drawings and specifications, controlling the distance between the hollow square piles (1) according to the width of the retaining wall panels (2), and constructing the hollow square piles (1); S300, according to the position of the hollow square pile (1) after the construction is completed, determine the installation area of ​​the retaining wall (2) and then perform earth excavation, install the retaining wall (2) in the installation area, and connect the two to the prestressed concrete hollow square pile through a connecting mortar (4), and the mortar thickness is controlled between 10 and 20 mm; S400, filling the circular cavity of the hollow square pile (1) with a core filler (8) to seal it, filling the hole of the retaining wall plate (2) with extruded board fragments (6) to seal it, and connecting the retaining wall plate (2) and the crown beam (7) with anchoring steel bars (3); S500. After the main structure is constructed, a comprehensive quality inspection is conducted to confirm that all joints are firm, the crown beam (7) is installed in place, and the mortar connection is dense. Functional tests including water pressure tests are conducted to determine whether the stability and safety of the structure meet the requirements. S600. Perform backfilling operation according to the design plan.

2. The construction method of a prefabricated pile foundation retaining wall structure according to claim 1, characterized in that: Step S200 specifically includes: S201. Select appropriate specifications of prestressed concrete hollow square piles according to the design drawings, ensure that they meet the design requirements including technical indicators such as bearing capacity, prepare mechanical equipment required for construction, inspect the construction site, remove obstacles, and ensure that the construction site is flat for mechanical operation; S202. According to the instructions of the design drawings, accurately measure and mark the positions of the prestressed concrete hollow square piles, and use a pile driver to drive the prestressed concrete hollow square piles into the soil until the depth required by the design is reached; S203, controlling the distance between the square piles to ensure that the distance between the square piles matches the width of the precast slab, and the distance between the square piles is determined according to the width of the precast slab; S204. After the piling is completed, the piles are visually inspected to ensure that there are no cracks or damage. After the piling is completed, necessary static load tests are carried out to verify whether the bearing capacity of the pile foundation meets the design requirements.

3. The construction method of a prefabricated pile foundation retaining wall structure according to claim 2, characterized in that: In step S203, two prestressed concrete hollow square piles and a prefabricated slab form a simply supported structure, and the spacing of the square piles needs to be adjusted according to specific design requirements and site conditions to avoid affecting the overall bearing performance of the retaining wall; The square pile spacing d p for: Among them, w b is the width of the baffle, k s is the safety factor, take 0.9-1.05, c l is the earth pressure distribution coefficient, which indicates the distribution of earth pressure at different depths.

4. The construction method of a prefabricated pile foundation retaining wall structure according to claim 2, characterized in that: In step S204, the static load test is specifically to test the single pile ultimate bearing capacity Q of the hollow square pile (1). u , the ultimate bearing capacity of the single pile is Q u : Among them, F max is the maximum loading load of hollow square piles, F c is the initial load of the hollow square pile, K is the safety factor, which is 1.

05. η f is the bearing capacity correction factor, which is determined by the soil conditions and the situation of the pile end entering the bearing layer. η d It is the depth correction coefficient, which indicates the influence of burial depth on bearing capacity.

5. A construction method for an assembled prefabricated pile foundation retaining wall structure according to any one of claims 1 to 4, characterized in that: Step S300 specifically includes: S301. Determine the installation location of the prefabricated panels according to the design drawings, mark the boundary line of the excavation area on the ground, prepare the necessary construction equipment, clean the construction area, and ensure that there are no obstacles that hinder the construction; S302. Use mechanical equipment to excavate according to the design requirements. The excavation depth should ensure that the prefabricated panels can reach the design elevation after installation. During the excavation process, pay attention to monitoring the stability of the slope and take reinforcement measures to prevent landslides. After the excavation is completed, use measuring tools to check whether the plane size and depth of the excavation area meet the design requirements; S303, using a lifting device to stably hoist the retaining wall plate (2) to a designated position, the side of the retaining wall plate (2) is connected to the hollow square pile (1) by mortar, and the thickness of the mortar should be controlled between 10 and 20 mm; S304. During the installation process, check the verticality and flatness of the prefabricated panels at any time to ensure that the joints with adjacent panels are tight. The gaps in the middle need to be filled with fine stone concrete to enhance the rigidity of the overall structure.

6. The construction method of a prefabricated pile foundation retaining wall structure according to claim 5, characterized in that: In step S302, the stability of the slope is monitored and the safety factor F of the slope needs to be determined. s , specifically: Where R is the anti-sliding force of the slope, T is the sliding force of the slope.

7. The construction method of a prefabricated pile foundation retaining wall structure according to claim 6, characterized in that: The anti-sliding force R of the slope is specifically: R=∑(γ i ·A i ·sin(a i )+c i ·L i +tan(φ i )·N i ); Among them, γ i is the dry density of the i-th soil layer, A i is the area of ​​the i-th soil layer, α i is the inclination angle of the i-th soil layer, c i is the cohesion of the i-th soil layer, L i is the length of the i-th soil layer along the sliding surface, φ i is the internal friction angle of the i-th soil layer, N i is the normal force of the i-th soil layer; The sliding force T of the slope is: T=∑(γ i ·V i )·sin(β); Among them, V i is the volume of the i-th soil layer, β is the average inclination of the slope.

8. A construction method for an assembled prefabricated pile foundation retaining wall structure according to any one of claims 1 to 4, characterized in that: Step S400 specifically includes: S401, filling the circular cavity of the hollow square pile (1) with a core filler (8) to seal it, and filling the holes of the retaining wall (2) with extruded board fragments (6) to seal it, wherein the extruded board fragments (6) in the holes at both ends of each retaining wall (2) are located 500 mm below the hole; S402. Accurately place the crown beam on the top of the prefabricated component according to the design drawings and mark it with ink lines. Tie the steel bar skeleton of the crown beam according to the design requirements to ensure that the number, diameter and spacing of the steel bars meet the design specifications; S403. Install the formwork to form the shape of the crown beam. The formwork should be stable to prevent deformation when pouring concrete. Pour the concrete evenly into the formwork and vibrate it to make it dense and free of voids.

9. The construction method of a prefabricated pile foundation retaining wall structure according to claim 8, characterized in that: In step S400, the gap of the retaining wall plate (2) needs to be monitored, specifically: a certain water pressure or air pressure is applied inside the template, and the test is started after the pressure is stable, and a flow meter is used to record the volume V of liquid or gas leaking through the joint per unit time. leak , record the test time t, and calculate the leakage pressure P at the joint leak , the leakage pressure P at the calculated joint leak for: Among them, P leak is the leakage pressure at the joint, V leak is the volume of liquid or gas leaking through the joint per unit time, A seam is the total area of ​​the joint, t is the test time, s.

10. An assembled prefabricated pile foundation retaining wall structure, implemented using the construction method according to any one of claims 1 to 9, characterized in that: It comprises a hollow square pile (1) and a retaining wall plate (2) arranged on one side of the hollow square pile (1); The retaining wall panels (2) are multiple and arranged in a row to form a retaining wall surface. The gap between two adjacent retaining wall panels (2) is filled with fine stone concrete (5) to achieve connection. The fine stone concrete (5) is poured after the retaining wall panels (2) are spliced ​​on site. The hollow square piles (1) are arranged at equal distances on the rear side of the retaining wall surface and at the connection between two adjacent hollow square piles (1). The two are connected by arranging a connecting mortar (4), wherein the connecting mortar (4); Anchor steel bars (3) are provided in the middle of the retaining wall plate (2), and the anchor steel bars (3) are exposed from the top of the retaining wall plate (2); The retaining wall plate (2) is a porous hollow structure, and the holes on the top thereof are provided with extruded board fragments (6) to block the holes, and anchoring steel bars (3) are provided in the holes at both ends of each retaining wall plate (2), and the anchoring steel bars (3) extend upward, and the extended part is bent toward a side close to the hollow square pile (1); The top of the hollow square pile (1) is flush with the top of the retaining wall plate (2), and a crown beam (7) is provided on the top of both. The bent portion of the anchor steel bar (3) extending out of the retaining wall plate (2) is anchored in the crown beam (7), so that the anchor steel bar (3) is fixedly connected to the hollow square pile (1) and the retaining wall plate (2); The hollow square pile (1) is a columnar structure with a square cross-section as a whole, with a circular cavity in the middle, and a core filling (8) is arranged in the cavity.

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