A shallow foundation post-combination pile reinforcing structure for active building and a construction method thereof

Abstract

The application relates to a shallow foundation post-combined pile reinforcing structure of an active building and a construction method thereof, which comprises the following steps: digging a cast-in-place pile hole outside a shallow foundation, drilling a steel pipe pile hole, and inserting a steel pipe pile into the steel pipe pile hole; a foundation bearing platform is arranged at the upper parts of the cast-in-place pile and the steel pipe pile, a pile core steel reinforcement cage, a counter-pressure supporting plate and a connecting cap plate are arranged at the upper part of the steel pipe pile; during concrete pouring construction, the cast-in-place pile concrete pouring construction is first carried out, and the position of the steel pipe pile is controlled through stable anchoring plates and the self-weight of the cast-in-place pile concrete; strain gauges are arranged on the lower surfaces of frame beams near the shallow foundation, and reflective markers are arranged outside the structural columns; reinforcing supporting columns are arranged between the frame beams and building ground plates, rigid supporting bodies and pit-out solidifying bodies are arranged outside the excavated operation grooves. The application can improve the bearing capacity of the shallow foundation, reduce the influence of foundation reinforcing construction on the active building, and reduce the construction difficulty.

Description

Technical Field

[0001] This application relates to the field of shallow foundation reinforcement technology, specifically to a post-installed composite pile reinforcement structure for shallow foundations of existing buildings and its construction method. Background Technology

[0002] To enhance the load-bearing capacity of existing building shallow foundations and improve their functionality and safety, foundation reinforcement is often necessary. As a widely used building foundation structure, improving the load-bearing capacity of shallow foundations has always been a crucial aspect of building reinforcement. During shallow foundation reinforcement construction, technical issues such as increasing load-bearing capacity and protecting existing buildings must be addressed.

[0003] Existing technology includes a shallow foundation reinforcement structure comprising a pile cap, anchored static pressure piles, a pile sealing plate, and a filling layer. The pile cap is either a correction of the existing shallow foundation or an additional foundation added to the existing shallow foundation. Piling holes are drilled on the upper surface of the pile cap, with the static pressure piles located within these holes, their tops situated within the hole section of the existing shallow foundation or pile cap. Concrete is poured into the pile holes, and anchor bars are installed at the top of the anchored static pressure piles, anchored within the concrete in the pile holes. Anchored piles penetrate the pile cap from its upper surface and are positioned around the pile holes, with their upper ends protruding from the pile cap's upper surface. Concrete is poured into the pile holes to seal the anchored piles, forming a pile sealing plate. While this construction method can achieve pile reinforcement of shallow foundations, the structure fails to achieve combined reinforcement of steel pipe piles and cast-in-place piles, making it difficult to simultaneously protect the existing building. Its improvement in foundation bearing capacity and overall structural integrity is limited. Summary of the Invention

[0004] The purpose of this invention is to provide a post-installed composite pile reinforcement structure for shallow foundations of existing buildings and its construction method, which effectively reduces the on-site construction difficulty of the post-installed composite pile reinforcement structure for shallow foundations of existing buildings, improves the bearing capacity of shallow foundations, and reduces the impact of foundation reinforcement construction on existing buildings.

[0005] One technical solution adopted by this invention is: a construction method for post-installed composite pile reinforcement structure for shallow foundations of existing buildings, comprising the following steps:

[0006] Step S1: Prepare for construction by clearing debris from the area around the foundation reinforcement zone and conducting a survey around the shallow foundation of the building to be reinforced. Determine the planar location of the steel pipe piles and prepare the necessary materials and equipment for construction.

[0007] Step S2: Deploy the safety monitoring system for existing buildings, attach reflective markers to the side walls of the structural columns above the shallow foundation, attach strain gauges to the lower surface of the frame beams, and set up reinforcing support columns between the ground slab and the frame beams near the shallow foundation. Weld the end plates of the support columns at the junctions of the reinforcing support columns with the frame beams and the ground slab, and set up column top beams at the top of the structural columns.

[0008] Step S3: Excavate the foundation soil support. First, solidify the foundation soil outside the shallow foundation in situ to form an external solidified body. Then, insert a rigid support body vertically on the side of the external solidified body facing the shallow foundation. Excavate the foundation soil above the top surface elevation of the shallow foundation between the shallow foundation and the rigid support body to form a construction pit. The width of the construction pit is 1~3m. Set a bottom pressure plate on the upper surface of the construction pit and set an adjustable pressure plate positioning body between the bottom pressure plate and the rigid support body.

[0009] Step S4: Treat the free surface of the shallow foundation. First, use a pneumatic pick or impact drill to roughen the interface of the upper surface of the shallow foundation, and then insert interface connecting bars by drilling holes on the outer surface of the shallow foundation.

[0010] Step S5: Construct bored piles. Excavate pile holes with a depth of 2-4m on both sides of the shallow foundation, and install a retaining wall along the direction of the pile holes to form a bored pile; the length of the retaining wall is the same as that of the bored pile.

[0011] Step S6: Insert the pilot hole for the steel pipe pile. Set the column side connecting bar at the bottom of the structural column and set the support ear plate with an "L" shaped cross section on the outer wall of the column side connecting bar. Set the construction platform plate on the support ear plate and the upper surface of the ground panel or foundation soil, and set the pilot hole drilling machine on the construction platform plate. Use the pilot hole drill bit of the pilot hole drilling machine to drill the pipe pile drilling hole. Set the support plate sleeve on the outer wall of the pipe pile insertion pipe and the post-grouting pipe. Use the support plate connecting bar to connect the pipe pile insertion pipe and the post-grouting pipe into a whole in advance. Insert the pipe pile insertion pipe and the post-grouting pipe into the cavity of the cast-in-place pile retaining wall at the same time, and firmly connect the post-grouting pipe to the cast-in-place pile retaining wall through the support plate control body and the retaining wall pressure plate.

[0012] Step S7: Grout the pile hole assembly, install a counter-pressure support plate on the top of the steel pipe pile, and install a stabilizing anchor bar on the counter-pressure support plate, so that the stabilizing anchor plate at the bottom of the stabilizing anchor bar is located at the bottom of the construction pit; install a core steel reinforcement cage on the top of the steel pipe pile, and tie the core steel reinforcement cage to the pile cap steel reinforcement cage as a whole; first, perform concrete pouring construction of the cast-in-place pile through the external grouting pipe of the steel pipe pile, and then use external concrete pouring equipment to press grout into the cavity of the steel pipe pile to form a core reinforcement body;

[0013] Step S8: Pour the foundation cap, remove the construction platform plate, and weld the connecting cap plate to the top of the pile core reinforcement cage; pour concrete around the cast-in-place piles and steel pipe piles to form the foundation cap.

[0014] Furthermore, the pit bottom pressure plate in step S3 is made of rolled steel plate and is welded to the pressure plate control body; the pressure plate control body includes bolts and screws, and the tightening directions of the screws on both sides of the bolts are opposite.

[0015] Furthermore, the interface connecting bars in step S4 are made of threaded steel bars or stainless steel pipes and are bonded to the shallow foundation by concrete injection.

[0016] Another technical solution adopted by the present invention is: a post-installed composite pile reinforcement structure for shallow foundations of existing buildings, comprising a shallow foundation, interface connecting bars, structural columns, reflective supports, frame beams, column top beams, strain gauges, reinforcing support columns, a ground slab, reaction support components, and anchoring components; the shallow foundation is partially embedded in the foundation soil, interface connecting bars are provided on the side of the shallow foundation, and a ground slab is provided on the surface of the foundation soil; one end of the structural column is connected to the shallow foundation, and the other end is connected to the column top beam, and reflective supports are provided on the structural column; the frame beam is provided on the column top beam, and strain gauges are provided on the frame beam; one end of the reinforcing support column is connected to the frame beam, and the other end is connected to the ground slab; the reaction support components are provided at the end where the structural column is connected to the shallow foundation, and one end of the anchoring components is connected to the reaction support components, and the other end is connected to the foundation soil;

[0017] The reaction support assembly includes an external solidification body, column-side connecting bars, support ear plates, a foundation reinforcement cage, and a foundation foundation. The external solidification body is arranged around the perimeter of the shallow foundation. A column-side connecting bar is provided at one end of the structural column connected to the shallow foundation. An L-shaped support ear plate is provided on the outer wall of the column-side connecting bar. A foundation foundation is provided between the external solidification body and the shallow foundation, and a foundation reinforcement cage is provided inside the foundation foundation.

[0018] The anchoring assembly includes steel pipe piles, counter-pressure support plates, cast-in-place piles, stabilizing anchor bars, stabilizing anchor plates, pile core steel cages, and connecting cap plates; one end of the cast-in-place pile is connected to the foundation cap, and the other end is connected to the foundation soil; the cast-in-place pile includes a pile hole and a retaining wall, and the pile hole is equipped with a pipe insertion pipe, a post-grouting pipe, a retaining wall pressure plate, a support sleeve, a support connecting bar, and a support positioning body; the pipe insertion pipe is located at the center of the pile hole, the post-grouting pipe surrounds the pipe insertion pipe, the support sleeve is provided on the outer wall of the pipe insertion pipe and the post-grouting pipe, the support sleeve on the outer wall of the pipe insertion pipe and the post-grouting pipe is connected by the support connecting bar, a retaining wall pressure plate is provided on the retaining wall, and a support positioning body is provided between the retaining wall pressure plate and the support sleeve on the outer wall of the post-grouting pipe;

[0019] The steel pipe pile is installed inside the pile insertion tube and penetrates the pile insertion tube; one end of the steel pipe pile is inserted into the foundation cap, and the other end is inserted into the foundation soil; a counter-pressure support plate and a pile core reinforcement cage are provided at the end of the steel pipe pile connected to the foundation cap, a stabilizing anchor bar is provided on the counter-pressure support plate, a stabilizing anchor plate is provided at the bottom end of the stabilizing anchor bar, the pile core reinforcement cage is connected to the foundation cap reinforcement cage, and a connecting cap plate is provided on the pile core reinforcement cage.

[0020] Furthermore, the steel pipe pile is provided with grout seepage holes, and the steel pipe pile is provided with a core reinforcement.

[0021] Furthermore, the strain gauge is a concrete surface strain gauge or a steel plate strain gauge; the reflective marker is a cross-shaped reflective marker, and it is evenly spaced vertically along the structural column, with a quantity of 2 to 3 reflective markers.

[0022] Furthermore, the solidified body outside the pit is cement slurry, quicklime, or microbial slurry.

[0023] Furthermore, the inner diameter of the support sleeve is 1.1 to 1.3 times the outer diameter of the post-grouting pipe or the pipe pile insertion pipe, and the support sleeve is welded to the support plate connecting reinforcement; the support plate positioning body includes bolts and screws, the tightening directions of the screws on both sides of the bolt are opposite, and the screws on both sides of the bolt are welded to the support sleeve and the retaining wall pressure plate respectively; the retaining wall pressure plate is made of rolled steel plate, with a circular arc cross section, and the outer diameter is the same as the inner diameter of the cast-in-place pile retaining wall.

[0024] Furthermore, the connecting cap plate is made of steel strips or steel bars welded into a grid shape, with a circular basin-shaped cross-section.

[0025] Furthermore, a support end plate is provided at the end of the reinforcing support column that connects to the ground panel.

[0026] The beneficial effects of this invention are as follows:

[0027] (1) In this invention, a pile hole for cast-in-place piles is first excavated on the outside of the shallow foundation, and then a pile hole for steel pipe piles is drilled. Steel pipe piles are then inserted into the pile holes. A foundation cap is set on the upper part of the cast-in-place piles and the steel pipe piles. A core steel cage, a counter-pressure support plate, and a connecting cap plate are set on the top of the steel pipe piles. This can further enhance the integrity of the steel pipe piles, the foundation cap, and the cast-in-place piles.

[0028] (2) In the concrete pouring construction, the present invention first pours concrete for the cast-in-place piles and controls the position of the steel pipe piles by using the self-weight of the anchor plate and the cast-in-place pile concrete, thus solving the problem of the steel pipe piles floating during the concrete pouring process.

[0029] (3) The present invention sets strain gauges on the lower surface of the frame beam near the shallow foundation and sets reflective marks on the outside of the structural column, which can simultaneously monitor the stress and deformation of the components during the shallow foundation reinforcement construction; at the same time, the present invention sets reinforcing support columns between the frame beam and the building ground slab, which can effectively reduce the impact of on-site construction on existing building components; and sets rigid support bodies and external solidification bodies on the outside of the excavation trench, which improves the stability of the foundation soil during construction. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart of the construction method according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the construction state in step S2 of this embodiment of the invention;

[0033] Figure 3 This is a schematic diagram of the construction state in step S4 of an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the construction state in step S6 of this embodiment of the invention;

[0035] Figure 5 This is a schematic diagram (b) of the construction state in step S6 of this embodiment of the invention;

[0036] Figure 6 This is a schematic diagram of the completed structure according to an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the steel pipe pile structure according to an embodiment of the present invention;

[0038] Figure 8 This is a side sectional view of a cast-in-place pile according to an embodiment of the present invention;

[0039] Figure 9 This is a cross-sectional view of a cast-in-place pile according to an embodiment of the present invention;

[0040] Figure 10 for Figure 4 A magnified view of part A in the middle;

[0041] Figure 11 for Figure 5 A magnified view of part B in the middle section;

[0042] Figure 12for Figure 6 A magnified view of part C in the middle.

[0043] Explanation of reference numerals in the attached diagram: 1-Shallow foundation, 2-Steel pipe pile, 3-Structural column, 4-Frame beam, 5-Reflective marker, 6-Strain gauge, 7-Reinforcing support column, 8-Ground slab, 9-Support column end plate, 10-Column top beam, 11-Foundation soil, 12-External solidification body, 13-Reinforced support body, 14-Construction pit, 15-Pit bottom pressure plate, 16-Pressure plate positioning body, 17-Interface connection reinforcement, 18-Pile hole for cast-in-place pile, 19-Pile retaining wall, 20-Column side 21-Connecting bar, 22-Supporting ear plate, 23-Construction platform plate, 24-Pre-hole drilling rig, 27-Pre-hole drill bit, 28-Pile insertion pipe, 29-Post-grouting pipe, 30-Wall protection pressure plate, 31-Grouting seepage hole, 32-Support casing, 33-Support connecting bar, 34-Support positioning body, 35-Counter pressure support plate, 36-Stabilizing anchor bar, 37-Pile core reinforcement cage, 38-Pile cap reinforcement cage, 39-Cast-in pile, 40-Pile core reinforcement body, 42-Connecting cap plate, 43-Foundation cap. Detailed Implementation

[0044] To better understand the above-described objects, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention; however, the invention may be practiced in other ways different from those described herein, and therefore, the invention is not limited to the specific embodiments disclosed below.

[0045] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art described herein. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” etc., are used only to indicate relative positional relationships, which change accordingly when the absolute position of the described object changes.

[0046] like Figure 1 As shown, this embodiment of the invention employs a construction method for a post-installed composite pile reinforcement structure for shallow foundations of existing buildings, comprising the following steps:

[0047] Step S1: Prepare for construction by clearing debris from the area around the foundation reinforcement zone and surveying the area around the shallow foundation 1 of the building to be reinforced. Determine the planar location of the steel pipe piles 2 and prepare the materials and equipment required for construction.

[0048] Step S2: Deploy the safety monitoring system for the existing building. Affix reflective markers 5 to the side wall of the structural column 3 above the shallow foundation 1, attach strain gauges 6 to the lower surface of the frame beam 4, and set up reinforcing support columns 7 between the ground slab 8 near the shallow foundation 1 and the frame beam 4. Weld the support column end plate 9 at the junction of the reinforcing support column 7 with the frame beam 4 and the ground slab 8, and set up a column top beam 10 at the top of the structural column 3.

[0049] Step S3: Excavate the foundation soil 11 for support. First, solidify the foundation soil 11 outside the shallow foundation 1 in situ to form an external solidified body 12. Then, insert a rigid support body 13 vertically on the side of the external solidified body 12 facing the shallow foundation 1. Excavate the foundation soil above the top surface elevation of the shallow foundation 1 between the shallow foundation 1 and the rigid support body 13 to form a construction pit 14. The width of the construction pit 14 is 1~3m. Set a pit bottom pressure plate 15 on the upper surface of the construction pit 14, and set an adjustable pressure plate control body 16 between the pit bottom pressure plate 15 and the rigid support body 13. The pit bottom pressure plate 15 is made of rolled steel plate and is welded to the pressure plate control body 16. The pressure plate control body 16 includes bolts and screws, and the tightening directions of the screws on both sides of the bolts are opposite.

[0050] Step S4: Treat the exposed surface of the shallow foundation 1. First, use a pneumatic pick or impact drill to roughen the interface of the upper surface of the shallow foundation 1. Then, insert interface connecting bars 17 by drilling holes on the outer surface of the shallow foundation 1. The interface connecting bars 17 are made of threaded steel bars or stainless steel pipes and are bonded to the shallow foundation 1 by concrete injection.

[0051] Step S5: Construct bored piles 39. On both sides of the shallow foundation 1, bored pile holes 18 with a depth of 2-4m are dug, and a bored pile retaining wall 19 is arranged on the inner side wall of the bored pile hole 18 along the direction of the bored pile 39 to form the bored pile 39; the length of the bored pile retaining wall 19 is the same as that of the bored pile 39.

[0052] Step S6: Insert the pilot hole for the steel pipe pile 2, set the column side connecting bar 20 at the bottom of the structural column 3, and set the support ear plate 21 with an "L" shaped cross section on the outer wall of the column side connecting bar 20; set the construction platform plate 22 on the upper surface of the support ear plate 21 and the ground panel 8 or the foundation soil 11, and set the pilot hole drilling machine 23 on the construction platform plate 22, and use the pilot hole drill bit 24 of the pilot hole drilling machine 23 to drill the pipe pile drilling hole; install the support plate sleeve 31 on the outer wall of the pipe pile insertion pipe 27 and the post-grouting pipe 28, and use the support plate connecting bar 32 to pre-connect the pipe pile insertion pipe 27 and the post-grouting pipe 28 into a whole, insert the pipe pile insertion pipe 27 and the post-grouting pipe 28 into the cavity of the cast-in-place pile retaining wall 19 at the same time, and firmly connect the post-grouting pipe 28 to the cast-in-place pile retaining wall 19 through the support plate control body 33 and the retaining wall pressure plate 29.

[0053] Step S7: Grouting is performed on the pile hole assembly. A counter-pressure support plate 34 is installed on the top of the steel pipe pile 2, and a stabilizing anchor bar 35 is installed on the counter-pressure support plate 34, so that the stabilizing anchor plate 36 at the bottom of the stabilizing anchor bar 35 is located at the bottom of the construction pit 14; a pile core reinforcement cage 37 is installed on the top of the steel pipe pile 2, and the pile core reinforcement cage 37 is tied to the pile cap reinforcement cage 38 into a whole; first, concrete pouring construction of the cast-in-place pile 39 is carried out through the external grouting pipe 28 of the steel pipe pile 2, and then grouting is performed into the cavity of the steel pipe pile 2 through the external concrete pouring equipment to form the pile core reinforcement body 40.

[0054] Step S8: Pour the foundation cap 43, remove the construction platform plate 22, and weld the connecting cap plate 42 to the top of the pile core steel cage 37; pour concrete around the cast-in-place pile 39 and the steel pipe pile 2 to form the foundation cap 43.

[0055] In this embodiment of the invention, the shallow foundation 1 is a strip foundation with a depth of 1m and a bottom width of 1m, and the concrete strength grade is C30. The steel pipe pile 2 is made of rolled steel pipe with a diameter of 220mm, and grout seepage holes 30 are pre-installed on the outer wall of the steel pipe pile 2; the grout seepage holes 30 are 30mm long and 10mm wide. The structural column 3 is a reinforced concrete column with a cross-sectional dimension of 300mm×300mm and a concrete strength grade of C35. The frame beam 4 and the column top beam 10 are both reinforced concrete beams with a cross-sectional dimension of 250mm×400mm and a concrete strength grade of C35. The reflective markers 5 are cross-shaped reflective markers 5, with two vertically arranged along the structural column 3 at a spacing of 2m. The strain gauge 6 is a vibrating wire type concrete surface strain gauge 6. The reinforcing support column 7 is made of rolled steel pipe with a support diameter of 100mm. The ground panel 8 is a concrete floor with a concrete strength grade of C30 and a thickness of 100mm. The support column end plate 9 is rolled from a 10mm thick steel plate. The foundation soil 11 is a plastic cohesive soil. The external solidification body 12 is solidified with cement grout, and the cement is 32.5 ordinary Portland cement. The rigid support body 13 is made of wire-drawn steel sheet piles with a length of 1.5m. The construction pit 14 is 1.5m wide and 0.8m deep. The pit bottom pressure plate 15 is rolled from a 10mm thick steel plate and is welded to the pressure plate control body 16; the pressure plate control body 16 includes a 60mm diameter threaded rod and bolts, with the tightening directions of the threaded rods on both sides of the bolts opposite. The interface connecting bar 17 is made of 25mm diameter threaded steel bar and is bonded to the shallow foundation 1 concrete with adhesive.

[0056] Piling pile holes 18 with a depth of 3m are excavated on both sides of the shallow foundation 1. Piling pile retaining walls 19 are installed on the inner wall of the pile holes 18 along the direction of the piles 39, forming the piles 39. The retaining walls 19 are precast reinforced concrete with an outer diameter of 1000mm, and the concrete strength grade of the piles 39 is C30. The length of the retaining walls 19 is the same as that of the piles 39. The column-side connecting bars 20 are rolled from 10mm thick steel plates, with an inner cross-section identical to that of the structural column 3. The column-side connecting bars 20 are securely connected to the structural column 3 using studs. The supporting ear plates 21 are cut from 10mm thick steel plates, with an "L" shaped cross-section, and are welded to the column-side connecting bars 20. The construction platform plate 22 is rolled from 6mm thick steel plates. The pilot hole drilling machine 23 is a small spiral drilling machine with a pilot hole diameter of 250mm. The pilot hole drill bit 24 is an alloy drill bit, and the diameter of the hole for drilling the pipe pile is 250mm.

[0057] The support sleeve 31 is made of rolled steel pipe and comes in two specifications: 90mm inner diameter and 250mm inner diameter. The 90mm inner diameter support sleeve 31 contains a post-grouting pipe 28, while the 250mm inner diameter support sleeve 31 contains a pile insertion pipe 27. The pile insertion pipe 27 has an inner diameter of 230mm, and the post-grouting pipe 28 has a diameter of 50mm. The support connecting reinforcement 32 is made of rolled steel plate with a thickness of 10mm. The retaining wall pressure plate 29 is made of rolled steel plate with a thickness of 3mm, has an arc-shaped cross-section, and its outer diameter is the same as the inner diameter of the cast-in-place pile retaining wall 19. The support control body 33 includes bolts and 30mm diameter threaded rods, with the tightening directions of the threaded rods on both sides of the bolts opposite. The counter-pressure support plate 34 is made of rolled steel plate with a thickness of 10mm, and has pre-set holes for the insertion of stabilizing anchor bars 35. The stabilizing anchor bar 35 is a 30mm diameter threaded rod. The stabilizing anchor plate 36 is rolled from a 10mm diameter steel plate and is vertically welded to the stabilizing anchor bar 35. The pile core reinforcement cage 37 and the foundation reinforcement cage 38 are both made of threaded steel bars with diameters of 25mm and 10mm, respectively. The pile core reinforcement body 40 is made of fine aggregate concrete with a strength grade of C35. The connecting cap plate 42 is rolled from a 10mm thick steel plate, is 20cm wide, has a circular basin shape, and a diameter of 1200mm. The foundation foundation 43 is cast from C35 strength concrete and has a height of 900mm.

[0058] In this embodiment of the invention, a pile hole 18 for cast-in-place piles is first excavated outside the shallow foundation 1, followed by drilling a pile hole for steel pipe piles 2, and then inserting steel pipe piles 2 into the pile hole. A foundation cap 43 is set on the upper part of the cast-in-place piles 39 and the steel pipe piles 2, and a core reinforcement cage 37, a counter-pressure support plate 34, and a connecting cap plate 42 are set on the top of the steel pipe piles 2, which can further enhance the integrity of the steel pipe piles 2, the foundation cap 43, and the cast-in-place piles 39. During concrete pouring, the concrete for the cast-in-place piles 39 is poured first, and the position of the steel pipe piles 2 is controlled by the stabilizing anchor plate 36 and the self-weight of the concrete for the cast-in-place piles 39, thus solving the problem of the steel pipe piles 2 floating during the concrete pouring process. In this embodiment of the invention, strain gauges 6 are installed on the lower surface of the frame beam 4 near the shallow foundation 1, and reflective markers 5 are installed on the outer side of the structural column 3, which can simultaneously monitor the stress and deformation of the components during the reinforcement construction of the shallow foundation 1. At the same time, the invention sets up reinforcing support columns 7 between the frame beam 4 and the building ground slab 8, which can effectively reduce the impact of on-site construction on existing building components. Stiff support bodies 13 and external solidification bodies 12 are set on the outer side of the excavation trench, which improves the stability of the foundation soil 11 during construction.

[0059] like Figures 2-12As shown, following the above steps, a post-installed composite pile reinforcement structure for shallow foundations of existing buildings can be obtained, including a shallow foundation 1, interface connecting bars 17, structural columns 3, reflective beams 5, frame beams 4, column top beams 10, strain gauges 6, reinforcing support columns 7, ground panels 8, reaction support components, and anchoring components; the shallow foundation 1 is partially embedded in the foundation soil 11, the shallow foundation 1 has interface connecting bars 17 on its side, and the foundation soil 11 has a ground panel 8 on its surface; one end of the structural column 3 is connected to the shallow foundation 1, and the other end is connected to the column top beam 10, and the structural column 3 has reflective beams 5; the frame beam 4 is set on the column top beam 10, and the frame beam 4 has strain gauges 6; the reflective beams 5 and strain gauges 6 can simultaneously monitor the stress and deformation of the components during the shallow foundation 1 reinforcement construction process. The strain gauge 6 can be a concrete surface strain gauge 6 or a steel plate strain gauge; the reflective marker 5 is a cross-shaped reflective marker 5, and is evenly spaced vertically along the structural column 3, with 2 to 3 reflective markers 5 in number. One end of the reinforcing support column 7 is connected to the frame beam 4, and the other end is connected to the ground slab 8; the end of the reinforcing support column 7 connected to the ground slab 8 is also provided with a support end plate 9 to improve the connection strength; the reinforcing support column 7 can effectively reduce the impact of on-site construction on existing building components. The reaction support assembly is set at the end where the structural column 3 connects to the shallow foundation 1, and one end of the anchoring assembly is connected to the reaction support assembly, and the other end is connected to the foundation soil 11.

[0060] The reaction support assembly includes an external solidification body 12, column-side connecting bars 20, support ear plates 21, a foundation reinforcement cage 38, and a foundation foundation 43. The external solidification body 12 is arranged around the periphery of the shallow foundation 1. A column-side connecting bar 20 is provided at one end of the structural column 3 connected to the shallow foundation 1. An L-shaped support ear plate 21 is provided on the outer wall of the column-side connecting bar 20. A foundation foundation 43 is provided between the external solidification body 12 and the shallow foundation 1, and a foundation reinforcement cage 38 is provided inside the foundation foundation 43. The external solidification body 12 is cement grout, quicklime, or microbial slurry, which can effectively improve the stability of the foundation soil 11 during construction.

[0061] The anchoring assembly includes a steel pipe pile 2, a counter-pressure support plate 34, a cast-in-place pile 39, a stabilizing anchor bar 35, a stabilizing anchor plate 36, a pile core reinforcement cage 37, and a connecting cap plate 42. One end of the cast-in-place pile 39 is connected to the foundation cap 43, and the other end is connected to the foundation soil 11. The cast-in-place pile 39 includes a pile hole 18 and a pile retaining wall 19. The pile hole 18 is equipped with a pipe insertion pipe 27, a post-grouting pipe 28, a retaining wall pressure plate 29, a support sleeve 31, a support connecting bar 32, and a support positioning body 33. The pipe insertion pipe 27 is located at the center of the pile hole 18. The post-grouting pipe 28 is arranged around the pipe insertion pipe 27. The support sleeve 31 is provided on the outer wall of the pipe insertion pipe 27 and the post-grouting pipe 28. The inner diameter of the sleeve 31 is 1.1 to 1.3 times the outer diameter of the post-grouting pipe 28 or the pipe pile insertion pipe 27. The support sleeve 31 on the outer wall of the pipe pile insertion pipe 27 and the post-grouting pipe 28 is connected by the support plate connecting bar 32. The support sleeve 31 is welded to the support plate connecting bar 32. A retaining wall pressure plate 29 is provided on the cast-in-place pile retaining wall 19. The retaining wall pressure plate 29 is made of rolled steel plate with a circular arc cross section and an outer diameter that is the same as the inner diameter of the cast-in-place pile retaining wall 19. A support plate control body 33 is provided between the retaining wall pressure plate 29 and the support sleeve 31 on the outer wall of the post-grouting pipe 28. The support plate control body 33 includes a bolt and a threaded rod. The tightening directions of the threaded rods on both sides of the bolt are opposite. The threaded rods on both sides of the bolt are welded to the support sleeve 31 and the retaining wall pressure plate 29, respectively. The support plate control body 33 can stably connect the rear grouting pipe 28 to the wall protection pressure plate 29.

[0062] The steel pipe pile 2 is installed inside and through the pile insertion pipe 27. The steel pipe pile 2 has grout seepage holes 30. A core reinforcement body 40 is installed inside the steel pipe pile 2 to enhance its compressive strength. One end of the steel pipe pile 2 is inserted into the foundation cap 43, and the other end is inserted into the foundation soil 11. A counter-pressure support plate 34 and a core reinforcement cage 37 are installed at the end of the steel pipe pile 2 connected to the foundation cap 43. A stabilizing anchor bar 35 is installed on the counter-pressure support plate 34, and a stabilizing anchor plate 36 is installed at the bottom of the stabilizing anchor bar 35. The core reinforcement cage 37 is connected to the cap reinforcement cage 38, and a connecting cap plate 42 is installed on the core reinforcement cage 37. The connecting cap plate 42 is made of steel strips or reinforcing bars welded into a grid shape, with a circular basin-shaped cross-section. The foundation cap 43 set on the upper part of the cast-in-place pile 39 and the steel pipe pile 2, the pile core steel cage 37 set on the top of the steel pipe pile 2, the counter-pressure support plate 34 and the connecting cap plate 42 can further enhance the integrity of the steel pipe pile 2, the foundation cap 43 and the cast-in-place pile 39.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for post-installed composite pile reinforcement structure for shallow foundations of existing buildings, characterized in that, Includes the following steps: Step S1: Prepare for construction by clearing debris from the area around the foundation reinforcement zone and surveying the area around the shallow foundation of the building to be reinforced; determine the planar location of the steel pipe piles and prepare the materials and equipment required for construction. Step S2: Deploy the safety monitoring system for existing buildings, attach reflective markers to the side walls of the structural columns above the shallow foundation, attach strain gauges to the lower surface of the frame beams, and set up reinforcing support columns between the ground slab and the frame beams near the shallow foundation. Weld the end plates of the support columns at the junctions of the reinforcing support columns with the frame beams and the ground slab, and set up column top beams at the top of the structural columns. Step S3: Excavate the foundation soil support. First, solidify the foundation soil outside the shallow foundation in situ to form an external solidified body. Then, insert a rigid support body vertically on the side of the external solidified body facing the shallow foundation. Excavate the foundation soil above the top surface elevation of the shallow foundation between the shallow foundation and the rigid support body to form a construction pit. The width of the construction pit is 1~3m. Set a bottom pressure plate on the upper surface of the construction pit and set an adjustable pressure plate positioning body between the bottom pressure plate and the rigid support body. Step S4: Treat the free surface of the shallow foundation. First, use a pneumatic pick or impact drill to roughen the interface of the upper surface of the shallow foundation, and then insert interface connecting bars by drilling holes on the outer surface of the shallow foundation. Step S5: Construct bored piles. Excavate pile holes with a depth of 2-4m on both sides of the shallow foundation, and install a retaining wall along the direction of the pile holes to form a bored pile; the length of the retaining wall is the same as that of the bored pile. Step S6: Insert the pilot hole for the steel pipe pile. Set the column side connecting bar at the bottom of the structural column and set the support ear plate with an "L" shaped cross section on the outer wall of the column side connecting bar. Set the construction platform plate on the support ear plate and the upper surface of the ground panel or foundation soil, and set the pilot hole drilling machine on the construction platform plate. Use the pilot hole drill bit of the pilot hole drilling machine to drill the pipe pile drilling hole. Set the support plate sleeve on the outer wall of the pipe pile insertion pipe and the post-grouting pipe. Use the support plate connecting bar to connect the pipe pile insertion pipe and the post-grouting pipe into a whole in advance. Insert the pipe pile insertion pipe and the post-grouting pipe into the cavity of the cast-in-place pile retaining wall at the same time, and firmly connect the post-grouting pipe to the cast-in-place pile retaining wall through the support plate control body and the retaining wall pressure plate. Step S7: Grout the pile hole assembly, install a counter-pressure support plate on the top of the steel pipe pile, and install a stabilizing anchor bar on the counter-pressure support plate, so that the stabilizing anchor plate at the bottom of the stabilizing anchor bar is located at the bottom of the construction pit; install a core steel reinforcement cage on the top of the steel pipe pile, and tie the core steel reinforcement cage to the pile cap steel reinforcement cage as a whole; first, perform concrete pouring construction of the cast-in-place pile through the external grouting pipe of the steel pipe pile, and then use external concrete pouring equipment to press grout into the cavity of the steel pipe pile to form a core reinforcement body; Step S8: Pour the foundation cap, remove the construction platform plate, and weld the connecting cap plate to the top of the pile core reinforcement cage; pour concrete around the cast-in-place piles and steel pipe piles to form the foundation cap.

2. The construction method for a post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 1, characterized in that, The pit bottom pressure plate in step S3 is made of rolled steel plate and is welded to the pressure plate control body; the pressure plate control body includes bolts and screws, and the tightening directions of the screws on both sides of the bolts are opposite.

3. The construction method for a post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 1, characterized in that, The interface connecting bars in step S4 are made of threaded steel bars or stainless steel pipes and are bonded to the shallow foundation by concrete injection.

4. A post-installed composite pile reinforcement structure for shallow foundations of existing buildings, characterized in that, The system includes a shallow foundation, interface connecting bars, structural columns, reflective supports, frame beams, column top beams, strain gauges, reinforcing support columns, a ground slab, reaction support components, and anchoring components. The shallow foundation is partially embedded in the foundation soil, with interface connecting bars on its sides. A ground slab is installed on the surface of the foundation soil. One end of each structural column is connected to the shallow foundation, and the other end is connected to the column top beam. Reflective supports are installed on the structural column. The frame beam is mounted on the column top beam and has strain gauges installed on it. One end of each reinforcing support column is connected to the frame beam, and the other end is connected to the ground slab. The reaction support components are located at the end where the structural column connects to the shallow foundation. One end of each anchoring component is connected to the reaction support component, and the other end is connected to the foundation soil. The reaction support assembly includes an external solidification body, column-side connecting bars, support ear plates, a foundation reinforcement cage, and a foundation foundation. The external solidification body is arranged around the perimeter of the shallow foundation. A column-side connecting bar is provided at one end of the structural column connected to the shallow foundation. An L-shaped support ear plate is provided on the outer wall of the column-side connecting bar. A foundation foundation is provided between the external solidification body and the shallow foundation, and a foundation reinforcement cage is provided inside the foundation foundation. The anchoring assembly includes steel pipe piles, counter-pressure support plates, cast-in-place piles, stabilizing anchor bars, stabilizing anchor plates, pile core steel cages, and connecting cap plates; one end of the cast-in-place pile is connected to the foundation cap, and the other end is connected to the foundation soil; the cast-in-place pile includes a pile hole and a retaining wall, and the pile hole is equipped with a pipe insertion pipe, a post-grouting pipe, a retaining wall pressure plate, a support sleeve, a support connecting bar, and a support positioning body; the pipe insertion pipe is located at the center of the pile hole, the post-grouting pipe surrounds the pipe insertion pipe, the support sleeve is provided on the outer wall of the pipe insertion pipe and the post-grouting pipe, the support sleeve on the outer wall of the pipe insertion pipe and the post-grouting pipe is connected by the support connecting bar, a retaining wall pressure plate is provided on the retaining wall, and a support positioning body is provided between the retaining wall pressure plate and the support sleeve on the outer wall of the post-grouting pipe; The steel pipe pile is installed inside the pile insertion tube and penetrates the pile insertion tube; one end of the steel pipe pile is inserted into the foundation cap, and the other end is inserted into the foundation soil; a counter-pressure support plate and a pile core reinforcement cage are provided at the end of the steel pipe pile connected to the foundation cap, a stabilizing anchor bar is provided on the counter-pressure support plate, a stabilizing anchor plate is provided at the bottom end of the stabilizing anchor bar, the pile core reinforcement cage is connected to the foundation cap reinforcement cage, and a connecting cap plate is provided on the pile core reinforcement cage.

5. A post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 4, characterized in that, The steel pipe pile is provided with grout seepage holes, and the steel pipe pile is provided with a core reinforcement.

6. The post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 4, characterized in that, The strain gauge is a concrete surface strain gauge or a steel plate strain gauge; the reflective markers are cross-shaped reflective markers, which are evenly spaced vertically along the structural column, and the number of reflective markers is 2 to 3.

7. The post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 4, characterized in that, The solidified material outside the pit is cement slurry, quicklime, or microbial slurry.

8. A post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 4, characterized in that, The inner diameter of the support sleeve is 1.1 to 1.3 times the outer diameter of the post-grouting pipe or the pipe pile insertion pipe. The support sleeve is welded to the support plate connecting reinforcement. The support plate positioning body includes bolts and screws. The screws on both sides of the bolt have opposite tightening directions. The screws on both sides of the bolt are welded to the support sleeve and the retaining wall pressure plate, respectively. The retaining wall pressure plate is made of rolled steel plate with an arc-shaped cross section and an outer diameter that is the same as the inner diameter of the cast-in-place pile retaining wall.

9. A post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 4, characterized in that, The connecting cap plate is made of steel strips or steel bars welded into a grid shape, with a circular basin-shaped cross-section.

10. A post-installed composite pile reinforcement structure for shallow foundations of existing buildings according to claim 4, characterized in that, The end of the reinforcing support column that connects to the ground panel is provided with a support column end plate.

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