A construction method for reinforcing structure of slope collapse caused by failure of foundation pit water-stop curtain

Abstract

The present invention discloses a construction method for reinforcing a slope collapse structure due to failure of a foundation pit water-stop curtain. A first row of support pipes and a second row of support pipes are installed on one side of the collapse area near the foundation pit, and a barrier assembly is installed between the two; then a closed structure is formed to backfill the collapse area. The present invention makes full use of effective components such as slope protection piles in the original maintenance structure as fulcrums, simplifies the construction process, and reduces construction costs; through the provision of support assemblies and barrier assemblies, the steel pipes, non-woven fabrics and other materials used are low in cost and extremely easy to obtain, which is convenient for emergency construction; and the support assemblies and barrier assemblies can further act as templates to facilitate subsequent backfilling of the collapse area; by filling concrete underwater, the exposed anchor rods in the collapse area are completely wrapped, part of the pile-anchor force system is restored, and the reliability of the original support function is increased. Through the backfilling of plain soil and the construction of the surface structure, the original function of the site is restored and the potential safety hazards of the site are eliminated.

Description

Technical Field

[0001] The invention belongs to the technical field of foundation pit slope reinforcement, and in particular relates to a construction method for a foundation pit water-stop curtain failure slope collapse reinforcement structure. Background Art

[0002] With the increasing number of extreme weather conditions, the hazards to foundation pit slopes have increased. Some foundation pit curtain water-stopping support structures that have been in place for a long time will fail to function properly and cause water to enter the foundation pit. Long-term flooded foundation pits are prone to local collapse of the slopes after heavy rains, which require timely repairs. Otherwise, the collapse will further expand and cause greater harm. Conventional construction plans require supporting formwork and pouring concrete, but the slope collapse site is more complicated, and due to the failure of the water curtain, there is often water accumulation in the foundation pit. The site has major safety hazards, and the space is small or irregular and does not meet conventional operating conditions, so a simpler and safer design plan is needed. Summary of the invention

[0003] The present invention provides a construction method for reinforcing a collapsed slope due to failure of a foundation pit water-stopping curtain, which is used to solve technical problems such as convenient sealing disposal, emergency backfilling and repair of reinforced slopes after failure of the water-stopping curtain around the foundation pit.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A construction method for reinforcing a slope collapse caused by failure of a foundation pit water-stop curtain, wherein a collapse area exists on one side of a slope protection pile of a constructed foundation pit and the water-stop curtain falls off, the groundwater below the foundation pit is pressurized groundwater, the groundwater flows into the foundation pit and the water level exceeds the base elevation;

[0006] The application of foundation pit water-stop curtain failure slope collapse reinforcement structure, the specific steps are as follows:

[0007] Step 1: Evaluate the safety of the original curtain support structure to determine whether the structural reliability of the top beam of the slope protection pile and the effectiveness of the original pile anchor components meet the design requirements; check the dangerous factors in the construction area, clean up the unstable soil on the slope, and clean up the debris in the collapsed area;

[0008] Step 2: Determine the landslide slope and the scope of the subsidence area; determine the depth of the subsidence area, as well as the width and length of the subsidence area at the ground level;

[0009] Step 3: Determine the depth of the support assembly based on the depth of the collapsed area, and determine the length of the support assembly based on the length of the collapsed area; wherein the support assembly is arranged in a tube row and is divided into two inner and outer rows, a first row of support tubes and a second row of support tubes;

[0010] Step 4: pre-install a first row of support pipes on one side of the collapse area near the slope protection piles, install the enclosure assembly after the first row of support pipes are installed, and then install a second row of support pipes outside the enclosure assembly;

[0011] Step 5: The top ends of the first row of support tubes and the second row of support tubes are higher than the top elevation of the crown beam, and the portions of the first row of support tubes and the second row of support tubes extending out of the top of the crown beam are detachably connected with a hanging assembly; one end of the hanging assembly is fixedly connected to the extended ends of the first row of support tubes and the second row of support tubes, and the other end is hung on the crown beam;

[0012] Step six: Use the underwater concrete pouring method to slowly pour concrete in layers on the underwater collapse area to form a lower backfill layer. The top surface elevation of the lower backfill layer exceeds the water surface elevation and is higher than the anchor elevation of the anchor rod at the slope protection pile. Use plain soil to backfill and compact it above the lower backfill layer to form an upper backfill layer. Set a top surface layer on the top of the slope to restore the original hardened site function, thereby completing the reinforcement of the collapsed slope due to the failure of the foundation pit water-stop curtain.

[0013] Furthermore, when determining that the structural reliability of the crown beam at the top of the slope protection pile and the effectiveness of the original pile-anchor components meet the design requirements, determine whether there is no obvious structural damage and displacement in the collapse area and surrounding slope protection piles and crown beams, there is no deformation of the underlying soil, and the crown beam still has the force-bearing performance required by the design, and whether the integrity of the exposed anchor rods in the collapse area meets the design requirements.

[0014] Furthermore, the hanging assembly includes a vertically arranged hanging rod, a carrying rod vertically connected to the top of the hanging rod, a hanging adapter detachably connected between the hanging rod and the carrying rod, a clamping rod arranged horizontally and upwardly perpendicular to the carrying rod, and a carrying adapter detachably connected between the clamping rod and the carrying rod.

[0015] Furthermore, the hanging rod is arranged on the side of the crown beam adjacent to the foundation pit, the carrying rod is arranged on the top of the crown beam and passes through the first row of support tubes and the second row of support tubes; the clamping rod is clamped on the side of the second row of support tubes adjacent to the collapse area; the clamping rod is arranged throughout the length of the second row of support tubes, and the carrying rod and the hanging rod are arranged at intervals in the length of the second row of support tubes.

[0016] Furthermore, the first row of support pipes and the second row of support pipes are driven into the soil at the bottom of the subsidence area to a depth of not less than 1500mm, and the first row of support pipes and the second row of support pipes are continuously arranged along the inner side of the crown beam and fully cover the subsidence area; the upper part of the first row of support pipes and the second row of support pipes is not less than 200mm higher than the top elevation of the crown beam.

[0017] Furthermore, the first row of support tubes and the second row of support tubes are both made of steel tubes, and the strength of the steel tubes is greater than the lateral concrete pressure resisted during concrete pouring and after stabilization; gaps are set at the anchor rod positions when the first row of support tubes and the second row of support tubes are driven and installed.

[0018] Furthermore, the enclosure assembly includes two parallel and vertically arranged enclosure side bars and a main enclosure connected between the two enclosure side bars; the enclosure side bars are arranged adjacent to the collapse area and close to the first row of support tubes, and a second row of support tubes is arranged outside the main enclosure.

[0019] Furthermore, the main enclosure is made of non-woven fabric, and the two ends are wrapped around the enclosure side rods and fixed by wire tying; when the single width of the main enclosure is smaller than the length of the collapse area, multiple enclosure components are connected and arranged;

[0020] In the height direction, the height of the main enclosure is smaller than the height of the collapsed area, and the height setting requirements are met through vertical overlap, and the overlap is not less than 10mm and is tightened with binding.

[0021] Furthermore, when the enclosure assembly is lowered, it is lowered at an angle, and the bottom of the enclosure assembly returns to the specified position, thereby facilitating the insertion of the anchor rod; or a recess is pre-arranged at the main enclosure according to the position of the anchor rod; or the joint of multiple enclosure assemblies is set at the position of the anchor rod.

[0022] Furthermore, when the lower backfill layer is poured in layers through concrete, the original groundwater is slowly squeezed out of the collapsed area and discharged into the foundation pit; when the amount of groundwater is large, the pumping operation is carried out in the early stage, and the concrete is poured only when the water level reaches the pouring design requirements;

[0023] The portion of the upper backfill layer that exceeds the top of the crown beam is set as a slope, and the top surface layer set on the top is poured with concrete to form a hardened surface layer; monitoring points are set at the slope to monitor slope deformation and settlement.

[0024] The beneficial effects of the present invention are embodied in:

[0025] 1) The present invention provides support components and enclosure components, wherein the steel pipes, non-woven fabrics and other materials used are low in cost and easily available, which is convenient for emergency construction; and the support components and enclosure components can further serve as templates to facilitate the subsequent backfilling of the collapsed area;

[0026] 2) The present invention makes full use of effective components such as slope protection piles in the original maintenance structure as the focus point, simplifies the construction process and reduces the construction cost;

[0027] 3) The present invention completely wraps the exposed anchor rods in the collapsed area by filling concrete underwater, restores part of the pile-anchor force system, and increases the reliability of the original support function. By backfilling with bare soil and constructing the surface structure, the original function of the site is restored and the potential safety hazards of the site are eliminated.

[0028] The present invention makes great use of the original effective structures to form a closed system, meet the conditions for pouring concrete, fill the local collapsed parts, restore the integrity of the site, and ensure the safety of subsequent use. Other features and advantages of the present invention will be described in the subsequent description, and partly become obvious from the description, or can be understood by practicing the present invention; the main purpose and other advantages of the present invention can be achieved and obtained through the solutions specifically pointed out in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a side section view of the slope collapse reinforcement structure due to failure of the foundation pit water-stop curtain;

[0030] Figure 2 It is a top view of the slope collapse reinforcement structure due to failure of the foundation pit water-stop curtain;

[0031] Figure 3 It is a schematic diagram of the structure of the enclosure assembly;

[0032] Figure 4 It is a schematic diagram of the reinforcement structure after backfilling.

[0033] Figure markings: 1-foundation pit, 2-base, 3-water level line, 4-slope protection piles, 5-crown beam, 6-anchor rod, 7-landslide slope, 8-collapse area, 9-hanging assembly, 91-hanging rod, 92-hanging adapter, 93-carrying rod, 94-carrying adapter, 95-clamping rod, 10-support assembly, 101-first row of support pipes, 102-second row of support pipes, 11-enclosure assembly, 111-enclosure side rod, 112-main enclosure, 12-backfill interface, 13-slope top, 14-top surface layer, 15-lower backfill layer, 16-upper backfill layer. DETAILED DESCRIPTION

[0034] Taking a new city project as an example, the water-stop curtain on one side of the existing foundation pit fell off, forming a landslide slope and a collapsed area, resulting in the exposure of anchor rods and slope protection piles, and the first three prestressed anchor rods, of which the anchor section is about 0.5 meters long, and clear water seepage can be seen at the bottom of the collapsed part. Underground pressurized water surged and flowed into the foundation pit 1, and the water level line 3 exceeded the elevation of the base 2; in order to deal with the collapse of the foundation pit 1 in time, the foundation pit water-stop curtain failed and the slope collapse reinforcement structure was repaired.

[0035] Combination Figures 1 to 4 As shown in the figure, the failure of the foundation pit water-stop curtain is used to reinforce the slope collapse structure. The specific steps are as follows:

[0036] Step 1: Evaluate the safety of the original curtain support structure to determine whether the structural reliability of the top beam 5 of the slope protection pile 4 and the effectiveness of the original pile anchor components meet the design requirements; check the dangerous factors in the construction area, clean up the unstable soil on the slope, and clean up the debris in the collapse area 8.

[0037] When the structural reliability of the top beam 5 of the slope protection pile 4 and the effectiveness of the original pile anchor components meet the design requirements, determine whether there is no obvious structural damage and displacement in the collapse area 8 and the surrounding slope protection piles 4 and the top beam 5, the base 2 soil is not deformed, and the top beam 5 still has the force performance required by the design, and the exposed anchor rods 6 in the collapse area 8 are intact and meet the design requirements. Perform safety calculations on the slope support system structure to determine whether the support system can resist lateral concrete pressure during concrete pouring.

[0038] Step 2: determine the landslide slope 7, measure the scope of the subsidence area 8; clarify the depth of the subsidence area 8, as well as the width and length of the subsidence area 8 at the ground.

[0039] Step 3: Determine the depth of the support assembly 10 based on the depth of the collapsed area 8, and determine the length of the support assembly 10 based on the length of the collapsed area 8; wherein the support assembly 10 is arranged in a tube row and is divided into two inner and outer rows of a first row of support tubes 101 and a second row of support tubes 102.

[0040] Step 4: pre-install a first row of support pipes 101 on one side of the collapse area 8 near the slope protection piles 4 . After the first row of support pipes 101 are installed, the enclosure assembly 11 is installed, and then a second row of support pipes 102 is installed outside the enclosure assembly 11 .

[0041] Step 5. The top ends of the first row of support tubes 101 and the second row of support tubes 102 are higher than the top elevation of the crown beam 5. The parts of the first row of support tubes 101 and the second row of support tubes 102 extending out of the top of the crown beam 5 are detachably connected with a hanging assembly 9; one end of the hanging assembly 9 is fixedly connected to the extending ends of the first row of support tubes 101 and the second row of support tubes 102, and the other end is hung on the crown beam 5.

[0042] In this embodiment, the hanging assembly 9 comprises a hanging rod 91 arranged vertically, a carrying rod 93 vertically connected to the top of the hanging rod 91, a hanging adapter 92 detachably connected between the hanging rod 91 and the carrying rod 93, a clamping rod 95 arranged horizontally and vertically upward to the carrying rod 93, and a carrying adapter 94 detachably connected between the clamping rod 95 and the carrying rod 93. The hanging rod 91, the carrying rod 93 and the clamping rod 95 are all made of steel pipes, and the hanging adapter 92 and the carrying adapter 94 are both clamping fasteners.

[0043] In this embodiment, when used, the hanging rod 91 is arranged on the side of the crown beam 5 adjacent to the foundation pit 1, the carrying rod 93 is arranged on the top of the crown beam 5 and passes through the first row of support tubes 101 and the second row of support tubes 102; the clamping rod 95 is clamped on the side of the second row of support tubes 102 adjacent to the collapse area 8; the clamping rod 95 is arranged in the length direction of the second row of support tubes 102, and the carrying rod 93 and the hanging rod 91 are arranged at intervals in the length direction of the second row of support tubes 102.

[0044] Among them, the first row of support pipes 101 and the second row of support pipes 102 are driven into the soil at the bottom of the collapse area 8 to a depth of not less than 1500mm, and the steel pipes are continuously arranged along the inner side of the crown beam 5 and fully cover the collapse area 8; the upper part of the first row of support pipes 101 and the second row of support pipes 102 is not less than 200mm higher than the top elevation of the crown beam 5.

[0045] In addition, the strength of the steel pipe is greater than the lateral concrete pressure it can resist during concrete pouring and after stabilization; gaps are provided at the anchor rod 6 positions when the first row of support pipes 101 and the second row of support pipes 102 are installed.

[0046] In this embodiment, the enclosure assembly 11 includes two parallel and vertically arranged enclosure side rods 111 and a main enclosure 112 connected between the two enclosure side rods 111; the enclosure side rods 111 are arranged adjacent to the collapse area 8 and close to the first row of support tubes 101, and a second row of support tubes 102 is arranged outside the main enclosure 112.

[0047] In this embodiment, the main enclosure 112 is made of non-woven fabric, and its two ends are wrapped around the enclosure side rods 111 and fixed by wire tying; when the single width of the main enclosure 112 is smaller than the length of the collapse zone 8, it is connected and arranged by multiple enclosure assemblies 11; in the height direction, the height of the main enclosure 112 is smaller than the height of the collapse zone 8, and the height setting requirements are met by vertical overlap, and the overlap is not less than 10 mm and is tied tightly.

[0048] When the enclosure assembly 11 is lowered, it is lowered at an angle, and the bottom of the enclosure assembly 11 returns to the specified position, thereby facilitating the penetration of the anchor rod 6; or a notch is pre-arranged at the main enclosure 112 according to the position of the anchor rod 6; or the joint of multiple enclosure assemblies 11 is set at the position of the anchor rod 6.

[0049] Step six, adopt the method of underwater concrete pouring, and slowly pour concrete in layers on the underwater collapse area 8 to form a lower backfill layer 15. The top surface elevation of the lower backfill layer 15 exceeds the water surface elevation and is higher than the anchor elevation of the anchor rod 6 at the slope protection pile 4; the top of the lower backfill layer 15 is backfilled with plain soil and compacted to form an upper backfill layer 16; a top surface layer 14 is set on the top of the slope 13 to restore the original hardened site function, thereby completing the reinforcement of the collapsed slope due to the failure of the water-stop curtain of the foundation pit 1.

[0050] In this embodiment, when the lower backfill layer 15 is poured with concrete in layers, the original groundwater is slowly squeezed out of the collapsed area 8 and discharged into the foundation pit 1; when the amount of groundwater is large, pumping operations are carried out in the early stage, and when the water level reaches the pouring design requirements, concrete pouring is carried out; the part of the upper backfill layer 16 that exceeds the top of the crown beam 5 is set as a slope, and the top surface layer 14 set on the top is formed by pouring concrete to form a hardened surface layer; monitoring points are set at the slope to monitor slope deformation and settlement.

[0051] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that a technician familiar with the technical field can think of within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A construction method for reinforcing a foundation pit water-stop curtain failure slope collapse structure, characterized in that: A collapsed area (8) exists on one side of the slope protection pile (4) of the constructed foundation pit (1) and the water-stop curtain falls off. The groundwater below the foundation pit (1) is pressurized groundwater. The groundwater flows into the foundation pit (1) and the water level (3) exceeds the elevation of the base (2). The construction method of the slope collapse reinforcement structure using the failure of the foundation pit water-stop curtain is as follows: Step 1: Evaluate the safety of the original curtain support structure to determine whether the structural reliability of the top beam (5) of the slope protection pile (4) and the effectiveness of the original pile anchor components meet the design requirements; check the dangerous factors in the construction area, clean up the unstable soil on the slope, and clean up the debris in the collapsed area (8); Step 2: determine the landslide slope (7), measure the scope of the subsidence area (8); determine the depth of the subsidence area (8), and the width and length of the subsidence area (8) at the ground surface; Step 3: determining the depth of the support assembly (10) based on the depth of the collapsed area (8), and determining the length of the support assembly (10) based on the length of the collapsed area (8); The support assembly (10) is arranged in a tube row and is divided into two inner and outer rows, a first row of support tubes (101) and a second row of support tubes (102); Step 4: pre-arrange a first row of support pipes (101) on one side of the collapse area (8) near the slope protection piles (4); after the first row of support pipes (101) are installed, the enclosure assembly (11) is installed, and then a second row of support pipes (102) is arranged outside the enclosure assembly (11); Step 5: The top ends of the first row of support tubes (101) and the second row of support tubes (102) are higher than the top elevation of the crown beam (5), and the portions of the first row of support tubes (101) and the second row of support tubes (102) extending out of the top of the crown beam (5) are detachably connected with a hanging assembly (9); wherein one end of the hanging assembly (9) is fixedly connected to the extended ends of the first row of support tubes (101) and the second row of support tubes (102), and the other end is hung on the crown beam (5); Step 6: Use the method of pouring concrete underwater to slowly pour concrete in layers on the underwater collapse area (8) to form a lower backfill layer (15). The top surface elevation of the lower backfill layer (15) exceeds the water surface elevation and is higher than the anchor elevation of the anchor rod (6) at the slope protection pile (4). Use plain soil to backfill and compact it above the lower backfill layer (15) to form an upper backfill layer (16). Set a top surface layer (14) on the top of the slope (13) to restore the original hardened site function, thereby completing the reinforcement of the collapsed slope due to the failure of the foundation pit water-stop curtain.

2. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 1, characterized in that: In step 1, when determining that the structural reliability of the crown beam (5) at the top of the slope protection pile (4) and the effectiveness of the original pile-anchor component meet the design requirements, determine whether the subsidence area (8) and the surrounding slope protection piles (4) and the crown beam (5) have no obvious structural damage and displacement, the soil of the base (2) has no deformation, and the crown beam (5) still has the stress performance required by the design, and whether the exposed anchor rod (6) in the subsidence area (8) is intact and meets the design requirements.

3. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 1, characterized in that: The hanging assembly (9) comprises a hanging rod (91) arranged vertically, a carrying rod (93) vertically connected to the top of the hanging rod (91), a hanging adapter (92) detachably connected between the hanging rod (91) and the carrying rod (93), a clamping rod (95) arranged horizontally and vertically to the carrying rod (93), and a carrying adapter (94) detachably connected between the clamping rod (95) and the carrying rod (93).

4. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 3, characterized in that: The hanging rod (91) is arranged on a side of the crown beam (5) adjacent to the foundation pit (1); the carrying rod (93) is arranged on the top of the crown beam (5) and passes through the first row of support tubes (101) and the second row of support tubes (102); the clamping rod (95) is clamped on a side of the second row of support tubes (102) adjacent to the collapsed area (8); the clamping rod (95) is arranged along the length of the second row of support tubes (102); and the carrying rod (93) and the hanging rod (91) are arranged at intervals along the length of the second row of support tubes (102).

5. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 4, characterized in that: The first row of support pipes (101) and the second row of support pipes (102) are driven into the soil at the bottom of the subsidence area (8) to a depth of not less than 1500 mm. The first row of support pipes (101) and the second row of support pipes (102) are continuously arranged along the inner side surface of the crown beam (5) and completely cover the subsidence area (8). The upper parts of the first row of support pipes (101) and the second row of support pipes (102) are not less than 200 mm above the top elevation of the crown beam (5).

6. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 5, characterized in that: The first row of support pipes (101) and the second row of support pipes (102) are both made of steel pipes, the strength of which is greater than the strength of the steel pipes in resisting lateral concrete pressure during concrete pouring and after stabilization; gaps are provided at the positions of the anchor rods (6) when the first row of support pipes (101) and the second row of support pipes (102) are installed.

7. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 1, characterized in that: The enclosure assembly (11) comprises two enclosure side bars (111) arranged in parallel and vertically, and a main enclosure (112) connected between the two enclosure side bars (111); the enclosure side bars (111) are arranged adjacent to the collapse area (8) and close to the first row of support tubes (101), and a second row of support tubes (102) is arranged outside the main enclosure (112).

8. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 7, characterized in that: The main enclosure (112) is made of non-woven fabric, and its two ends are wrapped around the enclosure side bars (111) and fixed by wire tying; when the width of a single piece of the main enclosure (112) is smaller than the length of the collapsed area (8), multiple enclosure assemblies (11) are connected and arranged; In the height direction, the height of the main enclosure (112) is less than the height of the collapsed area (8), and the height setting requirements are met through vertical overlap, and the overlap is not less than 10 mm and is tightened and tied.

9. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 8, characterized in that: When the enclosure assembly (11) is lowered, it is lowered at an angle, and the bottom of the enclosure assembly (11) is returned to the designated position, thereby facilitating the insertion of the anchor rod (6); or a notch is pre-arranged at the main enclosure (112) according to the position of the anchor rod (6); or the joint of multiple enclosure assemblies (11) is arranged at the position of the anchor rod (6).

10. The construction method of a foundation pit water-stop curtain failure slope collapse reinforcement structure as claimed in claim 1, characterized in that: When the lower backfill layer (15) is poured in layers by concrete, the existing groundwater is slowly squeezed out of the collapsed area (8) and discharged into the foundation pit (1) and pumped out; when the amount of groundwater is large, pumping operations are carried out in the early stage, and concrete pouring is carried out only when the water level reaches the pouring design requirements; The portion of the upper backfill layer (16) that exceeds the top of the crown beam (5) is set as a slope, and the top surface layer (14) set on the top is poured with concrete to form a hardened surface layer; monitoring points are set at the slope to monitor slope deformation and settlement.

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