Reinforcing structure based on existing retaining wall and construction method

Abstract

This application relates to a reinforcement structure and construction method for existing retaining walls, belonging to the field of geotechnical engineering reinforcement and geological disaster management. For soil containing slip surfaces and adjacent retaining walls, a borehole is drilled at a downward angle extending to the far side of the slip surface. A hollow reinforcement rod is inserted into the borehole, equipped with a pressure-responsive barrier to divide the soil into a permeable consolidation zone and a high-strength anchoring zone. A return hole is provided at the borehole end, and a hydrophilic capillary core bundle is arranged inside the rod to reversibly draw out and vaporize water accumulated at the bottom of the borehole. This structure achieves integrated drainage and reinforcement design through a single borehole. The permeable consolidation zone releases hydrostatic pressure behind the wall, alleviating overload, while the high-strength anchoring zone ensures the soil and rod are anchored to resist slip instability and extend the structural lifespan. The capillary core bundle specifically solves the problem of water accumulation in the dead corner of the downward-angled borehole, achieving the goal of synergistic effect between drainage and reinforcement.

Description

Technical Field

[0001] This invention relates to geotechnical engineering reinforcement and geological disaster management, and particularly to a reinforcement structure and construction method based on existing retaining walls. Background Technology

[0002] Against the backdrop of accelerated urbanization and the renovation of old residential areas, existing retaining walls face two core stability risks due to increased service life, drainage system failure, and increased load behind the walls (such as new roads / buildings). These risks include water damage caused by water accumulation softening the soil and reducing bearing capacity, and overloading caused by excessive additional loads on top. At the same time, the limited urban space (narrow alleys, historical districts) and the landscape requirement of "restoring the old as it was" impose rigid constraints on the spatial adaptability (not occupying space outside the wall) and the invisibility (not damaging the landscape) of reinforcement technologies.

[0003] Currently, reinforcement technologies mainly fall into the following three categories: First, pouring a new concrete layer or installing steel ribs on the outside of the existing retaining wall is a reinforcement technique that is limited by insufficient space and landscape damage, making it difficult to apply widely. Secondly, the use of micropiles or anchors to effectively transfer vertical loads to deep, stable foundations can alleviate the large additional loads on the top of existing retaining walls. However, this reinforcement technique results in a gravity drainage dead zone in the boreholes that accommodate the micropiles or anchors due to their downward inclination. This causes water to accumulate and become unable to drain. Long-term water accumulation and softening not only reduce the mechanical parameters of the deep soil but also lead to corrosion of the reinforcing steel in the anchorage section.

[0004] Third, a separate approach was adopted, where anchor holes and drainage holes coexisted, meaning anchor holes and drainage holes were drilled separately. This method increased the number of holes drilled, disturbed the wall structure, and resulted in low construction efficiency.

[0005] Due to the shortcomings of existing technologies, there is an urgent need in this field for a reinforcement technology that reduces disturbance and damage to the soil inside the retaining wall and slows down the soil settlement rate. Summary of the Invention

[0006] This invention provides a reinforcement structure and construction method based on an existing retaining wall. Its purpose is to provide a new reinforcement technology to reduce damage to the inner soil, maintain soil stability, and prevent structural instability.

[0007] To achieve the above objectives, embodiments of the present invention provide a reinforcement structure based on an existing retaining wall, including a retaining wall and soil located on one side of the retaining wall, wherein a slip surface is formed within the soil, including: A borehole (30) is drilled in the retaining wall (10) and the soil (20) and extends in the soil (20) to the side of the slip surface (21) away from the retaining wall (10). Several of the boreholes (30) form a depression angle in the retaining wall (10) and the soil (20), and the depression angle is an acute angle. A hollow reinforcing rod (40) is inserted into the borehole (30). A pressure-responsive barrier (50) is provided on the hollow reinforcing rod (40). The pressure-responsive barrier (50) divides the soil (20) along the length of the borehole (30) into a permeable consolidation zone (60) for filling porous graded permeable mortar and a high-strength anchoring zone (70) for filling non-permeable high-strength grout. The high-strength anchoring zone (70) is located on the side of the permeable consolidation zone (60) away from the retaining wall (10). A return hole is provided on the side of the hollow reinforcing rod (40) near the borehole opening. A hydrophilic capillary core bundle (80) is arranged inside the hollow reinforcing rod (40) to draw water from the bottom of the borehole (30) against gravity.

[0008] Preferably, the pressure-responsive barrier (50) includes a flexible expansion bladder arranged radially on the hollow reinforcing rod (40) and a one-way valve arranged on the flexible expansion bladder. The one-way valve is located on the side of the flexible expansion bladder facing the bottom of the hole, and the one-way valve allows non-permeable high-strength slurry to flow into the flexible expansion bladder from bottom to top.

[0009] Preferably, the hydrophilic capillary core bundle (80) is woven from multiple strands of modified hydrophilic glass fiber bundles or hydrophilic polyester fiber bundles.

[0010] Preferably, a countersunk hole (31) is provided at the opening of the drill hole (30), and a locking anchor is provided at one end of the hollow reinforcing rod (40) near the opening. The locking anchor is located inside the countersunk hole (31), and a decorative cover plate (32) is embedded outside the countersunk hole (31). One end of the hydrophilic capillary core bundle (80) is located inside the hollow reinforced rod (40), and the other end is distributed in the countersunk hole (31).

[0011] Preferably, the porous graded permeable mortar is formed by mixing single-graded aggregate with a particle size of 3mm-10mm with epoxy resin binder.

[0012] This application also provides a construction method applied to the aforementioned reinforced structure, comprising: S10. A number of boreholes (30) with a preset depth and a preset angle are opened on the side of the retaining wall (10) away from the soil (20), and the bottom of each borehole (30) is located at the far end of the slip surface (21). S20. Obtain the interval between the slip surface (21) and the retaining wall (10), and select a hollow reinforcing rod (40) with a length between the interval and the hole depth. A pressure-responsive barrier (50) is fixed on the hollow reinforced rod (40); A reflux hole is made at a preset position between the hollow reinforced rod (40) and the pressure-responsive barrier (50), and a temporary plugging agent (90) is filled into the reflux hole to seal it. S30. Insert the hydrophilic capillary core bundle (80) into the hollow reinforcing rod (40) and fix it; S40. After the hollow reinforcing rod (40) is inserted into the borehole (30), the grouting pipe is inserted through the center of the hollow reinforcing rod (40) to the bottom of the hole. Then, non-permeable high-strength grout is pumped into the borehole (30) at the first preset pressure. When the grouting pressure rises to the second preset pressure, the pumping is stopped and the grout is left to stand for initial solidification. S50. Pump porous graded permeable mortar into the space between the hollow reinforcing rod (40) and the borehole (30) at the third preset pressure until the borehole (30) is filled.

[0013] Preferably, in step S50, after the porous graded permeable mortar has cured, a locking anchor is installed at one end of the hollow reinforcing rod (40) near the hole to fix the hollow reinforcing rod (40) to the retaining wall (10).

[0014] The above-described solution of the present invention has the following beneficial effects: First, this application achieves the concept of integrated reinforcement and drainage by injecting different types of grout into the same borehole. The permeable consolidation zone is filled with porous graded permeable mortar to ensure the release of hydrostatic pressure behind the wall. The high-strength anchoring zone is filled with non-permeable high-strength grout to ensure the anchoring effect between the soil and the hollow reinforcement rod, prevent structural instability, and extend the service life and durability.

[0015] Secondly, the release of pore water behind the wall: the hydrophilic capillary core bundle can draw the water accumulated in the borehole out against gravity and vaporize it in the air, alleviating the problem of water accumulation in dead corners caused by drilling at a downward angle.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the present invention; Figure 2 yes Figure 1 A schematic diagram of part A in the middle; Figure 3 yes Figure 1 A schematic diagram of Part B; Figure 4 This is a schematic diagram of the hollow reinforcing rod and the temporary plugging agent.

[0018] [Explanation of Labels in the Attached Image] 10-Retaining wall, 20-Soil, 21-Slip surface 30 - Drilling, 31 - Countersunk hole, 32 - Decorative cover plate 40-Hollow reinforced rod body 50-Pressure-responsive barrier element 60-Permeable consolidation zone 70-High-strength anchorage zone 80-Hydrophilic capillary flow guide core bundle.

[0019] 90- Temporary plugging agent, 91- Coating, 92- Soluble matter. Detailed Implementation

[0020] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0021] like Figure 1-4 As shown, an embodiment of the present invention provides a reinforcement structure based on an existing retaining wall, including an existing retaining wall 10 and soil 20 disposed on one side of the retaining wall 10, wherein the soil 20 forms a slip surface 21 due to settlement and other reasons.

[0022] The reinforcement structure also includes boreholes 30 drilled within the retaining wall 10 and the soil 20. These boreholes 30 are located on the side of the retaining wall 10 away from the soil 20 and extend towards the soil 20 to the side of the slip surface 21 away from the retaining wall 10. Multiple boreholes 30 are arranged in parallel within the retaining wall 10 and the soil 20, each forming an acute angle of depression. Hollow reinforcement rods 40 are inserted into the boreholes 30, and pressure-responsive barrier elements 50 are installed on the hollow reinforcement rods 40. These pressure-responsive barrier elements 50 divide the soil 20 along the length of the boreholes 30 into a permeable consolidation zone 60 near the retaining wall 10 and a high-strength anchoring zone 70 away from the retaining wall 10. The permeable consolidation zone 60 is filled with porous graded permeable mortar, while the high-strength anchoring zone 70 is filled with impermeable high-strength grout.

[0023] A reflux hole is also provided at one end of the hollow reinforced rod 40 near the orifice.

[0024] A hydrophilic capillary guide core bundle 80 is also provided inside the hollow reinforced rod body 40. The hydrophilic capillary guide core bundle 80 draws out the water accumulated at the bottom of the drill hole 30 in the hollow reinforced rod body 40 against gravity.

[0025] Preferably, the hollow reinforced rod 40 is formed by detachably connecting multiple tubes end to end.

[0026] Based on the concept of integrated soil consolidation and drainage, this application divides the soil 20 into zones using a pressure-responsive barrier 50, forming two different functional zones within the same borehole 30: a permeable consolidation zone 60 and a high-strength anchoring zone 70. This ensures both the pull-out and shear bearing capacity of the hollow reinforcement rod 40 and the release of water pressure from the soil 20.

[0027] The high-strength anchoring zone 70 is filled with a non-permeable high-strength grout. After curing, the non-permeable high-strength grout can provide sufficient anchoring force for the hollow reinforced rod 40, ensuring that the grout, soil 20, and hollow reinforced rod 40 in the high-strength anchoring zone 70 can bear sufficient pull-out or shear bearing capacity.

[0028] The permeable consolidation zone 60 is filled with porous graded permeable mortar. The porous graded permeable mortar is formed by mixing single graded aggregate with a particle size of 3mm-10mm with epoxy resin binder. The solidified filled porous graded permeable mortar has a porosity of more than 20%, which can effectively release the net water pressure behind the wall. The pore water can enter the bottom of the borehole 30 through the permeable consolidation zone 60 and the return hole. Under the action of the surface tension of the hydrophilic capillary guide core bundle 80 and the humidity gradient formed by the evaporation of the hollow reinforcing rod 40, the pore water at the bottom of the borehole 30 can be effectively drawn out and vaporized.

[0029] By combining the hollow reinforcing rod 40 and the hydrophilic capillary guide core bundle 80, the problem of water accumulation at the bottom of the borehole 30 in traditional technology cannot be drained, eliminating the hidden danger of deep water accumulation softening the soil 20. It also reduces the number of boreholes 30 and avoids the soil 20 from being disturbed and damaged, thus preventing the soil 20 from settling more severely.

[0030] The pressure-responsive barrier 50 includes a flexible expansion bladder ringed around the hollow reinforcing rod 40. This expansion bladder can increase its volume to seal the borehole 30, preventing the mixing of porous graded permeable mortar and impermeable high-strength grout during grouting. A one-way valve is also installed on the flexible expansion bladder. This one-way valve is located at the bottom of the flexible expansion bladder and opens downwards, allowing the impermeable high-strength grout to flow upwards into the flexible expansion bladder.

[0031] Once the impermeable high-strength grout fills the high-strength anchoring zone 70, it enters the flexible expansion bag through a one-way valve, radially expanding the flexible expansion bag along the borehole 30, thus achieving the sealing effect of the flexible expansion bag. Under the action of the one-way valve, the impermeable high-strength grout in the flexible expansion bag cannot flow out.

[0032] In this embodiment, the check valve is a duckbill valve made of rubber.

[0033] Furthermore, the hydrophilic capillary core bundle 80 is woven from multiple strands of modified hydrophilic glass fiber bundles or hydrophilic polyester fiber bundles. The outer wall of the hollow reinforced rod body 40 is coated with an anti-corrosion coating to ensure the long-term service performance of this application in humid environments.

[0034] A countersunk hole 31 is formed at the opening of the borehole 30. A locking anchor is provided at one end of the hollow reinforcing rod 40 near the opening. The locking anchor is fixed in the countersunk hole 31 to fix the hollow reinforcing rod 40. The aforementioned hydrophilic capillary guide core bundle 80 is fixed in the hollow reinforcing rod 40, with one end located at the bottom of the borehole 30 and the other end distributed in the countersunk hole 31.

[0035] Preferably, a decorative cover plate 32 is provided outside the countersunk hole 31, which is used to seal and decorate the countersunk hole 31.

[0036] In this application, the countersunk hole 31 and the locking anchor embedded in the countersunk hole 31 can prevent the hollow reinforcement rod 40 from occupying the red line space outside the wall during construction. The appearance after reinforcement can be consistent with the original wall, which perfectly meets the needs of urban micro-renewal and historical building protection.

[0037] This application also provides a construction method for the aforementioned reinforced structure, comprising the following steps: S10. A borehole 30 is provided on one side of the soil 20 of the retaining wall 10. Multiple boreholes 30 are provided, and the bottom of each borehole 30 is located at the far end of the slip surface 21.

[0038] A countersunk hole 31 is drilled on the side of the existing retaining wall 10 away from the soil 20 using a drilling tool. Then, a drilling tool with a drill bit is used to drill a hole 30 in the countersunk hole 31 towards the soil 20. The hole 30 is drilled according to a preset depth and preset angle of depression. The depth of the hole 30 should be greater than the distance between the slip surface 21 and the retaining wall 10, that is, the bottom of the hole 30 should be located on the side of the slip surface 21 away from the retaining wall 10. The hole diameter should be greater than the diameter of the hollow reinforcing rod 40.

[0039] S20. Obtain the distance between the slip surface 21 and the retaining wall 10, and select a hollow reinforcing rod 40 with a length between the distance between the slip surface and the hole depth; fix a pressure-responsive barrier 50 on the hollow reinforcing rod. Make a return hole at a preset position between the hollow reinforcing rod 40 and the pressure-responsive barrier 50, and fill the return hole with a temporary plugging agent 90 to seal the return hole; The distance between the slip surface 21 and the retaining wall 10 is estimated using existing technology. A hollow reinforcing rod 40 that meets the length requirements is selected. The length of the hollow reinforcing rod 40 is between the distance between the slip surface 21 and the hole depth.

[0040] A pressure-responsive barrier 50 is fixed to the hollow reinforcing rod 40, and the position of the one-way valve is adjusted so that the one-way valve opening faces the bottom of the hole. A reflux hole is formed on the hollow reinforcing rod 40, and the distance between the reflux hole and the pressure-responsive barrier 50 meets a preset value. In this application, the reflux hole is located between the top of the hollow reinforcing rod 40 and the pressure-responsive barrier 50, biased towards the pressure-responsive barrier 50. A temporary plugging agent 90 is filled into the formed reflux hole to seal it. In this application, the temporary plugging agent 90 is in a solid state when anhydrous, which can seal the reflux hole. Under long-term contact with water, the temporary plugging agent 90 begins to slowly dissolve, losing its sealing effect, so that the reflux hole resumes its water-guiding function.

[0041] In this application, the temporary plugging agent 90 includes a solid soluble substance 92 and a coating 91 encapsulating the soluble substance 92. The coating 91 is a hydrophobic material or a slow-release membrane. The coating 91 effectively prevents moisture from contacting pore water or water in the grout, thus sealing the return hole during grouting. After the grout solidifies, the coating 91 gradually breaks down under long-term infiltration of pore water, and the soluble substance 92 begins to slowly dissolve, restoring the water-conducting function of the return hole.

[0042] In this embodiment, the soluble substance 92 can be industrial rock, urea, etc., and the hydrophobic material can be paraffin wax.

[0043] Preferably, in this application, the return hole is funnel-shaped, and the diameter of the end of the return hole near the outer wall of the hollow reinforcing rod 40 is smaller than the diameter of the end near the inner wall of the hollow reinforcing rod 40. The funnel-shaped return hole reduces the contact area with the porous graded permeable mortar by utilizing the smaller diameter end, thereby slowing down the damage rate of the coating 91 and allowing more time for the porous graded permeable mortar to solidify. Furthermore, when the coating 91 is damaged, pore water enters the grouting hole and comes into contact with the coating 91 located on the side with the larger diameter of the grouting hole. At this time, the contact area between the pore water and this part of the coating 91 is relatively large, which can accelerate the dissolution rate of this part of the coating 91. This allows for faster opening of the grouting hole after the porous graded permeable mortar has solidified, enabling the application to be put into use sooner.

[0044] S30. Insert the hydrophilic capillary core bundle 80 into the hollow reinforcing rod 40 and fix it.

[0045] The hydrophilic capillary core bundle 80 is inserted into the hollow reinforcing rod 40, and both ends extend out of the hollow reinforcing rod 40 and are fixed respectively.

[0046] S40. After the hollow reinforcing rod 40 is inserted into the borehole 30, the grouting pipe is inserted through the center of the hollow reinforcing rod 40 to the bottom of the hole. Then, non-permeable high-strength grout is pumped into the borehole 30 at the first preset pressure. When the grouting pressure rises to the second preset pressure, the pumping is stopped and the grout is left to stand for initial solidification.

[0047] The hollow reinforcing rod 40 is inserted into the borehole 30, with a distance reserved between the bottom of the hollow reinforcing rod 40 and the bottom of the hole. The grouting pipe is inserted through the center of the hollow reinforcing rod 40 to the bottom of the hole, and impermeable high-strength grout is pumped into the borehole 30 at a first preset pressure. As the impermeable high-strength grout is pumped in, the grout level in the high-strength anchoring zone 70 of the borehole 30 increases, and after filling, it enters the flexible expansion bag through a one-way valve, causing the flexible expansion bag to expand radially along the borehole 30. As the grouting pressure fed back by the impermeable high-strength grout increases, when it increases to a second preset pressure, it indicates that the flexible expansion bag has expanded to the preset volume and can completely seal the borehole 30. At this point, grouting is stopped, and the borehole is left to solidify.

[0048] S50. Pump porous graded permeable mortar into the space between the hollow reinforcing rod 40 and the borehole 30 at the third preset pressure until the borehole 30 is filled.

[0049] After the impermeable high-strength grout solidifies, porous graded permeable mortar is pumped between the hollow reinforcing rod 40 and the borehole 30 at a third preset pressure until the space between them is filled with porous graded permeable mortar. After the porous graded permeable mortar has solidified, a locking anchor is installed at the end of the hollow reinforcing rod 40 near the borehole opening to fix the hollow reinforcing rod 40 to the retaining wall 10.

[0050] Because a temporary plugging agent 90 is installed at the grouting hole, the non-permeable high-strength grout and porous graded permeable mortar will not flow out of the grouting hole when flowing through the return hole. After the two grouts solidify, the pore water in the soil 20 is in long-term contact with the temporary plugging agent 90, which damages the coating 91, causing the temporary plugging agent 90 to lose its sealing effect. The pore water can flow into the hollow reinforcing rod 40 through the grouting hole and flow to the bottom of the hole under the action of gravity. The pore water and other accumulated water deposited at the bottom of the hole are vaporized into the air through the hydrophilic capillary guide core bundle 80, thus completing the drainage of the water accumulated at the bottom of the hole.

[0051] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A reinforcement structure based on an existing retaining wall, comprising a retaining wall (10) and soil (20) located on one side of the retaining wall (10), wherein a slip surface (21) is formed within the soil (20), characterized in that, include: A borehole (30) is drilled in the retaining wall (10) and the soil (20) and extends in the soil (20) to the side of the slip surface (21) away from the retaining wall (10). Several of the boreholes (30) form a depression angle in the retaining wall (10) and the soil (20), and the depression angle is an acute angle. A hollow reinforcing rod (40) is inserted into the borehole (30). A pressure-responsive barrier (50) is provided on the hollow reinforcing rod (40). The pressure-responsive barrier (50) divides the soil (20) along the length of the borehole (30) into a permeable consolidation zone (60) for filling porous graded permeable mortar and a high-strength anchoring zone (70) for filling non-permeable high-strength grout. The high-strength anchoring zone (70) is located on the side of the permeable consolidation zone (60) away from the retaining wall (10). A return hole is provided on the side of the hollow reinforcing rod (40) near the borehole opening. A hydrophilic capillary core bundle (80) is arranged inside the hollow reinforcing rod (40) to draw water from the bottom of the borehole (30) against gravity.

2. The reinforcement structure based on an existing retaining wall according to claim 1, characterized in that: The pressure-responsive barrier (50) includes a flexible expansion bladder arranged radially on the hollow reinforcing rod (40) and a one-way valve arranged on the flexible expansion bladder. The one-way valve is located on the side of the flexible expansion bladder facing the bottom of the hole and allows non-permeable high-strength slurry to flow into the flexible expansion bladder from bottom to top.

3. The reinforcement structure based on an existing retaining wall according to claim 1, characterized in that: The hydrophilic capillary core bundle (80) is woven from multiple strands of modified hydrophilic glass fiber bundles or hydrophilic polyester fiber bundles.

4. The reinforcement structure based on an existing retaining wall according to claim 3, characterized in that: The borehole (30) has a countersunk hole (31) at the opening. The hollow reinforcing rod (40) is provided with a locking anchor at one end near the opening. The locking anchor is located inside the countersunk hole (31), and a decorative cover plate (32) is embedded outside the countersunk hole (31). One end of the hydrophilic capillary core bundle (80) is located inside the hollow reinforced rod (40), and the other end is distributed in the countersunk hole (31).

5. The reinforcement structure based on an existing retaining wall according to claim 1, characterized in that: The porous graded permeable mortar is formed by mixing single-graded aggregate with a particle size of 3mm-10mm with epoxy resin binder.

6. A construction method applied to the reinforced structure according to any one of claims 1-5, characterized in that, include: S10. A number of boreholes (30) with a preset depth and a preset angle are opened on the side of the retaining wall (10) away from the soil (20), and the bottom of each borehole (30) is located at the far end of the slip surface (21). S20. Obtain the interval between the slip surface (21) and the retaining wall (10), and select a hollow reinforcing rod (40) with a length between the interval and the hole depth. A pressure-responsive barrier (50) is fixed on the hollow reinforced rod (40); A reflux hole is made at a preset position between the hollow reinforced rod (40) and the pressure-responsive barrier (50), and a temporary plugging agent (90) is filled into the reflux hole to seal it. S30. Insert the hydrophilic capillary core bundle (80) into the hollow reinforcing rod (40) and fix it; S40. After the hollow reinforcing rod (40) is inserted into the borehole (30), the grouting pipe is inserted through the center of the hollow reinforcing rod (40) to the bottom of the hole. Then, non-permeable high-strength grout is pumped into the borehole (30) at the first preset pressure. When the grouting pressure rises to the second preset pressure, the pumping is stopped and the grout is left to stand for initial solidification. S50. Pump porous graded permeable mortar into the space between the hollow reinforcing rod (40) and the borehole (30) at the third preset pressure until the borehole (30) is filled.

7. The construction method according to claim 6, characterized in that: In step S50, after the porous graded permeable mortar has cured, a locking anchor is installed at one end of the hollow reinforcing rod (40) near the hole to fix the hollow reinforcing rod (40) to the retaining wall (10).

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