A diversion and reinforcement method for underground structure in karst area

Abstract

The application provides a diversion and reinforcement method for underground structures in karst areas, comprising the following specific steps: determining the position of an emergency diversion hole according to the position of a cave cavity and the position of an unfavorable anti-floating bottom plate of an underground structure; vertically drilling the emergency diversion hole and sleeving an emergency diversion pipe in the emergency diversion hole, wherein the emergency diversion pipe is provided with a plurality of water permeable holes; from bottom to top, grouting the emergency diversion pipe located below the cave cavity, in the cave cavity and between the top end of the cave cavity and the bottom plate of the underground structure; closing the emergency diversion pipe located in the bottom plate of the underground structure by a first closing plate; grouting the emergency diversion pipe in the bottom plate of the underground structure; closing the orifice of the emergency diversion pipe by a second closing plate and grouting the emergency diversion pipe in the orifice. The application can overcome the potential risks caused by the traditional karst cavity treatment process, effectively control the risk of sudden gushing water during the construction period of the underground structure and the risk of uneven settlement during the later operation.

Description

Technical Field

[0001] This invention relates to the field of flood control, and more particularly to a method for diverting and reinforcing underground structures in karst areas. Background Technology

[0002] Karst landforms are widely distributed in my country, especially in Guizhou, Yunnan, and the Lingnan provinces of Guangdong and Guangxi. Due to the numerous karst caves, their irregular distribution and structure, and abundant groundwater, water-rich karst areas are prone to geological disasters such as sudden water inrushes during deep foundation pit construction. This not only affects the smooth construction of deep foundation pits but may also damage the safety of the pits and the surrounding environment. Therefore, in the event of a sudden water inrush, rapid and efficient low-risk control is essential. However, neither direct filling nor pre-diversion followed by filling methods can achieve rapid, efficient, and precise control of karst water inrushes. Furthermore, the partial closure of karst cavities creates the potential hazard of water accumulation. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a diversion and reinforcement method for underground structures in karst areas. This method overcomes the potential risks associated with traditional karst cavity treatment processes and effectively controls the risks of sudden water inrush during the construction period and uneven settlement during later operation of underground structures.

[0004] To achieve the above objectives, the present invention provides a method for diverting and reinforcing underground structures in karst areas. 1. A method for diverting and reinforcing underground structures in karst areas, wherein the underground structure comprises, from top to bottom, an underground structure base slab, a cushion layer, and a stable rock layer, wherein a waterproof layer is located within the cushion layer, and the karst cavity is located within the stable rock layer, characterized by comprising the following specific steps:

[0005] S1. Determine the location of the emergency diversion hole based on the location of the karst cave cavity and the unfavorable location of the underground structure's bottom slab for anti-buoyancy.

[0006] S2. Vertically drill an emergency diversion hole, the bottom of which is located within a stable rock layer below the cave cavity; install an emergency diversion pipe inside the emergency diversion hole, the pipe having several permeable holes; by providing permeable holes, the sudden gushing water in the cave cavity can be discharged through the emergency diversion pipe, thus preserving the cave cavity's ability to handle sudden gushing water.

[0007] S3. When the monitoring of the heave of the underground structure floor slab and the sudden water inrush in the karst cavity meet the reinforcement standards, grouting is carried out from bottom to top into the emergency diversion pipes located below the karst cavity, inside the karst cavity, and between the top of the karst cavity and the underground structure floor slab.

[0008] S4. The emergency diversion pipe located in the underground structure floor slab is sealed by the first sealing plate to form the first anti-seepage system in the emergency diversion pipe;

[0009] S5. Grouting is carried out into the emergency diversion pipe inside the underground structure base slab to form a second anti-seepage system inside the emergency diversion pipe;

[0010] S6. Seal the opening of the emergency diversion pipe with the second sealing plate, and inject grout into the emergency diversion pipe at the opening to form the third anti-seepage system inside the emergency diversion pipe.

[0011] This invention, through the aforementioned diversion and reinforcement method, preserves the flow capacity of sudden water inrush within the karst cavity. Utilizing the permeable holes in the emergency diversion pipe within the cavity area, it initially serves as the primary drainage channel for emergency diversion within the underground structure and for sudden water inrush. Later, grouting rapidly transforms the emergency diversion pipe into an anti-uplift pile within the underground structure, and a three-layer anti-seepage system is implemented simultaneously. This resists the damage caused by sudden water inrush within the karst cavity while eliminating the potential for leakage, effectively overcoming the potential risks associated with traditional karst cavity treatment processes.

[0012] Optionally, the unfavorable location for buoyancy resistance of the underground structure's bottom slab in step S1 is calculated based on the buoyancy of the sudden inrush water in the karst cavity and the soil thickness at the top of the karst cavity.

[0013] Optionally, in step S2, vertical drilling of the emergency diversion hole specifically includes: using water-cooled drilling to drill through the underground structure's base slab, waterproof layer, and cushion layer, and then using an engineering drilling rig to drill through to the stable rock layer below the karst cavity. Water-cooled drilling can avoid damage to the drilling rig caused by the reinforced concrete structure in the underground structure's base slab, waterproof layer, or cushion layer.

[0014] Optionally, in step S2, a one-way valve is provided on the permeable hole located in the cave cavity to prevent the sudden flow of water in the emergency diversion pipe 7 from entering the cave cavity 2.

[0015] Optionally, in step S3, the specific method for grouting the emergency diversion pipe located below the karst cavity is as follows: the grout is injected into the emergency diversion pipe below the karst cavity in sections from bottom to top. The grout is injected in sections by sealing the holes in sections, which results in high grouting accuracy and controllable grouting effect.

[0016] Optionally, in step S3, the specific method for injecting grout into the emergency diversion pipe located between the top of the karst cavity and the bottom slab of the underground structure is as follows: the grout is injected into the emergency diversion pipe in sections between the top of the karst cavity and the bottom slab of the underground structure. By injecting the grout in sections, the grouting accuracy is high and the grouting effect is controllable.

[0017] Optionally, after step S6, the method further includes: filling the opening of the emergency diversion hole with micro-expansion grouting material so that the opening of the emergency diversion hole is flush with the surface of the underground structure bottom plate.

[0018] Optionally, the outer wall of the emergency diversion pipe is treated with an anti-corrosion layer to prevent the emergency diversion pipe from being corroded.

[0019] Optionally, the emergency diversion tube may be implanted entirely or welded into the emergency diversion hole in sections. The weld seams of the segmented emergency diversion tube shall be treated with anti-corrosion measures to reduce rusting at the weld seams and extend the service life of the emergency diversion tube.

[0020] Optionally, the slurry injected in steps S3 to S6 is a non-aqueous reactive two-component polyurethane.

[0021] Beneficial effects:

[0022] This invention, through the aforementioned diversion and reinforcement method, preserves the flow capacity of sudden water inrush within the karst cavity. Utilizing the permeable holes in the emergency diversion pipe within the cavity area, it initially serves as the primary drainage channel for emergency diversion within the underground structure and for sudden water inrush. Later, grouting rapidly transforms the emergency diversion pipe into an anti-uplift pile for the underground structure, simultaneously implementing a three-layer anti-seepage system. This resists the damage caused by sudden water inrush within the karst cavity while eliminating the risk of leakage. It effectively overcomes the potential risks associated with traditional karst cavity treatment processes, facilitating the control of sudden water inrush risks during underground structure construction and uneven settlement risks during later operation. The ingenious structural design and full utilization of component functions truly achieve precise control over the entire process of karst sudden water inrush risks. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a cross-sectional view of the diversion structure in the diversion and reinforcement method for underground structures in karst areas disclosed in this invention;

[0025] Figure 2 This is a cross-sectional view of the emergency diversion pipe grouting below the cavity of a karst cave in the diversion and reinforcement method for underground structures in karst areas disclosed in this invention.

[0026] Figure 3 This is a cross-sectional view of the emergency diversion pipe grouting inside the cavity of a karst cave and between the top of the cavity and the bottom slab of the underground structure in the diversion and reinforcement method for underground structures in karst areas disclosed in this invention.

[0027] Figure 4 This is a cross-sectional view of the first seepage prevention system of the diversion and reinforcement method for underground structures in karst areas disclosed in this invention;

[0028] Figure 5 This is a cross-sectional view of the second seepage prevention system in the diversion and reinforcement method for underground structures in karst areas disclosed in this invention;

[0029] Figure 6 This is a cross-sectional view of the third seepage prevention system and sealing treatment in the diversion and reinforcement method for underground structures in karst areas disclosed in this invention.

[0030] Attached reference numerals: 1. Emergency diversion hole; 2. Cave cavity; 3. Underground structural base plate; 4. Waterproof layer; 5. Cushion layer; 6. Stabilized rock layer; 7. Emergency diversion pipe; 8. Water-permeable hole; 9. Anti-corrosion layer; 10. One-way valve; 11. Rebar installation; 12. Sediment; 14. First sealing plate; 15. First grouting hole; 16. Second sealing plate; 17. Micro-expansion grouting material

[0031] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0034] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0035] See Figure 1 According to an embodiment of the present invention, a method for diverting and reinforcing underground structures in karst areas, the underground structure includes, from top to bottom, an underground structure base slab 3, a cushion layer 5, and a stable rock layer 6, wherein a waterproof layer 4 is located within the cushion layer 5, and a karst cavity 2 is located within the stable rock layer 6, comprising the following specific steps:

[0036] S1. Determine the location of emergency diversion hole 1 based on the location of the karst cavity 2 and the unfavorable location of the underground structure bottom plate 3 for anti-buoyancy.

[0037] Based on the buoyancy of the sudden inrush water in the cavity 2 and the soil thickness at the top of the cavity 2, the unfavorable location for buoyancy resistance of the underground structure's bottom slab 3 is calculated. The emergency diversion hole 1 is located near the unfavorable location for buoyancy resistance and should avoid the foundation beams and post-cast strips of the underground structure.

[0038] S2. Drill an emergency diversion hole 1 vertically. The bottom end of the emergency diversion hole 1 is located in the stable rock layer 6 below the cave cavity 2. Install an emergency diversion pipe 7 inside the emergency diversion hole 1. Set several water-permeable holes 8 on the emergency diversion pipe 7.

[0039] To avoid damage to the drilling rig caused by the reinforced concrete structure in the underground structure slab 3, waterproof layer 4, or cushion layer 5, water drilling is first used to drill through the underground structure slab 3, waterproof layer 4, and cushion layer 5; then, engineering drilling rigs are used to drill through the stable rock layer 6 below the cushion layer 5, so that the bottom of the emergency diversion hole 1 can be drilled through to the stable rock layer 6 below the karst cavity 2.

[0040] The emergency diversion pipe 7 is made of steel or similar materials. First, permeable holes 8 are evenly distributed on the emergency diversion pipe 7, and then the emergency diversion pipe 7 is inserted into the emergency diversion hole 1. By providing the permeable holes 8, the sudden surge of water in the karst cave cavity 2 can be discharged through the emergency diversion pipe 7, thus preserving the flow capacity of the karst cave cavity 2. During the diversion process, the sediment 12 at the bottom of the emergency diversion pipe 7 does not require special treatment; it can be cemented later by grouting. The emergency diversion pipe 7 is anchored to the underground structural base slab 3 using reinforcing bars 11. To prevent corrosion of the emergency diversion pipe 7, an anti-corrosion layer 9 is provided on its outer wall.

[0041] S3. During the construction of the underground structure, the heave of the underground structure's base slab 3 is monitored using methods such as elevation measurement and vertical displacement detection of soil layers. The volume of water seeping into the karst cavity 2 is also monitored using a flow meter. When the heave of the base slab 3 drops to the same level as the non-heave portion, avoiding the potential occurrence of water seepage in the karst cavity 2, and when the water volume is low, grouting is performed from bottom to top into the emergency diversion pipe 7 located below the karst cavity 2, inside the karst cavity 2, and between the top of the karst cavity 2 and the base slab 3. This segmented grouting method ensures high precision and controllable grouting effect.

[0042] S4. The emergency diversion pipe 7 located within the underground structure floor slab 3 is sealed by the first sealing plate 14, forming the first anti-seepage system within the emergency diversion pipe 7. The inner wall of the emergency diversion pipe 7 located within the underground structure floor slab 3 is sealed by fully welding the first sealing plate 14.

[0043] S5. Grouting is injected into the emergency diversion pipe 7 within the underground structure base slab 3 to form a second anti-seepage system within the emergency diversion pipe 7. An appropriate amount of non-aqueous reactive two-component polyurethane is injected to fill and diffuse it to the periphery of the emergency diversion hole 1 and the pores between the emergency diversion hole 1 and the waterproof layer 4 and the cushion layer 5, thereby repairing the waterproof system located below the underground structure base slab 3 that was damaged by the installation of the emergency diversion hole 1.

[0044] S6. Seal the opening of the emergency diversion pipe 7 with the second sealing plate, and inject grout into the emergency diversion pipe 7 at the opening to form the third anti-seepage system inside the emergency diversion pipe 7.

[0045] The inner wall of the emergency diversion pipe 7 at the opening of the emergency diversion hole 1 is sealed by fully welding the second sealing plate 16. An appropriate amount of non-aqueous reactive two-component polyurethane is injected into the emergency diversion pipe 7 at the opening to form a third anti-seepage system inside the emergency diversion pipe 7.

[0046] This invention, through the aforementioned diversion and reinforcement method, preserves the flow capacity of sudden-rush water in the karst cavity 2. Utilizing the permeable holes 8 in the emergency diversion pipe 7 within the karst cavity 2 area, it initially serves as the primary drainage channel for emergency diversion of the underground structure and the main discharge channel for sudden-rush water. Later, grouting rapidly transforms the emergency diversion pipe 7 into an anti-uplift pile for the underground structure, and a three-layer anti-seepage system is simultaneously implemented. This resists the damage caused by sudden-rush water within the karst cavity while eliminating the potential for leakage, achieving precise control over the risk of sudden-rush water in underground structures under construction in karst areas throughout the entire process.

[0047] See Figure 1 In some embodiments of the present invention, a one-way valve 10 is provided on the permeable hole 8 located in the cave cavity 2. By providing a one-way valve 10 on the permeable hole 8, the sudden gushing water in the cave cavity 2 can enter the emergency diversion pipe 7, while the sudden gushing water in the emergency diversion pipe 7 cannot enter the cave cavity 2, thereby preserving the flow capacity of the sudden gushing water in the cave cavity 2.

[0048] See Figure 1 In some embodiments of the present invention, the specific method for injecting grout into the emergency diversion pipe 7 located below the karst cavity 2 in step S3 is as follows:

[0049] Inside the emergency diversion pipe 7, non-aqueous reactive two-component polyurethane is injected in stages from bottom to top through sealing and sealing. Utilizing the permeable holes 8 of the emergency diversion pipe 7, rapid solidification and hardening of the internal filling and external wrapping of the stable rock stratum 6 are achieved, providing significant pull-out resistance to resist the buoyancy of sudden water inrushes in the karst cavity 2. This staged sealing and injection of non-aqueous reactive two-component polyurethane ensures high grouting precision and controllable grouting effects.

[0050] See Figure 1In some embodiments of the present invention, the specific method for grouting the emergency diversion pipe 7 located in the cavity 2 of the karst cave in step S3 is as follows: Grouting the emergency diversion pipe 7 in the cavity 2 of the karst cave, firstly calculate the internal cavity volume of the emergency diversion pipe 7, and achieve low-pressure and high-efficiency filling of non-aqueous reactive two-component polyurethane grout by controlling the grouting amount and grouting rate.

[0051] See Figure 1 In some embodiments of the present invention, the specific method for injecting the emergency diversion pipe 7 located between the top of the karst cavity 2 and the underground structural slab 3 in step S3 is as follows: Non-aqueous reactive two-component polyurethane is injected into the emergency diversion pipe 7 between the top of the karst cavity 2 and the underground structural slab 3 in stages with sealed openings. By injecting the non-aqueous reactive two-component polyurethane in stages with sealed openings, the grouting accuracy is high and the grouting effect is controllable.

[0052] See Figure 6 In some embodiments of the present invention, after step S6, the method further includes: filling the opening of the emergency diversion hole 1 with micro-expansion grout 17 so that the opening of the emergency diversion hole 1 is flush with the surface of the underground structure bottom plate 3, so that the surface of the underground structure is restored to the state before the construction of the emergency diversion hole 1, which facilitates the normal functioning of the underground structure.

[0053] See Figure 1 In some embodiments of the present invention, the emergency diversion pipe 7 is implanted entirely or welded in sections into the emergency diversion hole 1. The weld seams of the segmented emergency diversion pipe 7 are treated with anti-corrosion measures to reduce rusting at the weld seams and extend the service life of the emergency diversion pipe 7.

[0054] See Figure 1 In some embodiments of the present invention, the first sealing plate 14 and the second sealing plate 16 are respectively provided with a first grouting hole 15 and a second grouting hole, and the grout is injected into the underground structure bottom plate 3 or the inner cavity of the emergency diversion pipe 7 at the opening of the emergency diversion pipe 7 through the first grouting hole 15 and the second grouting hole respectively.

[0055] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for diverting and reinforcing underground structures in karst areas, wherein the underground structure comprises, from top to bottom, an underground structure base slab, a cushion layer, and a stable rock layer, wherein a waterproof layer is located within the cushion layer, and karst cavities are located within the stable rock layer, characterized in that, The specific steps include the following: S1. Determine the location of the emergency diversion hole based on the location of the karst cave cavity and the unfavorable location of the underground structure's bottom slab for anti-buoyancy. S2. Drill an emergency diversion hole vertically, with the bottom end of the emergency diversion hole located in a stable rock layer below the cavity of the karst cave; install an emergency diversion pipe inside the emergency diversion hole, with several water-permeable holes on the emergency diversion pipe; S3. When the monitoring of the heave of the underground structure floor slab and the sudden water inrush in the karst cavity meet the reinforcement standards, grouting is carried out from bottom to top into the emergency diversion pipes located below the karst cavity, inside the karst cavity, and between the top of the karst cavity and the underground structure floor slab. S4. The emergency diversion pipe located in the underground structure floor slab is sealed by the first sealing plate to form the first anti-seepage system in the emergency diversion pipe; S5. Grouting is carried out into the emergency diversion pipe inside the underground structure base slab to form a second anti-seepage system inside the emergency diversion pipe; S6. Seal the opening of the emergency diversion pipe with the second sealing plate, and inject grout into the emergency diversion pipe at the opening to form the third anti-seepage system inside the emergency diversion pipe.

2. The diversion and reinforcement method according to claim 1, characterized in that, The unfavorable location for buoyancy resistance of the underground structure bottom plate in step S1 is calculated based on the buoyancy of the sudden inrush water in the karst cavity and the soil thickness at the top of the karst cavity.

3. The diversion and reinforcement method according to claim 1, characterized in that, In step S2, the vertical drilling of the emergency diversion hole specifically includes: using a water drill to drill through the underground structure's bottom slab, waterproof layer, and cushion layer, and then using an engineering drilling rig to drill through to the stable rock layer below the karst cavity.

4. The diversion and reinforcement method according to claim 1, characterized in that, In step S2, a one-way valve is installed on the water-permeable hole located in the cavity of the karst cave.

5. The diversion and reinforcement method according to claim 1, characterized in that, In step S3, the slurry is injected into the emergency diversion pipe below the cavity of the karst cave in sections from bottom to top.

6. The diversion and reinforcement method according to claim 1, characterized in that, In step S3, the slurry is injected in sections into the emergency diversion pipe between the top of the cave cavity and the bottom plate of the underground structure.

7. The diversion and reinforcement method according to claim 1, characterized in that, Step S6 is followed by filling the opening of the emergency diversion hole with micro-expansion grouting material so that the opening of the emergency diversion hole is flush with the surface of the underground structure bottom plate.

8. The diversion and reinforcement method according to any one of claims 1-7, characterized in that, The outer wall of the emergency diversion pipe is treated with an anti-corrosion layer.

9. The diversion and reinforcement method according to claim 8, characterized in that, The emergency diversion pipe is either inserted entirely or welded into the emergency diversion hole in sections, and the weld seams of the sectioned emergency diversion pipe are treated with anti-corrosion measures.

10. The diversion and reinforcement method according to claim 8, characterized in that, The slurry injected in steps S3 to S6 is a non-aqueous reactive two-component polyurethane.

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