A waterproof and drainage structure and construction method in a single-layer lining of a super-large-span hard-rock cavern

Abstract

The present invention discloses a waterproof and drainage structure and a construction method in a single-layer lining of a super-large-span hard-rock cavern, which relates to the technical field of drainage of super-large-span underground projects. It includes a cavern surrounding rock, in which there are main seepage fissures. The waterproof and drainage structure includes a waterproof concrete layer, an elastic waterproof cushion layer, and a reinforced concrete layer arranged in sequence from left to right. Before the construction of the waterproof concrete layer, the main seepage fissures are treated first. A treatment component is arranged in the main seepage fissures, and a drainage component is arranged in the elastic waterproof cushion layer. The treatment component is connected to the drainage component. The structure of the present invention has durability. The waterproof concrete layer, the elastic waterproof cushion layer, and the reinforced concrete layer form a three-level waterproof barrier, as well as measures such as a drainage network, effectively blocking the groundwater seepage path, delaying the corrosion of the lining steel bars, prolonging the service life of the structure, and providing long-term reliable waterproof protection for super-large-span caverns.

Description

Technical Field

[0001] The present invention relates to the technical field of drainage for extra-large-span underground engineering, and particularly to a waterproof and drainage structure and construction method in a single-layer lining of an extra-large-span hard-rock cavern. Background Art

[0002] In the construction of extra-large-span hard-rock caverns, with the increase of the span, the lining structure faces more complex deformation and seepage pressure problems. Especially for an extra-large-span underground cavern with a span of 80 meters, its lining thickness is limited, and the conventional waterproof and drainage system is difficult to effectively cope with the deformation and seepage challenges it brings. The traditional waterproof and drainage design usually relies on rigid structures, which are prone to problems such as structural cracking and leakage when facing large-span and highly deformed caverns. The layout of waterproof drainage pipes in the prior art often has defects such as unreasonable arrangement and unsmooth drainage channels, and fails to effectively consider the convergence deformation of the cavern and the change of water flow pressure, resulting in water retention or pipe blockage, thus affecting the long-term stability of the system.

[0003] At the same time, there are also great challenges in the maintenance of the traditional drainage system. Especially in a complex underground environment, the waterproof and drainage facilities are easily blocked by sediment or corroded, resulting in a decline in the drainage effect and increasing the maintenance cost during long-term operation. In addition, the installation and debugging work of the traditional system during the construction process is cumbersome, the construction period is long, and a large amount of labor and on-site adjustment are often required, which not only increases the construction cost but also affects the construction progress of the project. Therefore, there is an urgent need for a new waterproof and drainage system that can effectively meet the special needs of extra-large-span caverns and provide a more reliable waterproof and drainage solution. Summary of the Invention

[0004] In view of the above technical problems, the present invention discloses a waterproof and drainage structure in a single-layer lining of an extra-large-span hard-rock cavern, including a cavern surrounding rock, in which there are main water seepage fissures. The waterproof and drainage structure includes a waterproof concrete layer, an elastic waterproof cushion layer, and a reinforced concrete layer arranged in sequence from left to right. Before the waterproof concrete layer is constructed, the main water seepage fissures are treated. A treatment component is arranged in the main water seepage fissures, and a drainage component is arranged in the elastic waterproof cushion layer. The treatment component is connected to the drainage component;

[0005] The treatment component includes a filter sand pipe, which is a gravel filter sand pipe, and a first gravel layer is arranged in the filter sand pipe.

[0006] Further, the waterproof concrete layer includes a first-layer waterproof concrete, which is constructed on the outer side of the cavern surrounding rock. When the first-layer waterproof concrete is constructed, a plurality of stainless steel brackets are pre-embedded, and the plurality of stainless steel brackets are evenly distributed along the height direction of the cavern surrounding rock.

[0007] Further, the elastic waterproof cushion layer includes an elastic cushion layer, which is made of polyurethane elastomer and is spray-formed on site with seamless joints. The drainage component is arranged inside the elastic cushion layer, and a polyurea waterproof coating is sprayed on the outer side of the elastic cushion layer.

[0008] Further, the reinforced concrete layer includes concrete canvas, which is connected to the polyurea waterproof coating. Round holes are formed in the concrete canvas, anchor rods are arranged in the round holes, the anchor rods are connected to the drainage component, and a steel mesh is hung on the anchor rods. After reinforced concrete is sprayed on the steel mesh, primary lining concrete is formed. An inspection door is arranged on the reinforced concrete layer.

[0009] Further, the drainage component includes two drain pipes, and the two drain pipes are connected by a six-way joint. One drain pipe penetrates the six-way joint from bottom to top, and the other drain pipe penetrates the six-way joint from right to left. The anchor rod is inserted into the six-way joint from the rear inlet and penetrates out from the front inlet of the six-way joint. Sealing rings are arranged at the joints of the six-way joint and the drain pipes, and a sealing ring is arranged at the front inlet of the six-way joint, while no sealing ring is arranged at the rear inlet of the six-way joint. The drain pipes are made of high-density ethylene material, the drain pipes are connected to stainless steel brackets, and the drain pipes are connected to filter sand pipes through flexible joints.

[0010] Further, the appearance of the drain pipe is designed with a gradient that is thick at the bottom and thin at the top.

[0011] Further, a detachable filter sand component is connected to the bottom of the drain pipe, and the position of the detachable filter sand component matches the position of the inspection door. The detachable filter sand component includes a filter sand tank, and a water inlet is arranged at the top end of the filter sand tank. The water inlet is connected to the bottom of the drain pipe. A quartz sand layer and a second gravel layer are arranged in the filter sand tank from top to bottom in sequence. A filtering pipe is arranged in the second gravel layer, and the filtering pipe is connected to the inside of the filter sand tank. A water outlet is connected to the filtering pipe, and the water outlet is connected to the bottom end of the filter sand tank. The water outlet is connected to a drainage ditch.

[0012] Further, a plurality of uniformly distributed drain pipes are connected to the filter sand tank.

[0013] The present invention also discloses a construction method for the waterproof and drainage structure in a single-layer lining of a super-large-span hard rock cavern, and the specific steps are as follows:

[0014] Step 1: The surrounding rock of the cavern is scanned by a geological radar, and then core drilling is carried out, and the treatment component is placed into the drill hole.

[0015] Step 2: Install the drain pipes and anchor rods, construct the waterproof concrete layer and embed a plurality of stainless steel brackets, connect the drain pipes to the plurality of stainless steel brackets, and then connect the drain pipes to the anchor rods through a six-way joint.

[0016] Step 3: Apply an elastic waterproof cushion layer. Spray an elastic cushion layer on the waterproof concrete layer to cover the drain pipes and the first layer of waterproof concrete, and then spray a polyurea waterproof coating on the outer side of the elastic cushion layer.

[0017] Step 4: Install a detachable sand filtration component connection every twenty meters along the length direction of the surrounding rock of the cavern. The bottoms of all drain pipes within each interval of twenty meters are all connected to the detachable sand filtration component.

[0018] Step 5: Apply a reinforced concrete layer on the outer layer of the polyurea waterproof coating.

[0019] The beneficial effects of the present invention compared with the prior art are as follows:

[0020] (1) Excellent deformation adaptability. By combining the elastic cushion layer and the polyurea waterproof coating, a certain sliding space is reserved between the drain pipes and the stainless - steel brackets, which can adapt to the convergence deformation of a cavern with a span of 80 meters. Compared with the traditional rigid structure, the leakage risk is reduced, and the durability of the structure is significantly improved.

[0021] (2) The active drainage system enhances the structural safety. By installing sand - filtering pipes at the water - seepage fissures to pre - treat the concentrated water flow, and combining with a drain - pipe network that is thick at the bottom and thin at the top, and using a six - way joint to integrate the bolt and the outlet of the sand - filtering pipe, an efficient drainage path design is achieved. This system actively guides the groundwater to drain out, avoiding the direct erosion of the water pressure on the lining structure, significantly reducing the leakage risk, and enhancing the safety of the cavern.

[0022] (3) The modular maintenance design prolongs the system life. By combining a switchable inspection door with a stainless - steel sand - filtering tank, using sand - filtering pipes for primary coarse filtration and a stone - sand - filtering tank for secondary fine filtration, a hierarchical filtration system is achieved. The sediment interception efficiency is improved, and the impurities in the quartz - sand filtration layer can be cleaned regularly to prevent the drain pipes from being blocked, reducing the later maintenance cost. The stainless - steel material of the sand - filtering tank and the brackets enhances the corrosion resistance, adapts to the humid environment, and significantly improves the durability and service life of the waterproof and drainage system.

[0023] (4) The construction efficiency and economy are improved. The six - way joint integrates the functions of drainage and bolt - positioning waterproofing, reducing the number of on - site drill holes and connectors, shortening the construction period. The drain pipes are light and durable, and the polyurethane elastomer spraying process simplifies the process, reducing the labor cost, taking into account both construction efficiency and economy.

[0024] (5) The structural durability is guaranteed. The waterproof concrete layer, the elastic cushion layer and the polyurea coating form a three - level waterproof barrier, as well as measures such as the drainage network, effectively blocking the groundwater seepage path, delaying the corrosion of the lining steel bars, extending the structure life, and providing long - term reliable waterproof protection for the super - large - span cavern.

[0025] (6) Construction is convenient and integrated with the structure. Modular prefabricated drain pipes, sand filtration pipes, and spray-formed elastic cushions reduce on-site splicing joints and improve construction efficiency. The integrated design of anchor bolts, six-way joints, and steel bar meshes enables simultaneous waterproofing and drainage and initial support, shortening the construction period. Description of the Drawings

[0026] Figure 1 This is a schematic diagram of the overall structure of the waterproofing and drainage structure for a super-large-span single-layer lining chamber of the present invention.

[0027] Figure 2 This is a sectional view of the waterproofing and drainage structure for a super-large-span single-layer lining chamber of the present invention.

[0028] Figure 3 This is a schematic diagram of the connection relationship between the anchor bolt and the drain pipe of the present invention.

[0029] Figure 4 This is a schematic diagram of the internal structure of the sand filtration tank of the present invention.

[0030] Figure 5 This is a schematic diagram of the sand filtration pipe structure of the present invention.

[0031] Reference numerals in the drawings: 1 - sand filtration pipe; 2 - drain pipe; 3 - first layer of waterproof concrete; 4 - stainless steel support; 5 - six-way joint; 6 - anchor bolt; 7 - elastic cushion; 8 - polyurea waterproof coating; 9 - sand filtration tank; 10 - concrete canvas; 11 - primary lining concrete; 12 - drainage ditch; 13 - inspection door; 14 - main seepage fissure; 15 - sealing ring; 16 - second gravel layer; 17 - water inlet; 18 - quartz sand layer; 19 - filtering pipe; 20 - water outlet. Detailed Embodiment

[0032] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0033] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0035] Embodiment: As Figures 1-5 shown, a waterproof and drainage structure in a single-layer lining of a super-large-span hard rock cavern includes the surrounding rock of the cavern. There are main seepage fissures 14 in the surrounding rock of the cavern. The waterproof and drainage structure includes a waterproof concrete layer, an elastic waterproof cushion layer, and a reinforced concrete layer arranged in sequence from left to right. Before the construction of the waterproof concrete layer, the main seepage fissures 14 are processed. A treatment component is arranged in the main seepage fissures 14, and a drainage component is arranged in the elastic waterproof cushion layer. The treatment component is connected to the drainage component; the treatment component includes a filter sand pipe 1. The filter sand pipe 1 uses a gravel filter sand pipe. A first gravel layer is arranged in the filter sand pipe 1. A filter layer is formed by piling up the first gravel layer. The particle size of the gravel in the first gravel layer is 10-20 mm. The pores between the first gravel layers are large and the water permeability is good, meeting the large-flow drainage requirements in the tunnel, so that water can quickly pass through the filter sand pipe 1 and enter the drainage component for discharge.

[0036] The waterproof concrete layer includes a first-layer waterproof concrete 3. The first-layer waterproof concrete 3 is constructed on the outer side of the surrounding rock of the cavern. When the first-layer waterproof concrete 3 is constructed, a plurality of stainless steel brackets 4 are embedded. The plurality of stainless steel brackets 4 are evenly distributed along the height direction of the surrounding rock of the cavern.

[0037] The elastic waterproof cushion layer includes an elastic cushion layer 7. The elastic cushion layer 7 uses a polyurethane elastomer and is formed by on-site spraying with seamless joints, adapting to complex curved surfaces. The drainage component is arranged in the elastic cushion layer 7. A polyurea waterproof coating 8 is sprayed on the outer side of the elastic cushion layer 7.

[0038] The reinforced concrete layer includes a concrete canvas 10. The concrete canvas 10 is connected to the polyurea waterproof coating 8. Round holes are formed in the concrete canvas 10. Anchor bolts 6 are arranged in the round holes. The anchor bolts 6 are connected to the drainage component. A steel mesh is hung on the anchor bolts 6. After spraying reinforced concrete on the steel mesh, a primary lining concrete 11 is formed, realizing the dynamic coupling of rigid support and flexible drainage and integrating the drainage and support structures. An inspection door 13 is arranged on the reinforced concrete layer. A rubber sealing ring is arranged in the inspection door 13, and a pressure sensor is installed on the inspection door 13.

[0039] The drainage assembly includes two drain pipes 2. The two drain pipes 2 are connected by a six-way joint 5. One drain pipe 2 penetrates the six-way joint 5 from bottom to top, and the other drain pipe 2 penetrates the six-way joint 5 from right to left. The anchor rod 6 is inserted into the six-way joint 5 from the rear inlet and passes through the front inlet of the six-way joint 5. Sealing rings 15 are provided at the connections between the six-way joint 5 and the drain pipes 2. The sealing rings 15 are made of medical-grade silicone material. A sealing ring 15 is provided at the front inlet of the six-way joint 5, and no sealing ring 15 is provided at the rear inlet of the six-way joint 5. The drain pipes 2 are made of high-density ethylene material. The drain pipes 2 are connected to the stainless steel brackets 4, and a certain sliding space is reserved between the drain pipes 2 and the stainless steel brackets 4. The drain pipes 2 are connected to the sand filter pipes 1 through flexible joints. The appearance of the drain pipes 2 is designed with a gradient of thick at the bottom and thin at the top. The bottom diameter of the drain pipes 2 is 150 mm, and the top diameter of the drain pipes 2 is 100 mm. The slope is ≥3%.

[0040] The bottom of the drain pipe 2 is connected with a detachable sand filtering assembly. The position of the detachable sand filtering assembly matches the position of the inspection door 13. Through the inspection door 13, it is convenient for the staff to regularly check and repair the detachable sand filtering assembly. The detachable sand filtering assembly includes a sand filtering tank 9. The sand filtering tank 9 is made of stainless steel material. An inlet 17 is provided at the top end of the sand filtering tank 9. The inlet 17 is connected to the bottom of the drain pipe 2. A quartz sand layer 18 and a second gravel layer 16 are sequentially arranged in the sand filtering tank 9 from top to bottom. The particle size of the quartz sand in the quartz sand layer 18 is 0.5 - 1 mm, and the thickness of the quartz sand layer 18 is 300 mm. A filtering pipe 19 is arranged in the second gravel layer 16. The filtering pipe 19 is connected to the inside of the sand filtering tank 9. An outlet 20 is connected to the filtering pipe 19. The outlet 20 is connected to the bottom end of the sand filtering tank 9. The outlet 20 is connected to a drainage ditch 12. Through the primary filtration of the treatment assembly and the secondary filtration of the detachable sand filtering assembly, the interception efficiency is >95%.

[0041] A construction method for the waterproof and drainage structure in a single-layer lining of a super-large-span hard rock cavern warehouse is as follows:

[0042] Step 1: The surrounding rock of the cavern is scanned by a geological radar to determine the position, width and water seepage volume of the main water seepage fissures 14 in the surrounding rock of the cavern. Mark the main water seepage fissures 14, draw a water seepage distribution map, screen the key areas, install the treatment assembly at the place where the water seepage volume is >5 L / min·m, and then drill a hole with a diameter of 250 mm and a depth of 2000 mm. Put the treatment assembly into the drill hole and connect it to the drain pipe 2;

[0043] Step 2: Install the drain pipe 2 and the anchor rod 6. First, excavate the surrounding rock of the cavern, apply a waterproof concrete layer and pre-embed multiple stainless steel brackets 4. Connect the drain pipe 2 with the multiple stainless steel brackets 4, leaving a certain sliding space between the drain pipe 2 and the stainless steel brackets 4. Then, the drain pipe 2 forms a cross shape through the six-way joint 5, and the anchor rod 6 penetrates through the six-way joint 5 for grouting. After grouting and fixing, use polyurethane sealant to seal the interface.

[0044] Step 3: Apply an elastic waterproof cushion layer. Spray the elastic cushion layer 7 on the waterproof concrete layer. The thickness of the elastic cushion layer 7 is 15 mm, and the elongation rate is ≥ 500%. It covers the drain pipe 2 and the first layer of waterproof concrete 3. Then, spray a polyurea waterproof coating 8 on the outside of the elastic cushion layer 7. The thickness of the polyurea waterproof coating 8 is 2 mm, and the tensile strength is 20 MPa.

[0045] Step 4: Set a detachable sand filtering component every twenty meters along the length direction of the surrounding rock of the cavern. The water inlet 17 at the top of the sand filtering tank 9 in the detachable sand filtering component is connected to the bottoms of all the drain pipes 2 every twenty meters, and the water outlet 20 at the bottom of the sand filtering tank 9 is connected to the drainage ditch 12.

[0046] Step 5: Apply a reinforced concrete layer on the outer layer of the polyurea waterproof coating 8. Lay the concrete canvas 10 on the outer layer of the polyurea waterproof coating 8, and then water it to make the concrete canvas 10 solidify. The anchor rod 6 passes through the round holes on the concrete canvas 10 and a steel mesh is hung. Spray the first layer of waterproof concrete C30 to reinforce the concrete. When laying the concrete canvas 10 and spraying the first layer of waterproof concrete C30 to reinforce the concrete, reserve the position of the inspection door 13 in advance.

[0047] For those skilled in the art, various corresponding changes or deformations can be made to the above technical methods and concepts, and all such changes or deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A waterproof and drainage structure in a single-layer lining of a super-large-span hard-rock cavern, comprising a cavern surrounding rock, and there are main water seepage fissures (14) in the cavern surrounding rock, characterized in that: The waterproof and drainage structure includes a waterproof concrete layer, an elastic waterproof cushion layer, and a reinforced concrete layer arranged in sequence from left to right. Before the construction of the waterproof concrete layer, the main seepage fissures (14) are first treated. A treatment component is arranged in the main seepage fissures (14), a drainage component is arranged in the elastic waterproof cushion layer, and the treatment component is connected to the drainage component; The treatment component includes a filter sand pipe (1), and the filter sand pipe (1) is a gravel filter sand pipe. A first gravel layer is arranged in the filter sand pipe (1); The reinforced concrete layer includes a concrete canvas (10). The concrete canvas (10) is connected to a polyurea waterproof coating (8). Round holes are formed in the concrete canvas (10). Anchor bolts (6) are arranged in the round holes. The anchor bolts (6) are connected to the drainage component. A steel mesh is hung on the anchor bolts (6). After shotcrete is sprayed on the steel mesh, primary lining concrete (11) is formed. An inspection door (13) is arranged on the reinforced concrete layer; The drainage component includes two drain pipes (2). The two drain pipes (2) are connected through a six-way joint (5). One drain pipe (2) penetrates the six-way joint (5) from bottom to top, and the other drain pipe (2) penetrates the six-way joint (5) from right to left. The anchor bolt (6) is inserted into the six-way joint (5) from the rear inlet and penetrates out of the six-way joint (5) from the front inlet; The elastic waterproof cushion layer includes an elastic cushion layer (7). The elastic cushion layer (7) is made of a polyurethane elastomer, is formed by on-site spraying, and has a seamless joint. The drainage component is arranged in the elastic cushion layer (7), and a polyurea waterproof coating (8) is sprayed on the outer side of the elastic cushion layer (7).

2. The waterproof and drainage structure in the single-layer lining of a super-large-span hard-rock cavern as described in claim 1, characterized in that: The waterproof concrete layer includes a first layer of waterproof concrete (3). The first layer of waterproof concrete (3) is constructed on the outer side of the chamber surrounding rock. A plurality of stainless steel brackets (4) are embedded during the construction of the first layer of waterproof concrete (3). The plurality of stainless steel brackets (4) are evenly distributed along the height direction of the chamber surrounding rock.

3. The waterproof and drainage structure in the single-layer lining of a super-large-span hard-rock cavern as described in claim 1, wherein: Sealing rings (15) are arranged at the joints of the six-way joint (5) and the drain pipes (2). A sealing ring (15) is arranged at the front inlet of the six-way joint (5), and no sealing ring (15) is arranged at the rear inlet of the six-way joint (5). The drain pipes (2) are made of high-density ethylene material. The drain pipes (2) are connected to the stainless steel brackets (4), and the drain pipes (2) are connected to the filter sand pipe (1) through flexible joints.

4. The waterproof and drainage structure in the single-layer lining of a super-large-span hard-rock cavern as claimed in claim 1, characterized in that: The appearance of the drain pipe (2) is designed with a gradient of thick at the bottom and thin at the top.

5. The drainage prevention structure in a single-layer lining of a super-large-span hard rock cavern as claimed in claim 1, wherein: A detachable sand filtering assembly is connected to the bottom of the drain pipe (2). The position of the detachable sand filtering assembly matches the position of the inspection door (13). The detachable sand filtering assembly includes a sand filtering tank (9). An inlet (17) is arranged at the top end of the sand filtering tank (9). The inlet (17) is connected to the bottom of the drain pipe (2). A quartz sand layer (18) and a second gravel layer (16) are sequentially arranged in the sand filtering tank (9) from top to bottom. A filtering pipe (19) is arranged in the second gravel layer (16). The filtering pipe (19) is connected to the inside of the sand filtering tank (9). An outlet (20) is connected to the filtering pipe (19). The outlet (20) is connected to the bottom end of the sand filtering tank (9). The outlet (20) is connected to a drainage ditch (12).

6. The construction method of a waterproof and drainage structure in a single-layer lining of a super-large-span hard rock cavern as described in any one of the above claims 1-5, characterized in that, The specific steps are as follows: Step 1: The surrounding rock of the cavern is scanned by a geological radar, and then core drilling is carried out. The treatment assembly is placed into the drill hole. Step 2: Install the drain pipe (2) and the anchor rod (6). Apply a waterproof concrete layer and embed multiple stainless steel brackets (4). Connect the drain pipe (2) to the multiple stainless steel brackets (4), and then connect the drain pipe (2) to the anchor rod (6) through a six-way joint (5). Step 3: Apply an elastic waterproof cushion layer. Spray an elastic cushion layer (7) on the waterproof concrete layer to cover the drain pipe (2) and the first layer of waterproof concrete (3), and then spray a polyurea waterproof coating (8) on the outside of the elastic cushion layer (7). Step 4: Connect a detachable sand filtering assembly every twenty meters along the length direction of the surrounding rock of the cavern. The bottoms of all the drain pipes (2) within each interval of twenty meters are connected to the detachable sand filtering assembly. Step 5: Apply a reinforced concrete layer on the outer layer of the polyurea waterproof coating (8).

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