Pressure-released waterproof and drainage method suitable for water-rich soft surrounding rock tunnel
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN XIXING HIGHWAY ENGINEERING QUALITY INSPECTION CO LTD
- Filing Date
- 2026-06-11
- Publication Date
- 2026-08-07
AI Technical Summary
现有凸壳式排水板能够在一定程度上为初期支护与二次衬砌之间提供排水空间，但其抗压变形能力有限
[0026]1）本发明通过在双层凸壳排水板之间设置弹性让压构件，使防排水板在发挥排水作用的同时，能够主动吸收初期支护与二次衬砌之间的变形压力。在围岩发生大变形时，弹性让压构件发生可控压缩，为衬砌结构提供让压空间，避免刚性支护承受过大荷载，显著提高了支护系统的适应性和安全性。
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Figure CN122523091A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of tunnel engineering support and drainage technology, and specifically relates to a pressure-yielding drainage method suitable for water-rich soft surrounding rock tunnels. Background Technology
[0002] During the construction and operation of tunnels in water-rich, soft surrounding rock, the low strength, significant softening upon contact with water, and poor self-stabilizing ability of the surrounding rock make the tunnel prone to continuous deformation after excavation, which can lead to large deformation disasters in severe cases. Large deformation of the surrounding rock can not only cause cracking of the initial support, deformation of the steel frame, and spalling of shotcrete, but may also further compress the secondary lining, affecting the structural safety of the tunnel.
[0003] Among existing large deformation control technologies, yielding support measures are widely used, such as yielding steel frames, yielding anchors, and yielding joints. The basic idea of this type of measure is to allow the surrounding rock to deform within a certain range while ensuring the support constraint capacity, so as to release some stress in the surrounding rock and reduce the concentrated load borne by the support structure.
[0004] However, in water-rich, soft surrounding rock tunnels, large deformations of the surrounding rock are often accompanied by groundwater seepage. When the initial support deforms under pressure, the space between the initial support and the secondary lining is compressed or even pressed together, leading to blockage of the drainage channels behind the lining. Poor drainage causes the water pressure behind the lining to continuously increase, resulting in lining cracking, water leakage, structural deterioration, and even localized damage. Existing convex shell drainage boards can provide drainage space between the initial support and the secondary lining to a certain extent, but their compressive deformation resistance is limited. Under conditions of large surrounding rock deformation or high water pressure, the convex shell structure is easily flattened or damaged, leading to a decrease in drainage capacity. Therefore, it is necessary to propose a new drainage method that combines pressure-bearing support capacity, compressive deformation resistance, and continuous drainage capacity. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pressure-yielding drainage method suitable for water-rich, soft surrounding rock tunnels.
[0006] The objective of this invention is achieved through the following technical solution:
[0007] A pressure-relief drainage method suitable for water-rich, soft surrounding rock tunnels includes the following steps:
[0008] Initial support is applied to the surface of the water-rich, soft surrounding rock of the excavated tunnel.
[0009] A double-layer convex shell type pressure relief drainage board is laid on the surface of the initial support. The double-layer convex shell type pressure relief drainage board has a first convex shell drainage layer close to the initial support, a second convex shell drainage layer away from the initial support, and an elastic pressure relief member disposed between the first convex shell drainage layer and the second convex shell drainage layer.
[0010] A secondary lining is constructed so that the double-layer convex shell pressure relief drainage board is located between the initial support and the secondary lining.
[0011] The first and second convex shell drainage layers form a drainage space, and when the surrounding rock deforms, the elastic compression of the elastic pressure relief member absorbs the deformation pressure between the initial support and the secondary lining. At the same time, the double-layer convex shell pressure relief drainage board retains drainage channels after being compressed, so as to drain the water behind the lining.
[0012] Furthermore, the compression amount of the elastic pressure-relieving member after the secondary lining is poured is greater than 1.0-1.5 times the pre-designed deformation amount of the tunnel.
[0013] Furthermore, the arrangement density of the elastic pressure-relieving members is 12 to 20 per square meter, and their stiffness is configured such that, in the final compressed state after the secondary lining is poured, the load borne by the first convex shell drainage layer does not exceed 70% of its compressive strength.
[0014] Furthermore, the formula for calculating the stiffness of the elastic relief member is:
[0015]
[0016] in, The total stiffness of the elastically compressive member, expressed in N / m; This is the resultant force of the surrounding rock pressure, expressed in N / m. The maximum compression is designed in meters (m). The pressure is the water pressure behind the lining, measured in Pa. The area of the secondary lining subjected to water pressure is expressed in m² / m. The calculation formula is:
[0017]
[0018] in, The dynamic viscosity of water is expressed in Pa·s, and is taken as 0.001 Pa·s at room temperature. The seepage flow rate per unit length of tunnel, expressed in m³ / (s·m), is determined based on the engineering hydrogeological conditions. The characteristic length of the drainage path, in meters; The equivalent permeability of the initial drainage layer is expressed in m² and is determined by indoor water flow tests. The strain of the compressible body of the drainage layer is dimensionless. ,in This represents the initial height of the convex shell. Dimensionless for the maximum allowable compressible strain; The non-Darcy flow inertia coefficient is expressed in m⁻¹. This is the density of water, expressed in kg / m³. This represents the initial total drainage cross-sectional area, in m² / m.
[0019] Furthermore, the first convex shell drainage layer and the second convex shell drainage layer are respectively provided with a plurality of outwardly protruding convex shell units, and longitudinal or circumferential drainage channels are formed between adjacent convex shell units.
[0020] Furthermore, the bottom of the double-layer convex shell pressure relief drainage board is connected to the longitudinal drainage pipe or circumferential drainage blind pipe of the tunnel.
[0021] Furthermore, even after the first convex shell drainage layer is partially damaged, the second convex shell drainage layer still maintains drainage space.
[0022] Furthermore, the protrusion height of the convex shell in the first convex shell drainage layer is 15mm to 30mm, and the protrusion height of the convex shell in the second convex shell drainage layer is 10mm to 20mm, and the protrusion height of the convex shell in the first convex shell drainage layer is greater than or equal to the protrusion height of the convex shell in the second convex shell drainage layer; the initial distance between the back surface of the first substrate and the back surface of the second substrate is 5mm to 15mm. The convex shell is a hemispherical or frustum-shaped hollow shell structure, arranged in a quincunx or rectangular array on its respective substrate.
[0023] Furthermore, the elastic pressure-relieving component is a helical spring, a disc spring, a rubber spring, or a composite elastic component.
[0024] Furthermore, it also includes a waterproof membrane layer, which is disposed on the side of the second convex shell drainage layer near the secondary lining.
[0025] The beneficial effects of this invention are:
[0026] 1) This invention, by setting an elastic pressure-relief member between the double-layer convex shell drainage boards, enables the drainage boards to actively absorb the deformation pressure between the initial support and the secondary lining while performing their drainage function. When large deformations occur in the surrounding rock, the elastic pressure-relief member undergoes controllable compression, providing pressure-relief space for the lining structure, avoiding excessive load on the rigid support, and significantly improving the adaptability and safety of the support system.
[0027] 2) This invention employs a first convex shell drainage layer and a second convex shell drainage layer stacked together. Even if the first convex shell layer is locally damaged or flattened due to large deformation of the surrounding rock, the second convex shell drainage layer can still maintain an independent drainage space. This redundant design ensures that the groundwater behind the lining can be continuously discharged, effectively preventing drainage system failure, and is especially suitable for extreme working conditions such as high water pressure and large deformation.
[0028] 3) Due to the presence of elastic pressure-relieving components, a certain drainage gap is always maintained between the initial support and the secondary lining, avoiding the problems of traditional drainage boards being completely crushed and drainage channels being blocked under large deformations. The continuous unobstructed drainage channels allow the water pressure behind the lining to be effectively released, significantly reducing the risk of secondary lining cracking, leaking, or being partially damaged due to excessive water pressure, and improving the long-term operational safety of the tunnel. Attached Figure Description
[0029] Figure 1 This is a flowchart of a pressure-relief drainage method applicable to water-rich, soft surrounding rock tunnels in this invention.
[0030] Figure 2 Schematic diagram of a double-layer convex shell type pressure-relief drainage board structure;
[0031] Figure 3 This is a cross-sectional view of a double-layered convex shell type pressure-relief drainage board;
[0032] Figure 4 Diagram showing the application of double-layer convex shell pressure-relief drainage boards in tunnel lining structures.
[0033] In the figure, 1. Double-layer convex shell type pressure relief drainage board; 2. First convex shell drainage layer; 3. Second convex shell drainage layer; 4. Elastic pressure relief component. Detailed Implementation
[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.
[0035] See Figures 1-4 The present invention provides a technical solution:
[0036] like Figures 1-4 As shown, a pressure-yielding drainage method suitable for water-rich, soft surrounding rock tunnels includes the following steps:
[0037] After the tunnel excavation is completed, the initial support is first constructed according to the design requirements. The initial support may include support structures such as steel arches, shotcrete, anchor bolts or steel mesh.
[0038] After the initial support is completed and reaches the design strength, clean the surface dust and sharp protrusions, and begin laying the double-layer convex shell pressure relief drainage board 1.
[0039] The double-layer convex shell type pressure-relief drainage board 1 is a prefabricated composite structure, including a first convex shell drainage layer 2 (near the initial support side), whose convex shell protrusion height is 15mm to 30mm, and 25mm in this embodiment. The shell is a hemispherical hollow structure, and the convex shells are arranged in a quincunx pattern. The second convex shell drainage layer 3 (near the secondary lining side) has a convex shell height of 10mm to 20mm (this parameter range is the optimal range calculated by the mechanical matching model. If the convex shell height is less than 15mm, the drainage capacity is insufficient; if the initial spacing is less than 5mm, the elastic pressure relief adjustment space is limited, and neither can simultaneously meet the requirements of pressure relief and drainage coordination). It is also a hemispherical hollow structure and made of the same material.
[0040] like Figure 2 and Figure 3 As shown, elastic pressure-relieving components 4 are evenly arranged between the two drainage layers. In this embodiment, compression springs made of stainless steel are selected. The spring arrangement density is 12 to 20 per square meter. It is required that the compression amount of the springs after the secondary lining is poured is not less than 1.2 times the design allowable deformation amount of the tunnel.
[0041] The physical parameters of the tunnel are taken as follows: , , , , , , , , , , , The calculation yields:
[0042] The total stiffness of the elastically compressive member is calculated as follows:
[0043]
[0044] The tunnel has a circumferential length of 12 m per meter, and the density of elastic pressure-relief components is 16 per square meter. Therefore, the total number of elastic pressure-relief components per meter is... If there are [number] members, the required stiffness of a single elastic relief member is calculated as follows:
[0045]
[0046] like Figure 4 As shown, the first convex shell drainage board is positioned near the initial support, and the second convex shell drainage board is positioned near the secondary lining. Both the first and second convex shell drainage boards are equipped with multiple convex shell units, forming drainage channels between the convex shell units. After groundwater enters behind the lining, it can flow along the drainage channels into the longitudinal drainage pipe or the circumferential drainage blind pipe, and finally be discharged outside the tunnel structure.
[0047] An elastic pressure-relieving component is disposed between the first and second convex shell drainage plates. In this embodiment, the elastic pressure-relieving component is preferably a spring assembly. The spring assemblies can be arranged in an array along the longitudinal and circumferential directions of the tunnel, or they can be arranged more densely according to the locations where the surrounding rock deformation is concentrated.
[0048] When large deformation occurs in water-rich, weak surrounding rock, the rock pressure is transferred to the double-layered convex shell pressure-relief drainage board through the initial support. At this time, the elastic pressure-relief component undergoes compressive deformation, absorbing some of the deformation energy and providing a controllable pressure-relief space between the initial support and the secondary lining. Because the elastic pressure-relief component has a certain restoring force, the double-layered convex shell pressure-relief drainage board is not easily completely flattened, thus maintaining the drainage channel.
[0049] When the first convex shell drainage plate is damaged by localized concentrated pressure, the second convex shell drainage plate can still maintain basic drainage space, preventing the drainage system from completely failing. This reduces the water pressure behind the lining and decreases the risk of secondary lining cracking, leakage, and damage.
[0050] A waterproof membrane layer can also be installed on the side of the second convex shell drainage board near the secondary lining to improve the overall waterproof performance. The waterproof membrane layer can be composited with the second convex shell drainage board or laid separately on site.
[0051] This invention, through the combination of "double-layer convex shell drainage layer + elastic pressure relief component", can maintain an effective drainage channel under large deformation conditions, reduce the water pressure of the lining, and provide a controllable pressure relief space, which significantly improves the long-term safety and durability of the tunnel lining structure in water-rich soft surrounding rock.
[0052] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.
Claims
1. A pressure-relief drainage method applicable to tunnels in water-rich, soft surrounding rock, characterized in that: Includes the following steps: Initial support is applied to the surface of the water-rich, soft surrounding rock of the excavated tunnel. A double-layer convex shell type pressure relief drainage board is laid on the surface of the initial support. The double-layer convex shell type pressure relief drainage board has a first convex shell drainage layer close to the initial support, a second convex shell drainage layer away from the initial support, and an elastic pressure relief member disposed between the first convex shell drainage layer and the second convex shell drainage layer. A secondary lining is constructed so that the double-layer convex shell pressure relief drainage board is located between the initial support and the secondary lining. The first and second convex shell drainage layers form a drainage space, and when the surrounding rock deforms, the elastic compression of the elastic pressure relief member absorbs the deformation pressure between the initial support and the secondary lining. At the same time, the double-layer convex shell pressure relief drainage board retains drainage channels after being compressed, so as to drain the water behind the lining.
2. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: The compression amount of the elastic pressure-relieving member after the secondary lining is poured is 1.0-1.5 times greater than the pre-designed deformation amount of the tunnel.
3. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: The arrangement density of the elastic pressure-relieving members is 12 to 20 per square meter, and their stiffness is configured such that, in the final compressed state after the secondary lining is poured, the load borne by the first convex shell drainage layer does not exceed 70% of its compressive strength.
4. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 3, characterized in that: The formula for calculating the stiffness of the elastic relief member is: ； in, The total stiffness of the elastically compressive member, expressed in N / m; This is the resultant force of the surrounding rock pressure, expressed in N / m. The maximum compression is designed in meters (m). The pressure is the water pressure behind the lining, measured in Pa. The area of the secondary lining subjected to water pressure is expressed in m² / m. The calculation formula is: ； in, The dynamic viscosity of water is expressed in Pa·s, and is taken as 0.001 Pa·s at room temperature. The seepage flow rate per unit length of tunnel, expressed in m³ / (s·m), is determined based on the engineering hydrogeological conditions. The characteristic length of the drainage path, in meters; The equivalent permeability of the initial drainage layer is expressed in m² and is determined by indoor water flow tests. The strain of the compressible body of the drainage layer is dimensionless. ,in This represents the initial height of the convex shell. Dimensionless for the maximum allowable compressible strain; The non-Darcy flow inertia coefficient is expressed in m⁻¹. This is the density of water, expressed in kg / m³. This represents the initial total drainage cross-sectional area, in m² / m.
5. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: The first convex shell drainage layer and the second convex shell drainage layer are respectively provided with a plurality of outwardly protruding convex shell units, and longitudinal or circumferential drainage channels are formed between adjacent convex shell units.
6. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: The bottom of the double-layer convex shell pressure relief drainage board is connected to the longitudinal drainage pipe or circumferential drainage blind pipe of the tunnel.
7. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: Even after the first convex shell drainage layer is partially damaged, the second convex shell drainage layer still maintains drainage space.
8. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: The convex height of the convex shell in the first convex shell drainage layer is 15mm to 30mm, the convex height of the convex shell in the second convex shell drainage layer is 10mm to 20mm, and the convex height of the convex shell in the first convex shell drainage layer is greater than or equal to the convex height of the convex shell in the second convex shell drainage layer. The initial distance between the back surface of the first substrate and the back surface of the second substrate is 5mm to 15mm.
9. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: The elastic pressure relief component is a helical spring, disc spring, rubber spring, or composite elastic component.
10. The pressure-relief drainage method for tunnels in water-rich, soft surrounding rock as described in claim 1, characterized in that: It also includes a waterproof membrane layer, which is disposed on the side of the second convex shell drainage layer near the secondary lining.