A gradual lining structure for a traffic tunnel through an active fault and its construction method

Abstract

The present invention discloses a gradual lining structure for a traffic tunnel through an active fault. The gradual lining structure for a traffic tunnel through an active fault is configured to provide a surrounding rock reinforcement layer, an initial support layer, a deformation absorption layer, a waterproof layer, and a secondary lining layer in sequence from the outside to the inside within the anti-dislocation and deformation rate curve of the tunnel, thereby obtaining the gradual lining structure for the traffic tunnel through an active fault. The present invention also provides a construction method for the gradual lining structure for a traffic tunnel through an active fault. Compared with the prior art, the gradual lining structure for a traffic tunnel through an active fault of the present invention can make the stress and deformation of the tunnel lining structure uniform, avoid the dislocation and damage of the lining structure under fault dislocation, and at the same time make the tunnel pavement slope meet the driving requirements, thereby ensuring the structural and driving safety of the tunnel through an active fault.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering, and in particular to a gradual lining structure of a traffic tunnel passing through an active fault and a construction method thereof. Background Art

[0002] When constructing or planning highway and railway tunnels in the high-intensity earthquake zones of western China, many long tunnels inevitably cross active fault zones. Past tunnel earthquake damage data shows that fault movement can cause severe damage to tunnels and disrupt lines, posing a significant threat to tunnel safety and normal traffic flow.

[0003] Fault dislocation deformation is non-uniform, with the rate of deformation showing a pattern of rapid displacement on the main sliding surface and gradually decreasing towards the sides. The greater the dislocation deformation rate, the greater the stress on the secondary lining. Currently, seismic and dislocation-resistant technologies for tunnels through active faults include over-excavation to reserve deformation space, increasing the deformation capacity of lining segments, and installing shock-absorbing layers to buffer and absorb energy. However, the existing over-excavation, segmental and shock-absorbing structures have not taken into account the dislocation deformation mode of active faults. The lining along the longitudinal direction of the tunnel is a uniform structure. When the fault creeps or sticks, the lining structure is subjected to extremely uneven force, and serious damage is very likely to occur at the main sliding surface, which seriously threatens the tunnel and driving safety. At the same time, the existing technology arranges the deformation joints in the secondary lining layer and the main sliding surface of the fault in a butt-joint manner, so that the lining will be greatly misaligned at the main sliding surface of the fault, causing damage to the lining structure and a sharp change in the slope of the tunnel pavement. The vertical lane slope and the horizontal line curvature exceed the corresponding limit values. The secondary lining within a certain range on both sides of the main sliding surface needs to be removed for repair, which is difficult to repair, takes a long time to recover, and has high economic costs.

[0004] Therefore, how to provide a gradual lining structure for a traffic tunnel passing through an active fault so that when the lining undergoes gradual deformation under the action of the fault slippage, it can achieve the technical effect of preventing the lining from being damaged or dislocated, and ensuring that the tunnel is not damaged after the fault slippage or can be quickly opened to traffic after simple repair, is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0005] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a lining structure that is adapted to the fault displacement deformation mode, so that the stress and deformation of the lining structure under the fault displacement are more uniform, the structure is not damaged, the lane slope and line curvature meet the relevant requirements, and the tunnel function can be quickly restored after the earthquake.

[0006] To achieve the above-mentioned objectives, the present invention provides a gradual lining structure for a traffic tunnel passing through an active fault, 1. The gradual lining structure for a traffic tunnel passing through an active fault is located in the tunnel's anti-fault defense area, and the gradual lining structure for a traffic tunnel passing through an active fault includes: a surrounding rock reinforcement layer, the surrounding rock reinforcement layer is arranged along the entire circumference of the inner wall of the tunnel surrounding rock; an initial support layer, the initial support layer is arranged along the entire circumference of the inner wall of the surrounding rock reinforcement layer; a deformation absorbing layer, the deformation absorbing layer is arranged along the entire circumference of the inner wall of the initial support layer; a secondary lining layer, the secondary lining layer is arranged along the entire circumference of the inner wall of the deformation absorbing layer; a waterproof layer, the waterproof layer is arranged in the area above the arch of the tunnel, and the waterproof layer is located between the deformation absorbing layer and the secondary lining layer.

[0007] In the first aspect, the surrounding rock reinforcement layer is obtained by anchoring and grouting the inner wall of the tunnel surrounding rock; the radial dimension of the surrounding rock reinforcement layer is 3 to 5 m.

[0008] In the first aspect, the initial support layer is obtained by arranging metal mesh and PVA fiber sprayed concrete all around; the thickness of the initial support layer is the same as the thickness of the initial support layer in the non-fault defense area.

[0009] In the first aspect, the deformation absorbing layer includes: an upper arch absorbing layer, which is located between the initial support layer and the waterproof layer; a lower arch absorbing layer, which is located in the inverted arch area below the tunnel arch, and the lower arch absorbing layer includes a foam concrete layer and a pebble layer, and the foam concrete layer is located between the pebble layer and the secondary lining layer; wherein the upper arch absorbing layer and the foam concrete layer are both filled with foam concrete material; the thickness of the upper arch absorbing layer is the same as that of the lower arch absorbing layer, and the thickness of the foam concrete layer is the same as that of the pebble layer; the thickness of the upper arch absorbing layer is not greater than the ratio of the fault defense dislocation to the compression rate of the foam concrete.

[0010] In the first aspect, the secondary lining layer includes a plurality of reinforced concrete segments, each of which is arranged along the entire circumference of the inner wall of the surrounding rock reinforcement layer; the plurality of reinforced concrete segments are arranged adjacent to each other along the longitudinal direction of the tunnel, and a deformation joint is provided between any two adjacent reinforced concrete segments.

[0011] The present invention also provides a construction method for a gradual lining structure of a traffic tunnel passing through an active fault. The construction method is used for the construction of the above-mentioned gradual lining structure of a traffic tunnel passing through an active fault. The construction method includes: based on the geometric and movement characteristics of the active fault, the physical and mechanical parameters of the surrounding rock of the fault zone, and the spatial relationship between the tunnel and the fault, obtaining a geomechanical model of the surrounding rock in the active fault area; based on the response calculation of the rock mass in the active fault area under the fault defense dislocation, obtaining a fault dislocation deformation distribution curve within the anti-fault defense range of the tunnel; and differentiating the obtained dislocation distribution curve to obtain a fault dislocation deformation rate curve; within the anti-fault defense range of the tunnel, based on the fault dislocation deformation rate curve, arranging a surrounding rock reinforcement layer, an initial support layer, a deformation absorption layer, a waterproof layer and a secondary lining layer in sequence from the outside to the inside to obtain the gradual lining structure of the traffic tunnel passing through the active fault.

[0012] In the second aspect, in the longitudinal direction of the tunnel, the mechanical parameters of the surrounding rock reinforcement layer gradually decrease from the main sliding surface of the fault to both sides; the rate of decrease of the mechanical parameters is consistent with the fault dislocation deformation rate; the mechanical parameters include surrounding rock strength and elastic modulus.

[0013] In the second aspect, the volume content of PVC in the PVA fiber shotcrete of the initial support layer located at the main sliding surface of the fault is 0.7%; in the longitudinal direction of the tunnel, the volume content of PVC in the PVA fiber shotcrete of the initial support layer gradually decreases to 0% from both sides of the main sliding surface of the fault; the rate of decrease of the volume content of the PVC is consistent with the dislocation deformation rate of the fault.

[0014] In the second aspect, the density of the foamed concrete of the deformation absorbing layer located at the main sliding surface of the fault is 300 kg / m 3 In the longitudinal direction of the tunnel, the density of the foam concrete gradually increases from the main sliding surface of the fault to both sides to 700kg / m 3 ; The density increase rate of the foam concrete is consistent with the fault dislocation deformation rate.

[0015] In the second aspect, the length of the reinforced concrete segment of the secondary lining layer located at the main sliding surface of the fault is 4m; in the longitudinal direction of the tunnel, the length of the reinforced concrete segment gradually increases from the main sliding surface of the fault to 12m on both sides; the increase rate of the length of the reinforced concrete segment is consistent with the dislocation deformation rate of the fault.

[0016] Beneficial effects:

[0017] The gradient lining structure of the traffic tunnel through the active fault of the present invention is provided with a surrounding rock reinforcement layer, an initial support layer, a deformation absorbing layer, a waterproof layer and a secondary lining layer in sequence from the outside to the inside within the anti-dislocation and fault protection range of the tunnel, wherein the surrounding rock reinforcement layer, the initial support layer and the deformation absorbing layer all adopt a gradient structure, so that the surrounding rock deformation transmitted to the secondary lining layer after the fault dislocation deformation passes through the three gradient layers of the surrounding rock reinforcement layer, the initial support layer and the deformation absorbing layer is more uniform, and the stress of the secondary lining layer is more uniform; at the same time, the length of the reinforced concrete segment of the secondary lining layer gradually increases from the two sides of the main sliding surface of the fault, so that the deformation of the secondary lining layer is smoother, and the dislocation and damage of the secondary lining layer is avoided; in addition, the part below the arch of the deformation absorbing layer includes a foam concrete layer and a pebble layer, and the foam concrete layer can absorb most of the deformation of the fault dislocation, and the pebble layer can absorb most of the deformation of the fault dislocation during the process of the fault dislocation. A certain fluidity can occur, and the flow of the pebble layer can buffer the local non-uniform deformation of the secondary lining layer, so that the curvature and slope of the secondary lining change gradually, ensuring that the road surface slope of the tunnel meets the driving requirements. It can be seen that the present invention forms a gradual lining structure that adapts to the fault dislocation, so that the secondary lining layer of the tunnel is evenly stressed and deformed, avoiding the dislocation and damage of the secondary lining layer under the fault dislocation, and at the same time making the tunnel road surface slope meet the driving requirements, ensuring the structure and driving safety of the tunnel through the active fault; furthermore, under the condition that the fault defense dislocation amount is the same, the gradual lining structure of the traffic tunnel through the active fault of the present invention, due to the construction of three gradual layers of surrounding rock reinforcement layer, initial support layer and deformation absorption layer, and the foam concrete layer and pebble layer are arranged in the area below the arch of the deformation absorption layer, can effectively reduce the thickness of the deformation absorption layer, thereby reducing the excavation area of ​​the tunnel, and having better economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic cross-sectional structure diagram of a gradual lining structure of a traffic tunnel through an active fault according to the present invention;

[0020] Figure 2 This is a schematic diagram of the longitudinal section structure of a gradual lining structure of a traffic tunnel through an active fault according to the present invention;

[0021] Figure 3 It is a fault dislocation deformation distribution curve diagram within the anti-fracture protection range of the tunnel of the present invention;

[0022] Figure 4 is a graph of the fault dislocation deformation rate of the present invention;

[0023] Figure 5 This is a deformation diagram of a gradual lining structure of a traffic tunnel through an active fault according to the present invention after the fault shifts;

[0024] Figure 6 This is a deformation diagram of the tunnel lining structure in the prior art after fault displacement.

[0025] Reference numerals:

[0026] 1. Surrounding rock reinforcement layer; 2. Tunnel surrounding rock; 3. Initial support layer; 4. Deformation absorption layer; 41. Upper arch absorption layer; 42. Lower arch absorption layer; 421. Foam concrete layer; 422. Pebble layer; 5. Secondary lining layer; 51. Reinforced concrete segment; 52. Deformation joint; 6. Waterproof layer; 7. Main sliding surface of fault; 8. Road surface; 9. Tunnel. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this invention.

[0028] Example 1

[0029] like Figures 1-2 As shown, this embodiment 1 provides a gradual lining structure for a traffic tunnel passing through an active fault, wherein the gradual lining structure for the traffic tunnel passing through an active fault is located in the anti-fault defense area of ​​the tunnel, and the gradual lining structure for the traffic tunnel passing through an active fault comprises: a surrounding rock reinforcement layer 1, wherein the surrounding rock reinforcement layer 1 is arranged along the entire circumference of the inner wall of the tunnel surrounding rock 2; an initial support layer 3, wherein the initial support layer 3 is arranged along the entire circumference of the inner wall of the surrounding rock reinforcement layer 1; a deformation absorbing layer 4, wherein the deformation absorbing layer 4 is arranged along the entire circumference of the inner wall of the initial support layer 3; a secondary lining layer 5, wherein the secondary lining layer 5 is arranged along the entire circumference of the inner wall of the deformation absorbing layer 4; and a waterproof layer 6, wherein the waterproof layer 6 is arranged in the area above the arch of the tunnel, and wherein the waterproof layer 6 is located between the deformation absorbing layer 4 and the secondary lining layer 5.

[0030] The gradient lining structure of the traffic tunnel through the active fault of the present invention is provided with a surrounding rock reinforcement layer 1, an initial support layer 3, a deformation absorbing layer 4, a waterproof layer 6 and a secondary lining layer 5 in sequence from the outside to the inside within the anti-dislocation defense range of the tunnel, wherein the surrounding rock reinforcement layer 1, the initial support layer 3 and the deformation absorbing layer 4 all adopt a gradient structure, so that the surrounding rock deformation transmitted to the secondary lining layer 5 after the fault dislocation deformation passes through the three gradient layers of the surrounding rock reinforcement layer 1, the initial support layer 3 and the deformation absorbing layer 4 is more uniform, and the stress on the secondary lining layer 5 is more uniform; at the same time, the length of the reinforced concrete segment 51 of the secondary lining layer 5 gradually increases from the main sliding surface 7 of the fault to both sides, so that the deformation of the secondary lining layer 5 is smoother, and the dislocation and damage of the secondary lining layer 5 are avoided; in addition, the part below the arch of the deformation absorbing layer 4 includes a foam concrete layer 421 and a pebble layer 422, and the foam concrete layer 421 can absorb most of the deformation of the fault dislocation, and the pebble layer 422 is at the fault dislocation. A certain fluidity may occur during the displacement process. The flow of the pebble layer 422 buffers the local non-uniform deformation of the secondary lining layer 5, causing the curvature and slope of the secondary lining to change gradually, ensuring that the slope of the road surface 8 of the tunnel 9 meets the driving requirements. It can be seen that the present invention forms a gradual lining structure that adapts to the fault dislocation, so that the secondary lining layer 5 of the tunnel 9 is evenly stressed and deformed, avoiding the dislocation and damage of the secondary lining layer 5 under the fault dislocation, and at the same time making the slope of the road surface 8 of the tunnel 9 meet the driving requirements, ensuring the structure and driving safety of the tunnel through the active fault; furthermore, under the condition that the fault defense dislocation amount is the same, the gradual lining structure of the traffic tunnel through the active fault of the present invention, due to the construction of three gradual layers of surrounding rock reinforcement layer 1, initial support layer 3 and deformation absorbing layer 4, and the arrangement of foam concrete layer 421 and pebble layer 422 in the area below the arch of the deformation absorbing layer 4, can effectively reduce the thickness of the deformation absorbing layer 4, thereby reducing the excavation area of ​​the tunnel 9, and having better economy.

[0031] In some possible implementations, the surrounding rock reinforcement layer 1 is obtained by anchoring and grouting the inner wall of the tunnel surrounding rock 2; the radial dimension of the surrounding rock reinforcement layer 1 is 3 to 5 m.

[0032] Specifically, the anchored grouting anchor rods are inserted into the tunnel surrounding rock 2, and concrete slurry is injected into the tunnel surrounding rock 2 through the grouting anchor rods to reinforce the tunnel surrounding rock 2 and at the same time to buffer the force transmitted to the secondary lining layer 5, so that the secondary lining layer 5 is subjected to more uniform force.

[0033] In some possible implementations, the initial support layer 3 is obtained by arranging metal mesh and PVA fiber sprayed concrete all around; the thickness of the initial support layer 3 is the same as the thickness of the initial support layer in the non-offset defense area.

[0034] Specifically, the metal mesh is arranged around the surrounding rock reinforcement layer 1, and a metal mesh concrete structure is formed on the metal mesh by spraying PVC fiber shotcrete, which constitutes the initial support layer 3. The initial support layer 3 plays a supporting role. In addition, the volume content of PVC in the PVC fiber shotcrete in the initial support layer 3 is variable, and the volume content of PVC is in the range of 0 to 0.7%, so that the initial support layer 3 can better buffer the force transmitted to the secondary lining layer 5, and make the secondary lining layer 5 more evenly stressed.

[0035] In some possible implementations, the deformation absorbing layer 4 includes: an upper arch absorbing layer 41, wherein the upper arch absorbing layer 41 is located between the initial support layer 3 and the waterproof layer 6; a lower arch absorbing layer 42, wherein the lower arch absorbing layer 42 is located in the inverted arch area below the tunnel arch, and the lower arch absorbing layer 42 includes a foam concrete layer 421 and a pebble layer 422, wherein the foam concrete layer 421 is located between the pebble layer 422 and the secondary lining layer 5; wherein the upper arch absorbing layer 41 and the foam concrete layer 421 are both filled with foam concrete material; the thickness of the upper arch absorbing layer 41 is the same as that of the lower arch absorbing layer 42, and the thickness of the foam concrete layer 421 is the same as that of the pebble layer 422; the thickness of the upper arch absorbing layer 41 is not greater than the ratio of the fault defense dislocation to the compression rate of the foam concrete.

[0036] Specifically, the upper arch absorption layer 41 is entirely filled with foam concrete, and the foam concrete layer 421 of the lower arch absorption layer 42 is filled with foam concrete, which can buffer the force transmitted to the secondary lining layer 5, absorb most of the deformation of the fault dislocation, and make the secondary lining layer 5 more evenly stressed; at the same time, the pebble layer 422 of the lower arch absorption layer 42, located between the foam concrete layer 421 and the secondary lining layer 5, can have a certain fluidity during the fault dislocation process, and the local non-uniform deformation of the secondary lining layer 5 is buffered by the flow of the pebble layer 422, so that the curvature and slope of the secondary lining gradually change, ensuring that the slope of the road surface 8 of the tunnel 9 meets the driving requirements.

[0037] In some possible implementations, the secondary lining layer 5 includes a plurality of reinforced concrete segments 51, each of which is arranged along the entire circumference of the inner wall of the surrounding rock reinforcement layer 1; the plurality of reinforced concrete segments 51 are arranged adjacent to each other along the longitudinal direction of the tunnel, and a deformation joint 52 is arranged between any two adjacent reinforced concrete segments 51.

[0038] Specifically, the length of the reinforced concrete segment 51 of the secondary lining layer 5 varies in the longitudinal direction of the tunnel. The length of the reinforced concrete segment 51 ranges from 4 to 12 meters, and the average length is relatively large, which improves the economy of the gradual lining structure of the traffic tunnel through the active fault. In addition, in the present invention, the length of the reinforced concrete segment 51 at the main sliding surface 7 of the fault is 4 meters, which is relatively small, and a deformation joint 52 is set between any two adjacent reinforced concrete segments 51. The deformation joint 52 and the main sliding surface 7 of the fault are staggered. When the fault dislocation is greater than the fault defense dislocation, the present invention can limit the damage range of the secondary lining layer 5 to within 4 meters, and the damage range is small and easy to repair.

[0039] Example 2

[0040] like Figures 1 to 6 As shown, the second embodiment of the present invention provides a construction method for a gradual lining structure of a traffic tunnel through an active fault, and the construction method is used for the construction of a gradual lining structure of a traffic tunnel through an active fault as described in the first embodiment. The construction method comprises: obtaining a geomechanical model of the surrounding rock of the active fault region based on the geometric and motion characteristics of the active fault, the physical and mechanical parameters of the surrounding rock of the fault zone, and the spatial relationship between the tunnel and the fault; calculating the response of the rock mass in the active fault region under the fault defense dislocation amount; obtaining a fault dislocation deformation distribution curve within the anti-fault defense range of the tunnel; and differentiating the dislocation distribution curve to obtain a fault dislocation deformation rate curve; within the anti-fault defense range of the tunnel, based on the fault dislocation deformation rate curve, sequentially arranging a surrounding rock reinforcement layer, an initial support layer, a deformation absorption layer, a waterproof layer, and a secondary lining layer from the outside to the inside to obtain the gradual lining structure of the traffic tunnel through the active fault;

[0041] Specifically, the fault dislocation deformation rate curve plays an important role in constructing the gradual lining structure of the active fault traffic tunnel of the present invention; in the present invention, the mechanical parameters in the surrounding rock reinforcement layer gradually decrease from the two sides of the fault main sliding surface, the volume content of PVC in the PVA fiber shotcrete of the initial support layer gradually decreases from the two sides of the fault main sliding surface, the density of the foam concrete of the deformation absorption layer gradually increases from the two sides of the fault main sliding surface, and the length of the reinforced concrete segment of the secondary lining layer gradually increases from the two sides of the fault main sliding surface. The above-mentioned reduction and increase rates The rate is consistent with the fault dislocation deformation rate, so that the gradual lining structure of the traffic tunnel through the active fault of the present invention is adapted to the fault dislocation deformation mode of the active fault. The gradual lining structure of the traffic tunnel through the active fault of the present invention is gradual, and the lining undergoes gradual deformation under the action of the fault dislocation, thereby avoiding damage to the lining structure or dislocation, making the stress and deformation of the lining structure more uniform under the fault dislocation, and the structure is not damaged. The lane slope and line curvature meet the relevant requirements, thereby achieving the technical effect of not damaging the tunnel after the fault dislocation or achieving rapid traffic after simple repair.

[0042] It should be noted that the construction method of the gradual lining structure of a traffic tunnel passing through an active fault in this embodiment 2 is used for the construction of the gradual lining structure of a traffic tunnel passing through an active fault described in the above embodiment 1. Therefore, the performance principle of the gradual lining structure of the traffic tunnel passing through an active fault will not be repeated here. For the undetailed parts, please refer to embodiment 1.

[0043] In some possible implementations, in the longitudinal direction of the tunnel, the mechanical parameters of the surrounding rock reinforcement layer gradually decrease from the main sliding surface of the fault to both sides; the rate of decrease of the mechanical parameters is consistent with the deformation rate of the fault dislocation; the mechanical parameters include surrounding rock strength and elastic modulus; the volume content of PVC in the PVA fiber sprayed concrete of the initial support layer located at the main sliding surface of the fault is 0.7%; in the longitudinal direction of the tunnel, the volume content of PVC in the PVA fiber sprayed concrete of the initial support layer gradually decreases from the main sliding surface of the fault to 0% on both sides; the rate of decrease of the volume content of PVC is consistent with the deformation rate of the fault dislocation; the density of the foam concrete of the deformation absorption layer located at the main sliding surface of the fault is 300kg / m 3 In the longitudinal direction of the tunnel, the density of the foam concrete gradually increases from the main sliding surface of the fault to both sides to 700kg / m 3 The density increase rate of the foam concrete is consistent with the deformation rate of the fault dislocation; the length of the reinforced concrete segment of the secondary lining layer located at the main sliding surface of the fault is 4m; in the longitudinal direction of the tunnel, the length of the reinforced concrete segment gradually increases from the main sliding surface of the fault to both sides to 12m; the increase rate of the length of the reinforced concrete segment is consistent with the deformation rate of the fault dislocation

[0044] Specifically, the mechanical parameters of the surrounding rock reinforcement layer gradually decrease from both sides of the main sliding surface of the fault, the volume content of PVC in the PVA fiber shotcrete of the initial support layer gradually decreases from both sides of the main sliding surface of the fault, and the density of the foam concrete of the deformation absorption layer gradually increases from both sides of the main sliding surface of the fault, showing a gradual change. The above-mentioned reduction rate and increase rate are consistent with the fault dislocation deformation rate, so that the gradual structure of the surrounding rock reinforcement layer, the initial support layer and the deformation absorption layer are adapted to the fault dislocation deformation mode, so that the surrounding rock deformation transmitted to the secondary lining layer is more uniform, the stress of the secondary lining layer is more uniform, and the damage or dislocation of the lining structure is avoided, so that the stress and deformation of the lining structure under the fault dislocation are more uniform, the structure is not damaged, the lane slope and the line curvature meet the relevant requirements, and the tunnel is not damaged or can be simply repaired after the fault dislocation. At the same time, due to the construction of three gradient layers of surrounding rock reinforcement layer, initial support layer and deformation absorption layer, and the layout of foam concrete layer and pebble layer in the area below the arch of the deformation absorption layer, the thickness of the deformation absorption layer can be effectively reduced, thereby reducing the excavation area of ​​the tunnel, and being more economical. In addition, the average length of the reinforced concrete segment is relatively large, which improves the economy of the gradient lining structure of the traffic tunnel through the active fault. At the same time, the length of the reinforced concrete segment at the main sliding surface of the fault is 4m, which is relatively small, and a deformation joint is set between any two adjacent reinforced concrete segments. The deformation joint and the main sliding surface are staggered, so that when the fault dislocation is greater than the fault defense dislocation, the present invention can limit the damage range of the secondary lining layer to within 4m, and the damage range is small and easy to repair.

[0045] In order to further illustrate the technical solution of the present application in detail to support the technical problem to be solved by the present application, the preparation method is described below with specific examples, such as Example 1.

[0046] Example 1

[0047] background:

[0048] A highway tunnel with a circular cross-section vertically crosses an active fault. This fault is a normal fault with a dip of 50 degrees, a fortified fault displacement of 50 cm, and a tunnel clearance radius of 6.5 m. In the unfortified section, the tunnel's primary support is constructed with 30 cm thick C30 shotcrete, and the secondary lining is constructed with 50 cm thick C40 reinforced concrete.

[0049] A construction method for a gradual lining structure of a traffic tunnel passing through an active fault:

[0050] Based on the geometric and kinematic characteristics of the active fault, the physical and mechanical parameters of the surrounding rock in the fault zone, and the spatial relationship between the tunnel and the fault, a three-dimensional finite element model of the rock mass in the active fault area is obtained. Based on the deformation calculation of the rock mass under the fault fortification dislocation, the fault dislocation deformation distribution curve within the tunnel fortification range is obtained. The fault dislocation deformation rate curve is obtained by differentiating the dislocation deformation distribution curve.

[0051] Within the anti-fault protection range of the tunnel, based on the fault dislocation deformation rate curve, a surrounding rock reinforcement layer, an initial support layer, a deformation absorption layer, a waterproof layer and a secondary lining layer are sequentially arranged from the outside to the inside to obtain a gradual lining structure of a traffic tunnel through an active fault;

[0052] The parameter construction process for laying out the gradual lining structure of a traffic tunnel through an active fault includes:

[0053] Within the anti-fault defense range of the tunnel, based on the distance from the main sliding surface of the fault in the fault dislocation deformation rate curve, the surrounding rock reinforcement layer, the initial support layer and the deformation absorption layer are divided into 10 areas with a length of 3m along the longitudinal direction of the tunnel. The 10 areas are: -21m to -18m, -18m to -15m, -15m to -12m, -12m to -9m, -9m to -6m, -6m to -3m, -3m to 0m, 0m to 3m, 3m to 6m, and 6m to 9m, wherein a negative number represents a distance to the left from the main sliding surface of the fault, and a positive number represents a distance to the right from the main sliding surface of the fault;

[0054] Anchoring and grouting reinforcement is arranged around the tunnel surrounding rock. The thickness of the surrounding rock reinforcement layer is 5m. The surrounding rock strength and elastic modulus of the surrounding rock reinforcement layer reinforced by grouting are adjusted so that the reinforced uniaxial compressive strength of the surrounding rock reinforcement layer in the area corresponding to the main sliding surface of the fault is not less than 10MPa. The surrounding rock strength and elastic modulus of the surrounding rock reinforcement layer in the remaining 9 areas on both sides gradually decay according to the deformation rate of the fault dislocation deformation rate curve.

[0055] The initial support layer is arranged along the entire circumference of the surrounding rock reinforcement layer. The initial support layer is composed of C30 metal mesh and PVA fiber sprayed concrete. The thickness of the initial support layer is consistent with that of the non-defended section. The PVC volume content of the PVA fiber sprayed concrete in the area corresponding to the main sliding surface of the fault is 0.7%. Based on the fault dislocation deformation rate curve, the PVC volume content of the 10 areas from left to right is: 0.068%, 0.12%, 0.145%, 0.15%, 0.18%, 0.23%, 0.7%, 0.52%, 0.29%, and 0.05%.

[0056] A deformation absorbing layer is laid along the entire perimeter of the initial support layer. Based on the fault displacement of 50 cm and the average compression rate of foam concrete of about 70%, the thickness of the deformation absorbing layer is not greater than the ratio of the fault displacement to the average compression rate of foam concrete, which is 71 cm. The thickness of the deformation absorbing layer is 60 cm, the thickness of the upper arch absorption layer is 60 cm, the thickness of the foam concrete layer is 30 cm, and the thickness of the pebble layer is 30 cm. The density of the foam concrete material in the area corresponding to the main sliding surface of the fault is 300 kg / m 3 Based on the fault dislocation deformation rate curve, the density of the foam concrete materials in the 10 regions from left to right is: 700 kg / m 3 、660kg / m 3 、650kg / m 3 、640kg / m 3 、620kg / m 3 、590kg / m 3 300kg / m 3 , 400kg / m 3 , 550kg / m 3 , 700kg / m 3 ;

[0057] A waterproof layer is laid along the upper arch absorption layer. The layout of the waterproof layer is consistent with that of the normal section. The waterproof layer is composed of geotextile and EVA waterproof board.

[0058] The secondary lining layer is constructed using C40 reinforced concrete, with the thickness of the secondary lining layer being consistent with that of the non-defended section. The deformation joints of the secondary lining layer are staggered with the main fault sliding surface, so that the main fault sliding surface is located in the middle of the reinforced concrete segment. The reinforced concrete segment in the area corresponding to the main fault sliding surface is 4 meters long, and the deformation joints of the tunnel vault and invert arch are aligned. Based on the fault dislocation deformation rate curve, the lengths of the reinforced concrete segments in the 10 areas are, from left to right, 12 meters, 10 meters, 4 meters, 4 meters, 6 meters, 9 meters, and 12 meters.

[0059] Based on the above-determined thickness of the initial support layer, the thickness of the deformation absorbing layer, the thickness of the secondary lining layer and the clearance radius of the tunnel being 30cm, 60cm, 50cm and 6.5m respectively, the excavation radius of the defense section tunnel is 7.9m.

[0060] Conclusion: The schematic diagram of the gradual lining structure of the traffic tunnel through the active fault obtained in the above Example 1 is shown in Figures 1-2 The fault dislocation deformation distribution curve during the construction process is shown in Figure 3 The fault dislocation deformation rate curve is shown in Figure 4When the fault shift occurs, the deformation diagram of the gradual lining structure of the active fault traffic tunnel of the present invention is shown in FIG. Figure 5 ,Depend on Figure 5 It can be seen that after the fault shift occurs, the secondary lining layer of the gradual change lining structure of the present invention undergoes gentle deformation, and the secondary lining layer does not undergo dislocation or damage. At the same time, the lining curvature and slope undergo a gradual change, ensuring that the tunnel road slope meets the driving requirements. However, after the fault shift occurs, the lining structure of the tunnel lining in the prior art undergoes obvious dislocation and damage. Figure 6 It can be seen that the gradient lining structure of the traffic tunnel through active faults of the present invention can make the tunnel lining structure bear stress and deform evenly, avoid the dislocation and damage of the lining structure under fault movement, and at the same time make the road slope of the tunnel meet the driving requirements, ensuring the structural and driving safety of the tunnel through active faults.

[0061] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A gradual lining structure for a traffic tunnel through an active fault, characterized in that: The gradual lining structure of the traffic tunnel through the active fault is located in the tunnel anti-fault defense area, and the gradual lining structure of the traffic tunnel through the active fault includes: A surrounding rock reinforcement layer (1), the surrounding rock reinforcement layer (1) being arranged along the entire circumference of the inner wall of the tunnel surrounding rock (2); An initial support layer (3), the initial support layer (3) being arranged along the entire circumference of the inner wall of the surrounding rock reinforcement layer (1); A deformation absorbing layer (4), the deformation absorbing layer (4) being arranged along the entire circumference of the inner wall of the initial supporting layer (3); A secondary lining layer (5), the secondary lining layer (5) being arranged along the entire circumference of the inner wall of the deformation absorbing layer (4); A waterproof layer (6), the waterproof layer (6) being arranged in an area above the arch portion of the tunnel (9), the waterproof layer (6) being located between the deformation absorbing layer (4) and the secondary lining layer (5); The deformation absorbing layer (4) comprises: an upper arch absorbing layer (41), the upper arch absorbing layer (41) being located between the initial support layer (3) and the waterproof layer (6); a lower arch absorbing layer (42), the lower arch absorbing layer (42) being located in the inverted arch area below the arch of the tunnel (9), the lower arch absorbing layer (42) comprising a foam concrete layer (421) and a pebble layer (422), the foam concrete layer (421) being located between the pebble layer (422) and the lower arch absorbing layer (422). between the secondary lining layers (5); wherein the upper arch absorbing layer (41) and the foam concrete layer (421) are both filled with foam concrete material; the thickness of the upper arch absorbing layer (41) is the same as the thickness of the lower arch absorbing layer (42), and the thickness of the foam concrete layer (421) is the same as the thickness of the pebble layer (422); the thickness of the upper arch absorbing layer (41) is not greater than the ratio of the fault defense dislocation to the compression rate of the foam concrete; The secondary lining layer (5) comprises a plurality of reinforced concrete segments (51), each of the reinforced concrete segments (51) being arranged along the entire circumference of the inner wall of the surrounding rock reinforcement layer (1); the plurality of reinforced concrete segments (51) are arranged adjacent to each other along the longitudinal direction of the tunnel (9), and a deformation joint (52) is provided between any two adjacent reinforced concrete segments (51).

2. The gradual lining structure of a traffic tunnel through an active fault according to claim 1, characterized in that: The surrounding rock reinforcement layer (1) is obtained by anchoring and grouting the inner wall of the tunnel surrounding rock (2); the radial dimension of the surrounding rock reinforcement layer (1) is 3 to 5 m.

3. The gradual lining structure of a traffic tunnel through an active fault as claimed in claim 2, characterized in that: The initial support layer (3) is obtained by arranging metal mesh and PVA fiber shotcrete all around; the thickness of the initial support layer (3) is the same as the thickness of the initial support layer in the non-fault defense area.

4. A construction method for a gradual change lining structure of a traffic tunnel through an active fault, the construction method being used for the construction of a gradual change lining structure of a traffic tunnel through an active fault according to any one of claims 1 to 3, the construction method comprising: Based on the geometric and kinematic characteristics of the active fault, the physical and mechanical parameters of the surrounding rock of the fault zone, and the spatial relationship between the tunnel and the fault, a geomechanical model of the surrounding rock of the active fault area is obtained. Based on the response calculation of the rock mass in the active fault area under the fault defense dislocation, a fault dislocation deformation distribution curve within the anti-dislocation defense range of the tunnel is obtained. The fault dislocation deformation distribution curve is derived to obtain a fault dislocation deformation rate curve. Within the anti-dislocation and fault protection range of the tunnel, based on the fault dislocation deformation rate curve, the surrounding rock reinforcement layer, the initial support layer, the deformation absorption layer, the waterproof layer and the secondary lining layer are arranged in sequence from the outside to the inside to obtain a gradual lining structure of the traffic tunnel through the active fault.

5. The construction method of a gradual lining structure for a traffic tunnel through an active fault as claimed in claim 4, characterized in that: In the longitudinal direction of the tunnel, the mechanical parameters of the surrounding rock reinforcement layer gradually decrease from the main sliding surface of the fault to both sides; the rate of decrease of the mechanical parameters is consistent with the fault dislocation deformation rate; the mechanical parameters include surrounding rock strength and elastic modulus.

6. The construction method of a gradual lining structure for a traffic tunnel through an active fault as claimed in claim 5, characterized in that: The volume content of PVC in the PVA fiber shotcrete of the initial support layer located at the main sliding surface of the fault is 0.7%; in the longitudinal direction of the tunnel, the volume content of PVC in the PVA fiber shotcrete of the initial support layer gradually decreases to 0% from both sides of the main sliding surface of the fault; the rate of decrease of the volume content of PVC is consistent with the dislocation deformation rate of the fault.

7. The construction method of a gradual lining structure for a traffic tunnel through an active fault as claimed in claim 6, characterized in that: The density of the foam concrete in the deformation absorbing layer located at the main sliding surface of the fault is 300 kg / m 3 In the longitudinal direction of the tunnel, the density of the foam concrete gradually increases from the main sliding surface of the fault to both sides to 700kg / m 3 ; The density increase rate of the foam concrete is consistent with the fault dislocation deformation rate.

8. The construction method of a gradual lining structure for a traffic tunnel through an active fault as claimed in claim 7, characterized in that: The length of the reinforced concrete segment of the secondary lining layer located at the main sliding surface of the fault is 4m; in the longitudinal direction of the tunnel, the length of the reinforced concrete segment gradually increases from both sides of the main sliding surface of the fault to 12m; the rate of increase in the length of the reinforced concrete segment is consistent with the dislocation deformation rate of the fault.

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