A ring cavity drilling and blasting method tunnel anti-break structure and construction method

Abstract

The application relates to the technical field of tunnels and underground engineering, in particular to a drill-and-blast method tunnel anti-dislocation structure provided with a ring cavity and a construction method; the anti-dislocation structure is arranged in a moving fault influence section, the anti-dislocation structure comprises, from outside to inside, primary support, a buffer layer and secondary lining, the buffer layer comprises a filling material and a cavity arranged in the filling material, and the cavity is arranged along a ring direction of the tunnel. The cavity arranged in the buffer layer can provide a smooth movement path for filling material fragments which are firstly destroyed in the arch part or the side wall, the fragments of the material at the stress concentration position of the buffer layer slide to the lower part along the cavity under the action of gravity, a free space which can accommodate fault dislocation is formed at the destruction position, stress concentration caused by material accumulation at the destruction position is avoided, and the secondary lining is prevented from being destroyed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel and underground engineering, and particularly relates to a drill-and-blast tunnel anti-dislocation structure with a ring cavity and a construction method. BACKGROUND

[0002] When a tunnel passes through an active fault, without corresponding engineering measures to deal with, the dislocation of the active fault, especially large displacement dislocation, will cause serious damage to the tunnel lining structure. The damage to the lining structure will easily cause the failure of the tunnel waterproofing, and the infinite water supply into the tunnel will seriously threaten the safety of driving and life and property, and even make the tunnel difficult to repair. Therefore, solving the serious threat of large displacement active fault dislocation to the tunnel structure is a major technical problem in tunnel engineering construction.

[0003] The key to the tunnel anti-active fault dislocation is to make the dislocation shear force of the active fault not act or less act on the secondary lining, and a more effective way is to add a buffer layer between the primary support and the secondary lining, and release part of the surrounding rock deformation through the buffer layer to reduce the pressure of the surrounding rock on the lining. The materials used for the buffer layer generally include rubber, foamed concrete, EPS concrete, polyurethane and polystyrene. Rubber and other materials can absorb the energy of seismic motion, but the elastic modulus is small in the normal operation state, which is not conducive to the stability of the secondary lining. Foamed concrete, polystyrene and other materials have a certain elastic modulus and compressive strength, and can be used for anti-dislocation structure, but the pore size of the material is small, and after a limited compression stroke, the material is compacted, and the severe shear action of the fault will still be transmitted to the secondary lining through the compacted filling layer, until the entire lining structure is compressed and sheared, so the fault dislocation amount that can be adapted is small.

[0004] In addition to the limitations of the buffer layer material itself, the existing buffer layer is also not conducive to the anti-dislocation of the tunnel in structure. After the buffer layer material is compressed and damaged, it is easy to accumulate in place, and the gap between the irregular fragments reduces the volume of the fragment accumulation body, thereby further reducing the compression stroke of the buffer layer.

[0005] In summary, for the buffer layer structure of the tunnel anti-dislocation structure, the existing buffer material has a limited compressible amount under large displacement active dislocation, and the buffer layer structure relying solely on the compression of the material further reduces the available compression stroke of the original thickness buffer layer. Therefore, there is an urgent need for a tunnel anti-dislocation structure and construction method with better compression performance and larger available compression stroke, so that the tunnel can adapt to the large dislocation amount of active fault dislocation. SUMMARY

[0006] In order to solve the above problems, in one aspect, the application provides a drill-and-blast tunnel anti-fault structure with annular cavities, which is arranged in a section affected by an active fault, and comprises, from outside to inside, primary support, a buffer layer and secondary lining, the buffer layer comprises a filling material and cavities arranged in the filling material, and the cavities are arranged along the annular direction of the tunnel.

[0007] Further, the cavities are multiple, and the multiple cavities are arranged in the filling material along the longitudinal direction of the tunnel in sequence; and the adjacent cavities are arranged in a spaced manner.

[0008] Further, the cavities are arranged in a whole annular direction of the tunnel.

[0009] Further, the filling material is provided with a pipe material for forming the cavities; and the pipe material has a circular cross section.

[0010] Further, the pipe material is fixed to the primary support by a U-shaped clamp.

[0011] Further, the pipe material is a PVC pipe, a glass pipe or a corrugated pipe.

[0012] Further, the filling material comprises porous brittle concrete.

[0013] Further, a first waterproof structure is arranged between the filling material and the secondary lining.

[0014] Further, a second waterproof structure is arranged between the filling material and the primary support.

[0015] In another aspect, the application further provides a construction method of the drill-and-blast tunnel anti-fault structure with annular cavities, comprising the following steps:

[0016] S1: applying the primary support to ensure the stability of the primary support and surrounding rock;

[0017] S2: applying the buffer layer;

[0018] S3: applying the secondary lining.

[0019] Compared with the prior art, the application has the following beneficial effects due to the above technical scheme:

[0020] 1) The tunnel anti-dislocation structure provided by the present application is provided with a cavity in the buffer layer, which can provide a smooth movement path for the broken filling material pieces of the arch part or side wall, and the broken pieces of the buffer layer stress concentration area slide along the cavity to the lower part under the action of gravity, on the one hand, avoiding the further compression of the traditional buffer material after the available compression stroke, thereby generating a large pressure resistance to the secondary lining, which can effectively prevent the damage of the secondary lining, on the other hand, the broken material slides along the cavity to the empty part, that is, the volume of the material at the damage position is further reduced, that is, the compression performance of the raw material is improved, the available compression stroke of the buffer layer is increased, the thickness of the buffer layer required to adapt to a certain dislocation fault displacement is reduced, thereby reducing the tunnel excavation section and saving the construction cost.

[0021] 2) The tunnel anti-dislocation structure provided by the present application is provided with a cavity in the buffer layer, which can provide a smooth movement path for the broken filling material pieces of the arch part or side wall, and the broken pieces of the buffer layer stress concentration area slide along the cavity to the lower part under the action of gravity, on the one hand, avoiding the further compression of the traditional buffer material after the available compression stroke, thereby generating a large pressure resistance to the secondary lining, which can effectively prevent the damage of the secondary lining, on the other hand, the broken material slides along the cavity to the empty part, that is, the volume of the material at the damage position is further reduced, that is, the compression performance of the raw material is improved, the available compression stroke of the buffer layer is increased, the thickness of the buffer layer required to adapt to a certain dislocation fault displacement is reduced, thereby reducing the tunnel excavation section and saving the construction cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The transverse section schematic diagram of the tunnel anti-dislocation structure provided by the present application is shown in the following figure.

[0024] Figure 2 The longitudinal section schematic diagram of the tunnel anti-dislocation structure provided by the present application is shown in the following figure.

[0025] Figure 3 The structure schematic diagram of the U-shaped clamp in the tunnel anti-dislocation structure provided by the present application is shown in the following figure.

[0026] Figure 4 The structure schematic diagram of the steel plate in the tunnel anti-dislocation structure provided by the present application is shown in the following figure.

[0027] 1-Primary support; 2-Filling material; 3-Pipe material; 31-Cavity; 4-Secondary lining; 5-U-shaped hoop; 6-Compression part; 7-Steel plate; 8-Expansion bolt; 9-Deformation joint; 10-First water stop; 11-Second water stop; 12-First waterproof and drainage structure. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described in the description of the embodiments of the present application in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application. In the drawings, the size and relative size of a part may be exaggerated for clarity.

[0029] In the description of the present application, unless explicitly specified and limited, the terms "connection", "connection" should be interpreted broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, it can be the internal communication of two elements or the interaction relationship of two elements, and those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0030] In the description of the present application, the terms "up", "down", "left", "right", "front", "back" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the present application.

[0031] In addition, in the description of the present application, the terms "first", "second" are only used to distinguish in description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In addition, the features limited by "first", "second" can explicitly or implicitly include one or more features.

[0032] Embodiment 1

[0033] As shown in the description accompanying drawings Figure 1 and 2 The present application provides a drill and blast tunnel anti-fault structure with a circumferential cavity, which is arranged in a fault-affected section, and the anti-fault structure comprises, from outside to inside, primary support 1, buffer layer and secondary lining 4, the buffer layer comprises filling material 2 and cavity 31 arranged in the filling material 2, and the cavity 31 is arranged along the circumferential direction of the tunnel.

[0034] Specifically, a buffer layer is arranged between the primary support 1 and the secondary lining 4, and a cavity 31 is arranged in the filling material 2 and extends along the circumferential direction of the tunnel; the cavity 31 in the filling material 2 provides a path for the material fragments, and the fragments of the filling material 2 after being destroyed can slide into the lower part under the action of gravity, so that a free space for accommodating the fault dislocation is formed at the destroyed position, stress concentration caused by material accumulation at the destroyed position is avoided, and the secondary lining is prevented from being destroyed; the destroyed material slides into the empty position along the cavity, which is equivalent to further reducing the volume of the material after compression and destruction at the destroyed position, that is, the compression performance of the raw material is improved, the available compression stroke of the buffer layer is increased, and the dislocation displacement amount of the material adapting to the active fault is improved; in an ideal state, the tunnel after compression and destruction is completely slid into the cavity, the destroyed position is compressed to a material volume of 0, that is, the compression rate of the buffer layer at the control section is 100%, which is significantly greater than the case of using rubber, foam concrete or other materials alone as the filling material, thereby reducing the thickness of the buffer layer, and reducing the tunnel excavation section and saving construction costs.

[0035] Preferably, the number of the cavities 31 can be set according to actual needs, and at least one cavity 31 is arranged in the filling material 2.

[0036] Preferably, the cavities 31 are arranged along the circumferential direction of the tunnel and can be a half ring or a whole ring; when the cavities 31 are a half ring, the filling material is arranged between the primary support 1 and the secondary lining 4 at the bottom of the tunnel, and no cavity 31 is arranged at the top of the tunnel; of course, the arrangement position of the cavities 31 can be set according to actual needs.

[0037] In this embodiment, the primary support 1 and the secondary lining 4 have the same structure as in a conventional drill-and-blast tunnel, and appropriate support parameters can be selected through engineering analogy and stress analysis; the support parameters of the primary support 1 and the secondary lining 4 are not limited in this embodiment.

[0038] In an optimized embodiment, the number of the cavities 31 is multiple, and the multiple cavities 31 are arranged in the filling material 2 along the longitudinal direction of the tunnel in sequence; the gap between adjacent cavities 31 is filled with the filling material 2, and the distance between adjacent cavities can be adjusted according to needs.

[0039] In an optimized embodiment, the cavities 31 are arranged in a whole ring along the circumferential direction of the tunnel to form a circumferential cavity, and the cavities 31 can provide sufficient accommodation space and available compression stroke for any compression and destruction position in the whole ring.

[0040] In an optimized embodiment, the filling material 2 is provided with a pipe material 3 for forming the cavity 31; the cross section of the pipe material 3 is a circular cross section.

[0041] Specifically, in order to facilitate the formation of cavity 31 within the filling material 2, a tube 3 is provided as the outer mold of cavity 31, cavity 31 is formed inside the tube 3, and the filling material 2 covers the outside of tube 31.

[0042] Preferably, the pipe 3 can be crushed by the fragments of the filling material 2. Under the displacement of the active fault, the pipe 3 is crushed and destroyed, providing a disposal space and allowing the fragments to slide.

[0043] In an optimized implementation, the pipe material 3 is preferably a flexible thin-walled PVC pipe, glass pipe, corrugated pipe, etc.

[0044] In the optimized implementation method, the pipe 3 is fixed to the initial support 1 by U-shaped clamps to ensure the stability of the pipe 3 during the construction of filling materials, and is fixedly connected to the initial support 1 by U-shaped clamps.

[0045] As one specific implementation method, see the appendix to the instruction manual. Figure 3 and 4 As shown, this is one type of U-shaped clamp structure. The U-shaped clamp includes a U-shaped stirrup 5 and a clamping member 6. The curvature of the U-shaped stirrup 5 is adapted to the curvature of the pipe 3. The pipe 3 can be placed inside the U-shaped stirrup 5 and fixed to the U-shaped stirrup 5 by the clamping member 6. The two ends of the clamping member 6 are connected to the U-shaped stirrup 5. The pipe 3 abuts against the clamping member 6. The two ends of the U-shaped stirrup 5 are connected to the initial support 1, which can fix the pipe 3.

[0046] Preferably, steel plates 7 are welded or bolted to the two ends of the U-shaped stirrup 5. The steel plates 7 are embedded in the initial support 1 by expansion bolts 8, so that the U-shaped stirrup can be fixed on the initial support 1.

[0047] In the optimized implementation, the pipe 3 is assembled from multiple bends, with an overlap length of 10-20cm between adjacent bends. The bends serve as the outer mold for forming a circumferential cavity. The pipe 3 is arranged circumferentially along the tunnel using multiple bends, forming a large-diameter circumferential cavity within the filling material 2.

[0048] In an optimized implementation method, under fault displacement, the pipe (such as PVC pipe or glass pipe) is squeezed and ruptured, which can form a chute for the fragments of the filling material to slide through after the material is destroyed. After the material at the damaged part slides into the cavity, it forms a free space that can absorb the fault displacement, avoid stress concentration caused by material accumulation at the damaged location, and prevent secondary lining damage.

[0049] As one specific implementation method, the overlap between adjacent bends can be connected in a tongue and groove manner, with an overlap length of 10-20cm; it can also be fixed by a joint.

[0050] In an optimal embodiment, the filling material 2 comprises porous brittle concrete, which has the advantages of large porosity and low strength. In actual use, the filling material 2 comprises foamed concrete or SAP concrete (i.e. porous concrete with superabsorbent resin as pore former).

[0051] The filling material 2 fills the gaps between the adjacent pipes 3. The larger the cavity diameter and the smaller the spacing, the greater the compression stroke of the buffer layer, and the greater the dislocation amount of the active fault. However, the larger the cavity diameter and the smaller the spacing, the smaller the nominal compressive strength of the buffer layer, which is not conducive to the stability and safety of the fault-resistant structure during normal operation.

[0052] Preferably, in actual application, the diameter D and the spacing L of the cavity are determined by the thickness t of the buffer layer, the required compression stroke Δh of the buffer layer, the maximum average compressive stress σ allowed by the filling material, and the compressive strength σ of the filling material. c Therefore, D and L need to satisfy the following conditions:

[0053] πD 2 ≥ 4ΔhL (Formula 1)

[0054]

[0055] In an optimal embodiment, a first waterproof and drainage structure 12 is arranged between the filling material 2 and the secondary lining 4, wherein the first waterproof and drainage structure 12 comprises waterproof plates and / or drainage plates.

[0056] In an optimal embodiment, a second waterproof and drainage structure is arranged between the filling material 2 and the primary support 1, wherein the second waterproof and drainage structure comprises waterproof plates and / or drainage plates to improve the waterproof and drainage performance of the lining. Of course, whether the second waterproof and drainage structure is arranged or not can be determined according to actual needs.

[0057] In some embodiments, the cavity can serve as a drainage chamber for waterproofing, and in this case, the first waterproof and drainage structure and the second waterproof and drainage structure can be omitted.

[0058] Preferably, in the construction process, the secondary lining 4 comprises a first construction section lining and a second construction section lining, and a deformation joint 9 is arranged between the first construction section lining and the second construction section lining. The deformation joint 9 is filled with joint sealant. A first waterstop 10 is arranged between the lining and the filling material, and the first waterstop 10 is preferably a back-sticking rubber waterstop. A second waterstop 11 is further arranged in the lining, and the second waterstop 11 is preferably a center-buried rubber waterstop. The construction of the filling material and the waterstop in the present application is not described in detail, which belongs to the conventional construction method.

[0059] Example 2

[0060] The application further provides a construction method of the anti-crack structure of the drill-and-blast method tunnel with the annular cavity as described in Embodiment 1, comprising the following steps:

[0061] S1: applying the primary support 1 to ensure the stability of the primary support 1 and the surrounding rock;

[0062] S2: applying the buffer layer;

[0063] S3: applying the secondary lining 4.

[0064] Preferably, the buffer layer comprises the filling material 2 and the cavity 31 arranged in the filling material 2.

[0065] Preferably, the filling material 2 is preferably porous brittle concrete, and the cavity 31 is formed by the pipe material 3.

[0066] Specifically, the pipe material 3 is preferably a PVC pipe jointed together, and then after the excavation and the construction of the primary support 1 are completed, the positioning steel bars are laid on the inverted arch part to form a laying pad, and then the corresponding PVC pipes are laid according to the designed interval and the diameter of the cavity, and the bottom porous brittle concrete is prepared and poured.

[0067] After the construction of the bottom of the buffer layer is completed, the U-shaped hoop 5 is installed on the inner surface of the primary support 1 along the annular direction, the end of the U-shaped hoop 5 is welded on the steel plate 7, the steel plate 7 is fixed on the primary support 1 by the expansion bolts 8, then the PVC pipe is installed along the annular direction of the tunnel arch wall, the PVC pipe is fixed as the outer mold of the cavity of the buffer layer by the pressing member 6, the pressing member 6 can be fixed on the U-shaped hoop 5 by winding the thin steel wire, the formwork is erected layer by layer from bottom to top along the annular direction on the free side, and the porous brittle concrete is poured layer by layer to form the filling material 2, the formwork is removed after the porous brittle concrete reaches the preset strength, the geotextile, waterproof board and other waterproof and drainage structures are installed on the inner side of the filling material 2, and finally the secondary lining 4 is poured to complete the construction of the buffer layer structure.

[0068] Those skilled in the art should understand that the present application can be implemented in many other specific forms without departing from the spirit and scope of the present application. Although the embodiments of the present application have been described, it should be understood that the present application should not be limited to this embodiment, and those skilled in the art can make changes and modifications within the spirit and scope of the present application as defined in the appended claims.

Claims

1. A fault-resisting structure for a drill-and-blast tunnel having a circumferential cavity, the fault-resisting structure being provided in a section affected by a moving fault, characterized in that, The anti-fault structure comprises, from outside to inside, an initial support, a buffer layer and a secondary lining, the buffer layer comprises a filling material and cavities arranged in the filling material, the cavities are arranged along the ring direction of the tunnel; the number of the cavities is multiple, and multiple cavities are arranged in the filling material along the longitudinal direction of the tunnel; adjacent cavities are arranged at intervals, the cavities are arranged in a whole ring along the ring direction of the tunnel, and the filling material is provided with a pipe material for forming the cavities; the cross section of the pipe material is a circular section; the pipe material is arranged as an outer mold of the cavity, the cavity is formed inside the pipe material, and the filling material is wrapped outside the pipe material; under the movement of the active fault, the pipe material is extruded and damaged, providing a space for accommodating and sliding of the debris; the diameter D and the spacing L of the cavity are determined by the thickness t of the buffer layer, the required compression stroke Δh of the buffer layer, the maximum average compression stress σ allowed by the filling material and the compression strength σ c It is determined that D and L need to meet the following conditions: (Formula 1) (Formula 2).

2. The anti-disjointing structure of a drill and blast method tunnel with a ring- shaped cavity according to claim 1, characterized in that, The pipe is fixed to the primary support by a U-shaped clamp.

3. The anti-disjointing structure of a drill and blast method tunnel with a ring- shaped cavity according to claim 1, characterized in that, The pipe is a PVC pipe, a glass pipe or a corrugated pipe.

4. The anti-disjointing structure of a drill and blast method tunnel with a ring- shaped cavity according to claim 1, characterized in that, The filling material comprises porous brittle concrete.

5. The anti-disjointing structure of a drill and blast method tunnel with a ring- shaped cavity according to claim 1, characterized in that, A first waterproof structure is arranged between the filling material and the secondary lining.

6. The anti-disjointing structure of a drill and blast method tunnel with a ring- shaped cavity according to claim 1, characterized in that, A second waterproof structure is arranged between the filling material and the primary support.

7. A method of constructing a fault-resistant structure of a drill-and-blast tunnel having a ring-shaped cavity according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1: applying a primary support to ensure stability of the primary support and surrounding rock; S2: applying the buffer layer; S3: applying the secondary lining.

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