CN217813496U - Support system for crossing high-ground-stress fault fracture zone - Google Patents

Abstract

The utility model provides a pass through broken area support system of high ground stress fault, including the leading little pipe layer of one end setting in tunnel outside country rock and tunnel preliminary bracing structure and the flexible supporting construction of setting between the leading little pipe layer other end and tunnel outside country rock, flexible supporting construction sets up between tunnel preliminary bracing structure outside and tunnel outside country rock, and is provided with between flexible supporting construction and the tunnel outside country rock and reserves the space, and tunnel preliminary bracing structure inboard still is provided with tunnel secondary lining, tunnel preliminary bracing structure and flexible supporting construction all pass through system's mortar stock and tunnel country rock anchor. The utility model discloses a strut system utilizes tunnel preliminary bracing structure and flexible supporting construction to constitute "gentle just after earlier" supporting mode makes tunnel preliminary bracing structure atress evenly can not appear local atress and too big phenomenon that arouses tunnel secondary lining uplift, effectively reduces the lining and warp the fracture, and structural design is reasonable, the construction is simple and convenient and excellent in use effect.

Description

Support system for crossing high-ground-stress fault fracture zone

Technical Field

The utility model belongs to the technical field of the tunnel construction, specifically belong to a pass through broken area of high ground stress fault and strut system.

Background

In recent years, in underground engineering such as railway tunnels, highway tunnels, urban subways and the like which are being built and planned, soft rock tunnels (also called weak surrounding rock tunnels) occupy a high proportion, the length and the span of the tunnels are also increasingly large, and a large number of tunnels are still in special geology such as loess with a large pore structure, water-rich fully-weathered granite, a water-rich fault fracture zone, a debris flow stratum, a sandy gravel stratum, a loose accumulation body and the like. It is very difficult to construct large-section and large-span tunnels in the strata, and collapse phenomenon often occurs in the construction process. The fault fracture zone refers to a fracture zone which is formed by relatively moving two disks of a fault and mutually squeezing the two disks to fracture nearby rocks to form a fracture zone which is approximately parallel to a fault surface. The construction difficulty of the weak surrounding rock tunnel penetrating through the fault fracture zone is very high, particularly when the stratum is a water-rich stratum, the rock mass fracture provides more favorable conditions for occurrence and enrichment of underground water, and the phenomena of sudden surge such as tunnel debris flow, fragment flow and landslide are very easy to occur, so that the tunnel engineering is extremely damaged, and the construction difficulty is very high. Therefore, when the tunnel passes through a high ground stress fault, the tunnel face is easy to collapse, the construction risk is high, the construction difficulty is high, and the construction progress is slow. And after the secondary lining of the primary supporting structure tunnel of the tunnel is constructed, the problems of lining uplift cracking, arch frame deformation and the like are easy to occur due to the influence of structural stress.

For a high ground stress weak surrounding rock tunnel, large deformation is one of common engineering disasters. The traditional way is that increase tunnel primary support structure's intensity and rigidity, sets up the cover and encircles, and main supporting mode is mostly to add twice or multichannel tunnel primary support structure, increases tunnel secondary lining intensity, expands to dig into the better circular section of atress performance, and stress relief technique (leading pilot tunnel stress release, reservation deformation stress release), let pressure stock supporting construction etc.. The comprehensive analysis of the supporting scheme of the high-ground-stress fault fracture zone also has the following defects:

(1) The construction cost is high, the working procedure is complicated, the progress is slow, and the construction period is prolonged; (2) controlling the large deformation effect of the soft rock to be general or even ineffective; (3) The secondary lining of the tunnel is usually applied under the condition that the primary supporting structure of the tunnel is deformed and not converged, the stress of the secondary lining of the tunnel is large, and the reliability, the safety and the durability of the tunnel structure cannot be guaranteed.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem that exists among the prior art, the utility model provides a pass through broken area of high ground stress fault and strut system, structural design is reasonable, the construction is simple and convenient and excellent in use effect.

In order to achieve the above purpose, the utility model provides a following technical scheme: the utility model provides a pass through broken area support system of high ground stress fault, includes that one end sets up the little pipe layer in advance in the tunnel outside country rock and sets up tunnel preliminary bracing structure and the flexible supporting construction between little pipe layer other end in advance and the tunnel outside country rock, wherein, flexible supporting construction sets up between tunnel preliminary bracing structure outside and tunnel outside country rock, and is provided with between flexible supporting construction and the tunnel outside country rock and reserves the space, tunnel preliminary bracing structure inboard still is provided with tunnel secondary lining, tunnel preliminary bracing structure and flexible supporting construction all pass through system's mortar stock and tunnel country rock anchor.

Further to the tunnel excavation direction is the place ahead, and leading little pipe layer is a plurality of by the back forward to the tunnel on the body advance little pipe that carries out advance support, the inside cavity of leading little pipe is provided with a plurality of injected holes on its pipe shaft, and leading little pipe one end is the slip casting stiff end, and the other end is the pointed end that is provided with out the thick liquid seam.

Furthermore, the length of a pipe body of the advanced small pipe provided with grouting holes is 3-5 m, and four grouting holes are uniformly distributed on each section of the pipe body of the advanced small pipe along the length direction.

Furthermore, the tip is composed of four fan-shaped steel sheets, and a slurry outlet seam is formed between every two adjacent fan-shaped steel sheets.

Furthermore, a fine wire mesh is arranged inside the tip.

Furthermore, the flexible supporting structure comprises three layers of reinforcing mesh sheets, concrete is filled between the two layers of reinforcing mesh sheets close to one side of the primary supporting structure of the tunnel to form a concrete layer, a grid arch is arranged in the concrete layer, and the grid arch is fixed with one end of a system mortar anchor rod; the high-polymer elastic filler is filled between the two layers of reinforcing steel bar net sheets close to one side of the tunnel surrounding rock to form a high-polymer filler layer, and waterproof plate layers are arranged between two sides of the high-polymer filler layer and the reinforcing steel bar net sheets.

Furthermore, the grid arch is of a steel bar structure, and the high polymer elastic filler is coal ash polyurethane.

Further, the tunnel preliminary bracing structure includes the steel bow member, seted up leading little pipe hole on the steel bow member, the one end of leading little pipe is squeezed into the country rock through leading little pipe hole.

Further, a waterproof plate layer is hung on the inner side of the tunnel primary supporting structure, and a foaming layer is filled between the waterproof plate layer and the tunnel primary supporting structure.

Furthermore, the advanced small pipe layer is arranged on an arc line corresponding to a 120-degree angle at the top end of the tunnel arch, and the advanced small pipe layer is double-layer.

Compared with the prior art, the utility model discloses following beneficial effect has at least:

the utility model discloses a pass through high ground stress fault broken zone supporting system, combine together leading little pipe and system mortar stock and form the whole reinforced structure of hole peripheral rock that carries out whole reinforcement to tunnel hole outside surrounding rock, the novel flexible supporting construction who adds between tunnel outside surrounding rock and tunnel preliminary bracing structure, through flexible supporting construction and leading little pipe slip casting protection tunnel face safe excavation tunnelling, tunnel preliminary bracing structure lags the implementation; set up the reservation space of controllable deformation release between flexible supporting construction and country rock, satisfy tunnel large deformation demand in earlier stage, through flexible supporting construction's deformation and release effect, make tunnel primary support structure warp controllably, tunnel primary support structure constitutes "first gentle just after" supporting mode makes tunnel primary support structure atress evenly can not appear local atress too big phenomenon that arouses tunnel secondary lining uplift with flexible supporting construction, effectively reduces lining cutting deformation fracture, the utility model discloses a supporting system structural design is reasonable, the construction is simple and convenient and excellent in use effect.

Furthermore, the grille arch frame arranged in the flexible supporting structure also plays a certain supporting role, which is equivalent to the primary supporting structure of the tunnel for the first time;

furthermore, the double-layer waterproof plate layer in the flexible structure can play a good waterproof role, and fracture water in a broken zone is prevented from corroding and damaging a steel structure in the tunnel supporting structure;

further, the utility model discloses fill one deck foaming layer between secondary lining and tunnel primary support structure, further alleviated tunnel deformation space not enough problem, can effectively solve the broken area of high ground stress fault and appear later stage country rock and continuously warp and the uneven scheduling problem of atress.

Drawings

FIG. 1 is a high ground stress fault fracture zone support diagram;

FIG. 2 is a detailed view of the flexible support structure;

FIG. 3 is a view of a custom made advanced microcatheter;

FIG. 4 is a top view of a tip of a small lead catheter;

FIG. 5 is a side view of a steel arch;

in the drawings: 1-tunnel section; 2-locking the foot anchor rod; 3-lower locking feet anchor rod; 4-primary tunnel supporting structure; 5-flexible supporting structure; 6-system mortar anchor rod; 7-leading small conduit, 71 grouting hole, 72 tip grouting seam, 73 grouting fixed end, 74 fine wire netting and 75 grout outlet seam; 8-a foamed layer; 9-waterproof board layer; 10-secondary lining of the tunnel; 11-steel bar mesh; 12-concrete; 13-a polymeric elastic filler; 14-a grid arch; 15-leading small catheter hole; 16-steel arch centering; 17-reserved gap

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description.

As shown in fig. 1, the utility model discloses a weak surrounding rock tunnel support system of broken zone of crossing fault under high ground stress, including tunnel preliminary bracing structure 4, flexible supporting structure 5, leading little pipe layer 7 and tunnel secondary lining 10, wherein, tunnel preliminary bracing structure 4 inboard is provided with tunnel secondary lining 10, is provided with flexible supporting structure 5 between the tunnel preliminary bracing structure 4 outside and the tunnel outside surrounding rock, and flexible supporting structure 5 is used for having played the self-adaptation supporting role to the large deformation of preliminary surrounding rock after the tunnel excavation; be provided with between flexible supporting construction 5 and the tunnel outside country rock and reserve space 17, reserve space 17 and be used for the country rock deformation to reserve certain deformation space and prevent tunnel primary support construction 4 atress uneven phenomenon that tunnel secondary lining 10 rises, leading little pipe layer is fixed and is used for carrying out the whole reinforcement to the peripheral rock in hole on the tunnel outside country rock, tunnel primary support construction 4, flexible supporting construction 5 and leading little pipe layer all through system's mortar stock 6 and tunnel country rock anchor, wherein:

the excavation direction of the tunnel is taken as the front, the advanced small conduit layers are a plurality of advanced small conduits 7 for supporting the tunnel upper cavity body from back to front in an advanced manner, and grouting is performed to surrounding rock cracks of the fault fracture zone through the advanced small conduits, so that the self-stability capability of the excavated surrounding rock is improved;

as shown in fig. 3, the leading small pipe 7 is preferably hollow, and has a grouting fixing end 73 at one end and a tip end provided with a grout outlet slit 72 at the other end, and a plurality of grouting holes 71 are further provided in the leading small pipe 7.

Preferably, the diameter of the grouting hole 71 is 7mm, the advanced small catheter 7 comprises a main grouting part of the circular grouting hole 71, the length of the main grouting part is 3.0-5.0 m, four grouting holes 71 are uniformly distributed on each section of the body of the advanced small catheter 7 along the length direction, the grouting holes on the same circular plane form a plane, and the distance between the circular planes formed by the two grouting holes arranged along the longitudinal direction of the advanced small catheter 7 is 35cm;

as shown in FIG. 4, the tip of the small advanced duct 7 is composed of four fan-shaped steel sheets, a slurry outlet gap 72 is formed between two adjacent fan-shaped steel sheets to facilitate slurry outlet, and a fine wire mesh with a distance of 3mm is arranged inside the tip to prevent the small advanced duct 7 from being blocked due to drilling slag in the installation process of the small advanced duct 7.

Preferably, the width of the slurry outlet slit 72 is 3mm.

As shown in fig. 2, the flexible supporting structure 5 is composed of three layers of reinforcing mesh sheets 11, a waterproof slab layer 9, a polymer elastic filler 13, a concrete layer 12 and a grid arch 14, wherein the concrete layer 12 is formed by filling concrete between the two layers of reinforcing mesh sheets 11 close to one side of the primary supporting structure 4 in the tunnel, the grid arch 14 is arranged in the concrete layer 12, the grid arch 14 is fixed at one end of a system mortar anchor rod 6, and the grid arch 14 and the reinforcing mesh sheets 11 play a flexible supporting role, which is equivalent to a primary supporting structure of the tunnel for the first time;

polymer elastic fillers are filled between the two layers of reinforcing steel bar net sheets 11 close to one side of the surrounding rock outside the tunnel to form a polymer filler layer 13, a waterproof plate layer 9 is arranged between the polymer filler layer 13 and the two layers of reinforcing steel bar net sheets 11, and the reinforcing steel bar net sheets 11 and the waterproof plate layer 9 jointly play a role in fixing the polymer filler layer 13;

preferably, during construction of the flexible structure 5, the outer steel bar net piece 11 used for fixing the polymer elastic filler is fixed at the end part of the system mortar anchor rod 6 and welded, then the welded waterproof plate layer 9 is arranged and fixed on the outer steel bar net piece 11 through the sticking hooks, the outer steel bar net piece of the grid arch 14 is welded on the grid arch 14, the distance between two layers of steel bar net pieces 11 on one side close to the surrounding rock on the outer side of the tunnel is 20-50 cm, and the reserved gap 17 is determined according to the deformation state of the surrounding rock on site.

Preferably, the grid arch 14 is of a steel bar structure;

preferably, the high-molecular elastic filler is fly ash polyurethane, and the compatibility between the polyurethane matrix and the fly ash modified by the coupling agent is obviously improved. The fly ash is applied to the resin matrix, so that the production cost can be reduced, and the effective utilization of the fly ash can be realized.

The tunnel primary supporting structure 4 comprises a steel arch 16, a reinforcing mesh 11, a locking anchor pipe and concrete 12, wherein the steel arch 16 is fixed by a system mortar anchor rod 6, the double-layer reinforcing mesh 11 is hung on the steel arch 16, the grouting locking anchor pipe is arranged at the arch foot of the steel arch 16, and all components are formed into a whole by spraying concrete;

as shown in fig. 5, the steel arch frame 16 is provided with a leading small guide pipe hole 15, when the leading small guide pipe 7 is constructed, the leading small guide pipe 7 is driven into surrounding rocks from the leading small guide pipe hole 15 by a rock drill, and then welding is carried out at a blank opening.

The lock foot anchor pipe is including locking foot stock 2 and lower lock foot stock 3 for prevent that arch foot department from appearing stress concentration and appearing great deformation.

Preferably, a waterproof sheet layer 9 is further arranged on the inner side of the tunnel primary supporting structure 4, and a foaming layer 8 is arranged between the waterproof sheet layer 9 and the tunnel primary supporting structure 4 and used for further relieving the problem of insufficient deformation space of the tunnel, so that the problems of large deformation, uneven stress and the like of a high ground stress fault fracture zone can be effectively solved.

A supporting method for a high-ground-stress fault broken tunnel can solve the problem of continuous deformation of surrounding rocks caused by structural stress. Firstly, the problem of rapid deformation of surrounding rocks in the initial stage of tunnel excavation is solved by reserving gaps between the flexible supporting structure 5 and the surrounding rocks in advance (comprehensively judging according to the magnitude of the ground stress of a tunnel site selection area and the state of the surrounding rocks), and after the tunnel initial supporting structure 4 is constructed, the high-molecular elastic filling layer and the grid arch 14 of the flexible supporting structure 5 can well adapt to the asymmetric deformation of the surrounding rocks in the later stage. The tunnel preliminary bracing structure 4 of combination can restrict tunnel 4 and realize the back great deformation in tunnel, can prevent to produce behind one's back cavity again, the loose circle enlarges, the big deformation scheduling problem that brings about then, can increase tunnel preliminary bracing structure 4's stability simultaneously again, avoid tunnel preliminary bracing structure 4 atress uneven local uplift destruction problem that appears, prevent the phenomenon such as steelframe distortion, the rupture, the limit is invaded to the primary lining, optimize tunnel preliminary bracing structure's atress nature, guarantee supporting structure's safety.

(1) The double-layer advanced small catheter layer is applied as follows: the outer inserting angles of the advanced small guide pipes 7 are respectively 10-15 degrees of gentle inclination angle and 30-40 degrees of steep inclination angle, and the upper layer and the lower layer are arranged in a staggered mode and are arranged in the range of 120 degrees of the arch portion.

The external insertion angle of the leading small conduit 7 is 10-15 degrees, the V-grade surrounding rock and the IV-grade shallow surrounding rock are arranged in the range of 120 degrees of the arch part, and the IV-grade deep surrounding rock is arranged in the range of 90 degrees of the arch part. And performing one-ring advanced support for every two excavation supports in a circulating way.

The leading small guide pipe 7 is 4.5m long in length, the horizontal lap joint length is not less than 1.0m, and the leading small guide pipe 7 is made of hot-rolled seamless steel pipes, the diameter of the leading small guide pipe is 42mm, and the wall thickness of the leading small guide pipe is 4mm. Grouting holes 71 are drilled in the pipe wall of the small advanced guide pipe 7, the aperture of each grouting hole 71 is 7mm, the hole distance is 15cm, and the grouting holes are arranged in a quincunx shape. And a grouting hole with the tail part of 30cm is not drilled to serve as a grouting fixing end 73.

(2) After the tunnel is excavated and before the flexible support 5 is constructed, a system mortar anchor rod 6 is additionally arranged, an upper layer reinforcing mesh piece 11 of the flexible support structure 5 is welded on the radial system mortar anchor rod 6, the distance between the anchor rods is 3.5m, and a grid arch 14 is fixed on the system mortar anchor rod 6, wherein the distance between the arches is 0.6-1.2 m. And then the lower layer steel mesh sheet 11 of the flexible supporting structure 5 is welded on the grid arch 14. Bonding the pre-designed waterproof slab layer 9 to form a sealed structure, and arranging the waterproof slab layer 9 between two reinforcing mesh sheets 11 at a distance of 10-50 cm. And injecting the macromolecular elastic filler into the structure of the waterproof board layer 9, and sealing after the waterproof board layer is filled with the macromolecular elastic filler to form a macromolecular elastic filling layer 13.

(4) The tunnel primary supporting structure 4 is applied as follows: the tunnel primary support structure 4 adopts an I20a steel frame, a plurality of system mortar anchor rods 6 with the length of 2.5m and the diameter of 25mm are used for fixing, the annular space between the system mortar anchor rods 6 is 2m, the longitudinal space between the steel supply frames 16 is 1 truss/0.6-1.0 m, double-layer steel bar meshes with the diameter of 8mm are hung on the steel supply frames 16, the hole space between the double-layer steel bar meshes is 20 multiplied by 20cm, and 4 steel bars with the length of 4.5m and the diameter of 42mm are adopted. And grouting and locking the legs after the leg locking anchor pipes are arranged. The sprayed concrete is 6 to 33cm, and all the components are integrated.

(5) After the tunnel primary supporting structure 4 is finished, a waterproof plate layer 9 is hung on the inner side of the tunnel primary supporting structure 4 by using a trolley, a foaming layer 8 is filled between the waterproof plate layer 9 and the tunnel primary supporting structure 4, then demolding and grouting are carried out, tunnel secondary lining concrete is injected, and a tunnel secondary lining 10 is obtained.

The utility model provides a pass through broken area of high ground stress fault and strut system comprises little pipe, flexible supporting construction in advance, reservation space, tunnel preliminary bracing structure and tunnel secondary lining concrete and struts the system of multilayer of hard and soft parallel:

(1) the tunnel face is protected by a flexible supporting structure and the small advanced duct grouting to safely excavate and tunnel, and the primary supporting structure of the tunnel is constructed in a lagging mode;

(2) a reserved gap capable of controlling deformation release is arranged between the advanced flexible supporting structure and the surrounding rock, the requirement for large deformation of the tunnel in the early stage is met, meanwhile, a double-layer waterproof plate layer in the flexible structure can play a good waterproof role, and the condition that a steel structure in the tunnel supporting structure is damaged due to the erosion of fracture water in a broken zone is avoided;

(3) the deformation of the primary tunnel supporting structure is controllable through the deformation pre-release effect, and the primary tunnel supporting structure and the flexible supporting structure form a 'flexible-first-rigid-later' supporting mode, so that the deformation and cracking of the lining can be effectively reduced;

(4) after the deformation is released, the stress of the primary tunnel supporting structure continuously acts on the ground stress, is reduced by high ground stress within a period of time and then continuously rises, then the secondary lining is applied in time, and a foaming layer is filled between the secondary lining and the primary tunnel supporting structure to meet the requirement of continuous deformation of surrounding rocks.

Claims (8)

1. The support system for the fault fracture zone passing through the high ground stress is characterized by comprising an advanced small guide pipe layer, a tunnel primary support structure (4) and a flexible support structure (5), wherein one end of the advanced small guide pipe layer is arranged in surrounding rocks on the outer side of a tunnel, the tunnel primary support structure (4) and the flexible support structure (5) are arranged between the other end of the advanced small guide pipe layer and the surrounding rocks on the outer side of the tunnel, the flexible support structure (5) is arranged between the outer side of the tunnel primary support structure (4) and the surrounding rocks on the outer side of the tunnel, a reserved gap (17) is formed between the flexible support structure (5) and the surrounding rocks on the outer side of the tunnel, a tunnel secondary lining (10) is further arranged on the inner side of the tunnel primary support structure (4), and the tunnel primary support structure (4) and the flexible support structure (5) are anchored with the surrounding rocks through a system mortar anchor rod (6);

the flexible supporting structure (5) comprises three layers of reinforcing mesh sheets (11), concrete is filled between the two layers of reinforcing mesh sheets (11) close to the tunnel primary supporting structure (4) to form a concrete layer (12), a grid arch (14) is arranged in the concrete layer (12), and the grid arch (14) is fixed with one end of the system mortar anchor rod (6); polymer elastic fillers are filled between two layers of reinforcing steel bar net sheets (11) close to one side of the tunnel surrounding rock to form a polymer filler layer (13), and a waterproof plate layer (9) is arranged between both sides of the polymer filler layer (13) and the reinforcing steel bar net sheets (11);

a waterproof plate layer (9) is hung on the inner side of the tunnel primary supporting structure (4), and a foaming layer (8) is filled between the waterproof plate layer (9) and the tunnel primary supporting structure (4).

2. The support system for the fault-breaking zone crossing high ground stress according to claim 1, wherein the excavation direction of the tunnel is taken as the front direction, the advanced small conduit layer is a plurality of advanced small conduits (7) for performing advanced support on the tunnel upper cavity body from back to front, the advanced small conduits (7) are hollow, a plurality of grouting holes (71) are formed in the conduits, one end of each advanced small conduit (7) is a grouting fixing end (73), and the other end of each advanced small conduit is a tip end provided with a grout outlet gap (72).

3. The support system for the fracture zone across the high geostress fault according to claim 2, characterized in that the length of the pipe body of the grouting hole (71) arranged on the leading small pipe (7) is 3 m-5 m, and four grouting holes (71) are uniformly distributed on each section of the pipe body of the leading small pipe (7) along the length direction.

4. The high-ground-stress-crossing fault belt support system of claim 2, wherein the tip is composed of four fan-shaped steel sheets, and a slurry outlet seam (72) is formed between two adjacent fan-shaped steel sheets.

5. A cross high ground stress fault zone support system according to claim 2, wherein a fine wire mesh is provided inside the tip.

6. The high-ground-stress-crossing fault-breaking-zone supporting system according to claim 1, wherein the grid arch (14) is of a steel bar structure, and the high-molecular elastic filler is fly ash polyurethane.

7. The fault-breaking zone crossing high ground stress supporting system according to claim 1, wherein the tunnel primary supporting structure (4) comprises a steel arch (16), the steel arch (16) is provided with a small leading guide pipe hole (15), and one end of the small leading guide pipe (7) is driven into surrounding rock through the small leading guide pipe hole (15).

8. The through high-ground-stress fault-breaking-zone supporting system according to claim 1, wherein the advanced small conduit layers are arranged on an arc line corresponding to an angle of 120 degrees at the top end of the tunnel arch, the arrangement range of the small conduits can be adjusted according to the surrounding rock state, and the advanced small conduit layers are double-layered.

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