Buffering and pressure-yielding composite support structure and support method for soft surrounding rock tunnels

Abstract

The present invention discloses a buffering and pressure-yielding composite support structure and support method for a soft surrounding rock tunnel, which is an arched structure, and includes anchor spraying support, buffer support and reinforced support from the outside to the inside, and both ends of the buffer support and reinforced support in the circumferential direction are fixed to the inverted arch cast at the bottom of the tunnel. The buffer support mainly plays a role of buffering and energy absorption and seismic isolation, including a buffer corrugated plate and an elastic layer covering the inner surface of the buffer corrugated plate. The buffer corrugated plate includes a plurality of first corrugated culverts, and the plurality of first corrugated culverts can be spliced ​​into one body in the circumferential and axial directions through a buffer assembly to float axially or circumferentially. The reinforced support can provide stable rigid support for the surrounding rock by strengthening the combination of the corrugated plate and concrete, and play a role in overall stability and support resistance of the support. The common bearing and deformation of the support body and the surrounding rock are achieved, and the deformation amount and deformation rate of the surrounding rock are effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel engineering, and in particular to a buffering and pressure-yielding composite support structure and a support method for a soft surrounding rock tunnel. Background Art

[0002] Tunnels are engineering structures buried in the ground and are a form of human use of underground space. Tunnels can be divided into traffic tunnels, hydraulic tunnels, municipal tunnels, and mining tunnels. In rock underground projects such as tunnels, the surrounding rock mass that undergoes a change in stress state due to the influence of excavation is called surrounding rock.

[0003] The instability and failure of soft rock tunnels is essentially due to the formation pressure effect. The redistributed secondary stress after tunnel excavation interacts with the deformation and strength characteristics of the surrounding rock. When the secondary stress value exceeds the plastic limit or strength limit of some surrounding rocks or causes the surrounding rocks to enter a significant rheological state, the surrounding rocks will undergo significant deformation, cracking, loosening, and destruction, showing an obvious formation pressure effect. After tunnel excavation, the surrounding rock that previously supported the tunnel body is removed, and the tunnel wall is exposed to the air, causing the surrounding rock stress to be readjusted. Both the surrounding rock and the tunnel wall deform in the direction of the tunnel clearance, so the tunnel wall needs to be supported.

[0004] The Chinese utility model patent CN208966352U discloses a support structure for a tunnel in a soft rock area. The technical problem solved by the patent is that the traditional initial support structure of a soft rock tunnel generally adopts a single-layer grid steel frame anchor spraying or an I-beam anchor spraying. However, under the action of high ground stress, the deformation of soft rock has the characteristics of large initial deformation, fast deformation rate, long deformation duration, and large deformation amount. The patent still has some shortcomings. Due to the creep characteristics of the soft surrounding rock, it is very easy to have a long initial support deformation time, large deformation amount, fast deformation rate, and long duration. The surrounding rock is squeezed out of the intrusion limit in a large area. After the support is subjected to the pressure of the tunnel rock wall, the splicing position is very likely to deform or break, and the deformation exceeds the limit, requiring continuous renovation, which seriously affects the construction progress, increases the construction cost, and brings many safety hazards to the construction. At this stage, preventing the surrounding rock from further deforming and converging inevitably requires the initial support structure to have high stiffness and high strength, which in turn leads to the high cost of the support structure, so it is necessary to have strong flexibility to adapt to this deformation convergence. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a buffering and pressure-yielding composite support structure and support method for soft surrounding rock tunnels, which allows the surrounding rock to produce a certain amount of rheological deformation after lining is applied, and keeps the deformation of the surrounding rock within a controllable range, thereby realizing the common bearing and deformation of the support body and the surrounding rock, and effectively controlling the deformation amount and deformation rate of the surrounding rock.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] The buffering and pressure-yielding composite support structure for soft rock tunnels is an arched structure, characterized in that it includes anchor spraying support, buffering support and reinforcing support in sequence from outside to inside, and both ends of the buffering support and reinforcing support in the circumferential direction are fixed to the invert cast at the bottom of the tunnel;

[0008] The buffer support comprises a buffer corrugated plate and an elastic layer covering the inner surface of the buffer corrugated plate, wherein the buffer corrugated plate comprises a plurality of first corrugated culverts, and the plurality of first corrugated culverts are spliced ​​into one body in both the circumferential and axial directions through a buffer assembly so as to be axially or circumferentially floating;

[0009] Strengthening support, including strengthening corrugated plate, the strengthening corrugated plate includes a plurality of corrugated arch rings spliced ​​axially, the corrugated arch rings are formed by splicing a plurality of second corrugated culvert pieces circumferentially, the second corrugated culvert pieces are both circumferentially fixed with end face flanges, the end face flanges include radially arranged end plates fixed to the second corrugated culvert pieces, and folding plates protruding from the second corrugated culvert pieces are provided at both radial ends of the end plates, the angle between the folding plates and the end plates is an obtuse angle, the two end face flanges connected are fitted together, and bolt assemblies are passed through the folding plates for fixing;

[0010] A concrete medium layer is filled between the buffer corrugated plate and the reinforcing corrugated plate;

[0011] The edge of the first corrugated culvert has an outwardly facing right-angled flanged groove, and the openings of the two adjacent flanged grooves on the two first corrugated culverts are arranged opposite to each other;

[0012] The buffer assembly includes a connecting cover which is arranged outside two connected flanged grooves, the connecting cover includes a top wall with the same curvature as the buffer corrugated plate, and has side walls extending radially inward at both ends of the top wall. An extension plate is also provided in the middle of the top wall which radially passes between the two flanged grooves and extends into the concrete medium layer. The two flanged grooves are arranged on both sides of the extension plate. After the flanged grooves are matched with the connecting cover, they have an circumferential or axial elastic displacement and a radial elastic displacement.

[0013] A further technical solution is that the two axially connected corrugated arch rings are connected by a reinforcing beam, the reinforcing beam includes a web fixed to the two second corrugated culverts, and wing plates are provided at the upper and lower ends of the web to form an "I"-shaped structure, the end face flange is located between the two wing plates of the reinforcing beam, and the folded plate is abutted against the corresponding wing plate.

[0014] A further technical solution is that the two axial ends of the corrugated arch ring have vertical inward one-way flanges, and the one-way flanges on the two axially connected corrugated arch rings are fitted to the web of the reinforcing beam and fixed by a bolt assembly.

[0015] A further technical solution is that the waveform of the second corrugated culvert includes a trapezoidal wave, wherein the interior of the trapezoidal wave has an I-beam penetrating the end face flange.

[0016] A further technical solution is that: a long strip sliding hole is opened on the top wall of the connecting cover, a T-shaped sliding rod passing through the sliding hole is provided on the flanged card slot, and a locking cap is provided at the other end of the sliding rod, and a first spring is sleeved on the sliding rod inside the flanged card slot;

[0017] A second spring in a compressed state is provided between the flanged card slot and the corresponding side wall. The second spring can drive the flanged card slot to be close to the extension plate and can move the two flanged card slots away from each other after further compression.

[0018] A further technical solution is that: both sides of the extension plate have barbs arranged in a fishbone shape.

[0019] A further technical solution is that the buffer support also includes a plurality of arc-shaped buffer plates located outside the buffer corrugated plate, the openings of the buffer plates face the buffer corrugated plate, and the tops of the buffer plates are fixed to the anchor spray support.

[0020] A further technical solution is that the plurality of buffer plates have at least two specifications with different diameters, and after being subjected to force, the diameters thereof contact the buffer corrugated plates in order from large to small.

[0021] A further technical solution is that: a plurality of connecting bolts protruding radially inward are fixed on the anchor spray support, and the top of the buffer plate is connected and fixed to the connecting bolts.

[0022] The buffering and pressure-yielding composite support method for a soft surrounding rock tunnel is characterized in that the above-mentioned buffering and pressure-yielding composite support structure for a soft surrounding rock tunnel is applied, and the method comprises the following steps:

[0023] S1. Establish anchor spraying support

[0024] S1.1 Fix the connection bolts on the flexible steel wire mesh, and fix the flexible steel wire mesh on the rock wall of the tunnel after excavation, so that there is a gap between the flexible steel wire mesh and the rock wall of the tunnel;

[0025] S1.2 Pass multiple anchor rods through the flexible steel wire mesh and fix them on the tunnel rock wall;

[0026] S1.3 Shotcrete is sprayed so that the flexible steel mesh is buried in the concrete and the connecting bolts extend radially out of the concrete;

[0027] S2. Establish buffer support

[0028] S2.1 After the anchor spraying support is stable, cast the invert at the bottom of the tunnel;

[0029] S2.2 Install the buffer corrugated plate, and flexibly assemble the plurality of first corrugated culverts in the axial and circumferential directions through the buffer assembly;

[0030] S2.3 Fix the elastic layer on the inner surface of the buffer corrugated plate, and apply a release agent on the inner surface of the elastic layer;

[0031] S3. Establish reinforced support

[0032] S3.1 Install the reinforced corrugated plate, axially assemble multiple corrugated arch rings, and fill concrete between the buffer corrugated plate and the reinforced corrugated plate after a certain distance until the axial installation of the buffer corrugated plate is completed.

[0033] The beneficial effects of adopting the above technical solution are:

[0034] The support structure includes anchor spraying support, buffer support and reinforced support from outside to inside, forming a composite support with buffering and pressure relief.

[0035] Anchor-sprayed support uses anchor rods and shotcrete to support the surrounding rock. The anchor rods and shotcrete form a bearing structure with the surrounding rock. The shotcrete fills the gaps and makes up for the defects of the rock crystals. It can initially limit the free development of surrounding rock deformation, adjust the stress distribution of the surrounding rock, prevent the rock mass from loosening and falling, and provide safety for the subsequent support construction.

[0036] The buffer support is provided with buffer components at the axial and radial joints, and an elastic layer is provided between the buffer support and the reinforced support, allowing the buffer support to have axial, circumferential and radial elastic deformations after being compressed, so that the pressure on the buffer support can be released and buffered, playing a role of buffering and energy absorption for seismic isolation, and can adapt to the shape changes caused by rock bursts, frost heave or large deformation of soft rocks in the tunnel, realizing the common bearing and deformation of the support body and the surrounding rock, and the deformation is limited by the connecting cover, which will not cause damage to the joints, thereby effectively controlling the deformation amount and deformation rate of the surrounding rock.

[0037] Strengthening the support can provide stable rigid support for the surrounding rock by strengthening the combination of corrugated plates and concrete, and play a role in overall stability and support resistance of the support. The end face flanges are spliced ​​to form a snap-fit ​​structure, and the shear force of the connecting bolts is avoided by the inclined setting of the folded edges, which increases the stability of the end face flange splicing, that is, the overall support strength of the reinforced corrugated plate is improved. Concrete is poured between the reinforced corrugated plate and the buffer corrugated plate to provide high-strength support for the surrounding rock, further suppress the creep rate and deformation of the buffer corrugated plate, so that the total amount and rate of creep of the surrounding rock can be significantly reduced, and the creep can enter a stable state as soon as possible, shortening the adverse effect time of creep on the stability of the surrounding rock.

[0038] In addition, the specific form of the buffer component in the buffer support adopts a protective cover to cover the joints, which not only limits the deformation of the joints, but also prevents water from seeping in from the joints, and prevents impurities from entering the joints. It does not affect the elastic reset of the joints, can restore the deformation, and can also play the role of reinforcing ribs.

[0039] Moreover, the protective cover is provided with an extension plate extending into the reinforced concrete layer. The extension plate is cast in the concrete to fix the position of the connecting cover, provide a positioning reference for the buffer corrugated plate, and make the buffer corrugated plate exhibit dispersed multi-point displacement deformation after being subjected to force, thereby avoiding the overall deformation and displacement of the buffer corrugated plate and ensuring the stability of the buffer support.

[0040] The buffering and pressure-yielding composite support method for soft surrounding rock tunnels disclosed in the present invention can obtain the above-mentioned buffering and pressure-yielding composite support structure. After construction, the surrounding rock is allowed to produce a certain amount of rheological deformation after lining is applied, and the deformation of the surrounding rock is kept within a controllable range, thereby realizing the common bearing and deformation of the support body and the surrounding rock, and effectively controlling the deformation amount and deformation rate of the surrounding rock, controlling and reducing the adverse effects of rheology, ensuring the stability of the surrounding rock, and improving the stability and reliability of the project, which has important practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0042] Figure 1 It is a schematic diagram of the cross-sectional structure of the buffering and pressure-yielding composite supporting structure disclosed in the present invention;

[0043] Figure 2 It is a schematic diagram of the axonometric structure of the corrugated arch ring in the present invention;

[0044] Figure 3 It is a structural schematic diagram of the end face flange part of the present invention;

[0045] Figure 4 It is a schematic diagram of the axial cross-section structure of the corrugated arch ring in the present invention;

[0046] Figure 5 It is a schematic diagram of the structure of the elastic component at the axial joint in the present invention. DETAILED DESCRIPTION

[0047] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0048] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0049] like Figure 1~Figure 5 As shown, the buffering and pressure-yielding composite support structure for soft surrounding rock tunnels disclosed in the present invention is an arch structure, and the structure includes an anchor spray support 10, a buffering support 20 and a reinforcing support 30 from the outside to the inside, forming a buffering and pressure-yielding composite support, wherein both ends of the buffering support 20 and the reinforcing support 30 are fixed to the invert (not shown in the figure) cast at the bottom of the tunnel, and the invert belongs to the prior art in this field and will not be described here.

[0050] The anchor-spray support 10 adopts the measures of anchor rods 12 and shotcrete to support the surrounding rock. The anchor rods 12 and shotcrete form a bearing structure with the surrounding rock. The shotcrete fills the gaps and makes up for the defects of the rock crystals. It can initially limit the free development of the surrounding rock deformation, adjust the stress distribution of the surrounding rock, prevent the rock mass from loosening and falling, and provide safety guarantee for the construction of the later support.

[0051] The buffer support 20 mainly plays the role of buffering and energy absorption and seismic isolation. The buffer support 20 includes a buffer corrugated plate 21 and an elastic layer 22 covering the inner surface of the buffer corrugated plate 21. The buffer corrugated plate 21 includes a plurality of first corrugated culverts 211. The plurality of first corrugated culverts 211 are spliced ​​into one body in the circumferential and axial directions through buffer components so as to be axially or circumferentially floating.

[0052] The setting of the elastic layer 22 provides compressible space for radial deformation. The elastic layer 22 can be made of highly elastic and corrosion-resistant polyurethane with a thickness of not less than 3 cm. The elastic layer 22 can be a whole piece structure or a small piece structure fixed on each first corrugated culvert 211.

[0053] The buffer support 20 is provided with buffer components at the axial and radial joints, and an elastic layer 22 is provided between the buffer support 20 and the reinforced support 30, which allows the buffer support 20 to have axial, circumferential and radial elastic deformations after being compressed, so that the pressure on the buffer support 20 can be released and buffered, and play a role of buffering and energy absorption for seismic isolation. It can adapt to the shape changes caused by rock bursts, frost heave or large deformation of soft rocks in the tunnel, realize the common bearing and deformation of the support body and the surrounding rock, and the deformation is limited by the elastic components without causing damage to the joints, thereby effectively controlling the deformation and deformation rate of the surrounding rock.

[0054] The reinforced support 30 plays a role in the overall stability and resistance of the support structure. The reinforced support 30 includes a reinforced corrugated plate 31, which includes a plurality of corrugated arch rings 311 spliced ​​axially. The corrugated arch ring 311 is formed by splicing a plurality of second corrugated culverts in a circumferential direction. End flanges 312 are fixed at both ends of the circumferential direction of the second corrugated culvert. The end flanges 312 include radially arranged end plates fixed to the second corrugated culvert. Folding plates 3121 protruding from the second corrugated culvert are provided at both ends of the end plates in a radial direction. The angle between the folding plates 3121 and the end plates is an obtuse angle. The two end face flanges 312 connected are fitted together and fixed by bolt assemblies on the folding plates 3121. A concrete medium layer 32 is filled between the buffer corrugated plate 21 and the reinforced corrugated plate 31.

[0055] The reinforced support 30 can provide stable rigid support for the surrounding rock by strengthening the combination of the corrugated plate 31 and concrete, and play a role in overall stability and support resistance of the support. The end face flanges 312 are spliced ​​to form a snap-fit ​​structure, and the shear force of the connecting bolts is avoided by the inclined setting of the folded edges, which increases the stability of the splicing of the end face flanges 312, that is, the overall support strength of the reinforced corrugated plate 31 is improved. Concrete is poured between the reinforced corrugated plate 31 and the buffer corrugated plate 21 to provide high-strength support for the surrounding rock, further suppress the creep rate and deformation of the buffer corrugated plate 21, so that the total amount and rate of creep of the surrounding rock can be significantly reduced, and the creep can enter a stable state as soon as possible, shortening the adverse effect time of creep on the stability of the surrounding rock.

[0056] The buffer assembly of the present disclosure adopts the following structure: the edge of the first corrugated culvert 211 is provided with an outward, right-angled flanged slot 212, and the openings of the two adjacent flanged slots 212 on the two first corrugated culverts 211 are arranged opposite to each other. The buffer assembly includes a connecting cover 231 which is arranged outside the two adjacent flanged slots 212, the connecting cover 231 includes a top wall with the same curvature as the buffer corrugated plate 21, and has side walls extending radially inward at both ends of the top wall, and an extension plate 232 which radially passes between the two flanged slots 212 and extends into the concrete medium layer 32 in the middle of the top wall, the two flanged slots 212 are arranged on both sides of the extension plate 232, and the flanged slots 212 have an circumferential or axial elastic displacement and a radial elastic displacement after being matched with the connecting cover 231.

[0057] The specific form of the buffer component in the buffer support 20 adopts a protective cover to cover the joints, which not only limits the deformation of the joints, but also prevents water from seeping in from the joints, and prevents impurities from entering the joints. It does not affect the elastic reset of the joints, can restore the deformation, and can also play the role of reinforcing ribs.

[0058] Moreover, the protective cover is also provided with an extension plate 232 extending into the reinforced concrete layer. The extension plate 232 is cast in the concrete, and preferably has barbs 236 arranged in a fishbone shape on both sides of the extension plate 232 to enhance the stability of the connection between the extension plate 232 and the concrete medium layer 32, thereby fixing the position of the connecting cover 231, providing a positioning reference for the buffer corrugated plate 21, and making the buffer corrugated plate 21 exhibit dispersed multi-point displacement deformation after being subjected to force, thereby avoiding the overall deformation and displacement of the buffer corrugated plate 21 and ensuring the stability of the buffer support 20.

[0059] Furthermore, a long strip-shaped sliding hole is provided on the top wall of the connecting cover 231, a T-shaped sliding rod 233 passing through the sliding hole is provided on the flanged slot 212, and a locking cap is provided at the other end of the sliding rod 233, and a first spring 234 is sleeved on the sliding rod 233 inside the flanged slot 212. A second spring 235 in a compressed state is provided between the flanged slot 212 and the corresponding side wall, and the second spring 235 can drive the flanged slot 212 to be close to the extension plate 232, and can make the two flanged slots 212 move away from each other after further compression. When the buffer corrugated plate 21 is subjected to inward pressure, the first spring 234 is compressed to generate a radial inward displacement, and the second spring 235 is compressed to generate an axial or annular displacement, so that the buffer corrugated plate 21 can play a shock-isolating role of buffering and energy absorption.

[0060] In the buffering and pressure-yielding composite support structure for soft rock tunnels disclosed in the present invention, on the reinforcing corrugated plate 31, two axially connected corrugated arch rings 311 are connected by a reinforcing beam 313, and the reinforcing beam 313 includes a web fixed to two second corrugated culverts, and has wing plates at the upper and lower ends of the web, forming an "I"-shaped structure, and the end face flange 312 is located between the two wing plates of the reinforcing beam 313, and the folding plate 3121 is in contact with the corresponding wing plate. The reinforcing beam 313 has a large strength and can play a strong stable supporting role, and the folding plate 3121 of the end face flange 312 is located in the notch formed by the reinforcing beam 313, which can limit the deformation of the end face flange 312 and improve the stability and pressure resistance of the reinforcing corrugated plate 31.

[0061] Furthermore, both axial ends of the corrugated arch ring 311 have vertical inward one-way flanges 314 , and the one-way flanges 314 on the two axially connected corrugated arch rings 311 are attached to the web of the reinforcing beam 313 and fixed by bolt assemblies.

[0062] In addition, the waveform of the second corrugated culvert includes a trapezoidal wave, a notch is provided on the end face flange 312 corresponding to the trapezoidal wave, and an I-beam (not shown in the figure) is provided inside the trapezoidal wave to pass through the notch and thus penetrate the end face flange 312, the I-beam is arranged circumferentially along the trapezoidal wave, and the wing plate above the I-beam contacts the inner surface of the second corrugated culvert, further improving the strength of the second corrugated culvert. The I-beam can be spliced ​​in the form of multiple arc segments, and a connecting block is added at the joint of the web of two sections of the I-beam, and the connecting block covers the two sections of the I-beam on both sides of the joint and is fixed together by a bolt and nut assembly. The two ends of the whole I-beam can also be fixed to the invert. The horizontal crest of the trapezoidal wave makes it easier to install the I-beam, and by setting a trapezoidal wave with a horizontal crest, the contact area between the corrugated plate and the I-beam can be expanded, making the I-beam easier to install and ensuring sufficient stability.

[0063] In the buffering and pressure-yielding composite support structure for soft surrounding rock tunnels disclosed in the present invention, the buffering support 20 also includes a plurality of arc-shaped buffer plates 24 located outside the buffer corrugated plate 21, the opening of the buffer plate 24 faces the buffer corrugated plate 21, and the top is fixed to the anchor spraying support 10. Specifically, a flexible steel wire mesh 11 is embedded in the anchor spraying support 10, and a plurality of connecting bolts protruding radially inward are fixed on the steel wire mesh, and the top of the buffer plate 24 is connected and fixed to the connecting bolts.

[0064] The buffer plate 24 is deformed under pressure, which can also play a role in energy absorption and shock reduction. Moreover, the multiple buffer plates 24 have at least two specifications with different diameters. After being subjected to force, the diameters contact the buffer corrugated plate 21 in sequence from large to small, thereby gradually improving the compressive and shock-absorbing performance of the buffer plate 24, which can play a good energy absorption and buffering role. Finally, the force is transmitted to the buffer corrugated plate 21 through the buffer plate 24.

[0065] The buffering and pressure-yielding composite support method for a soft surrounding rock tunnel uses the above-mentioned buffering and pressure-yielding composite support structure for a soft surrounding rock tunnel, and comprises the following steps:

[0066] S1. Establish anchor spraying support 10

[0067] S1.1 Fix the connection bolts on the flexible steel wire mesh 11, and fix the flexible steel wire mesh 11 on the rock wall of the tunnel after excavation, so that there is a distance between the flexible steel wire mesh 11 and the rock wall of the tunnel;

[0068] S1.2 Pass multiple anchor rods 12 through the flexible steel wire mesh 11 and fix them on the tunnel rock wall. The length of the anchor rods 12 is 1.2-1.5 m and they are arranged in the surrounding rock with a spacing of about 0.5 m.

[0069] S1.3 spraying concrete, so that the flexible steel wire mesh 11 is buried in the concrete, and the connecting bolts extend radially out of the concrete;

[0070] S2. Establish buffer support 20

[0071] S2.1 After the anchor spraying support 10 is stable, cast the invert at the bottom of the tunnel;

[0072] S2.2 Install the buffer corrugated plate 21, and flexibly assemble the plurality of first corrugated culverts in the axial and circumferential directions through the buffer assembly;

[0073] S2.3 The elastic layer 22 is fixed on the inner surface of the buffer corrugated plate 21, and a release agent is applied to the inner surface of the elastic layer 22 so that the elastic layer 22 does not adhere to the poured concrete and the elastic layer 22 can be deformed freely;

[0074] S3. Establish reinforced support 30

[0075] S3.1 Install the reinforcing corrugated plate 31, axially assemble a plurality of corrugated arch rings 311, and fill concrete between the buffer corrugated plate 21 and the reinforcing corrugated plate 31 after a certain distance until the axial installation of the buffer corrugated plate 21 is completed.

[0076] The buffering and pressure-yielding composite support method for soft surrounding rock tunnels disclosed in the present invention can obtain the above-mentioned buffering and pressure-yielding composite support structure. After construction, the surrounding rock is allowed to produce a certain amount of rheological deformation after lining is applied, and the deformation of the surrounding rock is kept within a controllable range, thereby realizing the common bearing and deformation of the support body and the surrounding rock, and effectively controlling the deformation amount and deformation rate of the surrounding rock, controlling and reducing the adverse effects of rheology, ensuring the stability of the surrounding rock, and improving the stability and reliability of the project, which has important practical significance.

[0077] The above are only preferred embodiments of the present invention. Any simple modification, deformation and equivalent substitution made by anyone to the present invention based on the contents of the present invention shall fall within the protection scope of the present invention.

Claims

1. The buffer and pressure-yielding composite support structure used for soft surrounding rock tunnels is an arched structure, characterized by: The structure comprises, from the outside to the inside, an anchor spray support (10), a buffer support (20) and a reinforcement support (30), wherein both ends of the buffer support (20) and the reinforcement support (30) are fixed to an invert cast at the bottom of the tunnel; The buffer support (20) comprises a buffer corrugated plate (21) and an elastic layer (22) covering the inner surface of the buffer corrugated plate (21), wherein the buffer corrugated plate (21) comprises a plurality of first corrugated culverts (211), and the plurality of first corrugated culverts (211) are spliced ​​together in a circumferential and axial floating manner through a buffer assembly, and the buffer support (20) further comprises a plurality of arc-shaped buffer plates (24) located outside the buffer corrugated plate (21), the opening of the buffer plate (24) faces the buffer corrugated plate (21), and the top is fixed to the anchor spray support (10), and the plurality of buffer plates (24) have at least two specifications with different diameters, and after being subjected to force, the diameters contact the buffer corrugated plate (21) in descending order; The reinforced support (30) comprises a reinforced corrugated plate (31), wherein the reinforced corrugated plate (31) comprises a plurality of axially spliced ​​corrugated arch rings (311), wherein the corrugated arch rings (311) are formed by splicing a plurality of second corrugated culvert pieces circumferentially, wherein end face flanges (312) are fixed at both ends of the circumferential direction of the second corrugated culvert piece, wherein the end face flanges (312) comprise radially arranged end plates fixed to the second corrugated culvert piece, wherein folded plates (3121) protruding from the second corrugated culvert piece are provided at both ends of the end plates in the radial direction, wherein the angle between the folded plates (3121) and the end plates is an obtuse angle, wherein the two end face flanges (312) connected to each other are fitted together and are fixed by bolt assemblies passing through the folded plates (3121); A concrete medium layer (32) is filled between the buffer corrugated plate (21) and the reinforcing corrugated plate (31); The edge of the first corrugated culvert (211) has an outwardly facing, right-angled flanged groove (212), and the openings of the two connected flanged grooves (212) on the two first corrugated culverts (211) are arranged opposite to each other; The buffer assembly comprises a connecting cover (231) which is arranged outside two connected flanged grooves (212); the connecting cover (231) comprises a top wall with the same curvature as the buffer corrugated plate (21); side walls extending radially inward are provided at both ends of the top wall; and an extension plate (232) is provided in the middle of the top wall which radially passes between the two flanged grooves (212) and extends into the concrete medium layer (32); the two flanged grooves (212) are arranged on both sides of the extension plate (232); and the flanged grooves (212) and the connecting cover (231) have an circumferential elastic displacement and a radial elastic displacement after being matched.

2. The buffering and pressure-yielding composite support structure for soft surrounding rock tunnels according to claim 1 is characterized in that: Two axially connected corrugated arch rings (311) are connected via a reinforcing beam (313). The reinforcing beam (313) comprises a web fixed to two second corrugated culverts, and wing plates are provided at the upper and lower ends of the web to form an "I"-shaped structure. The end face flange (312) is located between the two wing plates of the reinforcing beam (313), and the folded plate (3121) abuts against the corresponding wing plate.

3. The buffering and pressure-yielding composite support structure for soft surrounding rock tunnels according to claim 2 is characterized in that: The two axial ends of the corrugated arch ring (311) are provided with one-way flanges (314) that are vertically inward, and the one-way flanges (314) on the two axially connected corrugated arch rings (311) are fitted to the web of the reinforcing beam (313) and fixed by a bolt assembly.

4. According to the buffering and pressure-relieving composite support structure for soft surrounding rock tunnels as described in claim 2, the waveform of the second corrugated culvert comprises a trapezoidal wave, and the interior of the trapezoidal wave has an I-beam penetrating the end face flange (312).

5. The buffering and pressure-yielding composite support structure for soft surrounding rock tunnels according to claim 1 is characterized in that: A long strip-shaped sliding hole is provided on the top wall of the connecting cover (231); a T-shaped sliding rod (233) passing through the sliding hole is provided on the flanged slot (212); a locking cap is provided at the upper end of the sliding rod (233) passing through the sliding hole; and a first spring (234) is sleeved on the sliding rod (233) inside the flanged slot (212); A second spring (235) in a compressed state is provided between the flanged card slot (212) and the corresponding side wall. The second spring (235) can drive the flanged card slot (212) to be close to the extension plate (232) and can move the two flanged card slots (212) away from each other after further compression.

6. The buffering and pressure-yielding composite support structure for soft surrounding rock tunnels according to claim 1 is characterized in that: The extension plate (232) has barbs (236) arranged in a fishbone shape on both sides.

7. The buffering and pressure-yielding composite support structure for soft surrounding rock tunnels according to claim 1 is characterized in that: A plurality of connecting bolts protruding radially inward are fixed on the anchor spray support (10), and the top of the buffer plate (24) is connected and fixed to the connecting bolts.

8. A buffering and pressure-yielding composite support method for soft surrounding rock tunnels, characterized in that: The buffering and pressure-yielding composite support structure for soft surrounding rock tunnels according to any one of claims 1 to 7 comprises the following steps: S1. Establish bolting and spraying support (10) S1.1 fixing a connection bolt on the flexible steel wire mesh (11), and fixing the flexible steel wire mesh (11) on the rock wall of the tunnel after excavation, so that there is a gap between the flexible steel wire mesh (11) and the rock wall of the tunnel; S1.2 Passing a plurality of anchor rods (12) through the flexible steel wire mesh (11) and fixing them on the rock wall of the tunnel; S1.3 spraying concrete so that the flexible steel wire mesh (11) is embedded in the concrete and the connecting bolts extend radially out of the concrete; S2. Establish buffer support (20) S2.1 After the anchor spray support (10) is stable, cast the invert at the bottom of the tunnel; S2.2 Install the buffer corrugated plate (21), and flexibly assemble the plurality of first corrugated culverts in the axial and circumferential directions through the buffer assembly; S2.3 fixing the elastic layer (22) on the inner surface of the buffer corrugated plate (21), and applying a release agent on the inner surface of the elastic layer (22); S3. Establish reinforced support (30) S3.1 Install the reinforcing corrugated plate (31), axially assemble a plurality of corrugated arch rings (311), and fill concrete between the buffer corrugated plate (21) and the reinforcing corrugated plate (31) after a certain distance until the axial installation of the buffer corrugated plate (21) is completed.

Images