A multi-directional coupling control structure and support method for irregular cross-sections of high ground pressure roadways

Abstract

The present invention discloses a multi-directional coupling control structure for a special-shaped section of a high-ground-pressure tunnel, comprising an upper regular trapezoidal structure and a lower rectangular structure, support structures are arranged on the upper side of the upper side wall and the lower side of the lower side wall, and a support structure perpendicular to the top plate is arranged on the upper roof, the support structure comprises parallel anchor cables 1 and 2 with high preload, anchor cables 1 and 2 are arranged in layers at intervals along the length direction of the tunnel; anchor cables 3 are arranged obliquely at both ends of the top plate along the length direction of the tunnel; pressure relief holes are arranged in the soft rock formations of the upper side and / or the lower side, and the inside of the pressure relief holes and the surrounding rocks nearby are filled with grouting reinforcement slurry. The present invention also discloses a support method for a multi-directional coupling control structure for a special-shaped section of a high-ground-pressure tunnel. The present invention adopts the above-mentioned control structure and support method to solve the problems of poor integrity, deformation resistance and stability of the surrounding rocks of existing high-ground-pressure tunnels.

Description

Technical Field

[0001] The invention relates to the technical field of mine support engineering, and in particular to a high ground pressure tunnel special-shaped cross-section multi-directional coupling control structure and a support method. Background Art

[0002] With the continuous increase in coal mining depth and tunnel cross-section, high-ground pressure tunnels are increasing, and how to ensure the stability of the surrounding rock of high-ground pressure tunnels is particularly important. At present, the commonly used tunnel cross-sections in coal mine tunnels are arched cross-sections and rectangular cross-sections. In the existing arched tunnels, when supporting the arch, anchor rods and cables are generally driven perpendicular to the surface of the arch. The anchor rods and cables are "radial" in the depth direction of the surrounding rock, that is, the spacing in the shallow part is small and the spacing in the deep part is large. The "radial" anchor rods and cables are often difficult to form effective prestressed superposition areas and working resistance superposition areas, resulting in poor integrity and deformation resistance of the anchored rock formation. Although the existing rectangular tunnels can implement parallel anchor rods and cables, the tunnel width is large and the roof needs to control the width of the top. At the same time, in order to meet the needs of equipment transportation and pipeline installation, the tunnel height is often large. The large width and height bring great difficulty to the stability control of the tunnel surrounding rock. At the same time, there is also a problem of uncoupling between the existing support structure and the surrounding rock. Therefore, it is urgent to optimize the cross-sectional morphology of the high ground pressure tunnel and improve the surrounding rock control structure. Summary of the invention

[0003] The purpose of the present invention is to provide a multi-directional coupling control structure for a special-shaped section of a high-ground pressure tunnel, so as to solve the problems existing in the existing arched section tunnels and rectangular section tunnels, such as large roof control width, low upper space utilization, radial support structure and difficulty in forming a bearing structure with high support resistance, and the existing support structure and surrounding rock are not coupled. Another purpose of the present invention is to provide a support method for a multi-directional coupling control structure for special-shaped end faces of high- and low-pressure tunnels.

[0004] To achieve the above-mentioned objectives, the present invention provides a multi-directional coupling control structure for a high-ground pressure tunnel with a special-shaped section, comprising an upper trapezoidal structure and a lower rectangular structure, wherein the upper side wall and the lower side wall are provided with support structures, and the upper top plate is provided with a support structure perpendicular to the top plate, wherein the support structure comprises parallel anchor cables 1 and 2 with high preload applied thereto, wherein the anchor cables 1 and 2 are arranged in layers at intervals along the length direction of the tunnel; anchor cables 3 are obliquely arranged at both ends of the top plate along the length direction of the tunnel; pressure relief holes are provided on the soft rock strata of the upper side and / or the lower side, and the interior of the pressure relief holes and the surrounding rocks nearby are filled with grouting reinforcement slurry.

[0005] Preferably, the lower part of the tunnel special-shaped cross-section structure is a rectangular structure, and the upper cross-section is a regular trapezoidal structure with a wider bottom and a narrower top; the tunnel special-shaped cross-section structure is in the shape of "small at the top and large at the bottom", and the width of the top plate of the upper section is smaller than the width of the bottom plate of the lower section.

[0006] Preferably, the lengths of anchor cable 1 and anchor cable 2 are not equal, they are short anchor cable and long anchor cable respectively, and the anchor cables 1 and anchor cables 2 of adjacent layers are staggered, and a coupled bearing structure with coordinated shallow and deep deformations is formed through the combined support of long and short anchor cables.

[0007] Preferably, the diameter of anchor cable 1 and anchor cable 2 is not less than 21 mm, the tensile strength is not less than 1860 MPa, and the preload force is not less than 300 kN.

[0008] Preferably, the anchor cable 1 and the anchor cable 2 of the same layer are connected by a steel support beam or a steel belt; the spacing adopted by the anchor cable 1 and the anchor cable 2 can form a highly prestressed anchor bearing structure based on parallel arrangement and mutual superposition between adjacent anchor cables.

[0009] Preferably, the diameter of anchor cable 1 and anchor cable 2 is not less than 21 mm, the tensile strength is not less than 1860 MPa, and the preload force is not less than 300 kN.

[0010] Preferably, the diameter of the anchor cable three is not less than 28 mm, the tensile strength is not less than 1860 MPa, and the angle between the anchor cable three and the vertical line of the top plate is 15-30°; the anchor cable three is equipped with a special-shaped tray or self-aligning ball pad that is adapted to its angle, and is connected with a steel beam along the direction of the tunnel.

[0011] Preferably, the anchor cable one, the anchor cable two and the anchor cable three are all high-strength and high-elongation anchor cables, and are equipped with pressure-relieving devices that can adapt to large deformation of the surrounding rock and avoid breakage and failure of the anchor cables.

[0012] Preferably, the soft rock strata in the upper and / or lower side parts are provided with large-diameter pressure relief holes with a diameter of 100 to 300 mm, and the inside of the pressure relief holes and the surrounding rocks nearby are filled with ultra-fine cement-based composite grouting reinforcement slurry.

[0013] The above-mentioned support method of the multi-directional coupling control structure of the high ground pressure tunnel with special-shaped section includes the following steps:

[0014] S1. Based on the stress environment, surrounding rock characteristics and safety production needs of the tunnel, determine the shape and size of the tunnel's special-shaped section, including the bottom plate width and lower side height of the lower rectangular section, and the upper side length and top plate width of the upper trapezoidal section;

[0015] S2. According to the determined special-shaped cross-section shape and size of the tunnel, the tunnel excavation work is completed by using a comprehensive excavation mechanized operation line;

[0016] S3. After the tunnel is excavated, anchor cable 1 and anchor cable 2 are used to support the roof, upper side and lower side. Anchor cable 1 and anchor cable 2 are arranged in parallel and in layers, forming a long and short anchor parallel arrangement and layered support structure with special-shaped sections.

[0017] S4, after the delayed excavation working face is 10m, the top corner anchor cables are set at both ends of the roof, and the adjacent anchor cables are connected with steel beams to form a tunnel top corner reinforcement control structure;

[0018] S5. After 30m of the delayed excavation working face, large-diameter pressure relief holes are drilled for pressure relief in the surrounding rock structure with soft rock layers in the upper and lower parts, so as to transfer the high stress to the deep part of the surrounding rock and provide deformation compensation space for the deformation of the soft rock layers;

[0019] S6. After the soft rock strata are relieved of pressure through the pressure relief holes and the surrounding rock stress tends to be stable, grouting reinforcement is then carried out on the large-diameter pressure relief holes to improve the deformation resistance of the soft rock strata.

[0020] The advantages and positive effects of the high ground pressure tunnel special-shaped section multi-directional coupling surrounding rock control structure and support method described in the present invention are:

[0021] (1) The present invention provides a novel composite structure of a special-shaped cross-section that combines an upper regular trapezoid with a lower rectangular shape. The width and height of the structure can meet the needs of personnel and equipment passage, mine ventilation and production safety. The structure adopts an "upper regular trapezoid" design, which not only reduces the width of the tunnel roof and maximizes the utilization rate of the upper space of the tunnel, but also improves the stability of the tunnel surrounding rock, reduces the amount of rock breaking and waste removal, and reduces the cost of tunnel excavation.

[0022] (2) The tunnel surrounding rock control structure proposed in the present invention includes a parallel arrangement structure of long and short anchor cables along the circumference of the tunnel, a layered support structure of long and short anchor cables along the depth direction of the surrounding rock, a large-diameter high-strength anchor cable steel beam structure at the top angle, and a coupling control structure for unloading control of the weak interlayer in the side. It can realize coupling control in multiple directions, effectively improve the stability of the anchored rock layer, and thus reduce the deformation of the surrounding rock in high-pressure tunnels.

[0023] (3) The parallel arrangement structure of long and short anchor cables proposed in the present invention is that the short anchor cables and long anchor cables installed in the lower side, upper side and top plate are in a "parallel arrangement" form, rather than a "radial arrangement" form of the arch section; the short anchor cables and long anchor cables implement high prestressing force support, and the tensioning prestressing force is greater than or equal to 300kN. The spacing between the short anchor cables and long anchor cables can form a high prestressed superposition area between adjacent anchor cables, and finally the short anchor cables, long anchor cables and surrounding rocks jointly form a high prestressed anchor bearing structure, thereby improving the integrity and deformation resistance of the anchor bearing structure.

[0024] (4) The long and short anchor cable layered support structure proposed in the present invention is a structure that uses two or more anchor cables of different lengths, with anchor cables of the same length forming one support layer. By combining two or more layered support arrangements, the coordinated coupling of the shallow broken surrounding rock reinforcement zone and the deep long anchor cable associated stability zone is achieved.

[0025] (5) For surrounding rock structures with weak rock layers in the upper and lower sides, a combination of pressure relief through large-diameter pressure relief holes and grouting reinforcement is used to not only transfer high stress to the deep surrounding rock, but also provide deformation compensation space for the deformation of the weak rock layers, and improve the stability of the tunnel surrounding rock, thereby reducing the cost of tunnel excavation and maintenance.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a front view of an embodiment of a high ground pressure tunnel special-shaped section multi-directional coupling control structure and support method of the present invention;

[0028] Figure 2 It is a left view of an embodiment of a high ground pressure tunnel special-shaped section multi-directional coupling control structure and support method of the present invention;

[0029] Figure 3 It is a top view of an embodiment of a high ground pressure tunnel special-shaped section multi-directional coupling control structure and support method of the present invention;

[0030] Figure 4 It is a schematic diagram of a pressure relief hole in an embodiment of a multi-directional coupling control structure and a support method for a high ground pressure tunnel with a special-shaped section according to the present invention.

[0031] Reference numerals

[0032] 1. Lower side; 2. Upper side; 3. Anchor cable 1; 4. Anchor cable 2; 5. Anchor cable 3; 6. Steel beam; 7. Pressure relief hole; 8. Steel belt; 9. Bottom plate; 10. Top plate. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0034] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0035] Example

[0036] Figure 1 The figure is a front view of an embodiment of a multi-directional coupling control structure and a support method for a high ground pressure tunnel with a special-shaped section according to the present invention. The multi-directional coupling control structure for a high ground pressure tunnel with a special-shaped section includes an upper side portion 2 and a lower side portion 1. The lower section of the lower side portion 1 is a rectangular structure, and the upper section of the upper side portion 2 is a regular trapezoidal structure with a wider bottom and a narrower top plate 10. The special-shaped section shape composed of a "lower rectangle" and an "upper regular trapezoid" not only reduces the top control width of the top plate 10, improves the utilization rate of the upper space section, reduces the amount of rock breaking and waste discharge, and reduces the cost of tunneling; it can also maximize the utilization rate of the tunnel section.

[0037] The cross-sectional shape and size of the upper and lower parts can be adjusted according to the stress characteristics and structural characteristics of the tunnel surrounding rock. The width and height of the special-shaped cross-sectional size should be able to meet the needs of personnel and equipment passage, mine ventilation and production safety.

[0038] Figure 2 It is a left view of an embodiment of a multi-directional coupling control structure and support method for a high ground pressure tunnel with a special-shaped section according to the present invention. Support structures are arranged on the upper side 2 and the lower side 1, and a support structure perpendicular to the top plate is arranged on the upper top plate. The support structure is a layered arrangement of anchor cables 13 and anchor cables 2 4. The lengths of anchor cables 13 and anchor cables 2 4 are different, and they are short anchor cables and long anchor cables respectively. Anchor cables of the same length constitute a support layer, and two or more layered support arrangements are formed by combination to achieve coordinated coupling between the shallow broken surrounding rock reinforcement zone and the deep long anchor cable associated stabilization zone.

[0039] The anchor cables 1 3 and the anchor cables 2 4 of the same layer are connected by steel beams or steel belts 8, and the steel belts 8 are JW support steel belts. The diameter of anchor cables 1 3 and anchor cables 2 4 is not less than 21 mm, and the tensile strength is not less than 1860 MPa. Anchor cables 1 3 and anchor cables 2 4 are arranged in parallel and applied with a preload force of not less than 300 kN. Anchor cables 1 3 and anchor cables 2 4 are arranged in parallel in staggered layers along the length direction of the tunnel. Anchor cables 1 3 and anchor cables 2 4 are parallel structures arranged along the peripheral direction of the tunnel, that is, parallel anchor cables 1 3 and anchor cables 2 4 are set in the lower side 1, the upper side 2 and the top plate 10, and a prestressed superposition area is formed between adjacent anchor cables 1 3 and anchor cables 2 4. Anchor cables 1 3, anchor cables 2 4 and the surrounding rock together form a high prestressed anchor bearing structure to improve the integrity and deformation resistance of the anchor bearing structure.

[0040] Figure 3 It is a top view of an embodiment of a multi-directional coupling control structure and support method for a high ground pressure tunnel with a special-shaped section according to the present invention. Anchor cables 3 5 are arranged obliquely at both ends of the roof 10 along the length direction of the tunnel, and the anchor cables 3 5 are connected by steel beams 6. The steel beam 6 is an I-beam or other steel sections. The anchor cable 3 5 is a high-strength anchor cable with a diameter of 28.6 mm and a tensile strength of 1860 MPa. The anchor cable 3 is at an angle of 15 to 30 degrees to the vertical line of the roof 10. The anchor cable 3 5 and the steel beam 6 are arranged along the direction of the tunnel to form a reinforced control structure for the top angle of the tunnel. The anchor cable 3 5 is used in conjunction with a special-shaped tray or self-aligning ball pad that is adapted to its angle.

[0041] Anchor cable 13, anchor cable 24 and anchor cable 35 all use high-strength, large-elongation anchor cables and are equipped with pressure-yielding devices that can adapt to large deformations of the surrounding rock to avoid breakage and failure of the anchor cables.

[0042] Figure 4 The schematic diagram of the pressure relief hole of an embodiment of a multi-directional coupling control structure and a support method for a high ground pressure tunnel with a special section of the present invention. A pressure relief coupling control structure is arranged on the weak interlayer on the side wall of the upper side part 2 and / or the lower side part 1. The pressure relief coupling control structure is a surrounding rock structure for the weak rock layer in the side part. The pressure relief coupling control structure includes a pressure relief hole 7, and the diameter of the pressure relief hole 7 is 100 to 300 mm. The inside of the pressure relief hole 7 and the surrounding rock near it are filled with ultra-fine cement-based composite grouting reinforcement slurry. First, a large-diameter pressure relief hole 7 is drilled for pressure relief to transfer high stress to the deep surrounding rock, and at the same time, the deformation of the weak rock layer provides deformation compensation space; after the weak rock layer is relieved of pressure, the large-diameter pressure relief hole 7 is grouting reinforced to improve the deformation resistance of the weak rock layer.

[0043] The above-mentioned support method of the multi-directional coupling control structure of the high ground pressure tunnel with special-shaped section includes the following steps:

[0044] S1. Based on the stress environment, surrounding rock characteristics and safety production needs of the tunnel, determine the shape and size of the tunnel's special-shaped section, including the width of the bottom plate 9 of the lower rectangular section, the height of the lower side 1, the side length of the upper side 2 of the upper trapezoidal section, and the width of the top plate 10.

[0045] S2. According to the determined shape and size of the tunnel's special section, a comprehensive tunneling mechanized operation line is used to complete the tunneling work.

[0046] S3. After the tunnel is excavated, the top plate 10, the upper side 2 and the lower side 1 are supported by anchor cables 13 and 4. The anchor cables 13 and 4 are arranged in parallel and in layers, forming a parallel arrangement and layered support structure of long and short anchors with special cross-section.

[0047] S4. After the excavation working face is delayed by 10m, top corner anchor cables 3 5 are installed at both ends of the roof, and adjacent anchor cables 3 5 are connected by steel beams 6 to form a tunnel top corner reinforcement control structure.

[0048] S5. After 30m of delayed excavation working face, large diameter pressure relief holes 7 are drilled to relieve pressure in the surrounding rock structure with soft rock layers in the upper and lower parts 2 and 1, so as to transfer high stress to the deep surrounding rock. At the same time, the deformation of the soft rock layers provides deformation compensation space.

[0049] S6. After the soft rock layer is depressurized through the pressure relief hole 7 and the surrounding rock stress tends to be stable, the large-diameter pressure relief hole 7 is reinforced by grouting to improve the deformation resistance of the soft rock layer.

[0050] Therefore, the present invention adopts the above-mentioned multi-directional coupling control structure and support method for the special-shaped section of the high-ground pressure tunnel, which can solve the problems of large roof control width, low upper space utilization, radial support structure and difficulty in forming a bearing structure with high support resistance, uncoupling between support structure and surrounding rock, and poor integrity and deformation resistance of the anchored rock layer.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A multi-directional coupling control structure for special-shaped sections of high ground pressure tunnels, characterized by: It comprises an upper trapezoidal structure and a lower rectangular structure, a support structure is arranged on the upper side wall and the lower side wall, a support structure perpendicular to the top plate is arranged on the upper top plate, the support structure comprises a parallel anchor cable 1 and an anchor cable 2 with a high preload, the anchor cable 1 and the anchor cable 2 are arranged in layers at intervals along the length direction of the tunnel; anchor cables 3 are arranged obliquely at both ends of the top plate along the length direction of the tunnel; pressure relief holes are arranged on the soft rock strata of the upper side and / or the lower side, and the inside of the pressure relief hole and the surrounding rock nearby are filled with grouting reinforcement slurry; The lengths of the anchor cable 1 and the anchor cable 2 are not equal, they are short anchor cable and long anchor cable respectively, the anchor cables 1 and 2 of adjacent layers are staggered, and a coupled bearing structure with coordinated shallow and deep deformation is formed through the joint support of long and short anchor cables; The anchor cables of the upper side and the anchor cables of the lower side are arranged in parallel; The anchor cable 1 and the anchor cable 2 of the same layer are connected by a steel bar joist or a steel belt; the spacing between the anchor cable 1 and the anchor cable 2 can form a highly prestressed anchor bearing structure based on a parallel arrangement and mutual superposition between adjacent anchor cables; The diameter of the anchor cable 1 and the anchor cable 2 is not less than 21 mm, the tensile strength is not less than 1860 MPa, and the preload force is not less than 300 kN; The diameter of the anchor cable three is not less than 28mm, the tensile strength is not less than 1860MPa, and the angle between the anchor cable three and the vertical line of the top plate is 15-30°; the anchor cable three is equipped with a special-shaped tray or self-aligning ball pad that is adapted to its angle, and is connected with a steel beam along the direction of the tunnel.

2. According to claim 1, a high ground pressure tunnel special-shaped cross-section multi-directional coupling control structure is characterized by: The lower part of the tunnel's special-shaped cross-section structure is a rectangular structure, and the upper cross-section is a regular trapezoidal structure with a wider bottom and a narrower top; the tunnel's special-shaped cross-section structure is in the form of "small at the top and large at the bottom", and the width of the top plate of the upper section is smaller than the width of the bottom plate of the lower section.

3. The multi-directional coupling control structure for special-shaped sections of high ground pressure tunnels according to claim 1 is characterized by: The anchor cable one, anchor cable two and anchor cable three are all high-strength and high-elongation anchor cables, and are equipped with pressure-relieving devices that can adapt to large deformation of the surrounding rock and avoid breakage and failure of the anchor cables.

4. The multi-directional coupling control structure for special-shaped sections of high ground pressure tunnels according to claim 1 is characterized by: The soft rock layers of the upper and / or lower side parts are provided with large-diameter pressure relief holes with a diameter of 100-300 mm, and the inside of the pressure relief holes and the surrounding rocks nearby are filled with ultra-fine cement-based composite grouting reinforcement slurry.

5. A method for supporting a high ground pressure tunnel with a special-shaped cross-section multi-directional coupling control structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Based on the stress environment, surrounding rock characteristics and safety production needs of the tunnel, determine the shape and size of the tunnel's special-shaped section, including the bottom plate width and lower side height of the lower rectangular section, and the upper side length and top plate width of the upper trapezoidal section; S2. According to the determined special-shaped cross-section shape and size of the tunnel, the tunnel excavation work is completed by using a comprehensive excavation mechanized operation line; S3. After the tunnel is excavated, anchor cable 1 and anchor cable 2 are used to support the roof, upper side and lower side. Anchor cable 1 and anchor cable 2 are arranged in parallel and in layers, forming a parallel arrangement and layered support structure of long and short anchors with special-shaped sections. S4, after the delayed excavation working face is 10m, the top corner anchor cables are set at both ends of the roof, and the adjacent anchor cables are connected with steel beams to form a tunnel top corner reinforcement control structure; S5. After 30m of the delayed excavation working face, large-diameter pressure relief holes are drilled for pressure relief in the surrounding rock structure with soft rock layers in the upper and lower parts, so as to transfer the high stress to the deep part of the surrounding rock and provide deformation compensation space for the deformation of the soft rock layers; S6. After the soft rock strata are relieved of pressure through the pressure relief holes and the surrounding rock stress tends to be stable, grouting reinforcement is then carried out on the large-diameter pressure relief holes to improve the deformation resistance of the soft rock strata.

Images