Support structure and working method for long-distance deep-buried TBM inclined shaft in water-rich complex rock stratum

Abstract

The application belongs to the technical field of tunnel support and discloses a support structure and working method for long-distance deep-buried TBM inclined shaft water-rich complex rock stratum, which comprises hierarchical pressure-release control anchor rods, anchor cables and, from outside to inside, a steel bar row, a steel mesh and a sprayed concrete layer arranged on the tunnel surrounding rock surface in sequence; the hierarchical pressure-release control anchor rod comprises a rod body, an outer ring, a pressure-release sleeve and an inner ring; in the initial state, the inner ring is pressed tightly on the rear end port of the inner cavity of the pressure-release sleeve through a nut at the rear end of the rod body; the front end of the pressure-release sleeve extends into a borehole and the outer ring is pressed tightly on the surrounding rock outside the borehole; a first-stage pressure-release friction fit is formed between the inner ring and the inner cavity of the pressure-release sleeve; a second-stage pressure-release friction fit is formed between the front end of the pressure-release sleeve and the outer ring. The application has the advantages that the self-bearing capacity of the surrounding rock is fully utilized and passive support is converted into active support; the hierarchical pressure-release control anchor rod and the anchor cable support together, and the support structure has good integrity and high strength.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tunnel support, and particularly relates to a support structure and working method for long-distance deep-buried TBM inclined shaft water-rich complex rock stratum. BACKGROUND

[0002] Water-rich sandstone belongs to soft rock, which has low strength and is easy to weather, has strong water sensitivity and softens when meeting water, has muddy cementation and is easy to expand, soften and even disintegrate under the action of water, so as to cause large displacement of roadway surrounding rock and coal rock dynamic disasters such as roof falling and collapse.

[0003] The elastic-plastic or viscoelastic-plastic mechanical behavior of adverse rock mass under the action of engineering disturbance leads to large deformation of the inclined shaft, wall peeling, collapse and other surrounding rock failure and instability phenomena, which seriously threatens the construction of the inclined shaft.

[0004] The anchor rod support parameter design is still mainly based on engineering experience, and there is still a lack of generally recognized initial design method of anchor rod support, which cannot well utilize the adaptability of different strata and causes waste of support materials.

[0005] In view of the complex engineering environment and the deformation characteristics of the TBM inclined shaft, an anchor net spray integrated support scheme of “anchor rod (cable) + steel mesh + sprayed concrete” is proposed from the perspective of changing the stress state of the surrounding rock and promoting the support and the surrounding rock to jointly bear. SUMMARY

[0006] The purpose of the present application is to provide a support structure and working method for long-distance deep-buried TBM inclined shaft water-rich complex rock stratum, which sets graded pressure-releasing control anchor rods, anchor cables, steel bars and steel mesh on the surrounding rock of the tunnel, and forms an integral whole through a sprayed concrete layer. In addition, the friction force between the pressure-releasing sleeve and the inner ring and the outer ring is used to form a primary pressure-releasing friction fit and a secondary pressure-releasing friction fit to achieve the effect of “first control, then release, then control again, and then release again” on the surrounding rock, so as to release the deformation of the surrounding rock, reduce the pressure of the surrounding rock and improve the stress of the surrounding rock.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A support structure for long-distance deep-buried TBM inclined shaft water-rich complex rock stratum, which comprises graded pressure-releasing control anchor rods, anchor cables, and steel bars, steel mesh and a sprayed concrete layer arranged in the surrounding rock surface of the tunnel from inside to outside, and the steel mesh is fixed to the surrounding rock surface by the graded pressure-releasing control anchor rods and the anchor cables.

[0009] The hierarchical pressure relief control anchor rod comprises a rod body, an outer ring, a pressure relief sleeve and an inner ring; in the initial state, the inner ring is pressed against the rear end of the inner cavity of the pressure relief sleeve through the nut at the rear end of the rod body; the front end of the pressure relief sleeve extends into the borehole and presses the outer ring against the surrounding rock outside the borehole; a first-stage pressure relief friction fit is formed between the inner ring and the inner cavity of the pressure relief sleeve; a second-stage pressure relief friction fit is formed between the front end of the pressure relief sleeve and the outer ring; wherein the friction force of the second-stage pressure relief friction fit is greater than that of the first-stage pressure relief friction fit.

[0010] The steel bar row is composed of a plurality of longitudinal steel bars and is distributed at intervals in the circumferential direction; the steel bar mesh presses the steel bar row against the surrounding rock surface; the shotcrete layer is sprayed on the surrounding rock surface to integrate the hierarchical pressure relief control anchor rod, the anchor cable, the steel bar row, the steel bar mesh and the shotcrete layer into a unitary structure.

[0011] The main body of the pressure relief sleeve is a cylindrical barrel; a tapered end head is arranged at the front end of the barrel; the limiting ring protrudes radially outward at the rear end of the barrel; a through hole is formed in the center of the tapered end head for the rod body to pass through; the diameter of the through hole is the same as the outer diameter of the rod body.

[0012] The outer ring comprises a fixed pressure relief ring, a ring table, an adjustable pressure relief component, a sliding groove, a guide ring and a driving assembly; the ring table is arranged along the annular outer edge of the front end surface of the fixed pressure relief ring; the inner wall surface of the fixed pressure relief ring is a longitudinal variable diameter section and is fitted to the tapered end head; four groups of adjustable pressure relief components are arranged at intervals in the circumferential direction; the adjustable pressure relief component comprises an adjustable pressure relief arc section, a connecting rod and a guide contact head; the rod body of the connecting rod is assembled in the sliding groove to guide the radial sliding of the connecting rod; the two ends of the connecting rod are connected to the adjustable pressure relief arc section and the guide contact head, respectively; the inner arc surface of the adjustable pressure relief arc section is fitted to the tapered end head; the guide contact head is in sliding contact with the inner ring of the guide ring; the inner ring of the guide ring is provided with four groups of guide variable diameter sections, each of which corresponds to one guide contact head; the guide variable diameter section comprises a small inner diameter section, a transition section and a large inner diameter section arranged in sequence; the guide ring is driven to rotate by the driving assembly.

[0013] The outer wall surface of the guide ring is provided with a ring of outer meshing teeth, the front end surface of the fixed pressure-relieving ring is provided with an annular guide groove, the rear end surface of the guide ring is provided with a convex rail, the convex rail on the guide ring is correspondingly matched and installed in the annular guide groove to constitute rotational guide support for the rotation of the guide ring; the driving assembly comprises a hydraulic telescopic rod and a straight rack fixedly arranged on the rod body of the hydraulic telescopic rod, and the straight rack is engaged and driven with the outer meshing teeth on the guide ring to drive the rotation of the guide ring.

[0014] The rod body is provided with a pressure sensor for monitoring the surrounding rock pressure, the pressure sensor is connected to the controller of the hydraulic telescopic rod for control, and the driving assembly is controlled based on the surrounding rock pressure data monitored by the pressure sensor to determine whether to drive the rotation of the guide ring; in the initial state, the transition section on the guide ring is in contact with the guide contact head; when it is necessary to increase the friction between the outer ring and the pressure-relieving sleeve, the guide ring is rotated to make the small inner diameter section contact the guide contact head and press the adjustable pressure-relieving arc section against the conical end head; when it is necessary to reduce the friction between the outer ring and the pressure-relieving sleeve, the guide ring is rotated to make the large inner diameter section contact the guide contact head to release the pressing of the adjustable pressure-relieving arc section against the conical end head.

[0015] The fixed pressure-relieving ring and the ring table jointly enclose a device mounting groove space, and the thicknesses of the adjustable pressure-relieving part, the sliding groove, the guide ring and the driving assembly are all less than the height of the ring table.

[0016] A working method related to the supporting structure of the long-distance deep-buried TBM inclined shaft in the water-rich complex rock layer, comprising the following steps:

[0017] S1: drilling a pre-grouting hole in the surrounding rock in front of the TBM to perform pre-reinforcement;

[0018] S2: after the TBM completes the excavation of the surrounding rock, drilling a hole in the surrounding rock to install a stepped pressure-relieving control anchor rod and anchor cable, the stepped pressure-relieving control anchor rod comprising a rod body, an outer ring, a pressure-relieving sleeve and an inner ring; wherein the drilling is divided into two steps, the first step is to drill a hole according to the diameter of the rod body, and the second step is to expand the hole according to the outer diameter of the cylinder of the pressure-relieving sleeve based on the drilled hole, and the depth of the expansion is the length of the pressure-relieving sleeve;

[0019] At the same time of installing the stepped pressure-relieving control anchor rod, laying a steel bar row and a steel mesh on the surface of the surrounding rock, the steel mesh pressing the steel bar row against the surface of the surrounding rock, and the steel mesh being fixed on the surface of the surrounding rock through the stepped pressure-relieving control anchor rod, the steel mesh and a steel rivet;

[0020] S3: in the process of surrounding rock deformation, when the surrounding rock pressure is greater than the friction force of the primary pressure release friction fit, the rod body drives the primary pressure release movement between the inner ring and the inner cavity of the pressure release sleeve, until the inner ring moves to the inner cylinder end of the pressure release sleeve and stops;

[0021] When the surrounding rock pressure is greater than the friction force of the secondary pressure release friction fit, the rod body drives the secondary pressure release movement between the front end of the pressure release sleeve and the outer ring and moves into the borehole, until the limit ring protruding at the rear end of the pressure release sleeve abuts on the outer ring and stops moving;

[0022] S4: after completing the installation and support process of the hierarchical pressure release control anchor rod, the surrounding rock surface is shotcreting reinforced, so that the hierarchical pressure release control anchor rod, the anchor cable, the steel bar row, the steel mesh and the shotcrete layer are integrated into a structure.

[0023] The advantages of the present application are:

[0024] (1) The surrounding rock itself bearing capacity is fully utilized, and passive support is converted into active support; the hierarchical pressure release control anchor rod and the anchor cable jointly support, the support structure has good integrity and high support strength; the support scheme is reasonably selected in combination with the deformation monitoring results of the surrounding rock of the roadway, efficient support is achieved, and support materials are saved;

[0025] (2) The hierarchical pressure release control anchor rod fully utilizes the hierarchical failure characteristics of the surrounding rock to maximize the self-stabilizing ability of the surrounding rock, and does not need to be repeatedly maintained, thereby saving support materials;

[0026] (3) The outer ring in the secondary pressure release friction fit with the pressure release sleeve is provided with an adjustable pressure release part on the basis of the fixed pressure release ring, which can flexibly adjust the pressure release amount based on the surrounding rock pressure to meet the requirements of different deformation amounts on site. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a support structure diagram of the surrounding rock of the tunnel in the present application;

[0028] Figure 2 It is a local enlarged schematic view of A in the present application; Figure 1

[0029] Figure 3 It is a side view of the hierarchical pressure release control anchor rod on the surrounding rock in the present application;

[0030] Figure 4 It is a side view of the hierarchical pressure release control anchor rod on the surrounding rock in the present application;

[0031] Figure 5 ​The side view of the two-stage pressure relief movement of the grading pressure relief control anchor rod on the surrounding rock in the application;

[0032] Figure 6 The detailed structure diagram of the local structure of the outer ring of the grading pressure relief control anchor rod in the application;

[0033] Figure 7 The B-B view in the application Figure 6 ;

[0034] Figure 8 The detailed structure diagram of the local structure of the adjustable pressure relief part in the outer ring in the application

[0035] Figure 9 The C-C view in the application Figure 8 .

[0036] As Figures 1-9 shown in the figure, the respective marks are:

[0037] Surrounding rock 1, rod body 2, inner ring 3, pressure relief sleeve 4, outer ring 5, nut 6, steel bar row 7, steel bar mesh 8, anchor cable 9, sprayed concrete layer 10;

[0038] Conical end 41, barrel 42, limiting ring 43;

[0039] Fixed pressure relief ring 51, adjustable pressure relief part 52, adjustable pressure relief arc segment 52a, connecting rod 52b, guide contact head 52c, sliding groove 53, guide ring 54, small inner diameter segment 54a, transition segment 54b, large inner diameter segment 54c, outer meshing tooth 55, ring table 56, telescopic drive rod 57, straight rack 58, annular guide groove 59. DETAILED DESCRIPTION

[0040] The features and other related features of the application are further described in detail below by examples in conjunction with the accompanying drawings, so as to facilitate the understanding of the same by the same industry technical personnel:

[0041] Example: as Figures 1-9 shown, the present embodiment specifically relates to a supporting structure for long-distance deep-buried TBM inclined shaft water-rich complex rock stratum, which comprises grading pressure relief control anchor rod, anchor cable 9, and steel bar row 7, steel bar mesh 8, and sprayed concrete layer 10 arranged in the surrounding rock surface of the tunnel from inside to outside in sequence.

[0042] As Figure 1 , 2As shown, the graded pressure relief control anchor bolts and anchor cables 9 are distributed circumferentially in the surrounding rock 1 and penetrate deep into the surrounding rock 1 for anchoring; the steel reinforcement row 7 is composed of several longitudinal steel bars and is distributed circumferentially in the surrounding rock 1 of the tunnel; the steel mesh 8 presses and fixes the steel reinforcement row 7 to the surrounding rock surface; the fixing between the steel mesh 8 and the surrounding rock surface is achieved by steel rivets (not shown in the figure), graded pressure relief control anchor bolts and anchor cables 9; the shotcrete layer 10 is sprayed on the surrounding rock surface to consolidate the graded pressure relief control anchor bolts, anchor cables 9, steel reinforcement row 7, steel mesh 8 and shotcrete layer 10 into an integrated structure; wherein the combination between the steel mesh 8 and the steel reinforcement row 7 constitutes the steel reinforcement skeleton of the integrated concrete structure.

[0043] like Figures 1-9 As shown, the graded pressure relief control anchor bolt includes a rod body 2, an outer ring 5, a pressure relief sleeve 4, and an inner ring 3.

[0044] like Figure 3 , 4 As shown in Figure 5, the main body of the pressure sleeve 4 is a cylindrical cylinder 42. The front end of the cylinder 42 is provided with a tapered end 41, and the rear end of the cylinder 42 is provided with a radially protruding limiting ring 43. A through hole for the rod 2 to pass through is opened in the center of the tapered end 41, and the diameter of the through hole is the same as the outer diameter of the rod 2. The outer diameter of the tapered end 41 gradually narrows and decreases in the longitudinal direction (towards the depth of the surrounding rock 1).

[0045] like Figure 3 , 4 As shown in 5, 6, 7, 8, and 9, the outer ring 5 includes a fixed pressure relief ring 51, a ring platform 56, an adjustable pressure relief component 52, a sliding groove 53, a guide ring 54, and a drive assembly. The ring platform 56 is set along the annular outer edge of the front end face of the fixed pressure relief ring 51. The two together enclose a groove space for the installation and arrangement of various components. The thickness of each of the aforementioned components is less than the height of the ring platform 56. During installation, the fixed pressure relief ring 51 and the ring platform 56 are fastened to the surrounding rock 1, thereby preventing the components in the groove space from being squeezed and damaged.

[0046] like Figure 3 , 4 As shown in Figures 5, 6, 7, 8, and 9, the inner wall of the fixed pressure ring 51 is a longitudinally variable diameter section that fits the tapered end 41; as... Figure 6 , 7As shown in Figures 8 and 9, four sets of adjustable pressure-relieving components 52 are arranged circumferentially. Each adjustable pressure-relieving component 52 includes an adjustable pressure-relieving arc segment 52a, a connecting rod 52b, and a guide contact head 52c. The rod body of the connecting rod 52b is assembled in the slide groove 53 to guide the connecting rod 52b radially. The two ends of the connecting rod 52b are respectively connected to the adjustable pressure-relieving arc segment 52a and the guide contact head. The inner arc surface of the adjustable pressure-relieving arc segment 52a can fit against the conical end 41. The guide contact head 52c slides in contact with the inner ring of the guide ring 54. The inner ring of the guide ring 54 is provided with four sets of guide diameter-changing segments. Each set of guide diameter-changing segments corresponds to a guide contact head 52c. The guide diameter-changing segments include a small inner diameter segment 54a, a transition segment 54b, and a large inner diameter segment 54c arranged in sequence. The rotation of the guide ring 54 is driven by a drive assembly.

[0047] A ring of external teeth 55 is provided on the outer wall surface of the guide ring 54, an annular guide groove 59 is provided on the front end surface of the fixed pressure ring 51, and a convex rail is provided on the rear end surface of the guide ring 54. The convex rail on the guide ring 54 is correspondingly matched and installed in the annular guide groove 59 to form a rotational guide support for the rotation of the guide ring 54. The drive assembly includes a hydraulic telescopic rod 57 and a rack 58 fixedly installed on the body of the hydraulic telescopic rod 57. The rack 58 meshes with the external teeth 55 on the guide ring 54 to drive the guide ring 54 to rotate.

[0048] like Figures 1-9 As shown in this embodiment, the working method of the support structure for a long-distance, deeply buried TBM inclined shaft in water-rich and complex rock strata includes the following steps:

[0049] (S1) Before the TBM excavation, pre-grouting holes are drilled in the surrounding rock to reinforce it in advance, improve the mechanical properties of the surrounding rock, give full play to the self-stabilizing effect of the surrounding rock, and improve its self-stability.

[0050] The specific method of advance grouting is as follows: First, according to the advance forecast information, use an advance drilling rig to drill through the hole in the TBM cutterhead to make advance drilling, and then connect the grouting pump to carry out advance grouting. In order to improve the grouting effect, the cement mortar is replaced with ultrafine cement-water glass dual liquid grout to ensure the injection range and grouting pressure, which reduces the water flow into the surrounding rock 1 to a certain extent, improves the physical and mechanical properties of the surrounding rock in the soft rock tunnel, such as compressive strength, tensile strength, shear strength, etc., and helps to achieve uniform bearing. According to the loosening range of the surrounding rock 1, the grouting hole is 300-400mm deeper than the loosening range of the surrounding rock 1.

[0051] (S2) After the TBM excavates the surrounding rock 1, it drills holes in the surrounding rock 1 to install graded pressure relief control anchor bolts and anchor cables 9. The installation steps of the graded pressure relief control anchor bolts are as follows: drill holes in the surrounding rock 1 based on the diameter of the rod body 2. On this basis, according to the outer diameter of the cylinder 42 of the pressure relief sleeve 4, enlarge the rear end of the first drilled hole. The enlargement depth is the length of the pressure relief sleeve 4, so that the pressure relief sleeve 4 can extend into the enlarged part during the subsequent graded pressure relief process. After the enlargement is completed, install the graded pressure relief control anchor bolts. The graded pressure relief control anchor bolts include the rod body 2, the outer ring 5, the pressure relief sleeve 4, and the inner ring 3.

[0052] It should be noted that, while installing the graded pressure relief control anchor bolts, steel bar rows 7 and steel mesh 8 are laid on the surface of the surrounding rock 1. The specific steps are as follows: the longitudinal steel bar rows 7 are arranged at intervals along the circumference on the surface of the surrounding rock 1, and the steel bar rows 7 are temporarily fixed by manual means or by a support. Then, the steel mesh 8 is laid to press the steel bar rows 7 tightly to the surface of the surrounding rock 1. Then, the steel mesh 8 is permanently fixed by driving steel bar rivets into the surrounding rock 1. At the same time, graded pressure relief control anchor bolts and anchor cables 9 are installed sequentially in the surrounding rock 1. The outer ring 5 at the rear end of the graded pressure relief control anchor bolt 9 can press and fix the steel mesh 8. Figure 3 , 4 (The steel mesh 8 is omitted in 5). In addition, the rear end of the anchor cable 9 can also be used to further tighten and fix the steel mesh 8.

[0053] S3: Implement graded pressure relief between the control anchor bolt and the surrounding rock 1, as detailed below:

[0054] In the initial state, the rear end of the rod 2 presses the inner ring 3 against the rear end of the inner cavity of the pressure-relieving sleeve 4 via the nut 6; the front end of the pressure-relieving sleeve 4 extends into the borehole and presses the outer ring 5 against the surrounding rock 1 outside the borehole; a first-level pressure-relieving friction fit is formed between the inner ring 3 and the inner cavity of the pressure-relieving sleeve 4; a second-level pressure-relieving friction fit is formed between the front end of the pressure-relieving sleeve 4 and the outer ring 5; wherein, the frictional force of the second-level pressure-relieving friction fit is greater than that of the first-level pressure-relieving friction fit. It should be noted that, in order to ensure sufficient frictional force, an interference fit is used between the inner ring 3 and the inner cavity of the pressure-relieving sleeve 4, and an interference fit is also used between the outer ring 5 and the pressure-relieving sleeve 4. When relative sliding occurs between the pressure-relieving sleeve 4 and the outer ring 5, the pressure-relieving sleeve 4 will cause radial compression to the inner ring of the fixed pressure-relieving ring 51 of the outer ring 5.

[0055] In the process of deformation of the surrounding rock 1, when the surrounding rock pressure gradually becomes greater than the frictional force of the primary yielding friction fit (i.e. the frictional force between the inner ring 3 and the yielding sleeve 4), the rod body 2 drives the primary yielding movement between the inner ring 3 and the inner cavity of the yielding sleeve 4. With the movement of the inner ring 3 to the inside of the surrounding rock 1, the deformation energy of the surrounding rock is gradually released during the movement, and the increasing speed of the surrounding rock pressure slows down. When the surrounding rock pressure is equal to the working resistance of the rod body 2, the yielding movement stops, and the yielding process ends. When the surrounding rock pressure is greater than the frictional force of the primary yielding friction fit, the primary yielding process continues until the inner ring 3 moves to the end of the inner cylinder of the yielding sleeve 4 and stops.

[0056] If the deformation of the surrounding rock continues to develop after the primary yielding ends, the surrounding rock pressure will continue to increase. At this time, if the surrounding rock pressure has not increased to the frictional force of the secondary yielding friction fit, the rod body 2 will deform to release the deformation energy of the surrounding rock. When the surrounding rock pressure increases to be greater than the frictional force of the secondary yielding friction fit, the outer ring 5 and the yielding sleeve 4 begin to slide relative to each other, and the secondary yielding process begins. The rod body 2 drives the conical end 41 of the yielding sleeve 4 to move to the deep part of the surrounding rock 1 and enter the reaming part of the drill hole. With the continuation of the yielding process, the deformation energy of the surrounding rock is released, and the increasing amplitude of the surrounding rock pressure slows down. When the size is equal to the secondary yielding working resistance (the frictional force of the secondary yielding friction fit), the yielding process stops, and the surrounding rock pressure and the supporting resistance reach equilibrium. The deformation of the surrounding rock is controlled in the process of the graded yielding. Finally, when the limiting ring 43 protruding at the rear end of the yielding sleeve 4 abuts against the outer ring 5, the movement stops.

[0057] It should be noted that the rod body 2 has a pressure sensor (not shown in the figure) for monitoring the surrounding rock pressure. The pressure sensor is connected to the controller of the hydraulic telescopic rod 57 for control. Based on the surrounding rock pressure data monitored by the pressure sensor, it is determined whether the driving assembly drives the guide ring 54 to rotate, i.e. when the secondary yielding occurs, if the surrounding rock pressure is less than the secondary yielding working resistance, the rod body 2 will deform to release the deformation energy of the surrounding rock. If the deformation of the rod body 2 continues, it will also be an unsafe process, so the adjustable yielding part 52 is needed to adjust the secondary yielding working resistance between the outer ring 5 and the yielding sleeve 4. The specific description is as follows:

[0058] In the initial state, the transition section 54b on the guide ring 54 is in contact with the guide contact head 52c; when it is necessary to increase the friction between the outer ring 5 and the yielding sleeve 4, the guide ring 54 is rotated so that the small inner diameter section 54a is in contact with the guide contact head 52c and the adjustable yielding arc section 52a is pressed against the tapered end head 41, so that the adjustable yielding arc section 52a is pressed against the tapered end head 41 under the guidance of the sliding groove 55, thereby increasing the secondary yielding resistance; when it is necessary to reduce the friction between the outer ring 5 and the yielding sleeve 4, the guide ring 54 is rotated so that the large inner diameter section 54c is in contact with the guide contact head 52c to release the pressing of the adjustable yielding arc section 52a against the tapered end head 41, so that the adjustable yielding arc section 52a does not block the tapered end head 41 when the tapered end head 41 is pulled towards the surrounding rock.

[0059] S4: After the installation and support process of the hierarchical yielding control anchor rod is completed, the surrounding rock surface is sprayed and reinforced to form a sprayed concrete layer 10, and the sprayed concrete layer 10 integrates the hierarchical yielding control anchor rod, the anchor cable 9, the steel bar row 7 and the steel mesh 8 into an integral structure.

[0060] The advantages of the embodiment are:

[0061] (1) The self-bearing capacity of the surrounding rock is fully utilized, and passive support is converted into active support; the hierarchical yielding control anchor rod and the anchor cable jointly support, the support structure has good integrity and high support strength; the support scheme is reasonably selected in combination with the deformation monitoring results of the surrounding rock of the roadway, thereby playing a high-efficiency support role and saving support materials;

[0062] (2) The hierarchical yielding control anchor rod fully utilizes the hierarchical failure characteristics of the surrounding rock to maximize the self-stability of the surrounding rock, and does not need to be repeatedly maintained, thereby saving support materials;

[0063] (3) The outer ring that performs secondary yielding friction with the yielding sleeve is provided with an adjustable yielding part on the basis of the fixed yielding ring, and can flexibly adjust the yielding amount based on the pressure of the surrounding rock to meet the requirements of different deformation amounts on site.

Claims

1. A supporting structure for long-distance deep-buried TBM inclined shaft in water-rich complex rock stratum, characterized in that The support structure comprises hierarchical pressure relief control anchor rods, anchor cables, and steel bars, steel meshes, and sprayed concrete layers arranged in sequence from inside to outside on the surrounding rock surface of the tunnel, the steel meshes are fixed on the surrounding rock surface by the hierarchical pressure relief control anchor rods and the anchor cables; The hierarchical pressure relief control anchor rod comprises a rod body, an outer ring, a pressure relief sleeve, and an inner ring; in the initial state, the inner ring is pressed against the rear end port of the inner cavity of the pressure relief sleeve by the nut at the rear end of the rod body; the front end of the pressure relief sleeve extends into the drill hole of the surrounding rock and presses the outer ring against the surrounding rock outside the drill hole; a first-stage pressure relief friction fit is formed between the inner ring and the inner cavity of the pressure relief sleeve; a second-stage pressure relief friction fit is formed between the front end of the pressure relief sleeve and the outer ring; wherein the friction force of the second-stage pressure relief friction fit is greater than that of the first-stage pressure relief friction fit; The main body of the pressure relief sleeve is a cylindrical barrel, the front end of the barrel is provided with a conical end head, and the rear end of the barrel is provided with a radially outwardly convex limiting ring; the center of the conical end head is provided with a through hole for the rod body to pass through, and the hole diameter of the through hole is the same as the outer diameter of the rod body; The outer ring comprises a fixed pressure relief ring, a ring table, an adjustable pressure relief part, a sliding groove, a guide ring, and a driving assembly; the ring table is arranged along the front end surface of the fixed pressure relief ring; the inner wall surface of the fixed pressure relief ring is a longitudinal variable diameter section and is fitted to the conical end head; the adjustable pressure relief part is arranged in four groups in the circumferential direction; the adjustable pressure relief part comprises an adjustable pressure relief arc section, a connecting rod, and a guide contact head; the connecting rod is assembled in the sliding groove to guide the radial sliding of the connecting rod; the two ends of the connecting rod are connected to the adjustable pressure relief arc section and the guide contact head, respectively; the inner arc surface of the adjustable pressure relief arc section is fitted to the conical end head; the guide contact head is in sliding contact with the inner ring of the guide ring; the inner ring of the guide ring is provided with four groups of guide variable diameter sections, each group of guide variable diameter sections corresponds to one guide contact head; the guide variable diameter section comprises a small inner diameter section, a transition section, and a large inner diameter section arranged in sequence; the guide ring is driven to rotate by the driving assembly; The outer wall surface of the guide ring is provided with a ring of outer teeth, the front end surface of the fixed pressure relief ring is provided with an annular guide groove, and the rear end surface of the guide ring is provided with a convex rail; the convex rail on the guide ring is installed in the annular guide groove in a corresponding matching manner to provide rotational guide support for the rotation of the guide ring; the driving assembly comprises a hydraulic telescopic rod and a straight rack fixed on the rod body of the hydraulic telescopic rod; the straight rack is engaged with the outer teeth on the guide ring to drive the rotation of the guide ring.

2. The supporting structure for long-distance deep-buried TBM inclined shaft in water-rich complex rock stratum according to claim 1, characterized in that The steel bars are composed of a plurality of longitudinal steel bars and are distributed in the circumferential direction; the steel meshes press the steel bars against the surrounding rock surface; the sprayed concrete layer is sprayed on the surrounding rock surface to integrate the hierarchical pressure relief control anchor rods, the anchor cables, the steel bars, the steel meshes, and the sprayed concrete layer into a unitary structure.

3. The supporting structure for long-distance deep-buried TBM inclined shaft in water-rich complex rock stratum according to claim 1, characterized in that The rod body of the hierarchical pressure relief control anchor rod is provided with a pressure sensor for monitoring the surrounding rock pressure, and the pressure sensor is connected to the controller of the hydraulic telescopic rod for control, and the driving assembly is controlled based on the surrounding rock pressure data monitored by the pressure sensor to determine whether the driving assembly drives the guide ring to rotate; In the initial state, the transition section on the guide ring is in contact with the guide contact head; When it is necessary to increase the friction between the outer ring and the pressure relief sleeve, the guide ring is rotated to make the small inner diameter section contact the guide contact head and press the adjustable pressure relief arc section against the conical end head; when it is necessary to reduce the friction between the outer ring and the pressure relief sleeve, the guide ring is rotated to make the large inner diameter section contact the guide contact head to release the pressure of the adjustable pressure relief arc section on the conical end head.

4. The supporting structure for long-distance deep-buried TBM inclined shaft in water-rich complex rock stratum according to claim 1, characterized in that The fixed pressure relief ring and the ring table jointly form a device installation groove space, and the thicknesses of the adjustable pressure relief part, the sliding groove, the guide ring and the driving assembly are all less than the height of the ring table.

5. A working method related to the supporting structure of long-distance deep-buried TBM inclined shaft in water-rich complex rock stratum according to any one of claims 1-4, characterized in that The working method comprises the following steps: S1: drilling a pre-grouting hole in the surrounding rock in front of the TBM to perform pre-reinforcement; S2: after the TBM completes excavation of the surrounding rock, drilling a hole in the surrounding rock to install a hierarchical pressure relief control anchor rod and an anchor cable, the hierarchical pressure relief control anchor rod comprising a rod body, an outer ring, a pressure relief sleeve and an inner ring; wherein the drilling is divided into two steps, the first step is to drill a hole according to the diameter of the rod body of the hierarchical pressure relief control anchor rod, and the second step is to expand the hole according to the outer diameter of the cylinder of the pressure relief sleeve on the basis of the drilled hole, and the expansion depth is the length of the pressure relief sleeve; At the same time of installing the hierarchical pressure relief control anchor rod, laying a steel bar row and a steel mesh on the surface of the surrounding rock, the steel mesh pressing the steel bar row against the surface of the surrounding rock, and the steel mesh being fixed on the surface of the surrounding rock through the hierarchical pressure relief control anchor rod, the steel mesh and a steel rivet; S3: in the process of deformation of the surrounding rock, when the surrounding rock pressure is greater than the friction force of the first pressure relief friction fit, the rod body of the hierarchical pressure relief control anchor rod drives the first pressure relief movement between the inner ring and the inner cavity of the pressure relief sleeve, and stops when the inner ring moves to the end of the inner cylinder of the pressure relief sleeve; When the surrounding rock pressure is greater than the friction force of the second pressure relief friction fit, the rod body of the hierarchical pressure relief control anchor rod drives the second pressure relief movement between the front end of the pressure relief sleeve and the outer ring and moves into the drilled hole, and stops when the limiting ring protruding from the rear end of the pressure relief sleeve abuts against the outer ring; S4: after completing the installation and support procedures of the hierarchical pressure relief control anchor rod, performing shotcrete reinforcement on the surface of the surrounding rock to integrate the hierarchical pressure relief control anchor rod, the anchor cable, the steel bar row, the steel mesh and the shotcrete layer into an integral structure.

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