Prestressed anchor cable supporting system for soft rock tunnel and mounting method of anchor cable supporting system

Abstract

The invention relates to a soft rock tunnel pre-stressed anchor cable supporting system and an installation method of the anchor cable supporting system. The pre-stressed anchor cable supporting system for the soft rock tunnel comprises a primary supporting structure, a steel belt supporting net and an anchoring system. The primary supporting structure is used for covering the inner wall of a tunnel and is provided with a plurality of pre-stressed anchor cable holes, the steel belt supporting net covers the inner wall of the primary supporting structure, and the steel belt supporting net is provided with a plurality of anchor cable mounting holes corresponding to the pre-stressed anchor cable holes. The steel belt supporting net is used for bearing the pressure of the primary supporting structure, a plurality of anchoring systems are installed on the steel belt supporting net corresponding to the anchor cable installation holes, and connecting pieces of the anchoring systems penetrate through the anchor cable installation holes to the interiors of the pre-stressed anchor cable holes so that the steel belt supporting net can be locked to the inner wall of the primary supporting structure. The steel belt supporting net bears the pressure of the primary supporting structure, deformation of the primary supporting structure is avoided, potential safety hazards are reduced, and the construction progress is accelerated.

Description

Technical Field

[0001] The present application relates to the technical field of civil engineering construction, and in particular to a prestressed anchor cable support system for a soft rock tunnel and an installation method of the anchor cable support system. Background Art

[0002] With the development of civil engineering technology, tunnel support technology has emerged. The initial support structure set by tunnel support technology can suppress tunnel deformation to a certain extent. However, in the soft rock tunnel section, due to the development of thin-layer gentle structural surfaces, the accumulation of rock creep and the increase of plastic zone, the bending of thin-layer structures under the action of lagging stress fields and shear failure of fracture surfaces occur, which are prone to serious deformation problems. At this time, the initial support structure will not be able to completely solve the deformation problem of soft rock, and there are great safety risks. Summary of the invention

[0003] Based on this, it is necessary to provide a prestressed anchor cable support system for a soft rock tunnel and an installation method of the anchor cable support system to address the support strength problem of the initial support structure when the deformation in the soft rock tunnel is too large.

[0004] A soft rock tunnel prestressed anchor cable support system, comprising:

[0005] The initial support structure is used to cover the inner wall of the tunnel and is provided with several prestressed anchor cable holes;

[0006] The steel belt support net is covered on the inner wall of the initial support structure and is used to bear the pressure of the initial support structure. The steel belt support net is provided with several anchor cable installation holes corresponding to the prestressed anchor cable holes;

[0007] The anchoring system is installed with several corresponding anchor cable installation holes on the steel belt support net, and the connecting parts of the anchoring system pass through the anchor cable installation holes to the inside of the prestressed anchor cable holes, so as to lock the steel belt support net to the inner wall of the initial support structure.

[0008] In one embodiment, the tunnel has a plurality of mutually parallel transverse sections, and the transverse sections are arranged perpendicular to the extension direction of the tunnel; and a plurality of transverse installation loops are arranged corresponding to the positions where the inner wall of the initial support structure intersects with the plurality of transverse sections;

[0009] The tunnel has several longitudinal sections parallel to each other, and the extension direction of the longitudinal sections is parallel to the extension direction of the tunnel; several longitudinal installation loops are arranged correspondingly at the positions where the inner wall of the initial support structure intersects with the several longitudinal sections;

[0010] The prestressed anchor cable hole is arranged at the intersection of the transverse installation loop line and the longitudinal installation loop line;

[0011] The steel belt support net is covered on the transverse installation loop and the longitudinal installation loop, and the steel belt support net includes: a plurality of steel belts continuously assembled along the transverse installation loop and the longitudinal installation loop, and the ends of the steel belts cover each other; anchor cable installation holes are opened at the ends of the steel belts that cover each other, so that the two anchor cable installation holes located at the ends of the steel belts are in a matching state;

[0012] The connecting piece of the anchoring system passes through two anchor cable installation holes in a matched state to the prestressed anchor cable hole to lock two adjacent steel belts to the inner wall of the initial support structure.

[0013] In one embodiment, the two ends of the steel belt are respectively set as a round hole end and a line hole end; the anchor cable installation hole is opened as a round hole at the round hole end, and the anchor cable installation hole is opened as a linear hole along the length direction of the steel belt at the line hole end;

[0014] The round hole end of the steel belt located on the same horizontal installation loop covers the wire hole end of the adjacent steel belt; the round hole end of the steel belt located on the same longitudinal installation loop covers the wire hole end of the adjacent steel belt.

[0015] In one of the embodiments, the connecting member of the anchoring system is configured as an anchor cable, and the anchoring system further comprises an anchor pad and an anchor;

[0016] The positioning end of the anchor cable passes through the anchor cable installation hole to the inside of the prestressed anchor cable hole, and the positioning end of the anchor cable is fixed inside the prestressed anchor cable hole;

[0017] The free end of the anchor cable is in a tensioned state relative to the positioning end of the anchor cable, the anchor pad is arranged between the positioning end and the free end of the anchor cable, and the anchor pad is pressed on the surface of the steel belt support mesh away from the initial support structure;

[0018] The anchor squeezes the side of the anchor plate away from the steel belt support net from the free end of the anchor cable to the positioning end.

[0019] In one embodiment, the width of the linear hole is equal to the diameter of the circular hole.

[0020] In one embodiment, the initial support structure includes: a lining concrete layer covering the inner wall of the tunnel and a support arch frame arranged in the lining concrete layer; the support arch frame includes a plurality of longitudinal support frames arranged parallel to the extension direction of the tunnel, the longitudinal support frames are arranged in parallel, and the longitudinal installation loop is arranged between two adjacent longitudinal support frames;

[0021] The supporting arch frame also includes a plurality of transverse supply frames arranged perpendicular to the extension direction of the tunnel. The transverse supply frames are arranged in parallel, and a transverse installation loop is arranged between two adjacent transverse supply frames.

[0022] In one of the embodiments, it also includes a secondary lining concrete layer covering the side of the steel belt support mesh facing away from the tunnel.

[0023] In one of the embodiments, an arch line is set in the tunnel, the initial support structure above the arch line is set as the arch section, and the initial support structure below the arch line is set as the side wall section; the prestressed anchor cable hole is opened in the arch section, and the secondary lining concrete layer covers the arch section and the side wall section.

[0024] A method for installing an anchor cable support system is applied to the above-mentioned prestressed anchor cable support system for a soft rock tunnel, and the method comprises:

[0025] Install the initial support structure on the inner wall of the tunnel, and mark the prestressed anchor points on the inner wall of the initial support structure;

[0026] Drill holes at the prestressed anchor points to form prestressed anchor holes, and fix the anchor positioning ends inside the prestressed anchor holes;

[0027] Assemble the steel belt along the transverse installation loop and the longitudinal installation loop, and assemble the steel belt with the anchor cable at the same time until a steel belt support net is formed;

[0028] Assemble the anchor plate and anchor to the anchor cable, and tension the free end of the anchor cable.

[0029] In one embodiment, drilling a hole at a prestressed anchor point to form a prestressed anchor hole, and fixing a positioning end of the anchor inside the prestressed anchor hole, comprises:

[0030] After the prestressed anchor hole is generated by the anchor drilling machine, the anchoring agent is placed into the prestressed anchor hole.

[0031] The above-mentioned prestressed anchor cable support system for soft rock tunnels includes an initial support structure, a steel belt support net and an anchoring system. The initial support structure is used to cover the inner wall of the tunnel and is provided with a number of prestressed anchor cable holes. The steel belt support net covers the inner wall of the initial support structure, and the steel belt support net is provided with a number of anchor cable installation holes corresponding to the prestressed anchor cable holes. The anchoring system is installed on the steel belt support net corresponding to the anchor cable installation holes. The connecting parts of the anchoring system pass through the anchor cable installation holes to the inside of the prestressed anchor cable holes to lock the steel belt support net to the inner wall of the initial support structure. The steel belt support net bears the pressure of the initial support structure to prevent the deformation of the initial support structure from encroaching on the lining structure line, reduce safety risks and hidden dangers, and speed up the construction progress.

[0032] A method for installing an anchor cable support system is applicable to the above-mentioned prestressed anchor cable support system for soft rock tunnels and has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a cross-sectional view of the prestressed anchor cable support system for a soft rock tunnel provided in the present application and the assembled tunnel.

[0034] FIG2 is a schematic diagram of the partial structure of the steel belt support net provided in this application.

[0035] FIG. 3 is a schematic diagram of the assembly between the steel belts provided in the present application.

[0036] FIG. 4 is a partial enlarged view of the area S in FIG. 1 .

[0037] Figure Number:

[0038] 1. Initial support structure; 2. Steel belt support net; 3. Anchor cable installation hole; 4. Steel belt; 5. Circular hole; 6. Linear hole; 7. Anchor cable; 8. Anchor pad; 9. Anchor; 10. Secondary lining concrete layer;

[0039] A. Extension direction of the horizontal installation loop; B. Extension direction of the vertical installation loop; C. Arch line. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0041] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0042] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0044] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0046] Refer to Figure 1, which is a cross-sectional view of the prestressed anchor cable support system for soft rock tunnels and the tunnel after assembly provided by the present application, including a prestressed anchor cable support system for soft rock tunnels, which is used to be set on the inner wall of the tunnel in the soft tunnel section to achieve stable support and reduce tunnel deformation. The prestressed anchor cable support system for soft rock tunnels includes an initial support structure 1, a steel belt support net 2 and an anchoring system. The above-mentioned initial support structure 1 is used to cover the inner wall of the tunnel, and the steel belt support net 2 is used to cover the inner wall of the initial support structure 1. A number of prestressed anchor cable holes are provided on the inner wall of the initial support structure 1. After the steel belt support net 2 covers the inner wall of the initial support structure 1, the anchor cable installation holes 3 will be opened one by one corresponding to the prestressed anchor cable holes. The anchoring system is installed on the steel belt support net 2 through the anchor cable installation hole 3. The connecting parts of the anchoring system pass through the anchor cable installation hole 3 to the inside of the prestressed anchor cable hole. The anchoring system will lock the steel belt support net 2 on the inner wall of the initial support structure 1 through the connecting parts, so that the steel belt support net 2 bears the pressure of the initial support structure 1, avoiding the deformation pressure of the tunnel from destroying the initial support structure 1.

[0047] The anchor cable support system can prevent the deformation of the initial support structure 1 from encroaching on the lining structure line, reduce safety risks and hidden dangers, and speed up the construction progress. By supporting the steel belt support net 2 on the inner wall of the initial support structure 1, the stress concentration in the surrounding rock can be dispersed, the relaxation of the surrounding rock can be inhibited, the stability of the tunnel structure itself can be improved, and the collapse and damage of the tunnel structure can be avoided.

[0048] Referring to Figures 2 and 3 of the specification, Figure 2 is a schematic diagram of the partial structure of the steel belt support net provided by the present application, and Figure 3 is a schematic diagram of the assembly between the steel belts provided by the present application, which shows that in one embodiment of the present application, there are several mutually parallel transverse sections and several mutually parallel longitudinal sections in the tunnel, wherein the transverse sections and the longitudinal sections are both virtual planes. The extension direction of the tunnel is perpendicular to the transverse section, and the extension direction of the longitudinal section is parallel to the extension direction of the tunnel. Several transverse installation loops are formed correspondingly at the positions where the inner wall of the initial support structure 1 intersects with the several transverse sections, and several longitudinal installation loops are formed correspondingly at the positions where the inner wall of the initial support structure 1 intersects with the several longitudinal sections. The figure shows the extension direction A of the transverse installation loop and the extension direction B of the longitudinal installation loop, wherein because the inner wall of the tunnel is set as a concave surface, the transverse installation loop and the longitudinal installation loop are actually arcs, and the figure is only a schematic line of the extension direction.

[0049] The prestressed anchor cable holes on the inner wall of the initial support structure 1 are arranged at the intersection of the transverse installation loop and the longitudinal installation loop. The steel belt support net 2 covers the inner wall of the initial support structure 1 along the transverse installation loop and the longitudinal installation loop. The steel belt support net 2 includes: a plurality of steel belts 4 continuously assembled along the transverse installation loop and a plurality of steel belts 4 continuously assembled along the longitudinal installation loop, and the transversely installed steel belts 4 and the longitudinally installed steel belts 4 are assembled with each other to form a mesh. The steel belts 4 on the same transverse installation loop or the same longitudinal installation loop can form a steel belt ring, and the plurality of steel belt rings are arranged in parallel.

[0050] Specifically, the anchor cable installation holes 3 are opened at the ends of the steel strips 4, and the ends of the adjacent steel strips 4 cover each other, so that the internal spaces of the anchor cable installation holes 3 with overlapping ends are connected, and the anchor cable installation holes 3 are in a mating state. The connecting piece of the anchoring system will penetrate the two anchor cable installation holes 3 in the mating state to the inside of the prestressed anchor cable hole, thereby connecting and locking the two adjacent steel strips 4 to the inner wall of the initial support structure 1.

[0051] In one embodiment of the present application, the two ends of the steel belt 4 are respectively set as a round hole end and a line hole end, the anchor cable installation hole 3 on the round hole end is opened as a round hole 5, and the anchor cable installation hole 3 on the line hole end is opened as a line hole 6, and the line hole 6 is extended along the length direction of the steel belt 4. On the same horizontal installation loop line, the round hole end of the steel belt 4 covers the line hole end of the adjacent steel belt 4, so that the round hole 5 and the line hole 6 are correspondingly set in a matching state.

[0052] On the same longitudinal installation loop, the round hole end of the steel belt 4 covers the linear hole end of the adjacent steel belt 4, so that the round hole 5 and the linear hole 6 are correspondingly arranged in a matching state.

[0053] The opening structure of the circular hole 5 and the linear hole 6 can be set with reference to the prior art. The circular hole 5 and the linear hole 6 cooperate in such a way that the position of the circular hole 5 in the linear hole 6 is adjusted and then positioned using an anchoring system.

[0054] The special point is that the four corners of the entire steel belt support net 2 need to be matched with each other through the round hole ends of the two steel belts 4. Using the wire hole ends of the steel belts 4 as the connecting ends for connecting adjacent steel belts 4 can facilitate the adjustment of the assembly distance between the steel belts 4.

[0055] Referring to Figure 4 of the specification, Figure 4 is a partial enlarged view of S in Figure 1, showing that in one embodiment of the present application, the connecting member of the above-mentioned anchoring system is set as an anchor cable 7, and the anchoring system also includes an anchor pad 8 and an anchor 9 that cooperate with the anchor cable 7. The positioning end of the anchor cable 7 passes through the anchor cable installation hole 3 to the inside of the prestressed anchor cable hole, and after penetration, the positioning end of the anchor cable 7 is fixed inside the prestressed anchor cable hole. The free end of the anchor cable 7 extends to the outside of the steel belt support net 2, the anchor pad 8 is sleeved on the anchor cable 7, and the anchor 9 is inserted from the free end of the anchor cable 7 until the anchor pad 8 is squeezed on the side surface of the steel belt support net 2 away from the initial support structure 1. The free end of the anchor cable 7 is in a tensioned state relative to its positioning end, so that the steel belt support net 2 is locked to the inner wall of the initial support structure 1 through the cooperation of the anchor pad 8 and the anchor 9.

[0056] The coordination between the anchor cable 7, anchor pad 8, anchor 9 and steel belt 4 can be set with reference to the prior art, which will not be elaborated in this article.

[0057] In one embodiment of the present application, the length of the above-mentioned steel belt 4 is the same as the spacing between the anchor cables 7. The width and thickness of the steel belt 4 need to be set in combination with the prestressing size of the free end of the anchor cable 7. The recommended thickness of the steel belt 4 is about 2.8 to 8 mm. The greater the prestressing size, the thicker the steel belt 4 needs to be set accordingly.

[0058] In one embodiment of the present application, the width of the linear hole 6 is equal to the diameter of the circular hole 5. By changing the connection method between the steel belt 4 and the anchor cable 7, the difficulty in installing the anchor cable caused by the deviation of the drilling size can be avoided, and the steel belts 4 can be connected into a ring to achieve a uniform force state. By changing the connection method between the anchor cable 7 and the steel belt 4, after the anchor cable 7 is tensioned, the anchor cable 7 and the supporting arch frame in the initial support structure 1 can be quickly stressed as a whole, reducing the deformation rate of the initial support structure 1, and controlling the deformation within a certain range.

[0059] In one embodiment of the present application, the opening diameter of the circular hole 5 on the steel strip 4 is φ32mm, and the length of the corresponding linear hole 6 is 15cm, and the width of the linear hole 6 is consistent with the diameter of the linear hole 6. The overlapping coverage length of two adjacent steel strips 4 is 15cm, ensuring that the steel strips 4 are connected and can adapt to the position of the prestressed anchor cable hole through the change of the matching position of the linear hole 6 and the circular hole 5. It is foreseeable that the matching method of the opening on the steel strip 4 is not limited to the above, and will not be elaborated here.

[0060] The diameter, length and spacing of the anchor cable 7 can be determined in combination with the acoustic detection of the surrounding rock loosening zone: if the surrounding rock loosening zone is too large, the diameter and length of the corresponding anchor cable 7 need to be adjusted, and the spacing between the rows should be increased, and the layout range of the anchor cable 7 is above the arch line C. For example: assuming that the surrounding rock loosening zone is within the range of 5~5.5m (meters), it is recommended to use an anchor cable 7 with a diameter of φ21.8mm (millimeter) and a length of L=8m, and the spacing between the rows is set to 1m.

[0061] Assuming that the loose zone of the surrounding rock is within the range of 7~7.5m, it is recommended to use an anchor cable with a diameter of φ28.6mm and a length of L=10m, with a spacing of 0.8m.

[0062] In one embodiment of the present application, the initial support structure 1 includes: a lining concrete layer covering the inner wall of the tunnel and a support arch frame in the lining concrete layer. The support arch frame includes a plurality of longitudinal support frames arranged parallel to the extension direction of the tunnel, and the longitudinal arch frames are parallel to each other and are all arranged in the lining concrete layer. The longitudinal installation loop is interspersed between adjacent longitudinal arch frames, so that the steel belt 4 installed along the longitudinal installation loop is also interspersed between adjacent longitudinal arch frames.

[0063] The supporting arch frame also includes a plurality of transverse support frames arranged perpendicular to the extension direction of the tunnel, the transverse support frames are arranged in parallel, and are all arranged in a lining concrete layer. The transverse installation loop is interspersed between adjacent transverse arch frames, so that the steel belt 4 installed along the transverse installation loop is also interspersed between adjacent transverse arch frames.

[0064] Among them, the specific setting method and setting structure of the initial support structure 1 can refer to the existing technology, and will not be elaborated in this article.

[0065] In one embodiment of the present application, the prestressed anchor cable support system for a soft rock tunnel further includes a secondary lining concrete layer 10, and the secondary lining concrete layer 10 covers a side of the steel belt support mesh 2 facing away from the tunnel.

[0066] After the prestressed anchor cable is implemented, only the exposed part of the anchor head needs to be cut off and then poured into the secondary lining concrete, which improves the construction progress. The specific setting method of the secondary lining concrete layer can refer to the existing technology and will not be expanded in this article.

[0067] In one embodiment of the present application, an arch line C is provided in the tunnel, the portion of the initial support structure 1 located above the arch line is the arch section, and the portion below the arch line is the side wall section. Prestressed anchor cable holes are provided in the arch section, and the secondary lining concrete layer 10 covers the arch section and the side wall section. By setting the position range of the initial support structure 1, an optimized support effect is obtained.

[0068] An installation method of an anchor cable support system is applied to the above-mentioned prestressed anchor cable support system for a soft rock tunnel, and the installation method comprises:

[0069] Step S1: Install the initial support structure 1 on the inner wall of the tunnel, and mark the prestressed anchor points on the inner wall of the initial support structure 1.

[0070] Specifically, a lining concrete layer of the initial support structure 1 is formed by spraying the initial support concrete on the inner wall of the tunnel, and then the positions are laid out according to the prestressed anchor points, and the positions are marked with a distinctively colored paint.

[0071] Among them, the layout operation of the prestressed anchor points can refer to the existing technology and be changed according to actual needs, which will not be elaborated in this article.

[0072] Step S2: drilling holes at the prestressed anchor points to generate prestressed anchor holes, and fixing the positioning ends of the anchor cables 7 inside the prestressed anchor holes.

[0073] Drill holes at the markings of the prestressed anchor points. For the top arch above the arch line C, use the MQTB-80 / 2.4 pneumatic leg anchor drill to drill holes. For the side wall below the arch line C, use the YT-28 pneumatic leg drill to drill holes. The drilling direction should be perpendicular to the rock surface, and the drilling depth should meet the design requirements of applying anchor prestress and the exposed length of the anchor 7 after installation within 15 to 25 cm. In addition, an I-beam is set inside the initial support structure 1, and the prestressed anchor hole is arranged between two I-beams.

[0074] Step S3: assembling the steel belt 4 along the transverse installation loop and the longitudinal installation loop, and assembling the steel belt 4 with the anchor cable 7 at the same time, until the steel belt support net 2 is formed.

[0075] Specifically, the steel belts 4 continuously assembled on the transverse installation loop and the steel belts 4 continuously assembled on the longitudinal installation loop are assembled to form a mesh, and the pressure of the initial support structure 1 is evenly borne by the steel belt support net 2.

[0076] Step S4: Assemble the anchor plate 8 and the anchor 9 onto the anchor cable 7, and tension the free end of the anchor cable 7.

[0077] The steel belt 4, anchor pad 8 and anchor 9 are installed in sequence along the transverse installation loop and the longitudinal installation loop. After the installation of the above structure is completed, the MQ22-500 / 63 pneumatic anchor cable tensioning machine is used to apply prestress to the anchor cable. The anchor cable is tensioned in place at one time. The stroke of the tensioning jack does not exceed 10 cm each time, and the maximum stroke is 12 cm. The tensioning force of the anchor cable is not less than 250KN. The actual elongation value and tensioning force of the anchor cable are recorded during the tensioning process.

[0078] In one embodiment of the present application, for step S2: drilling a hole at a prestressed anchor point to generate a prestressed anchor hole, fixing the positioning end of the anchor 7 inside the prestressed anchor hole, specifically including: after using an anchor drilling rig to generate a prestressed anchor hole, use a PE pipe to slowly push 2 sections of resin anchor along the borehole wall to the bottom of the prestressed anchor hole, after the anchor is pushed in and positioned, manually push the positioning end of the anchor into the bottom of the hole at a steady and uniform speed, use a handheld MQTB-80 / 2.4 pneumatic outrigger anchor drilling rig to rotate and stir the resin anchor at high speed, and control the stirring time to about 40s. Wait for 15 minutes before installing the steel belt 4, anchor plate 8, and anchor 9 in turn.

[0079] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A prestressed anchor cable support system for soft rock tunnels, characterized in that: include: The initial support structure is used to cover the inner wall of the tunnel and is provided with several prestressed anchor cable holes; A steel belt support net, covering the inner wall of the initial support structure, used to bear the pressure of the initial support structure, and the steel belt support net is provided with a plurality of anchor cable installation holes corresponding to the prestressed anchor cable holes; An anchoring system is installed on the steel belt support net corresponding to the anchor cable installation holes, and the connecting parts of the anchoring system pass through the anchor cable installation holes to the inside of the prestressed anchor cable holes, so as to lock the steel belt support net to the inner wall of the initial support structure.

2. The soft rock tunnel prestressed anchor cable support system according to claim 1 is characterized in that: The tunnel has a plurality of mutually parallel transverse sections, and the transverse sections are arranged perpendicular to the extension direction of the tunnel; a plurality of transverse installation loops are arranged correspondingly at positions where the inner wall of the initial support structure intersects with the plurality of transverse sections; The tunnel has a plurality of longitudinal sections parallel to each other, and the extension direction of the longitudinal sections is parallel to the extension direction of the tunnel; a plurality of longitudinal installation loops are correspondingly arranged at positions where the inner wall of the initial support structure intersects with the plurality of longitudinal sections; The prestressed anchor cable hole is arranged at the intersection of the transverse installation loop line and the longitudinal installation loop line; The steel belt support net is covered on the transverse installation loop and the longitudinal installation loop, and the steel belt support net includes: a plurality of steel belts continuously assembled along the transverse installation loop and the longitudinal installation loop, and the ends of the steel belts cover each other; the anchor cable installation holes are opened at the ends of the steel belts that cover each other, so that the two anchor cable installation holes located at the ends of the steel belts are in a matching state; The connecting piece of the anchoring system passes through the two anchor cable installation holes in a matched state to the prestressed anchor cable hole, so as to lock the two adjacent steel belts to the inner wall of the initial support structure.

3. The soft rock tunnel prestressed anchor cable support system according to claim 2 is characterized in that: The two ends of the steel belt are respectively arranged as a round hole end and a line hole end; the anchor cable installation hole is provided as a round hole at the round hole end, and the anchor cable installation hole is provided as a line hole along the length direction of the steel belt at the line hole end; The circular hole end of the steel belt located on the same horizontal installation loop covers the wire hole end of the adjacent steel belt; the circular hole end of the steel belt located on the same longitudinal installation loop covers the wire hole end of the adjacent steel belt.

4. The soft rock tunnel prestressed anchor cable support system according to claim 2, characterized in that: The connecting member of the anchoring system is configured as an anchor cable, and the anchoring system further comprises an anchor pad and an anchor; The positioning end of the anchor cable passes through the anchor cable installation hole to the inside of the prestressed anchor cable hole, and the positioning end of the anchor cable is fixed inside the prestressed anchor cable hole; The free end of the anchor cable is in a tensioned state relative to the positioning end of the anchor cable, the anchor pad is arranged between the positioning end and the free end of the anchor cable, and the anchor pad is pressed on the surface of the steel belt support net away from the initial support structure; The anchor squeezes the side of the anchor plate away from the steel belt support net from the free end of the anchor cable to the positioning end.

5. The soft rock tunnel prestressed anchor cable support system according to claim 3 is characterized in that: The width of the linear hole is equal to the diameter of the circular hole.

6. The soft rock tunnel prestressed anchor cable support system according to claim 2, characterized in that: The initial support structure comprises: a lining concrete layer covering the inner wall of the tunnel and a support arch frame arranged in the lining concrete layer; the support arch frame comprises a plurality of longitudinal support frames arranged parallel to the extension direction of the tunnel, the longitudinal support frames are arranged parallel to each other, and the longitudinal installation loop is arranged between two adjacent longitudinal support frames; The supporting arch frame also includes a plurality of transverse supply frames arranged perpendicular to the extension direction of the tunnel, the transverse supply frames are arranged in parallel, and the transverse installation loop is arranged between two adjacent transverse supply frames.

7. The soft rock tunnel prestressed anchor cable support system according to claim 1, characterized in that: It also includes a second lining concrete layer covering the side of the steel belt support mesh facing away from the tunnel.

8. The soft rock tunnel prestressed anchor cable support system according to claim 7, characterized in that: An arch line is provided in the tunnel, the initial support structure above the arch line is provided as an arch crown section, and the initial support structure below the arch line is provided as a side wall section; the prestressed anchor cable hole is opened in the arch crown section, and the secondary lining concrete layer covers the arch crown section and the side wall section.

9. An installation method of an anchor cable support system, applied to the prestressed anchor cable support system for a soft rock tunnel as claimed in claim 5, characterized in that: Methods include: Installing the initial support structure on the inner wall of the tunnel, and marking the positions of prestressed anchor cables on the inner wall of the initial support structure; Drilling holes at the prestressed anchor point to form the prestressed anchor hole, and fixing the positioning end of the anchor inside the prestressed anchor hole; Assembling the steel belt along the transverse installation loop and the longitudinal installation loop, and assembling the steel belt with the anchor cable until the steel belt support net is formed; The anchor plate and the anchor are assembled onto the anchor cable, and the free end of the anchor cable is tensioned.

10. The method for installing the anchor cable support system according to claim 9, characterized in that: The method comprises drilling a hole at the prestressed anchor point to generate the prestressed anchor hole, and fixing the positioning end of the anchor inside the prestressed anchor hole, comprising: After the prestressed anchor cable hole is generated by an anchor drill, an anchoring agent is placed into the prestressed anchor cable hole.

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