CN117685024A - Presplitting anchor injection deformation control structure and presplitting anchor injection deformation control method for high-pressure rock drift tunneling - Google Patents

Abstract

The invention discloses a presplitting anchor grouting deformation control structure and method for high-pressure rock drift tunneling, comprising the following steps: the method combines roadway support reinforcement and roadway blasting pressure relief, promotes the pre-split rock zone simultaneously along with construction of a tunneling surface in the construction process, avoids influence of pre-split rock zone construction on support, and can secondarily reinforce the integrity and effectiveness of a roadway support system due to the design of the arch pit reinforcement grouting anchor cable.

Description

Presplitting anchor injection deformation control structure and presplitting anchor injection deformation control method for high-pressure rock drift tunneling

Technical Field

The invention relates to the field of mine engineering roadway support, in particular to a presplitting anchor grouting deformation control structure and method for high-pressure rock roadway tunneling.

Background

In the coal exploitation design under a mine, exploitation roadways and mining area roadways are generally arranged in harder rock bodies of upper and lower top plates of each layer, continuous exploitation of working faces of two wings of the mining area is carried out, the phenomena of bulge ledge and bottom bulge are easy to occur in the roadway with strong mining influence caused by goaf top plate breakage due to gradual reduction of the width of a protective coal pillar or gradual weakening of bearing capacity, the original roadway can be used only through repeated brushing, expanding, reinforcing and maintaining, the problem that bulge ledge and the like occur along with acquisition operation of the roadway is solved, one of the two most commonly adopted measures is to relieve the high stress concentration degree of surrounding rocks of the roadway in a pressure relief mode at present, and the other is to improve the anti-damage capability of the surrounding rocks of the roadway through reinforcing support.

Under the condition that a rock mass is harder, the explosion pressure relief effect is obvious and strong in adaptability, but the explosion fracturing damage effect can destroy the integrity of surrounding rock of the roadway, the performance of a supporting structure is weakened and even the supporting structure is disabled, the explosion pressure relief effect and the supporting reinforcement effect are contradictory and unified, how to realize the synergistic double effect of the explosion pressure relief effect and the supporting reinforcement effect is a very important research subject, and the patent of the invention of the grant publication number CN109630134B discloses a one-time roadway supporting method of a roadway structure and a high-ground stress soft rock roadway.

Disclosure of Invention

The invention aims to provide a presplitting anchor grouting deformation control structure and method for high-ground rock roadway tunneling, which can manufacture presplitting rock belts below a roadway while tunneling the roadway, save the bottom reinforcement measures of a conventional roadway, and the method for manufacturing the presplitting rock belts does not influence the construction efficiency and the construction quality of an anchoring system, and the tunnel reinforcement is performed by using arch pit reinforcement grouting anchor cables when the roadway is close to a digging area, so that the integrity and the stability of the anchoring system are further improved.

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a pre-split anchor deformation control structure and method for high-ground rock drivage, comprising:

the tunnel is penetrated in a rock body, two pre-split rock belts are symmetrically arranged on two sides below the tunnel, the pre-split rock belts are arranged along with the full length of the tunnel, the pre-split rock belts are rock body zones filled with broken stone and dense in cracks, a concrete wall protection layer and a concrete spraying anchor layer are sequentially arranged on the surface of the side wall of the tunnel, and a plurality of high-strength anchor rods, lower arch anchor cables, high-pressure grouting anchor cables and arch pit reinforcing grouting anchor cables are arranged perpendicular to the inner wall anchors of the tunnel and extend into the rock body.

Preferably, a plurality of high-strength anchor rods are arranged at intervals between two sides of the roadway and the vault of the roadway, one end of each high-strength anchor rod, which is positioned in a rock body, is anchored by a resin anchoring agent, one end of each high-strength anchor rod, which is positioned on the side wall of the roadway, is tensioned and fixed on a W steel guard plate, a plurality of lower arch anchor cables are all anchored at the vault part of the roadway and are arranged at intervals staggered with a plurality of high-strength anchor rods, which are arranged at the vault of the roadway, one end of each lower arch anchor cable, which is positioned in the rock body, is anchored by the resin anchoring agent, and one ends of a plurality of adjacent lower arch anchor cables, which are positioned on the side wall of the roadway, are tensioned together on an anchor cable steel belt, and the W steel guard plate and the anchor cable steel belt are tightly attached to the concrete guard wall layer and are buried in the concrete spraying anchor layer.

Preferably, each high-pressure grouting anchor cable adopts a hollow grouting anchor cable, one end of the high-pressure grouting anchor cable, which is positioned in the rock body, is anchored by a resin anchoring agent, one end of the high-pressure grouting anchor cable, which is positioned on the side wall of the roadway, is anchored on an anchor cable supporting plate, the middle part of the high-pressure grouting anchor cable is anchored by a cement material, the high-pressure grouting anchor cables are divided into a plurality of top high-pressure grouting anchor cables and a plurality of roadway side high-pressure grouting anchor cables, the top high-pressure grouting anchor cables are arranged on the vault of the roadway and are vertically and upwards anchored in the rock body, and the roadway side high-pressure grouting anchor cable is transversely anchored in the rock body from the roadway side.

Preferably, each arch pit reinforced grouting anchor rope adopts a hollow grouting anchor rope, each arch pit reinforced grouting anchor rope is arranged between two adjacent lower arch part anchor ropes at intervals, one end of each arch pit reinforced grouting anchor rope, which is positioned on the side wall of a roadway, is anchored on an anchor rope supporting plate, the other end of each arch pit reinforced grouting anchor rope is anchored by a resin anchoring agent, and the middle part of each arch pit reinforced grouting anchor rope is anchored by a cement material.

Preferably, the concrete spraying and anchoring layer comprises a reinforcing mesh, the reinforcing mesh is paved and fixed along the surface of the concrete retaining wall layer, and the diameter of a reinforcing bar adopted by the reinforcing mesh is more than or equal to 8mm.

Preferably, the construction method of the Gao Deya rock roadway tunneling pre-splitting anchor grouting deformation control structure comprises the following steps of:

s1, drilling a heading face blast hole on a heading face of a roadway in the forward tunneling process of the roadway, drilling a presplitting area advanced blast hole obliquely downwards at the bottom of a junction of the heading face and roadway sides on two sides of the roadway, burying explosive and a detonator in the heading face blast hole and the presplitting area advanced blast hole, blocking by stemming, and cleaning broken stone of the heading face after the explosive of the heading face and the explosive of the presplitting area are detonated simultaneously;

s2, spraying concrete on the inner wall of the newly opened roadway to form the concrete wall protection layer;

s3, after the concrete retaining wall layer is initially set, drilling holes by a tool, installing the high-strength anchor rods and the anchor cables at the lower arch parts, installing corresponding anchorage devices in place, and completing tensioning operation of the anchor rods and the anchor cables;

s4, paving the reinforced mesh on the surface of the concrete retaining wall layer, and then performing concrete spraying to form the concrete spraying anchor layer;

s5, repeating the steps S1-S4, when the distance from the tunneling surface to the tunneling surface is more than or equal to 30m, installing, anchoring and tensioning the high-pressure grouting anchor cable, and carrying out superfine cement high-pressure grouting by using grouting equipment;

s6, repeating the step S5, and installing and anchoring and tensioning the arch pit reinforced grouting anchor cable when the horizontal distance L between the tunnel and the mining surface of the mining area main tunnel is less than or equal to 50M; and performing ultra-fine cement high-pressure grouting on the arch pit reinforced grouting anchor cable by using grouting equipment.

Preferably, the length of the pre-splitting area advanced blasting hole is more than or equal to 2m, the pre-splitting area advanced blasting hole inclines towards the front of the tunneling surface, an included angle formed by the pre-splitting area advanced blasting hole and the tunneling surface is more than or equal to 5 degrees, the pre-splitting area advanced blasting hole inclines towards the lower part of the roadway bottom plate, and an included angle between the pre-splitting area advanced blasting hole and an outward extending line of the roadway bottom plate is more than or equal to 5 degrees.

Preferably, the pre-splitting area advanced blasting holes are sequentially arranged as blasting pressure relief sections and blasting hole sealing sections along the end head to the hole extension direction.

Preferably, the high-pressure grouting anchor cable and the arch pit reinforced grouting anchor cable need to perform high-pressure grouting operation regularly after grouting is completed.

The invention at least comprises the following beneficial effects:

firstly, in the tunneling process of the roadway, advanced pre-explosion is carried out in a pressure relief area below the roadway in advance, so that the injuries to an anchor rod, an anchor rope and the roadway are avoided when the roadway is relieved after the roadway is completed, and the pre-cracking rock zone generated after the explosion does not influence the construction and the work of an anchoring structure above the roadway.

Secondly, the construction of the anchor rod and the anchor cable is carried out after the advanced pre-cracking pressure relief, so that the anchor rod and the anchor cable are more in line with a roadway in which the stress is redistributed after the pressure relief, the anchor rod system effect is fully exerted, and the pre-cracking area can be better cooperated.

Thirdly, an anchor spraying-prestress high-pressure grouting anchor cable combined support type process is adopted, construction running water is formulated according to the distance between the anchor spraying-prestress high-pressure grouting anchor cable and a tunneling surface, construction progress is guaranteed, and meanwhile, the excellent effect of roadway support is guaranteed.

Fourth, the arrangement of the pre-splitting rock belt effectively avoids the occurrence of the bottom bulging, and the tunnel can omit measures such as a conventional steel bracket and the like, so that the cost is saved.

Fifth, the arch pit reinforced grouting anchor cable carries out secondary reinforced grouting, and the method can effectively fill the newly generated cracks between the rock mass above the tunnel arch pit and the anchoring system due to continuous tunneling of the mining surface.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 is an elevation view of a face and a leading blasthole in one aspect of the present invention; a plan view of a tunneling surface, a pre-splitting rock zone and an advanced blast hole;

FIG. 2 is a plan view of a face and pre-fractured zone and advanced blastholes in one aspect of the present invention;

FIG. 3 is a schematic view of an anchor rod and cable according to one embodiment of the present invention;

FIG. 4 is a cross-sectional view of a roadway and surrounding rock mass in one embodiment of the present invention;

FIG. 5 is a schematic plan view of a rock mass where a roadway is located in one embodiment of the present invention;

FIG. 6 is a schematic view of construction in a roadway according to one embodiment of the present invention;

FIG. 7 is an expanded view of a roadway dome in accordance with one embodiment of the present invention;

FIG. 8 is a side view of a roadway wall in an embodiment of the invention.

Detailed Description

The present invention is described in further detail below with reference to the drawings and detailed description so as to enable those skilled in the art to practice the invention by referring to the description.

It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

It should be noted that the experimental methods described in the following embodiments, unless otherwise specified, are all conventional methods, and the components and parts, unless otherwise specified, are all commercially available; in the description of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "mounted," "connected," and "disposed" are to be construed broadly, and may be fixedly connected, disposed, or detachably connected, disposed, or integrally connected, disposed, for example. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. The terms "transverse," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used for convenience in describing and simplifying the description of the present invention based on the orientation or positional relationship shown in the drawings, and do not denote or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the present invention.

As shown in fig. 1 to 8, the present invention provides a pre-splitting anchor deformation control structure for high-pressure rock drift tunneling, comprising:

two pre-split rock belts 2 are symmetrically arranged on two sides below the roadway 1, the pre-split rock belts 2 are arranged along with the through length of the roadway 1, the pre-split rock belts 2 are rock mass zones filled with broken stones and dense cracks, a concrete wall protection layer 6 and a net-hanging concrete anchor spraying layer 61 are sequentially arranged on the side wall surface of the roadway 1, a plurality of high-strength anchor rods 31, lower arch anchor cables 32, high-pressure grouting anchor cables 4 and arch pit reinforced grouting anchor cables 5 are arranged perpendicular to the inner wall anchor of the roadway 1 and extend into the rock mass, in the technical scheme, the section of the roadway 1 can be arched or rectangular, the pre-split rock belts 2 are continuous rock mass fragmentation and crushing areas formed by blasting and blasting simultaneously after blasting hole charges are obliquely drilled downwards at the junction of a tunneling face and two sides of the roadway 1 during roadway tunneling, the distance between the pre-split rock zone 2 and the roadway 1 is more than or equal to 2m, the concentrated tangential stress originally concentrated on the roadway sides and the roadway bottoms at the two sides of the roadway 1 is transferred to the outside of the pre-split rock zone 2 by the pre-split rock zone 2, the roadway side rock columns become self-supporting rock rings, the bottom plate of the roadway 1 does not need to be additionally reinforced or manually cleaned in the future, the number and the size of the pre-split rock zones 2 are required to be initially designed according to the mechanical characteristics of the rock mass 10 and the roadway 1, the high-strength anchor rods 31 and the anchor cables 32 at the lower arch part adopt resin anchoring agents for end anchoring, the requirement of primary support strength is met, the peripheral rock mass 10 is inevitably disturbed in the tunneling process of the roadway 1 and the reinforcing process of the roadway 1, the grouting materials injected at the subsequent high pressure make the rock mass 10 outside the roadway 1 become a surrounding rock-grouting material combination in fact, the integrity of the anchoring system of the roadway 1 is further improved, and the failure probability of the anchor rods and the anchor cables is reduced.

In the technical scheme, when a large mining area roadway is continuously adjacent to a roadway 1, as the pre-cracked rock belts 2 are arranged on two sides below the roadway 1, the deformation speed of the whole roadway 1 is far lower than that of the roadway 1 which is not reinforced by a simple steel frame or is reinforced by a simple steel frame, when the distance L between the mining surface of the large mining area roadway 7 and the roadway 1 is smaller than a certain degree, in order to reinforce the influence of the original anchoring system, the arch pit reinforced grouting anchor cable 5 is constructed, high-pressure grouting is carried out, so that the anchoring system is further reinforced and fills up cracks which possibly newly occur between the rock body 10 above the arch pit of the roadway 1 and the anchoring system.

In another technical scheme, a plurality of high-strength anchor rods 31 are arranged at two sides of the roadway 1 and at intervals of the vault of the roadway 1, one end of each high-strength anchor rod 31, which is positioned in a rock body 10, is anchored by a resin anchoring agent, one end of the side wall of the roadway 1 is tensioned and fixed on a W steel guard plate 310, a plurality of lower arch anchor cables 32 are anchored at the vault of the roadway 1 and are arranged at intervals of staggered arrangement with the plurality of high-strength anchor rods 31, which are arranged at intervals of the vault of the roadway 1, one end of each lower arch anchor cable 32, which is positioned in the rock body, is anchored by the resin anchoring agent, one end of each lower arch anchor cable 32, which is positioned in the side wall of the roadway, is jointly tensioned on an anchor cable steel belt 320, the W steel guard plate 310 and the anchor cable steel belt 320 are tightly attached to the concrete retaining wall layer 6 and are buried in the concrete retaining layer 61, the high-strength anchor rods 31 and the lower arch anchor cables 32 are simultaneously constructed along with the roadway 1, firstly, holes are drilled at corresponding positions from the roadway 1 to the surrounding rock body 10 and are placed by the resin anchoring agent, the corresponding high-strength anchor rods 31 and the lower arch anchor cables 32 are respectively placed on the steel guard plates, the corresponding high-strength anchor rods 32 and the corresponding anchor cables are fixedly secured by the W guard plates by the steel belts 320.

In another technical scheme, each high-pressure grouting anchor cable 4 is a hollow grouting anchor cable, one end of each high-pressure grouting anchor cable 4, which is located in the rock body 10, is anchored by a resin anchoring agent, one end of each high-pressure grouting anchor cable 4, which is located on the side wall of the roadway 1, is anchored on an anchor cable supporting plate, the middle part of each high-pressure grouting anchor cable 4 is anchored by a cement material, the high-pressure grouting anchor cables 4 are divided into a plurality of top high-pressure grouting anchor cables 41 and a plurality of roadway side high-pressure grouting anchor cables 42, the top high-pressure grouting anchor cables 41 are arranged on the vault of the roadway 1 and are anchored in the rock body 10 vertically upwards, and the roadway side high-pressure grouting anchor cables 42 are transversely anchored in the rock body 10 from the side.

In another technical scheme, each arch pit reinforcement grouting anchor rope 5 is a hollow grouting anchor rope, each arch pit reinforcement grouting anchor rope 5 is arranged between two adjacent lower arch part anchor ropes 32 at intervals, one end of each arch pit reinforcement grouting anchor rope 5 positioned on the side wall of a roadway 1 is anchored on an anchor rope supporting plate, the other end of each arch pit reinforcement grouting anchor rope 5 is anchored by a resin anchoring agent, the middle part of each arch pit reinforcement grouting anchor rope 5 is anchored by a cement material, the arch pit reinforcement grouting anchor ropes 5 are uniformly distributed, and when the mining surface of a mining area main roadway 7 is close to the mining surface, the high-pressure grouting process adopted by each arch pit reinforcement grouting anchor rope 5 can effectively fill extra cracks of rock bodies 10 on two sides of the arch of the roadway 1 due to stress variation.

In another technical scheme, the concrete spraying and anchoring layer 61 comprises a reinforcing mesh 610, the reinforcing mesh 610 is paved and fixed along the surface of the concrete retaining wall layer 6, the diameter of reinforcing bars adopted by the reinforcing mesh 610 is more than or equal to 8mm, and the reinforcing mesh 610 is tightly spaced so that the concrete spraying and anchoring layer 61 can well protect the inner wall of the roadway 1, and rock burst of the roadway 1 is effectively avoided.

In another technical scheme, the construction method of the Gao Deya rock roadway tunneling pre-splitting anchor grouting deformation control structure comprises the following steps of:

s1, drilling a tunneling surface blasting hole 110 on a tunneling surface of a roadway 1 in the forward tunneling process of the roadway 1, drilling a pre-splitting area advanced blasting hole 20 obliquely downwards at the bottom of the junction of the tunneling surface 11 and roadway sides on two sides of the roadway 1, burying explosive and detonator in the tunneling surface blasting hole 110 and the pre-splitting area advanced blasting hole 20, blocking by stemming, and cleaning broken stone of the tunneling surface 11 after the explosive of the tunneling surface 11 and the explosive of the pre-splitting area are detonated simultaneously;

s2, spraying concrete on the inner wall of the newly opened roadway 1 to form a concrete wall protection layer 6;

s3, after the concrete retaining wall layer 6 is initially set, drilling holes by a tool, installing the high-strength anchor rods 31 and the anchor cables 32 at the lower arch parts, installing corresponding anchorage devices in place, and completing tensioning operation of the anchor rods and the anchor cables;

s4, paving the reinforcement mesh 610 on the surface of the concrete retaining wall layer 6, and then performing concrete spraying to form the concrete spraying anchor layer 61;

s5, repeating the steps S1-S4, when the distance from the tunneling surface 1 to be more than or equal to 30m, installing, anchoring and tensioning the high-pressure grouting anchor cable 4, and carrying out superfine cement high-pressure grouting by using grouting equipment;

s6, repeating the step S5, and installing and anchoring and tensioning the arch pit reinforced grouting anchor cable 5 when the horizontal distance L between the roadway 1 and the mining surface of the mining area main roadway 7 is less than or equal to 50M; and ultra-fine cement high-pressure grouting is carried out on the arch pit reinforced grouting anchor cable 5 by grouting equipment.

In the technical scheme, the strength labels of the sprayed concrete adopted by the concrete retaining wall layer 6 and the concrete spraying anchor layer 61 are not less than C30, the initial setting time is not more than 30min, specifically, in the step S2, corresponding anchor holes are formed in the rock mass 10 by utilizing a drilling machine and hole cleaning operation is carried out, then, the anchor cable or the end part of the anchor rod is used for propping up a resin anchoring agent cartridge into the anchor holes, the resin anchoring agent is rotationally stirred to a proper time by utilizing a stirrer to fix one end of the anchor cable or the anchor rod, which is positioned in the roadway 1, and finally, corresponding anchors are installed in the roadway 1 and the anchor cable is tensioned to the designed pretightening force by utilizing tensioning equipment. In step S5, specifically, the high-pressure grouting anchor cable 4 needs an additional grouting machine, and because the high-pressure grouting anchor cable 4 is used as a full-anchoring anchor cable to further strengthen the original anchoring system, another purpose is to fill the cracks in the rock body 10 with cement slurry, so that a distance of more than 30m from the driving face 1 is needed to ensure normal expansion of the on-site working face and the formation of a 'surrounding rock-grouting material combination' after grouting is not influenced by the driving work of the roadway 1, thereby ensuring the working effect of the anchoring system and greatly reducing the failure probability.

In another technical scheme, the length of the pre-splitting area advanced blasting holes 20 is more than or equal to 2m, the pre-splitting area advanced blasting holes 20 incline towards the front of the tunneling surface 1, an included angle formed by the pre-splitting area advanced blasting holes 20 and the tunneling surface 1 is more than or equal to 5 degrees, the pre-splitting area advanced blasting holes 20 incline towards the lower part of the bottom plate of the roadway 1, an included angle between the pre-splitting area advanced blasting holes 20 and the outward extending line of the bottom plate of the roadway 1 is more than or equal to 5 degrees, and the pre-splitting area advanced blasting holes 20 are required to be arranged and drilled at intervals strictly according to the design position of the pre-splitting rock zone 2.

In another technical scheme, the pre-splitting area advanced blasting hole 20 extends into the hole along the end head to be sequentially provided with a blasting pressure relief section 201 and a blasting hole sealing section 202, emulsion explosive and a detonator are filled in the blasting pressure relief section 201, then stemming is filled in the blasting hole sealing section 202, the emulsion explosive in the blasting pressure relief section 201 is detonated by the detonator, surrounding rock mass of the blasting pressure relief section 201 is crushed, surrounding cracks of a crushed rock mass area are dense, and the pre-splitting rock belt 2 is extended and prolonged.

In another technical scheme, the high-pressure grouting anchor cable 4 and the arch pit reinforced grouting anchor cable 5 need to perform high-pressure grouting operation regularly after grouting is completed.

The following are specific field examples:

specific examples are as follows:

according to the technical scheme, the underground mine Lu Ximou is subjected to field investigation under the mine, the large-area roof concrete spraying layer extrusion crushing of a part of the roadway is seriously influenced by the dynamic pressure of the coal face, the roof anchor rods and the anchor cables of the arch shoulder part of the lower wall are broken at multiple positions, the maximum displacement of the two sides of the roadway can reach 1500mm, the bulge of the roadway wall is seriously crushed, the bottom plate of the roadway presents bottom bulge deformation of different degrees, the maximum bottom bulge is 800mm, and the part of the roadway has to be overhauled for more than three times before the mining influence is caused, so that the normal connection of mining production of the mine is influenced, and the potential safety hazard is greatly caused.

The new open-1180 rock centralized transportation roadway adopts a straight wall semi-circular arch section, belongs to an all-rock roadway, has a tunneling width of 4.9m, a tunneling arch height of 3.95m and a tunneling wool section area of 16.77 square meters, adopts a presplitting anchor injection deformation control method, and aims to meet the requirements of ventilation, pedestrians, transportation and pipeline laying in a mine coal mining area.

The detailed parameters of the pre-splitting anchor grouting deformation control structure for the centralized rock transportation roadway tunneling are as follows:

1. blasting pressure relief

The aperture of the pressure relief hole is 42mm, the hole depth is 3000mm, the hole spacing is 1300mm, the pressure relief hole is inclined by 5 degrees towards the front of the tunneling surface, the pressure relief hole is inclined by 10 degrees downwards towards the horizontal plane, and 2KG rock emulsion explosive is filled in the pressure relief hole.

2. Supporting body along with tunneling surface

(1) High-strength anchor rod

Stock material specification: the special anchor rod for the left-handed non-longitudinal rib screw steel bar with the steel number of CRMG700 has the diameter phi 22mm, the length of 2.4M, the yield force of not less than 266kN, the ultimate breaking force of not less than 323kN, the elongation after breaking of not less than 17%, the impact absorption work of not less than 100J, the tail screw thread specification of M24 and the screw thread length of 150mm, and is formed by adopting a thread rolling process.

Stock layer board specification: 150X 10mm arch high strength layer board, steel brand Q235, high strength nut, high strength ball pad and antifriction nylon washer, and mechanical performance is matched with the anchor rod body, and bearing capacity is not lower than 346kN.

Anchor rod arrangement: the row spacing among the anchor rods is 900 multiplied by 900mm, and each row is 12; the pre-tightening moment of the anchor rod is required to reach 400 N.m, and can not exceed 600 N.m. The anchoring mode is as follows: the resin is lengthened and anchored, the diameter of a drilled hole is 30mm, one MSK2835 and one MSZ2860 resin anchoring agent are adopted, and the anchoring length is 1207mm. The anchor rods are all arranged vertically on the rock wall, and 5-degree errors are allowed in consideration of construction requirements.

W steel guard plate specification: adopting a W steel guard board to protect the surface, and adopting four-rib guard board specifications: thickness 8mm, width 280mm, length 330mm. Rock formation conditions allow the use of large pallets.

(2) Anchor cable support with lower arch part

Anchor cable form and specification: the anchor cable material is 21.8mm,1×19 high-strength low-relaxation prestressed steel strands, and the length is 6300mm. The diameter of the drilled hole is 32mm, three MSK2850 resin anchoring agents are adopted, and the anchoring length is 1470mm.

And (3) anchor cable arrangement: every 3 anchor cables are arranged on the top plate of the lower arch part, the row distance of the anchor cables is 1800mm, the distance is 1200/800mm, and the anchor cables are arranged perpendicular to the rock surface of the roadway. The initial tension pre-tightening force of the anchor cable design is 250kN.

The anchor cables are connected by adopting a high-strength three-hole T-shaped steel belt with the thickness of 2000mm multiplied by 180mm multiplied by 10mm, a matched backing plate and an anchor, the anchor cable at the lower arch part is timely constructed and supported along with a tunneling surface, and 3 anchor cables are matched with one high-rigidity T-shaped steel belt.

After the high-strength anchor rod and the anchor cable of the lower arch part are supported, the shotcrete construction of the surface of the roadway is intensively carried out, the thickness of a concrete spraying layer is not less than 70mm, and the surrounding rock and the anchor cable of the anchor rod are sealed in a full section.

3. High-pressure grouting anchor cable

The high-pressure grouting anchor cable is delayed by 30m from a tunneling surface to start construction grouting, and comprises 3 grouting anchor cables of a top high-pressure grouting anchor cable and two high-pressure grouting anchor cables, wherein one-shift concentrated high-pressure grouting is arranged every week.

(1) Top high-pressure grouting anchor cable

The high-pressure grouting anchor cable is subjected to lagging head-on 30m follow-up construction. Grouting anchor cables and common anchor cables are alternately arranged in a row. Anchor cable form and specification: the anchor cable material is hollow grouting anchor cable of phi 22mm and SKZ22-1/1860-5300, 1X 8 high-strength low-relaxation prestress steel strand, length 5300mm and drilling diameter phi 36mm.

The anchoring mode and the specification of the anchor cable supporting plate are the same as those of the common steel strand anchor cable. The number of anchoring agents in the holes is not more than 2.

And (3) anchor cable arrangement: 1 anchor cable is arranged in the middle of the top plate, the row distance of the anchor cable is 1800mm, and the anchor cable is arranged vertically to the rock face. The initial tension pre-tightening force of the anchor cable design is 200kN. The rubber sleeve and the hard plastic pipe are sleeved before tensioning, and the rubber sleeve expands and the hole wall is extruded to seal the hole after tensioning.

(2) Two-side high-pressure grouting anchor cable

Anchor cable form and specification: the type, the anchoring mode and the specification of the anchor cable supporting plate are the same as those of the top high-pressure grouting anchor cable.

And (3) anchor cable arrangement: each row of each side is provided with 1 anchor cable, the row distance of the anchor cable is 1800mm, the position of the anchor cable is 1000mm away from the bottom plate, and the vertical lane sides are arranged. The anchor cable design pretightening force: the initial tension pre-tension is 300kN.

The grouting material adopts superfine cement material to perform concentrated high-pressure grouting, the water-cement ratio is 0.6, and the grouting termination pressure is 8MPa

4. Arch pit reinforced grouting anchor cable

When the stope face is 50m horizontally away from the roadway, the arch pit reinforced grouting anchor cable is constructed, and concentrated high-pressure grouting is arranged every week.

Anchor cable form and specification: the type, the anchoring mode and the specification of the anchor cable supporting plate are the same as those of the top high-pressure grouting anchor cable.

And (3) anchor cable arrangement: each row of the upper arch pit and the lower arch pit is 1, and the row distance of the anchor cable is 1800mm

The grouting material adopts superfine cement material to perform concentrated high-pressure grouting, the water-cement ratio is 0.6, and the grouting termination pressure is 8MPa

5. Concrete spray layer

Mesh specification: the diamond metal net protection table is woven by 8# iron wires, the mesh specification is 50 multiplied by 50mm, and the length and width of the net sheet are 5000 multiplied by 1000mm respectively. Each row of 2 tablets.

Concrete specification: the thickness of the concrete spray layer is 70mm, the strength of the concrete is not lower than C30 (water: cement: sand: stone=1:2:5:3), the proportion of the quick setting water reducing additive for grouting is 5%, the surrounding rock is sealed on the whole section, and the exposed corrosion of the anchor rod and anchor cable reinforcing mesh is prevented.

Although embodiments of the present invention have been disclosed above, it is not limited to the details and embodiments shown and described, it is well suited to various fields of use for which the invention would be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.

Claims (9)

1. Presplitting anchor note deformation control structure of high-pressure rock drift is tunnelled, and is characterized in that includes:

the tunnel is penetrated in a rock body, two pre-split rock belts are symmetrically arranged on two sides below the tunnel, the pre-split rock belts are arranged along with the full length of the tunnel, the pre-split rock belts are rock body zones filled with broken stone and dense in cracks, a concrete wall protection layer and a concrete spraying anchor layer are sequentially arranged on the surface of the side wall of the tunnel, and a plurality of high-strength anchor rods, lower arch anchor cables, high-pressure grouting anchor cables and arch pit reinforcing grouting anchor cables are arranged perpendicular to the inner wall anchors of the tunnel and extend into the rock body.

2. The presplitting anchorage deformation control structure for high-pressure rock roadway tunneling according to claim 1, wherein a plurality of high-strength anchors are arranged at two sides of the roadway and at intervals of the vault of the roadway, one end of each high-strength anchor in the rock is anchored by a resin anchoring agent, one end of each high-strength anchor in the side wall of the roadway is tensioned and fixed on a W-shaped steel guard plate, a plurality of lower arch anchor cables are anchored at the vault part of the roadway and are arranged at intervals of the staggered arrangement of the plurality of high-strength anchors at the vault of the roadway, one end of each lower arch anchor cable in the rock is anchored by the resin anchoring agent, one end of each lower arch anchor cable in the side wall of the roadway is tensioned together by a cable steel belt, and the W-shaped steel guard plate and the cable steel belt are clung to the concrete retaining wall layer and are buried in the concrete spraying anchor layer.

3. The presplitting anchor grouting deformation control structure for high-pressure rock drivage according to claim 2, wherein each high-pressure grouting anchor cable is a hollow grouting anchor cable, one end of the high-pressure grouting anchor cable located in the rock body is anchored by a resin anchoring agent, one end of the high-pressure grouting anchor cable located on the side wall of the roadway is anchored on an anchor cable supporting plate, the middle part of the high-pressure grouting anchor cable is anchored by a cement material, the high-pressure grouting anchor cables are divided into a plurality of top high-pressure grouting anchor cables and a plurality of roadway wall high-pressure grouting anchor cables, the top high-pressure grouting anchor cables are arranged on the vault of the roadway and vertically anchored in the rock body, and the roadway wall high-pressure grouting anchor cables are transversely anchored in the rock body from roadway sides.

4. A presplitting anchor grouting deformation control structure for high-pressure rock drivage according to claim 3, wherein each arch pit reinforcement grouting anchor rope adopts a hollow grouting anchor rope, each arch pit reinforcement grouting anchor rope is arranged between two adjacent arch part anchor ropes at intervals, one end of each arch pit reinforcement grouting anchor rope, which is positioned on the side wall of a roadway, is anchored on an anchor rope supporting plate, the other end of each arch pit reinforcement grouting anchor rope is anchored by a resin anchoring agent, and the middle part of each arch pit reinforcement grouting anchor rope is anchored by a cement material.

5. The pre-split anchor grouting deformation control structure for high-pressure rock drivage according to claim 4, wherein the concrete anchor spraying layer comprises a steel bar net sheet, the steel bar net sheet is paved and fixed along the surface of the concrete retaining wall layer, and the diameter of steel bars adopted by the steel bar net sheet is not less than 8mm.

6. A construction method of a presplitting anchor grouting deformation control structure based on high-pressure rock drivage according to any one of claims 1 to 5, characterized by comprising the following steps:

s1, drilling a heading face blast hole on a heading face of a roadway in the forward tunneling process of the roadway, drilling a presplitting area advanced blast hole obliquely downwards at the bottom of a junction of the heading face and roadway sides on two sides of the roadway, burying explosive and a detonator in the heading face blast hole and the presplitting area advanced blast hole, blocking by stemming, and cleaning broken stone of the heading face after the explosive of the heading face and the explosive of the presplitting area are detonated simultaneously;

s2, spraying concrete on the inner wall of the newly opened roadway to form the concrete wall protection layer;

s3, after the concrete retaining wall layer is initially set, drilling holes by a tool, installing the high-strength anchor rods and the anchor cables at the lower arch parts, installing corresponding anchorage devices in place, and completing tensioning operation of the anchor rods and the anchor cables;

s4, paving the reinforced mesh on the surface of the concrete retaining wall layer, and then performing concrete spraying to form the concrete spraying anchor layer;

s5, repeating the steps S1-S4, when the distance from the tunneling surface to the tunneling surface is more than or equal to 30m, installing, anchoring and tensioning the high-pressure grouting anchor cable, and carrying out superfine cement high-pressure grouting by using grouting equipment;

s6, repeating the step S5, and installing and anchoring and tensioning the arch pit reinforced grouting anchor cable when the horizontal distance L between the tunnel and the mining surface of the mining area main tunnel is less than or equal to 50M; and performing ultra-fine cement high-pressure grouting on the arch pit reinforced grouting anchor cable by using grouting equipment.

7. The construction method according to claim 6, wherein the length of the pre-splitting area advanced blast hole is more than or equal to 2m, the pre-splitting area advanced blast hole is inclined towards the front of the tunneling surface, the included angle formed by the pre-splitting area advanced blast hole and the tunneling surface is more than or equal to 5 degrees, the pre-splitting area advanced blast hole is inclined towards the lower part of the roadway bottom plate, and the included angle between the pre-splitting area advanced blast hole and the outward extending line of the roadway bottom plate is more than or equal to 5 degrees.

8. The construction method according to claim 7, wherein the pre-splitting area is provided with a blasting pressure relief section and a blasting hole sealing section in sequence along the extension of the end head into the hole.

9. The construction method of claim 8, wherein the high-pressure grouting anchor cable and the arch pit reinforced grouting anchor cable are subjected to high-pressure grouting operation periodically after grouting is completed.