CN114753864A - Coal mine floor heave roadway side-control bottom-locking long and short anchor cable and composite grouting combined reinforcement method - Google Patents
Coal mine floor heave roadway side-control bottom-locking long and short anchor cable and composite grouting combined reinforcement method Download PDFInfo
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- CN114753864A CN114753864A CN202210421087.4A CN202210421087A CN114753864A CN 114753864 A CN114753864 A CN 114753864A CN 202210421087 A CN202210421087 A CN 202210421087A CN 114753864 A CN114753864 A CN 114753864A
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- grouting
- anchor cable
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- bottom plate
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/105—Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/003—Machines for drilling anchor holes and setting anchor bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/021—Grouting with inorganic components, e.g. cement
Abstract
The invention discloses a coal mine bottom heave roadway side control bottom locking long and short anchor cable and a composite grouting combined reinforcing method, which comprises the following steps: the method comprises the following steps of carrying out pre-grouting on two sides and side control supporting of a prestressed anchor cable, carrying out composite grouting on a bottom plate, carrying out combined locking supporting of the anchor cable and a foundation anchor cable, and simultaneously hardening by spraying concrete on the two sides and the bottom plate; the anchor cables on the two sides are long and short prestress combined anchor cables, anchoring is carried out by adopting an anchoring agent, the anchor cables on the lower legs are prestress grouting anchor cables, the anchor cables on the vertical anchor cables on the bottom plate are prestress anchor cables, and anchoring is carried out by adopting cement-based slurry. Compared with the poor long-term pressure relief effect of the pressure relief hole of the bottom plate and the complex construction process and high cost of the steel arch support, the invention can be applied to the coal mine tunnel to realize filling of two sides of coal pillar cracks and improvement of the lithology of the bottom plate, has simple working procedures and convenient construction, can effectively prevent the bottom heave and the deformation of the two sides caused by crack development and stress by controlling the combined reinforcement of the side locking long and short prestressed anchor cables and the composite grouting, and ensures the integrity of the tunnel and the stability during service.
Description
Technical Field
The invention relates to the field of deformation control of floor heave of a coal mine tunnel, in particular to a long anchor cable for controlling side and locking floor of a coal mine floor heave tunnel and a composite grouting combined reinforcement method.
Background
Along with the increase of the mining depth, the coal mine tunnel is influenced by the ground stress and the mining pressure more strongly after the excavation is finished, meanwhile, the coal pillars on the two sides of the coal mine tunnel are smaller in strength, the coal bed is broken, the bedding surface develops, the mudstone on the bottom plate is soft rock with lower strength, the two sides of the tunnel and the bottom plate are seriously deformed and displaced under the influence of high stress, the tunnel section is reduced, and the transportation and the ventilation are seriously influenced. In addition, the surrounding rock deformation that the heaving floor tunnel appears has seriously influenced the normal use in tunnel, is unfavorable for tunnel overall stability, because tunnel heaving has changed the bearing structure of tunnel surrounding rock and has strutted the atress mode between the system for tunnel surrounding rock is changeed and is produced concentrated stress, has aggravated the tunnel deformation, and then is influencing staff's in the pit normal operation and personal safety.
At present, the main modes of coal mine roadway support comprise anchor rod (cable) reinforcement, grouting reinforcement, various pressure relief methods and passive support members such as a U-shaped steel shed and an I-shaped steel shed. The anchor rod (cable) support construction process is simple, the cost is low, and the anchor rod (cable) support construction method is a main roadway support means; after grouting and reinforcement, the hard rock stratum with higher strength is formed together with the original rock stratum, and can bear larger stress; the pressure relief method enables the surrounding rock of the roadway to be in the stress reduction area, so that the pressure bearing strength of the original rock stratum of the roadway is met; passive supporting members such as U-shaped steel sheds and I-shaped steel sheds are high in cost and complex in installation, and shed legs are difficult to maintain after being bent. In view of the fact that the pressure relief method is not suitable for long-term use of roadways, the application of passive supporting members is complicated and costly, and there is therefore a great need in the art for improved reinforcement methods.
Disclosure of Invention
The invention provides a coal mine heaving floor roadway side-control bottom-locking long and short anchor cable and a composite grouting combined reinforcing method, which can effectively control deformation of a coal mine heaving floor roadway, improve the overall stability of the roadway and ensure the normal use of the roadway. The method specifically adopts a long and short prestressed anchor cable and composite grouting combined support mode to simultaneously carry out side control and bottom locking support on the roadway. The problem to be considered in the anchor cable supporting process is whether a complete and stable rock stratum can be driven to realize the anchoring effect and the active supporting effect, so that the anchor cables on the two sides are anchored by using an anchoring agent, and pre-grouting on the two sides is required to realize reinforcement of the broken layers on the sides before the anchor cables are installed, so that the tensioning effect of the anchor cables is ensured; the bottom plate is influenced by construction technologies such as drilling, deslagging and the like, the anchor cable and the grouting pipe are simultaneously placed in the bottom plate drill hole by using the method of prestressed anchor cable grouting, the free section is wrapped by the sleeve, the end anchoring effect of the anchor cable is realized after full-length grouting, meanwhile, slurry enters a mudstone crack to reinforce the rock stratum, and the bottom locking effect on the bottom plate is also realized while the anchoring force of the anchor cable is ensured to be realized.
In order to solve the problems, the invention provides a coal mine floor heave roadway side control bottom locking long and short anchor cable and a composite grouting combined reinforcing method, which comprises the following steps: the method comprises the following steps of carrying out pre-grouting on two sides and side control supporting of a prestressed anchor cable, carrying out composite grouting on a bottom plate, carrying out combined locking supporting of the anchor cable and a foundation anchor cable, and simultaneously hardening by spraying concrete on the two sides and the bottom plate; the anchor cables on the two sides are long and short prestress combined anchor cables, anchoring is carried out by adopting an anchoring agent, the anchor cables on the lower legs are prestress grouting anchor cables, the anchor cables on the vertical anchor cables on the bottom plate are prestress anchor cables, and anchoring is carried out by adopting cement-based slurry.
The method comprises the following specific steps:
s1, pre-grouting on two sides of the roadway according to the arrangement mode of the pre-grouting holes;
s2, two sides of short prestressed anchor cables of the roadway are constructed by adopting an anchor cable trolley, anchoring agents are filled in the short prestressed anchor cables and are tensioned to the required pretightening force, two sides of long prestressed anchor cables are constructed after the construction of the regional short prestressed anchor cables is finished, and the anchoring agents are filled in the short prestressed anchor cables and are tensioned to the required pretightening force; the short prestressed anchor cables and the long prestressed anchor cables are arranged at intervals;
s3, spraying concrete on the cross sections of the roadways at the two sides by using a shotcrete machine;
s4, constructing prestressed anchor cable drill holes on the bottom plate by using a down-the-hole drill, wherein the anchor cable drill holes comprise anchor cable drill holes on two sides of the bottom plate and a bottom plate vertical anchor cable drill hole in the middle of the bottom plate; then, a grouting pipe and an anchor cable are jointly installed in the pre-stressed anchor cable drilling hole;
s5, installing a corrugated pipe or an external sleeve with the inner wall coated with a lubricant at the free section of the anchor cable corresponding to the drilled hole, performing full-length grouting and realizing end part anchoring to complete the support of the anchor cable and the vertical anchor cable of the bottom plate;
and S6, spraying concrete on the bottom plate for hardening.
Optionally, in step S1, the arrangement manner of the pre-grouting holes includes: the distance between the pre-grouting holes is 3000mm, the row distance is 1300-1500mm, the three flowers are sequentially arranged in 2-1-2 rows according to the vertical row number of the units, and the depth of the grouting holes is 6000 mm.
Optionally, in step S1, the pre-grouting process includes: and (3) implementing pre-grouting on a front anchor cable support working surface, wherein the advance distance is 50 m.
More preferably, the grouting process comprises: drilling a grouting hole by adopting a rock drill and forming a hole by using an anchor drilling machine; during grouting, a grouting pipe is arranged in the hole, wherein the length of the grouting pipe is 5000 mm; and during grouting, the whole length is subjected to one-time grouting construction.
Further, more preferably, the grouting process comprises: sealing holes by using a grout stop plug during grouting, wherein the sealing length is not less than 500mm, and the grouting termination pressure is 2-3 MPa; in the grouting construction process, the grouting pressure is ensured as much as possible, corresponding measures are taken when local slurry leakage occurs, and the grouting is stopped or re-injected after pressurized water is added; when the rock stratum of the orifice section is broken, the grouting pressure which cannot meet the requirement by adopting the grout stop plug is caused by the slurry leakage, and whether the grouting amount in the hole can reach 3m or not is judged by taking the grouting amount as a standard3And if the grouting amount can not meet the requirement, adopting a secondary grouting mode.
Further, the secondary grouting mode comprises: and drilling a grouting hole at a proper position around the grouting hole, simultaneously drilling two 5000mm long grouting pipes in the grouting hole, wherein the bottom of the secondary grouting pipe is blocked by using an adhesive tape or plastic, the primary grouting ensures that the hole is fully filled, secondary grouting is carried out after the grout is initially set, the grouting pressure is not less than 2MPa, and the hole sealing is carried out by using quick-setting concrete to replace a grout stop plug.
Optionally, in step S2, the anchor cable used in the anchor cable trolley is a mining prestressed anchor cable, and the tensile strength of the steel strand thereof is 1720MPa, where the length of the short prestressed anchor cable is 4300mm, and the length of the long prestressed anchor cable is 7400 mm.
Optionally, in step S2, the diameter of the anchor cable trolley installation drill bit is 30mm, the short prestressed anchor cable hole depth is 4000 ± 100mm, and the long prestressed anchor cable hole depth is 7100 ± 100 mm; the mounting row spacing (namely row spacing multiplied by spacing) of the short prestressed anchor cable is 1000mm multiplied by (900-1000) mm; the long prestressed anchor cables are arranged in units with the vertical row number of 2-1-2 in a three-flower arrangement, the row pitch of the anchor cable holes is 2000mm, and the pitch is 900-1000 mm; after the anchor cable is installed, an anchoring agent is adopted for anchoring the end part; and the tensioning pretightening force of the anchor cable after installation is more than 150 kN.
In the invention, the row pitch refers to the shortest distance between two adjacent holes or anchor cables in the holes in the horizontal direction, and the pitch refers to the shortest distance between two adjacent holes or anchor cables in the holes in the vertical direction.
Further, in step S3, after the anchor cable support is completed, spraying grout on the sections of the roadway at the two sides, wherein the spraying grout adopts C20 concrete slurry, and the thickness of the sprayed layer is 100mm, so as to realize water isolation and surface reinforcement of the two sides of the roadway.
Further, in step S4, drilling a hole in the pre-stressed anchor cable of the bottom plate by using a down-the-hole drill, wherein the diameter of the drilled hole in the pre-stressed anchor cable is 50mm, the depth of the drilled hole in the anchor cable is 7100 ± 100mm, and the depth of the drilled hole in the vertical anchor cable of the bottom plate is 6000 ± 100 mm; the row distance of the anchor cables is 1000mm, and each row of 2 anchor cables is respectively arranged at a position 250mm away from the two sides, and the angle is 45 degrees downwards; the vertical anchor cable row spacing of bottom plate is 1000mm, and the interval is 1000mm, and every row is four, realizes the lock end to the tunnel bottom plate.
Further, in step S4, the length of the grouting pipe is 5000 mm.
Further, in step S5, the anchor cable corresponding to the drilled hole has an anchor cable anchoring section, the anchor cable anchoring section length of the ground anchor is 2300mm, and the anchor cable anchoring section length of the vertical anchor cable of the bottom plate is 2000 mm.
After the bottom plate is drilled into a hole, the anchor cable is inserted, and meanwhile the aluminum-plastic grouting pipe is inserted into the drilled hole, wherein if hole collapse is serious during construction drilling, the aluminum-plastic pipe and the anchor cable are bound together to rotate the lower pipe.
Further, in step S5, the anchor cable free section is wrapped by a corrugated pipe (or an outer sleeve with an inner wall coated with a lubricant) to achieve an end anchoring effect, and the full length inside the drill hole is subjected to primary grouting construction, wherein the end anchoring adopts a hole sealing material which is a grout stop plug, the hole sealing length is not less than 500mm, and the grouting termination pressure is 2-3 MPa; in the grouting construction process, the grouting pressure is ensured as much as possible, corresponding measures are taken when local slurry leakage occurs, and the grouting is stopped or re-injected after pressurized water is added; when the rock stratum of the orifice section is broken, the grouting pressure which cannot meet the requirement by adopting the grout stop plug is caused by the slurry leakage, and whether the grouting amount in the hole can reach 3m or not is judged by taking the grouting amount as a standard3And if the grouting amount can not meet the requirement, adopting a secondary grouting mode.
Wherein, the secondary slip casting mode is as above, including: and drilling a grouting hole at a proper position around the grouting hole, simultaneously drilling two 5000mm long grouting pipes in the grouting hole, wherein the bottom of the secondary grouting pipe is blocked by using an adhesive tape or plastic, the primary grouting ensures that the hole is fully filled, secondary composite grouting is carried out after the grout is initially set, the grouting pressure is not less than 2MPa, and the hole sealing is carried out by using quick-setting concrete to replace a grout stopping plug.
Further, in step S6, after the anchor cables and the vertical anchor cables of the bottom plate are supported, spraying cement on the roadway bottom plate, wherein the spraying cement is C20 concrete slurry, and the thickness of the sprayed layer is 200mm, so that the roadway bottom plate is waterproof and hardened.
The technical scheme provided by the invention has the advantages and beneficial effects at least comprising:
the invention provides a scheme for organically combining grouting and anchoring on a bottom plate and two sides of a bottom heave roadway simultaneously. The bottom plate utilizes anchor rope drilling to realize slip casting, not only the effect that the grout has replaced the anchoring agent has been used but also the tip anchor effect has been realized at anchor rope free section sleeve pipe simultaneously, and bottom plate slip casting can effectively accomplish the holistic modified reinforcement of bottom plate weak rock stratum and reach the lock end effect to the tunnel bottom plate, guarantee bottom plate rock stratum bearing capacity and the vertical anchor rope tip anchor effect of bottom plate, the length combination anchor rope anchor effect has been guaranteed in implementation of two group pre-grouting simultaneously, realize that the packing of coal seam crack forms the higher whole coal seam of intensity, two groups that the measure of controlling group can better bear horizontal stress and bring warp.
According to the invention, grouting modification and anchoring combined support means are adopted for both the bottom plate and the two sides, the difference is that the bottom plate selects foundation anchor cables to realize bottom locking effect with vertical anchor cables, and the two sides adopt length combined anchor cables to realize anchoring effect, so that the construction is simple, the cost is lower, the effect is better, and compared with U-shaped steel sheds and I-shaped steel sheds which are high in cost, complex in installation and difficult to repair after deformation and pressure relief means which cannot guarantee long-term service property of the roadway, the effective support of the bottom plate and the two sides is realized on the premise of simplicity and high efficiency, and the long-term stability of the roadway and the safe and efficient mining of the coal mine are guaranteed.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow diagram of a combined reinforcing method for long and short anchor cables and composite grouting for controlling side and locking bottom of a coal mine bottom heave roadway according to an embodiment of the invention;
FIG. 2 is a schematic view of a two-sided pre-grouting arrangement of the present invention;
FIG. 3 is a cross-sectional view of the cable bolt support of the present invention;
fig. 4 is a schematic view of a bottom plate anchor cable and grouting combined supporting structure in the invention.
Wherein the reference numerals are: 1-roadway side part; 2-grouting holes; 3-coal mine roadway; 4-short prestressed anchorage cable; 5-long prestressed anchor cables; 6-anchor cables; 7-vertical anchor cable of bottom plate; 8-spraying concrete layers on two sides; 9-spraying concrete on the bottom plate; 10-a lock; 11-drilling a bottom plate; 12-grouting pipe; 13-anchor cable free section; 14-anchor cable anchorage section; 15-a bellows; 16-stop-grouting plug; 17-tray.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a coal mine roadway bottom plate and a two-side supporting method which are easy to operate, low in cost and good in supporting effect.
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description thereof.
The invention provides a coal mine floor bulging roadway side-control bottom-locking long and short anchor cable and a composite grouting combined reinforcing method aiming at the phenomena of instability and large displacement of a coal mine roadway floor and two sides. Specifically, as shown in fig. 1 to 4, the specific implementation flow of the method includes:
s1, after excavation or repair of a coal mine tunnel 3 is completed, the tunnel width is 5500mm, the tunnel height is 3500mm, according to a two-side pre-grouting arrangement mode shown in figure 2, grouting and drilling are carried out on the tunnel side part 1 on any one side of two sides of the tunnel into a three-flower arrangement, the two-flower arrangement is 2-1-2 arrangement, three rows of grouting holes 2 are arranged on each side, the row spacing is 3m, the spacing is 1.3m, the distance is 0.4m from a top plate and 0.5m from a bottom plate, a rock drill is used for drilling, the hole diameter is 42mm, all grouting pipes with buried holes are adopted, the length of the grouting pipes with holes is 800mm, the grouting pipes with holes is 5000mm below the holes, after the hole opening is completed, grouting construction is carried out once in the whole length, a grout stop plug is adopted for hole sealing, the hole sealing length is not less than 500mm, and the grouting termination pressure is 2-3 MPa.
When the rock stratum at the orifice section is broken, the grouting pressure which cannot meet the requirement by adopting the grout stop plug due to the slurry leakage is judged by taking the grouting amount as a standard whether the grouting amount in the hole can reach 3m3And if the grouting amount cannot meet the requirement, selecting a secondary grouting mode.
Specifically, the secondary grouting mode is that a grouting hole is drilled at a proper position within the range of 500mm in the grouting hole, two grouting pipes (with the length of 5000mm and the bottoms of the secondary grouting pipes are plugged by adhesive tapes or plastics) are simultaneously arranged in the grouting hole, primary grouting is carried out to ensure that the hole is full, secondary grouting is carried out after the grout is initially set, the grouting pressure is not less than 2MPa, and quick-setting concrete is used for replacing a grout stop plug to seal the hole.
And S2, after the two sides of the steel tube are pre-grouted, constructing the prestressed anchor cables on the two sides. As shown in fig. 3, the two anchor cable sets are installed as follows:
firstly, drilling a hole with a diameter of 30mm and a hole depth of 4000 +/-100 mm by using an anchor cable trolley for constructing a short prestressed anchor cable 4, then installing a mine anchor cable with the diameter of 22mm multiplied by 4300mm, adopting an MSK2335 and an MSZ2360 resin anchoring agent for anchoring the end part, applying a prestress of 150kN, wherein the row pitch of the anchor cables is 1000mm multiplied by 900mm, the anchor cable is provided with a 300 multiplied by 16mm arch-shaped high-strength anchor cable supporting plate, a centering ball pad is matched, a phi 6.5mm welding reinforcing mesh is laid in a matching way, the specification is 3000 multiplied by 1200mm, four sides are closed, and the mesh is 100 multiplied by 100 mm.
Secondly, after the construction of the short prestressed anchor cable 4 is finished, an anchor cable trolley is adopted to construct a long prestressed anchor cable 5 to be drilled, the hole diameter is 30mm, the hole depth is 7100 +/-100 mm, a mine anchor cable with the diameter of 22mm multiplied by 7400mm is installed, one MSK2335 and two MSZ2360 resin anchoring agents are adopted to anchor the end part, 150kN prestress is applied, the long prestressed anchor cables 5 are arranged in 2-1-2 rows and in three-flower arrangement, the row pitch of the anchor cable holes is 2000mm, the space is 900mm, an arch-shaped high-strength anchor cable supporting plate with the diameter of 300 multiplied by 16mm is used for the anchor cable, an aligning ball pad is matched, and a reinforcing steel bar welding ladder beam with the diameter of 20mm is matched (the welding strength is not lower than the base metal strength).
And S3, after the anchor cables at the two sides are supported, spraying slurry on the sections of the roadway at the two sides to form a concrete spraying layer 8 at the two sides, wherein the concrete spraying layer 8 at the two sides is made of C20 concrete slurry, and the thickness of the concrete spraying layer 8 at the two sides is 100mm, so that water isolation and surface reinforcement of the two sides of the roadway are realized.
S4, after the two sides of concrete are sprayed, constructing a bottom plate vertical anchor cable and grouting and drilling holes by using a down-the-hole drill, wherein the hole diameter is 50mm, the hole depth of each two anchor foot cables 6 is 7100 +/-100 mm, the row spacing of the anchor cables is 1000mm, the two anchor foot cables 6 in each row are drilled and respectively arranged at positions 250mm away from the two sides, and the angle of each anchor cable is 45 degrees; the hole depth of the bottom plate vertical anchor cables 7 is 6000 +/-100 mm, the anchor cable interval is 1000 multiplied by 1000mm, and holes are drilled in each row of the four bottom plate vertical anchor cables 7.
S5, after the construction of the bottom plate drilling 11 is completed, the anchor cable and the grouting pipe 12 are inserted into the lower hole, the anchor cable comprises an anchor cable anchoring section 14 and an anchor cable free section 13, wherein the anchor cable 6 is a mine anchor cable with the diameter of phi 22mm multiplied by 7400mm, and the length of the anchor cable anchoring section 14 is 2300 mm; the vertical anchor cable 7 of the bottom plate is a mining anchor cable with the diameter of 22mm multiplied by 6300mm, the length of the anchor cable anchoring section 14 is 2000mm, the anchor cable free section 13 is wrapped by a corrugated pipe 15 or an external sleeve pipe with the inner wall coated with a lubricant, the length of the anchor cable hole grouting pipe 12 is 6000mm, and the length of the vertical anchor cable hole grouting pipe 12 of the bottom plate is 5000 mm. After the installation is finished, the full-length primary grouting construction is carried out, the hole sealing is carried out by adopting a grout stop plug 16, the hole sealing length is not less than 500mm, the grouting termination pressure is 2-3MPa, and the anchor rope anchoring section 14 realizes the end anchoring effect by using grout as an anchoring agent. Wherein, a matched tray 17 and a lock 10 are arranged above the hole sealing of the grout stop plug 16 for fixing.
When the rock stratum of the orifice section is broken, the grouting pressure which cannot meet the requirement due to the slurry leakage by adopting the slurry stop plug is judged whether the grouting amount in the hole can reach 3m or not by taking the grouting amount as a standard3And if the grouting amount cannot meet the requirement, selecting a secondary grouting mode.
Specifically, the secondary grouting mode is that a grouting hole is drilled at a proper position within the range of 500mm in the grouting hole, two grouting pipes (with the length of 5000mm and the bottoms of the secondary grouting pipes are plugged by adhesive tapes or plastics) are simultaneously arranged in the grouting hole, primary grouting is carried out to ensure that the hole is full, secondary grouting is carried out after the grout is initially set, the grouting pressure is not less than 2MPa, and quick-setting concrete is used for replacing a grout stop plug to seal the hole.
And S6, after the anchor cables 6 and the vertical anchor cables 7 of the bottom plate are supported, spraying cement on the roadway bottom plate to form a bottom plate concrete spraying layer 9, wherein the spraying cement adopts C20 concrete slurry, the thickness of the spraying layer 9 is 200mm, and the roadway bottom plate is waterproof and hardened.
According to the support method, the side control and bottom locking of the heaving floor tunnel are realized by adopting composite grouting matched with the long and short prestressed anchor cables, the self bearing capacity of rock strata of the bottom plate and the two sides is improved, the active support effect of the anchor cables is greatly ensured, and the overall stability of the tunnel is improved. Compared with a pressure relief method with a good short-term effect and the support of a U-shaped steel shed and an I-shaped steel shed which are high in cost and difficult to repair after deformation, the combined support structure formed by the support method is simple in construction, low in cost, high in combined support strength, capable of effectively controlling the damage of displacement, bottom bulging and the like of two sides and a bottom plate caused by stress influence, and high in practicability.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not to be construed as limiting the claims.
The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (10)
1. A coal mine bottom heave roadway side-control bottom-locking long and short anchor cable and composite grouting combined reinforcement method is characterized by comprising the following steps:
s1, pre-grouting on two sides of the roadway according to the arrangement mode of the pre-grouting holes;
s2, two short prestressed anchor cables of two sides of the roadway are constructed by adopting an anchor cable trolley, an anchoring agent is filled and tensioned to the required pretightening force, then two long prestressed anchor cables of two sides are constructed, the anchoring agent is filled and tensioned to the required pretightening force; the short prestressed anchor cables and the long prestressed anchor cables are arranged at intervals;
s3, after the step S2 is completed, spraying concrete on the sections of the roadways at the two sides by using a shotcrete machine;
s4, constructing prestressed anchor cable drill holes on the bottom plate by using a down-the-hole drill, wherein the anchor cable drill holes comprise anchor cable drill holes on two sides of the bottom plate and a bottom plate vertical anchor cable drill hole in the middle of the bottom plate; then, a grouting pipe and an anchor cable are jointly installed in the pre-stressed anchor cable drilling hole;
s5, installing a corrugated pipe or an external sleeve with the inner wall coated with a lubricant on the free section of the anchor cable in the anchor cable corresponding to the drilled hole, performing full-length grouting, realizing end anchoring, and completing the vertical anchor cable support of the anchor cable and the bottom plate;
s6, and then the floor sprays the concrete to harden.
2. The reinforcement method according to claim 1, wherein in step S1, the pre-grouting holes are arranged in a manner including: the distance between the pre-grouting holes is 3000mm, the row distance is 1300-1500mm, the three flowers are sequentially arranged in 2-1-2 rows according to the vertical row number of the units, and the depth of the grouting holes is 6000 mm.
3. The reinforcement method according to claim 1, wherein in step S1, the pre-grouting includes: and (3) implementing pre-grouting on a front anchor cable support working surface, wherein the advance distance is 50 m.
4. The reinforcement method according to claim 3, wherein in step S1, the grouting process includes: drilling the grouting holes by adopting a rock drill, and forming the holes by using an anchor drilling machine; during grouting, a grouting pipe is arranged in the hole, wherein the length of the grouting pipe is 5000 mm; and during grouting, the whole length is subjected to one-time grouting construction.
5. The reinforcement method according to claim 3, wherein in step S1, the grouting process includes: sealing holes by adopting a grout stop plug during grouting, wherein the sealing hole length is not less than 500mm, and the grouting termination pressure is 2-3 MPa; in the grouting construction process, the grouting pressure is ensured to be more than 2MPa as much as possible, and corresponding measures are taken to stop the leakage or re-grouting after pressurized water is carried out when local leakage occurs; when the rock stratum of the orifice section is broken, the grouting pressure which cannot meet the requirements by adopting the grout stop plug is caused by the leakage of the grout, whether the grouting amount in the hole can meet the requirements or not is judged by taking the grouting amount as a standard, and if the grouting amount cannot meet the requirements, a secondary grouting mode is adopted.
6. The reinforcement method according to claim 5, wherein in step S1, the secondary grouting mode includes: and drilling a grouting hole at a required proper position around the grouting hole, simultaneously drilling two 5000mm long grouting pipes in the grouting hole, wherein the bottom of the secondary grouting pipe is blocked by adopting an adhesive tape or plastic, the primary grouting ensures that the hole is fully filled, secondary grouting is carried out after the grout is initially set, the grouting pressure is not less than 2MPa, and quick-setting concrete is adopted for hole sealing.
7. The reinforcement method according to claim 1,
in step S2, the anchor cable used in the anchor cable trolley is a mining prestressed anchor cable, the tensile strength of the steel strand of the anchor cable trolley is 1720MPa, wherein the length of the short prestressed anchor cable is 4300mm, and the length of the long prestressed anchor cable is 7400 mm.
8. The reinforcement method according to claim 1, wherein in step S2, the anchor line trolley installation drill bit has a diameter of 30mm, a short prestressed anchor line hole depth of 4000 ± 100mm, and a long prestressed anchor line hole depth of 7100 ± 100 mm; the installation row spacing of the short prestressed anchor cables is 1000mm x (900-; the long prestressed anchor cables are arranged in units with the vertical row number of 2-1-2 in a three-flower arrangement, the row pitch of the anchor cable holes is 2000mm, and the pitch is 900-1000 mm; after the anchor cable is installed, an anchoring agent is adopted for anchoring the end part; after the anchor cable is installed, the tensioning pre-tightening force is larger than 150kN, so that the side control effect of the bottom-bulging roadway is achieved;
and/or in the step S3, C20 concrete slurry is adopted when the concrete is sprayed, the thickness of a sprayed layer is 100mm, and water isolation and surface reinforcement of two sides of the roadway are realized.
9. The reinforcement method according to claim 1,
in step S4, the diameter of the drilled hole of the prestressed anchor cable is 50mm, wherein the depth of the drilled hole of the anchor cable is 7100 ± 100mm, and the depth of the drilled hole of the vertical anchor cable of the bottom plate is 6000 ± 100 mm; the row distance of the anchor cables arranged in the anchor cable drilling holes is 1000mm, 2 anchor cables in each row are arranged at positions 250mm away from two sides respectively, and the setting angle is 45 degrees under the inclination; the row spacing of the bottom plate vertical anchor cables installed in the bottom plate vertical anchor cable drill holes is 1000mm, the interval is 1000mm, and four bottom plate vertical anchor cables in each row are arranged to achieve the bottom locking effect of the bottom heave roadway; the length of the grouting pipe is 5000 mm;
and/or in step S5, drilling a corresponding anchor cable to form an anchor cable anchoring section, setting the anchoring section length of the anchor cable to be 2300mm, and setting the anchoring section length of the vertical anchor cable of the bottom plate to be 2000 mm;
and/or in the step S5, performing primary grouting construction in the whole length of the drill hole, wherein the hole sealing material adopted for anchoring the end part is a grout stopping plug, the hole sealing length is not less than 500mm, and the grouting termination pressure is 2-3 MPa; in the grouting construction process, the grouting pressure is ensured as much as possible, corresponding measures are taken when local slurry leakage occurs, and the grouting is stopped or re-injected after pressurized water is added; when the rock stratum of the orifice section is broken, the grouting pressure which cannot meet the requirements by adopting the grout stop plug is caused by the leakage of the grout, whether the grouting amount in the hole can meet the requirements or not is judged by taking the grouting amount as a standard, and if the grouting amount cannot meet the requirements, a secondary grouting mode is adopted.
10. The reinforcing method according to claim 1, wherein in step S6, the shotcrete is C20 concrete slurry, and the thickness of the shotcrete layer is 200mm, so as to achieve waterproof and hardening reinforcement of the roadway floor.
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