CN113356904A - Three-anchor combined dynamic support method for deep well high-stress soft rock roadway - Google Patents

Abstract

The invention discloses a three-anchor combined dynamic support method for a deep well high-stress soft rock roadway, which aims to solve the problems that the traditional combined support has insufficient support strength, unstable support structure, unreasonable grouting parameters, improper grouting time, unreasonable grouting material selection and the like, seriously influences the grouting effect, causes the poor support effect of a plurality of deep well high-stress soft rock roadways, cannot meet the use requirement, needs frequent repair, wastes a large amount of manpower and material resources and seriously influences the safety production, and aims at the deformation characteristic of the deep well high-stress soft rock roadway, the invention combines the traditional anchor rod, anchor rope and anchor grouting support technology to form a novel deep well high-stress soft rock roadway support method, fully exerts the coupling effect of a support system by means of strong support, modification, full-closed support and the like, improves the bearing capacity and the support strength of the support structure, the deformation and the damage of the deep well high-stress soft rock roadway are effectively controlled.

Description

Three-anchor combined dynamic support method for deep well high-stress soft rock roadway

Technical Field

The invention relates to the technical field of coal mine roadway support, in particular to a three-anchor combined dynamic support method for a deep well high-stress soft rock roadway.

Background

The deep well high stress soft rock roadway has the characteristics of high ground pressure, large deformation, easy expansion, easy argillization, strong rheology, short self-stabilization time, large initial deformation rate, long deformation duration, sensitivity to stress disturbance and environmental change, obvious surrounding rock deformation space-time effect and the like.

Along with the increase of the mining depth of a mine, the stress of surrounding rocks of a roadway is continuously increased, soft rock roadways are more and more, the phenomena of obvious and strong ground pressure, large deformation of the roadway, serious bottom heave and the like are generally generated, the roadway supporting difficulty is large, the repair rate is high, the safety development of the mine is seriously restricted, and the problem of solving the problem is one of key problems related to the safety production of the coal mine.

For deep well high-stress soft rock roadways, support forms such as anchor net cable-shotcrete support, contractible metal bracket support, anchor net cable-shotcrete support, anchor grouting support and the like are mostly adopted, but a great deal of engineering practice shows that a single support form is infeasible in the high-stress soft rock roadway, the effect is not ideal when the traditional combined support is adopted, the reason that the single support is infeasible is that the support strength is insufficient, and the reason that the traditional combined support is invalid is that the support structure is unstable and is not coupled with the mechanical properties of surrounding rocks. The traditional combined supporting method only simply combines various supporting structures, and does not fully consider the supporting mechanism of the supporting body, the release of the energy accumulated in the surrounding rock and the exertion of the self-stability capability of the surrounding rock, so that the coupling effect of the supporting body and the surrounding rock on strength, rigidity and structure is difficult to realize. In the traditional anchor grouting support, due to the facts that grouting parameters are unreasonable, grouting time is not mastered properly, grouting materials are selected unreasonably and the like, grouting effects are seriously influenced, the supporting effect of a plurality of deep-well high-stress soft rock roadways is poor, the use requirements cannot be met, frequent repair is needed, a large amount of manpower and material resources are wasted, and safety production is seriously influenced.

Disclosure of Invention

The invention aims to solve the problems that the traditional combined support has insufficient support strength, unstable support structure, unreasonable grouting parameters, improper grouting time, unreasonable grouting material selection and the like, the grouting effect is seriously influenced, the support effect of a plurality of deep-well high-stress soft rock roadways is poor, the use requirements cannot be met, frequent repair is needed, a large amount of manpower and material resources are wasted, and the safety production is seriously influenced, and provides a three-anchor combined dynamic support method for the deep-well high-stress soft rock roadway.

The purpose of the invention can be realized by the following technical scheme: the three-anchor combined dynamic support method for the deep well high-stress soft rock roadway comprises the following steps:

s1: top slope primary anchor net cable spraying support and shallow hole grouting: determining a top wall primary support form, support materials, support parameters and quality requirements, and determining a shallow hole grouting mode, grouting parameters, grouting materials, grouting time and a grouting method;

s2: top slope secondary anchor net belt spray support and deep hole grouting: determining a top wall secondary support form, support materials, support parameters, support time and quality requirements, and determining a deep hole grouting mode, grouting parameters, grouting materials, grouting time and a grouting method;

s3: grouting and reinforcing the base plate: determining a reinforcement scheme, a reinforcement material, support parameters, reinforcement time and a construction method;

s4: and (5) checking the supporting effect.

As a preferred embodiment of the present invention, in S1, a roof side primary anchor net cable-jet support form: the combined support of anchor rods, metal nets, anchor cables and sprayed concrete is adopted. Supporting materials, parameters and quality requirements:

anchor rod: GM phi 22mm high-strength screw-thread steel anchor rod (the length of the anchor rod is not less than half of the roadway width); the matched iron trays are delta 10mm multiplied by 200mm, the spacing is not more than 800mm multiplied by 800mm, and one K2550 resin anchoring agent and two Z2550 resin anchoring agents are used for each anchor rod. The arrangement direction of the anchor rods should be as vertical as possible to the contour line of the roadway (or the main bedding surface of the rock stratum), and the included angle is not less than 75 degrees. Anchor rod anchoring force: not less than 80KN, anchor bolt torque: not less than 300 N.m. The distance between the top anchor rod and the head is not more than 300mm, the distance between the side anchor rod and the bottom plate is not more than 1000mm, and the distance between the side anchor rod and the head is not more than 1 cycle.

Metal mesh: the steel is processed into round steel with the diameter of 6mm, the length multiplied by the width is 2400mm multiplied by 900mm, the mesh specification is 100mm multiplied by 100mm, and self-connection is adopted. (the net sheets without self-connection conditions are bound and connected by adopting 14# iron wires in a double-strand mode, and the lap joint length is 100 mm).

Anchor rope: YMS phi 21.6mm prestressed anchor cables (the length of the anchor cable is not less than 1.5 times of the roadway width), iron trays delta 20mm multiplied by 300mm are used, and the space row pitch is not more than 1600mm multiplied by 1600 mm. One K2550 and three Z2550 type resin anchoring agents are used for each anchor cable. The anchor cable arrangement should be perpendicular to the roadway contour line. The pre-tightening force of the anchor cable is not less than 120KN, and the anchoring force is not less than 200 KN. The construction of the arch part anchor cable should follow the head-on, and the construction of the side part anchor cable can be delayed properly according to the lithological condition.

Concrete spraying: P.O 42.5.5 common Portland cement is selected as cement, medium coarse sand is selected as yellow sand, and the particle size of stones is 5-15 mm; the mixture ratio is water: cement: yellow sand: stone ═ 0.57: 1: 2: 2 (mass ratio), an accelerator with the cement consumption of 3-5 percent is added, the sprayed concrete strength is C20, the sprayed concrete thickness is 100mm, wherein the initial spraying is followed by the head, the thickness is 20-30 mm, and the delay of the head-on of the repeated spraying is not more than 30 m.

As a preferred embodiment of the invention, the shallow hole grouting in S1 generally adopts a phi 25 twist type hollow grouting anchor rod or a quarter grouting steel pipe, and the depth of the shallow hole grouting hole is determined according to the size of a surrounding rock loosening ring and is generally 2500 mm-3000 mm. The spacing is determined according to the diffusion radius of grouting, and is generally selected from 1200mm multiplied by 1200mm to 1600mm multiplied by 1600 mm. The grouting anchor rods or the grouting steel pipes are arranged perpendicular to the contour line of the roadway, the wall corner grouting anchor rods or the grouting steel pipes are downwards pricked for 30-45 degrees, the grouting anchor rods or the grouting steel pipes are required to be arranged before primary support re-spraying, grouting operation is required to be completed before secondary support implementation, the specific lagging head-on distance is determined according to the pressure display condition of the roadway and is generally 50-80 meters;

as a preferred embodiment of the present invention, in S2, the secondary anchor mesh belt spray support form: the combined support of anchor rods, metal nets, steel belts and sprayed concrete is adopted. Supporting materials, parameters and quality requirements:

anchor rod: GM phi 22 high-strength deformed steel bar anchor rod (the length of the anchor rod is +400 mm-600 mm of the length of a primary supporting anchor rod), the matched iron tray is delta 10mm multiplied by 200mm, the spacing is not more than 800mm multiplied by 800mm, each anchor rod uses one K2550 and two Z2550 type resin anchoring agents, the arrangement direction of the anchor rod is vertical to the contour line of the roadway (or the main bedding surface of the rock stratum) as much as possible, and the included angle is not less than 75 degrees. Anchor rod anchoring force: not less than 80KN, anchor bolt torque: not less than 300 N.m.

Metal mesh: the phi 6 round steel is processed, the length multiplied by the width is 2400mm multiplied by 1000mm, the mesh specification is 100mm multiplied by 100mm, and self-connection is adopted. (the net sheets without self-connection condition adopt 14# iron wire double strands for binding connection, and the lap joint length is 100mm)

Steel strip: the standard M4 steel strip is arranged along the roadway, and has the length of 4200mm, the row spacing of 800mm and the lap joint length of 100 mm.

Concrete spraying: P.O 42.5.5 common Portland cement is selected as cement, medium coarse sand is selected as yellow sand, and the particle size of stones is 5-15 mm; the mixture ratio is water: cement: yellow sand: stone ═ 0.57: 1: 2: 2 (mass ratio), 3-5% of accelerator of cement, C20 of sprayed concrete strength and 50mm of sprayed concrete thickness.

The secondary anchor mesh belt spraying support is constructed after obvious mine pressure appears in a roadway and the stress of surrounding rocks is properly released, generally the delay head-on distance does not exceed 200m, and the delay primary support completion time is 1-2 months;

as a preferred embodiment of the invention, the deep hole grouting in S2 generally adopts SKZ phi 22 hollow grouting anchor cables or quarter grouting steel pipes, the hole depth is 8000 mm-10000 mm, the spacing is determined according to the grouting diffusion radius, and generally 2000mm multiplied by 2000 mm-3000 mm multiplied by 3000 mm. Deep hole grouting is generally implemented within one month after secondary supporting, and the delay head-on is not more than 150 meters in principle;

as a preferred embodiment of the present invention, the floor grouting reinforcement in S3 is classified into a floor shallow hole grouting reinforcement and a floor deep hole grouting reinforcement. The bottom plate shallow hole grouting adopts a common hollow grouting anchor rod and fixes a channel steel bottom beam, the bottom plate deep hole grouting adopts a hollow grouting anchor cable or a quarter grouting steel pipe, wherein the specification of the grouting anchor rod is phi 25mm multiplied by 2500 mm-3000 mm, the spacing is determined according to the grouting diffusion radius, and the spacing is generally selected from 1200mm multiplied by 1200 mm-1600 multiplied by 1600 mm. The specification of the grouting anchor cable is phi 22mm multiplied by 6000 mm-8000 mm, the spacing is determined according to the grouting diffusion radius, generally 2000mm multiplied by 2000 mm-3000 mm multiplied by 3000mm is selected, 16# channel steel is selected as a channel steel bottom beam, the width is 200mm, two wings are upward, a web plate is downward, and the distance between anchor rod holes is 1300 mm. Specifically, the bottom plate reinforcing construction process comprises the following steps: clearing the roadway to 100mm below the designed bottom plate → grouting an anchor rod fixing channel steel for the backing plate → installing a grouting anchor rod → laying a cement floor for 100mm → shallow hole grouting → deep hole grouting → re-grouting (determined according to the observation result). The grouting reinforcement of the bottom plate is generally implemented after the secondary support of the side top of the roadway is completed, and the specific lag distance is determined according to the deformation condition of the floor heave of the roadway;

as a preferred embodiment of the invention, the shallow hole, deep hole and bottom plate grouting material can be ordinary 425# portland cement or a novel inorganic reinforcing material. Because the common Portland cement has the defects of low contractility, low condensation speed and low strength, the JD-WJF-1 type single-component novel inorganic reinforcing material or the JDAQ-4 type double-component novel inorganic reinforcing material which has the characteristics of superfine property, quick setting, no water precipitation, no shrinkage, micro expansion, high fluidity, high cohesiveness, high compressive strength, no high temperature generation, no chloride and the like is suitable for use. Specifically, shallow hole grouting and bottom plate grouting are carried out under the pressure of 2-3 Mpa, deep hole grouting is carried out under the pressure of 5-6 Mpa, and the water-cement ratio is 0.3-0.4: 1;

in a preferred embodiment of the present invention, the test of the supporting effect is performed by a method combining surface observation, surrounding rock deformation measurement, exploration of an exploration hole and reinjection. Firstly, when adopting and exploring the hole and exploring, every 20m in tunnel makes a set of hole of exploring, and top and two help are respectively one, increase a bottom plate hole during the bottom plate slip casting, and the hole is dark to be greater than slip casting stock (anchor rope) length 1m, explores the hole and is located slip casting hole diffusion range, adopts the drilling appearance to explore, explores the timely hole sealing of completion back, can not reach the designing requirement through inspection slip casting effect, must carry out the secondary slip casting. And secondly, grouting by adopting a field grouting hole, observing the grouting amount, and checking the grouting effect according to the grouting amount. Checking the content and the standard: the surface of the roadway is tightly sealed, and slurry does not leak; the surface of the tunnel has no water seepage and sprinkling phenomenon; the grouting range meets the design requirement, and the grouting is uniform without blind areas; the deformation of the surrounding rock is effectively controlled, and the phenomenon of obvious deformation and damage is avoided.

Compared with the prior art, the invention has the beneficial effects that:

1. aiming at the deformation characteristics of the deep well high-stress soft rock roadway, the invention combines the traditional anchor rod, anchor cable and anchor injection supporting technologies to form a novel deep well high-stress soft rock roadway supporting method, fully exerts the coupling effect of a supporting system through means of strong support, modification, full-closed support and the like, improves the bearing capacity and supporting strength of a supporting structure, and effectively controls the deformation and the damage of the deep well high-stress soft rock roadway;

2. the invention adopts JD series novel inorganic reinforcing material to replace ordinary portland cement as grouting reinforcing material, and has the advantages of high solidification speed, no shrinkage, high strength and high cost performance;

3. the main working procedures of the supporting structure body are divided into equal steps for construction, certain distance intervals exist in space, parallel operation can be performed in time, the influence on the footage of a working face is limited, and the single advancing level is favorably improved.

Drawings

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

FIG. 1 is a schematic view of a supporting structure of the present invention;

FIG. 2 is a schematic view of a primary support and shallow hole grouting structure of the present invention;

FIG. 3 is a schematic diagram of the secondary support and deep hole grouting structure of the present invention;

FIG. 4 is a schematic view of a grouting process according to the present invention;

FIG. 5 is a schematic view of roadway floor grouting according to the present invention;

FIG. 6 is a schematic view of the deep hole grouting pipe of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood 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.

Please refer to fig. 1-6;

the first embodiment is as follows:

the total length of a stone gate of a certain ore-935 m adhesive tape machine is 630m, and the elevation is minus 960.0 (T) to minus 935.0 (T). The lithology is mainly siltstone and mudstone, the fine sandstone and coal bed are secondary, the rock stratum inclination angle is about 7-12 degrees, and small structures such as local rock stratum fractures, sliding surfaces and the like are relatively developed. The tunnel section is excavated with width of 5500mm, excavation height of 4150m, net width of 5200mm and net height of 4000mm, and the permanent support form of the tunnel top is primary anchor net cable spraying and shallow hole grouting, secondary anchor net cable spraying and deep hole grouting. And (5) blasting and rock breaking step method construction is adopted.

The top slope primary support adopts anchor rods, metal nets, anchor cables, sprayed concrete support and shallow hole grouting.

Anchor rod: GM phi 22mm is 2600mm, the matched iron trays are delta 10mm is 200mm, the spacing is 800mm, and one K2550 resin anchoring agent and two Z2550 resin anchoring agents are used for each anchoring rod.

Metal mesh: the steel is processed into round steel with the diameter of 6mm, the length multiplied by the width is 2400mm multiplied by 900mm, the mesh specification is 100mm multiplied by 100mm, and self-connection is adopted.

Anchor rope: YMS phi 21.6mm is multiplied by 7300mm, matched iron trays are multiplied by 20mm, 300mm and 300mm, and the row spacing is multiplied by 1600 mm. One K2550 and three Z2550 type resin anchoring agents are used for each anchor cable.

Concrete spraying: P.O 42.5.5 ordinary portland cement is selected as the cement, the particle size of yellow sand is larger than 0.35mm, the particle size of stone is 5 mm-15 mm; the mixture ratio is water: cement: yellow sand: stone: setting accelerator 0.57: 1: 2: 2: 0.04 (mass ratio), the strength of the sprayed concrete is C20, and the thickness of the sprayed concrete is 100 mm.

Shallow hole grouting: adopting 4 to divide the thick liquid steel pipe separately, the hole depth 2800mm, row spacing 1600mm x 1600mm between, the slip casting liquid adopts JD-WJF-1 type material, the water cement ratio is 0.3 ~ 0.4: 1, grouting pressure is 2-3 MPa. When the grouting reaches the pressure stabilizing time, the grouting can be finished.

The secondary support of the top wall adopts anchor rods, metal meshes, steel strips, sprayed concrete support and deep hole grouting.

Anchor rod: GM phi 22 multiplied by 3000mm, matched iron trays are delta 10 multiplied by 200mm, the spacing is 800mm multiplied by 800mm, and one K2550 and two Z2550 type resin anchoring agents are used for each anchoring rod.

Metal mesh: the diameter 6mm round steel is processed, the length multiplied by the width is 2400mm multiplied by 1000mm, the mesh specification is 100mm multiplied by 100mm, and self-connection is adopted.

Steel strip: the standard M4 steel strip is arranged along the roadway, and has the length of 4200mm, the row spacing of 800mm and the lap joint length of 100 mm.

Concrete spraying: P.O 42.5.5 ordinary portland cement is selected as the cement, the particle size of yellow sand is larger than 0.35mm, the particle size of stone is 5 mm-15 mm; the mixture ratio is water: cement: yellow sand: stone: setting accelerator 0.57: 1: 2: 2: 0.04 (mass ratio), the strength of the sprayed concrete is C20, and the thickness of the sprayed concrete is 100 mm.

Deep hole grouting: adopting 4 to divide the thick liquid steel pipe separately, the hole depth 7000mm, the row spacing 2400mm is multiplied by 2400mm, the slip liquid adopts JD-WJF-1 type material, the water cement ratio is 0.3 ~ 0.4: and 1, grouting pressure is 5-6 MPa. When the grouting reaches the design pressure value, the grouting can be finished.

Top-side one-time anchor net cable-jet support construction process

The method comprises the steps of shift change safety inspection → lower part hole → charge, line connection, blasting, gun inspection → upper part hole top finding, upper part hole → charge, line connection, blasting, gun inspection → upper part top finding → arch part advanced support → top temporary support → top permanent support → upper part face facing protection → discharge of gangue, bottom cleaning gun inspection → upper part face finding → lower part upper part advanced support → lower part face facing protection → upper part permanent support → guniting.

The primary support follows the head. The empty top distance between the top anchor rod and the head-on is not more than 300mm, the distance between the side anchor rod and the bottom plate is not more than 1m, and the head-on is not more than a circulation distance.

Top wall secondary anchor mesh belt spraying support construction process

Safety inspection → erection of operation platform → installation of net sheet, drilling, installation of steel band and anchor rod → re-spraying of concrete → entering the next cycle.

And the secondary support is carried out after primary support construction is completed and the stress of the surrounding rock is primarily released.

Grouting construction: grouting steel pipe hole → installing grouting steel pipe → checking grouting pump and adopting clear water test → stirring slurry → starting grouting → first grouting two sides, then grouting arch, top → closing control valve → opening pressure relief valve.

The support quality requirement is as follows:

primary anchor net cable spraying support: the allowable deviation from the center line to any upper is 0-100 mm, and the net height is as follows: the allowable deviation from the waist line to the top plate and the bottom plate is 0-100 mm. The welding, laying and hooking of the metal mesh must comply with the design and specification regulations.

The distance between the top anchor rod and the head is not more than 300mm, the distance between the side anchor rod and the bottom plate is not more than 1000mm, and the distance between the side anchor rod and the head must not exceed one cycle. And (4) setting from outside to inside, and operating under the shielding of advance support and temporary support in the process of bolting. The distance between the anchor rods of the lowest row of slope and the bottom plate is not more than 300mm, the anchor rods of the lowest row are constructed along the bottom of a soft rock or high-pressure roadway, and the anchor rods of the lowest row are constructed at the side of a capillary ditch when the ditch is deep. And (4) drilling one anchor rod, installing one anchor rod and fastening to the design requirement. The anchor rod is firmly installed, the tray is tightly attached to the wall surface, and the non-contact part needs to be wedged tightly.

Anchor rod angle: the arrangement direction of the anchor rods is perpendicular to the contour line (or the main bedding surface of the rock stratum) of the roadway as much as possible, and the included angle is not less than 75 degrees; the anchor rod exposes: 10 mm-40 mm. Anchor rod anchoring force: not less than 80KN, anchor bolt torque: not less than 300 N.m. Allowed error of row spacing between anchor rods: plus or minus 100 mm. The metal net is tightly adhered to the rock surface. The quality requirement of the secondary support anchor rod is the same with that of the primary support.

The initial spraying is close to the head, and the thickness is not less than 20mm and not more than 30 mm. And re-spraying to form a tunnel to a gangue raking machine. The foundation depth is not less than 90% of the design, and the skirt wearing phenomenon caused by bare feet is avoided. And (3) making a group of C20 test blocks for each 30-50 m of the roadway sprayed concrete, wherein the size of each group of the test blocks is 100mm multiplied by 100mm, and the prepared test blocks are hung on the side part of the roadway for maintenance under the same conditions. Three-shift watering maintenance is carried out within 7 days after spraying to ensure that the sprayed layer does not crack; and spraying water for curing every day within 28 days to improve the strength of the sprayed layer.

The anchor cable specification is: phi 21.6mm multiplied by 7300mm, which is matched with a lock; each adopts 1 coil of K2550 resin cartridge and 3 coils of Z2550 resin cartridge, the pretightening force of the anchor cable is not less than 120KN, and the anchoring force is not less than 200 KN; the hole depth error is controlled to be +/-30 mm, the spacing allowed error is +/-100 mm, and the hole is exposed to be 150-250 mm. When the surrounding rock of the top plate is stable, only 3 top anchor cables of the arch part are constructed, and the distance from the head to the head is not more than 40 m; when the surrounding rock of the top plate is unstable, the anchor cable must follow the working face.

Grouting quality requirements:

the installation position of the shallow hole grouting hole packer is not less than 1500mm, and the installation position of the deep hole grouting hole packer is not less than 3000mm, and the installation position is properly adjusted according to the size of a loosening ring of surrounding rock. The installation of the grouting steel pipe comprises a grouting perforated pipe, a hole packer and a solid pipe in sequence.

Before grouting, a proper amount of clear water can be injected into the hole by pressure to wash and clean cracks in the rock mass, so that the bonding performance of the grout and the surrounding rock is improved. The grouting operation should be continuously carried out, interruption is not needed in the midway, and grouting interruption caused by mechanical failure, power failure, water cut, equipment failure and the like is avoided as much as possible.

Grouting:

the first step is as follows: grouting materials, grouting equipment, cotton yarns for hole sealing, binding wires and the like are prepared in advance by grouting construction units.

The second step is that: pumps and accessories (including high-pressure rubber pipes for grouting, tools, grouting pipes, u-shaped clamps, joints for connecting grouting pipes and the like), grouting materials and the like are transported to construction sites.

The third step: the pump and the mixing barrel are connected with corresponding power sources.

The fourth step: and checking whether the quantity of the hydraulic oil and the quantity of the lubricating oil in the pump meet the requirements or not, and starting the pump to check whether the pump can normally operate or not.

The fifth step: firstly, sealing the grouting holes.

And a sixth step: and (3) the hole sealing material can reach the sealing strength, and then grouting is started.

The seventh step: the grouting process, as shown in fig. 4, comprises a grouting 4-minute steel pipe, a 19mm or 25mm high-pressure pipe, a hydraulic grouting pump, a slurry suction pipe and a stirring barrel; a safety pressure relief valve is arranged on the high-pressure pipe;

checking the connection of the pump and the grouting pipeline, opening an output valve, starting grouting, suspending grouting, continuing grouting, finishing grouting, and cleaning the pump and the grouting pipeline by clear water.

Eighth step: in the grouting process, attention must be paid to observing the pump and the surrounding condition of a roadway, when slurry return (slurry still flows out through multiple times of pump pause operation) occurs on a coal wall, the slurry injected into the coal body is hardened through intermittent grouting, the slurry in the pump and the grouting pipe does not lose fluidity, and therefore slurry leakage cracks are blocked, double-liquid materials can be injected when slurry leakage is serious, and single-liquid materials are injected again after a slurry leakage channel is blocked.

The ninth step: the on-site cleaning is carried out, and equipment such as a grouting pump, a grouting pipe, a charging basket, a stirring barrel, a stop valve and the like is noticed to be cleaned.

Grouting sequence: grouting from bottom to top; the top plate should be grouted from left to right or from right to left, and in principle, the two sides can be arranged first and then the middle is arranged. In consideration of the large construction area range and the requirement on grouting quality, grouting is conducted in a mode of firstly conducting two ends and then conducting the middle, and firstly conducting the lower portion and then conducting the upper portion in principle. For each row of grouting pipes, performing row-by-row grouting, performing primary grouting and then performing secondary grouting; before grouting, a pressure release valve and a stop valve are required to be installed at the grouting pipe opening for matching use, and after single-hole grouting is finished, pressure release is carried out firstly and then hole replacement is carried out.

And (3) preparation of grouting liquid: the slurry is stirred and prepared in a slurry stirring barrel on site, clear water is added into a material stirring barrel according to a specified water-cement ratio, and then a reinforcing grouting material is added in proportion.

The grouting is started and it must be ensured that the grouting pressure is satisfactory. During grouting, attention should be paid to the fact that pressure cannot be too large, and if the top rib is abnormal, grouting pressure should be reduced.

Grouting amount: and stopping grouting until the grouting pressure reaches the upper limit of grouting pressure or the slurry leakage is difficult to block in principle, closing the stop valve in time to perform intermittent grouting when the slurry leakage occurs in the grouting process, and performing skip grouting if the slurry leakage occurs in adjacent holes. In the grouting process, the slurry leakage condition is observed in time, the slurry leakage channel mainly comprises an anchor cable (rod) hole, a large broken crack, a grouting drill hole and the like, and the common slurry leakage problem can be solved by an intermittent grouting method. When the slurry leakage channel is large, the slurry leakage channel can be plugged by cotton yarn or plugged by plugging material for stopping the pump. When grouting is interrupted due to large-scale leakage or excessive slurry consumption, the drill holes must be cleaned by pressurized water and re-injected after a period of time, and when the re-injected drill holes are blocked, the grouting quality of the peripheral drill holes must be ensured, and grouting holes must be repaired if necessary.

And after the slurry is injected, cleaning the inside and outside of the stirring barrel, equipment and pipelines by using clean water. And adding clear water into the barrel, simultaneously adding a small amount of lubricating oil, starting the grouting pump, and discharging residual slurry in the grouting pump so as to prevent the slurry from blocking the grouting pump and pipelines.

Example two:

a reinforcing scheme of an outer ring bottom plate at the bottom of a certain mine auxiliary well in a train yard is adopted;

overview of the engineering: the total length of the construction of the north outer ring coal penetrating section of the auxiliary shaft bottom yard is about 100m, the top wall of the roadway is supported by adopting secondary anchor net and cable belt injection, the clear height of the roadway is 4900mm, and the clear width of the roadway is 5400 mm. The maximum bottom bulging amount of the bottom plate exceeds 400mm in 2 months, the roadway is bedded twice, and the bottom plate reinforcement is required.

A bottom plate reinforcing and supporting scheme: the grouting reinforcement construction of the bottom plate is mainly implemented in six steps.

The method comprises the following steps: laying a grout stopping layer: and paving a 150mm terrace to form a grout stopping layer.

Step two: plugging a water channel of the bottom plate: and (3) grouting in sections to plug the water channel of the bottom plate, wherein the length of each section is preferably 100 m. The grouting drilling construction and grouting process comprises the following steps: firstly, constructing a shallow hole of 500-1000 mm at a subsection node position by using a common air hammer or an air coal drill, performing shallow hole pressureless grouting for 1-2 minutes, and preliminarily bonding loose rock masses in the range of about 1-1.5 m at the shallow part of a roadway. The hole diameter of the drill hole is determined according to the diameter of the grouting pipe, and the fixing effect of the grouting pipe is ensured. And secondly, after 24 hours of shallow grouting, continuously drilling a middle-depth grouting hole of 2000mm meters at the original designed drilling position by using an air hammer or air coal drill, bonding most loose bodies in the range of the loose ring into a whole after grouting, wherein the grouting pressure is still zero at the moment, and the grouting time is still controlled to be 1-2 minutes. Thirdly, after the middle hole is grouted for 24 hours, a ZQJJ-120/1.8 type bottom plate anchor cable drilling machine or other bottom plate drilling machines are used for constructing a 4000mm deep grouting hole in the original designed drilling position, non-pressure grouting is continuously carried out, and grouting time is controlled to be 1-2 minutes. Fourthly, constructing a bottom grouting hole with the depth of 8000mm at the position of the originally designed drilling hole, and performing deep hole pressureless grouting for 3 minutes.

Step three: bottom plate shallow layer pressureless grouting: and constructing 2500mm shallow layer non-pressure grouting holes at the central point of the divided roadway bottom plate at intervals of 20m, and performing shallow portion non-pressure grouting. The grouting amount of each drilling hole is different, the cement consumption of the initial grouting hole can exceed 40 bags or even more, and the grouting amount of the later drilling holes can be gradually reduced. The hole diameter of the drill hole is determined according to the diameter of the grouting pipe, and the fixing effect of the grouting pipe is ensured. If the 2500mm drilled hole cannot be formed at one time, the drilling can be performed by the above method from shallow to deep.

Step four: bottom plate deep hole low pressure grouting: constructing 8000mm deep grouting holes at the center of the divided roadway bottom plate with a row spacing of 4000mm x 4000mm, and performing deep small-pressure grouting with a grouting termination pressure of 3 MPa.

Step five: reinforcing the anchor cable of the bottom plate: phi 21.6mm multiplied by 7300mm, trays 10mm multiplied by 100mm, and pitch spacing 2000mm multiplied by 2400 mm. One K2550 and two Z2550 underwater resin anchoring agents are used for each anchor cable. The aperture of the anchor cable hole of the bottom plate is 30-50 mm, and the anchoring agent needs special processing to ensure three-diameter matching. Every 3 bottom plate anchor cables form a row, share a No. 18 channel steel beam with the length of 4400mm, and an iron tray with the thickness of 100mm multiplied by 10mm is arranged between the anchor cable lock and the channel steel beam so as to protect the lock and ensure the tensioning effect. The initial tension of the anchor cable of the bottom plate is not less than 12T. Lay the reinforcing bar net under the channel-section steel, the reinforcing bar net width is unanimous with the channel-section steel, reinforcing bar net specification: phi 6mm multiplied by 3000mm multiplied by 1000mm, mesh specification 100mm multiplied by 100mm, laying along the trend, and stubble lapping 100 mm.

Step six: and (3) deep hole high-pressure grouting of the bottom plate: constructing 8000mm deep grouting holes at 3200mm × 3200mm intervals, and performing deep high-pressure grouting with grouting termination pressure of 6 Mpa.

Supporting materials, parameters, quality requirements and construction process:

a. the required materials mainly comprise: hollow grouting pipes (1 m; 2 m; 2.5 m; 4m, 8m five types) with different lengths, JDAQ-4 type materials, 4400mm long No. 18 channel steel bottom beams, 2000mm long by 1000mm steel nets, phi 21.6mm by 7300mm anchor cables, trays phi 10mm by 100mm and the like. Every 3 bottom plate anchor cables form a row, an 18# channel steel beam with the length of 4400mm is shared to be matched with a 2000mm multiplied by 1000mm steel net to support the upper surface of each channel steel to reserve 3 holes, and the hole spacing is 2000 mm.

b. Floor reinforcement parameters and quality requirements

Concrete grout stopping layer: the paving thickness is 150mm, and the concrete proportion is strictly according to cement: yellow sand: 1, stone 1: 2: 2, and the concrete strength is C20. After the construction of the grout stop layer is finished, the concrete surface is ensured not to have obvious cracks, honeycombs and holes.

Grouting quality requirements: the water-cement ratio of bottom plate shallow hole grouting and deep hole grouting is 0.3-0.4: 1. after the grouting pipe is arranged, a special hole packer is required. During grouting, hardened, outdated reinforcing materials are prohibited from use. In the grouting process, in order to prevent the slurry from precipitating, the slurry should be stirred at any time to ensure the proportioning degree of the slurry. During grouting, construction is performed from two sides to the middle. And the shallow hole and the filling hole adopt pressureless grouting. The medium-pressure grouting of the deep hole is controlled at 3MPa, and the high-pressure grouting of the deep hole is controlled at 6 MPa. And during medium-pressure and high-pressure grouting, the air pressure of a grouting pump is adjusted in time, and the pressure is stabilized for 1-2 minutes, so that the filling quality is ensured.

Supporting an anchor cable by a bottom plate: the row spacing between anchor cables supported by the bottom plate is 2000mm multiplied by 2400mm, each anchor cable is anchored by 1 coil of K2460 and 2 coils of Z2460 anchoring agent, after 1 hour of solidification, the anchor cables are fastened by a tensioning instrument, the pre-tightening force of the anchor cables is 80-100 KN, and the anchoring force is not less than 200 KN.

The construction process flow comprises the following steps: 150mm for roadway bottom → 150mm for floor paving → water channel plugging by grouting at the end of construction joint → shallow hole pressureless grouting → deep hole medium pressure grouting → reinforcement of support anchor rope → deep hole high pressure grouting.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims (7)

1. The three-anchor combined dynamic support method for the deep well high-stress soft rock roadway is characterized by comprising the following steps of:

s1: carrying out primary anchor net cable-jet support on the top wall, and grouting shallow holes;

s2: carrying out mesh-belt spraying support on the top wall secondary anchor, and grouting deep holes;

s3: grouting and reinforcing the bottom plate;

s4: and (5) checking the supporting effect.

2. The deep well high stress soft rock roadway three-anchor combined dynamic support method according to claim 1, wherein before the roof side primary anchor net cable spraying support in S1, the method further comprises:

determining primary support information; the primary support information comprises a top wall primary support form, support materials, support parameters, quality requirements, shallow hole grouting modes, grouting parameters, grouting materials, grouting opportunity and grouting methods;

wherein, the top wall primary support mode is combined support by an anchor rod, a metal net, an anchor cable and sprayed concrete;

the length of each anchor rod is not less than half of the width of the roadway, an iron tray is matched, and each anchor rod uses three resin anchoring agents; the arrangement direction of the anchor rods is vertical to the included angle of the profile line of the roadway or the main bedding surface of the rock stratum or is not less than 75 degrees;

the metal net is processed by round steel and is connected in a self-connection mode;

the length of the anchor cable is not less than 1.5 times of the width of the lane, an iron tray is matched, and each anchor cable uses three resin anchoring agents; arranging an anchor cable to be vertical to the contour line of the roadway;

the sprayed concrete strength is C20, the sprayed concrete thickness is 100mm, the initial spraying is followed by the head-on, the thickness is 20-30 mm, and the head-on is not more than 30m after the repeated spraying.

3. The deep well high-stress soft rock roadway three-anchor combined dynamic supporting method according to claim 2, wherein phi 25 twist type hollow grouting anchor rods or four-quarter grouting steel pipes are adopted for shallow hole grouting, the grouting anchor rods or the grouting steel pipes are arranged perpendicular to the contour line of the roadway, and the corner grouting anchor rods or the grouting steel pipes are downwards rolled for 30-45 degrees.

4. The deep well high stress soft rock roadway three-anchor combined dynamic support method according to claim 1, wherein before the top wall secondary anchor mesh belt spraying support, further comprising:

determining secondary support information; the secondary support information comprises a top wall secondary support form, support materials, support parameters, support time, quality requirements, a deep hole grouting mode, grouting parameters, grouting materials, grouting time and a grouting method;

the secondary anchor mesh belt spraying support is combined support by an anchor rod, a metal mesh, a steel belt and sprayed concrete;

wherein the anchor rod is a high-strength deformed steel anchor rod, and the length of the anchor rod is the sum of the length of the anchor rod in primary support and 400-600 mm; an iron tray is matched, and each anchor rod uses three resin anchoring agents; the arrangement direction of the anchor rods is vertical to the included angle of the profile line of the roadway or the main bedding surface of the rock stratum or is not less than 75 degrees;

the metal net is processed by round steel and adopts self-connection;

the steel strips are arranged along the trend of the roadway.

5. The deep-well high-stress soft rock roadway three-anchor combined dynamic supporting method according to claim 1, wherein the bottom plate grouting reinforcement comprises bottom plate shallow hole grouting reinforcement and bottom plate deep hole grouting reinforcement; the bottom plate shallow hole grouting adopts a common hollow grouting anchor rod and fixes a channel steel bottom beam, and the bottom plate deep hole grouting adopts a hollow grouting anchor cable or a quarter grouting steel pipe; the bottom plate reinforcing construction process comprises the following steps: clearing the roadway to 100mm below the designed bottom plate → grouting the anchor rod to fix the channel steel → installing the grouting anchor rod → laying the cement floor 100mm → shallow hole grouting → deep hole grouting → re-grouting.

6. The deep well high stress soft rock roadway three-anchor combined dynamic supporting method according to claim 1, wherein the shallow hole, deep hole and bottom plate grouting material is ordinary 425# portland cement or a novel inorganic reinforcing material; grouting pressure of shallow hole grouting and bottom plate grouting is 2-3 Mpa, grouting pressure of deep hole grouting is 5-6 Mpa, and water-cement ratio is 0.3-0.4: 1.

7. the deep well high stress soft rock roadway three-anchor combined dynamic supporting method according to claim 1, wherein the supporting effect test is a test by combining surface observation, surrounding rock deformation measurement, exploration of exploration holes and reinjection;

when exploration is carried out through exploration holes, a group of exploration holes are drilled in every 20m of a roadway, the top and the two sides are respectively provided with one exploration hole, a bottom plate hole is additionally arranged when grouting is carried out on a bottom plate, the hole depth is larger than the length of a grouting anchor rod or an anchor cable by 1m, and the exploration holes are positioned in the diffusion range of the grouting holes;

when the drilling peeping instrument is used for probing, grouting is carried out by punching grouting holes on site, the grouting amount is observed, and the grouting effect is checked according to the grouting amount;

and sealing holes in time after probing is finished, and performing secondary grouting if the grouting effect is not detected to meet the design requirement.

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