CN115950746B - Roadway protection method for multi-coal seam gob-side entry retaining in real ground stress environment - Google Patents
Roadway protection method for multi-coal seam gob-side entry retaining in real ground stress environment Download PDFInfo
- Publication number
- CN115950746B CN115950746B CN202211668413.8A CN202211668413A CN115950746B CN 115950746 B CN115950746 B CN 115950746B CN 202211668413 A CN202211668413 A CN 202211668413A CN 115950746 B CN115950746 B CN 115950746B
- Authority
- CN
- China
- Prior art keywords
- test piece
- loading
- pressure
- main body
- cushion block
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a roadway protection method for multi-coal seam gob-side entry retaining in a real ground stress environment, which comprises the following steps: step one, preparing a sample; step two, preparing a simulation system for the dynamic disaster prevention and control technology of the multi-field coupling coal rock mass; thirdly, applying true triaxial prestress; applying true triaxial mining stress, changing the stress value of the No. 4 loading device in the Z direction to 6, 8 and 10MPa, unloading until the coal seam roof is damaged, and maintaining sigma after the damage z4 The gob-side entry retaining device is unchanged so as to simulate the gob-side entry retaining effect of the gob-side entry retaining; step five, starting a high-speed camera; visually monitoring and recording the whole loading process; step six, other tests in the same group; step seven, ending the test; the method can simulate the roadway protection effect of the large-size multi-seam gob-side entry retaining, and the simulation process is more real and reliable.
Description
Technical Field
The invention belongs to the technical field of coal mining simulation tests, and particularly relates to a roadway protection method for multi-coal-seam gob-side entry retaining in a real ground stress environment.
Background
The existing multi-coal-seam gob-side entry retaining simulation test method mainly has the following problems: (1) The adopted model has smaller size, has a certain space limitation in simulating the multi-coal seam gob-side entry retaining, and can not accurately simulate the real roadway protection scene of the multi-coal seam gob-side entry retaining in the real ground stress environment; and (2) visual monitoring cannot be realized in the simulation process.
Disclosure of Invention
The invention aims to provide a multi-coal-seam gob-side entry retaining roadway protection method in a real ground stress environment, which can simulate the roadway protection effect of a large-size multi-coal-seam gob-side entry retaining roadway, is more real and reliable in simulation process, and can realize visual monitoring of the simulation process.
The technical scheme adopted by the invention is as follows: a roadway protection method for multi-coal seam gob-side entry retaining in a real ground stress environment comprises the following steps:
step one, preparing a sample;
preparing a coal sample, namely selecting 2 blocks of raw coal to respectively cut and polish into a cuboid test piece with 140mm multiplied by 400mm multiplied by 1000mm to simulate a coal bed, wherein the flatness of the end face of the cuboid test piece is controlled within +/-0.05 mm;
preparing sandstone: 3 sandstones are selected to be cut and polished into a cuboid test piece with the thickness of 40mm multiplied by 400mm multiplied by 1000mm to simulate a top-bottom plate rock stratum and a middle rock stratum, and the flatness of the end face of the cuboid test piece is controlled within +/-0.05 mm;
firstly, placing sandstone of a simulated bottom layer into the bottom of a test piece box body, uniformly coating high-strength epoxy resin adhesive on the upper surface of the sandstone, uniformly coating high-strength epoxy resin adhesive on the upper surface and the lower surface of a raw coal sample respectively, then respectively placing the raw coal sample into the test piece box to be compacted and attached with sandstone of a bottom plate, then placing an intermediate rock layer of which the upper surface and the lower surface are uniformly coated with the high-strength epoxy resin adhesive, and an upper coal layer, and finally placing sandstone of a simulated top plate layer into the test piece box;
hoisting the test piece box body to a transport frame;
step two, preparing a simulation system for the dynamic disaster prevention and control technology of the multi-field coupling coal rock mass;
the multi-field coupling coal and rock mass dynamic disaster prevention and control technology simulation system comprises a main body model and a transport frame; the main body model has a true triaxial simulation experiment function and comprises a true triaxial loading system and a test piece box in the first step, wherein the test piece box and the shell of the main body model are made of high-strength transparent glass, and a high-speed camera is arranged outside the main body model; the X direction is provided with an independent hydraulic loading device for pressurization, and the maximum loading pressure is 5000kN; the Y, Z hydraulic loading devices are respectively provided with 4 groups of independent hydraulic loading devices for pressurization, the maximum loading pressure of a single group of hydraulic loading devices is 3000kN, each group of hydraulic loading devices can be independently controlled, loading of different acting forces in the length direction of 1000mm is realized, and the triaxial stress state of the underground reservoir can be simulated more truly;
the test piece box is sent into a true triaxial loading system through a transfer frame, so that a stress loading cushion block of the test piece box body corresponds to a pressure head in the true triaxial loading system one by one;
thirdly, applying true triaxial prestress;
according to the ground stress of the stratum, a true triaxial loading system is utilized to apply the ground stress to the simulated stratum, in the process of loading the stress, a pressure head is firstly moved to enable the pressure head to be in contact with a loading cushion block, and a certain prestress is applied to achieve sigma x ＝σ y ＝σ z Then loading Z, Y, X stress in three directions one by one in a step-type mode to reach a preset ground stress value;
applying true triaxial mining stress;
loading the Z-direction force, wherein the loading is controlled by displacement loading or stress loading, the stress value of a Z-direction No. 4 loading device is changed to 6, 8 and 10MPa, and unloading is carried out until the coal seam roof is damaged, and sigma is maintained after the damage z4 The gob-side entry retaining device is unchanged so as to simulate the gob-side entry retaining effect of the gob-side entry retaining;
step five, starting a high-speed camera;
visually monitoring the whole loading process, and recording a gob-side entry retaining lane protection process of the goaf;
step six, other tests in the same group;
changing sandstone material, or changing true triaxial stress and stress loading rate, and repeating the first to fifth steps;
step seven, ending the test;
after the test is completed, the force load is required to be unloaded to zero, then the hydraulic system is switched to low pressure, the test piece is unloaded, the computer and the controller are closed, the power supply is cut off, and the test is finished.
As the optimization of the scheme, the main body model comprises a main body high-pressure cavity module and a test piece box, wherein the outer shell of the main body high-pressure cavity module is of a high-pressure closed pressure bin structure with an outer circle and an inner circle, the outer circle is surrounded by a circular ring, a left circular end cover and a right circular end cover, the front cushion block, the rear cushion block, the upper cushion block and the lower cushion block are respectively arranged on the front, the rear, the upper cushion block and the lower cushion block of the inner wall of the circular ring, the front cushion block, the rear cushion block, the upper cushion block and the lower cushion block are surrounded to form a rectangular cavity for the test piece box to be put in, an axial hydraulic cylinder is arranged on the left circular end cover in a penetrating manner, a seepage channel is arranged on the middle part of the right circular end cover in a penetrating manner, wire harness pipeline leading-out holes are respectively arranged on the left circular end cover and the right circular end cover in a penetrating manner, a row of lifters are arranged on the top left and right at intervals of the lower cushion block, and the lifters can protrude out of the lower cushion block and also sink into the lower cushion block;
the test piece box is a rectangular test piece accommodating cavity formed by encircling a left side plate, a bottom plate, a top plate, a right side plate, a front side plate and a rear side plate through combining bolts, the rectangular test piece accommodating cavity is collinear with the axial lead of a high-pressure sealing pressure bin, a left pressure plate is arranged on the left side of the rectangular test piece accommodating cavity, a plurality of upper pressure plates are sequentially arranged on the top left and right sides of the rectangular test piece accommodating cavity, a plurality of front pressure plates are sequentially arranged on the front left and right sides of the rectangular test piece accommodating cavity, the axial hydraulic cylinder can penetrate through the left side plate and is connected with the left pressure plate, each upper pressure plate is connected with the top hydraulic cylinder through an upper cushion block penetrating through the upper pressure plate arranged on the top plate, each front pressure plate is connected with the lateral hydraulic cylinder through a side cushion block penetrating through the front side plate, a plurality of heating pipes and temperature control probes are arranged on the upper pressure plate, the front pressure plate, the bottom plate and the rear side plate, a plurality of ultrasonic probes are arranged on the upper openings of the upper pressure plate, the front pressure plate, the left pressure plate, the bottom plate and the right side plate, a row of rollers are arranged at intervals on the bottom of the test piece box, and when the test piece box is pushed into a main high-pressure cavity module, and the lifter is supported below the rollers;
the anti-channeling board is arranged right above the bottom plate and corresponds to the upper pressing plate one by one, a central air inlet hole and a plurality of annular grooves surrounding the central air inlet hole are formed in the anti-channeling board, all the annular grooves are communicated with the central air inlet hole through connecting grooves which are distributed in a divergent mode, an air inlet pipe transversely penetrates through the side wall of the test piece box to be connected to the bottom of the central air inlet hole, a ventilation partition plate is arranged above the anti-channeling board, filter plates are arranged at the left end and the right end of the test piece, and sealing gaskets are arranged on the upper end, the lower end, the front end and the rear end of the test piece.
It is further preferred that only one of the axial hydraulic cylinders has a maximum loading pressure of 5000kN; four groups of top hydraulic cylinders and lateral hydraulic cylinders are respectively arranged, each group of hydraulic cylinders is provided with two parallel hydraulic loading systems for pressurizing, one of the hydraulic cylinders is a static load loading system, the other hydraulic cylinder is a dynamic load loading system, the maximum loading pressure of a single group of hydraulic loading devices is 3000kN, each group of hydraulic loading systems is used for independently controlling one pressing plate and is arranged on the corresponding pressing plate in a left-right centering mode, and the axial hydraulic cylinders, the top hydraulic cylinders and the lateral hydraulic cylinders can all carry out dynamic and static load loading.
It is further preferred that the annular grooves are rectangular or circular and are equally spaced apart.
Still preferably, the device further comprises a main body frame for supporting the main body model, the main body frame is of a rectangular frame structure, the left end and the right end of the main body model extend out of the main body frame, a transfer sliding rail is arranged on the right side of the main body frame, the transfer sliding rail extends to the position right below the main body high-pressure cavity module, and the width of the transfer sliding rail is smaller than the inner hollow width of the main body frame; a test piece box lifting and conveying frame and a right round end cover conveying frame are slidably mounted on the transfer slide rail, and the test piece box lifting and conveying frame can perform lifting movement and is used for supporting the test piece box; the right round end cover transfer frame top is the arc and is used for holding up right round end cover, and test piece case lift transfer frame just in time enables in the test piece case horizontal push body high pressure chamber module after rising, and the top is less than the bottom of body high pressure chamber module behind the test piece case lift transfer frame decline to the below of slide-in body high pressure chamber module for right round end cover transfer frame can slide left to the installation of settlement position right round end cover.
It is further preferred that each lifter adopts a double supporting structure which is arranged at intervals and symmetrically, each lifter adopts independent hydraulic drive, and all lifters synchronously lift.
The invention has the beneficial effects that: the method can simulate the roadway protection effect of the large-size multi-seam gob-side entry retaining, the simulation process is more real and reliable, and the visual monitoring of the whole simulation process can be realized.
Drawings
FIG. 1 is a schematic diagram of the steps of the present invention.
Fig. 2 is a schematic diagram of a main body model of a simulation system of a multi-field coupling coal-rock mass dynamic disaster prevention and control technology.
Fig. 3 is an interior left view of fig. 2.
Fig. 4 is a schematic structural view of the specimen box.
Fig. 5 is an interior left view of fig. 4.
Fig. 6 is a simplified view of the arrangement of a heating tube, a temperature control probe, and an ultrasonic probe.
FIG. 7 is a simplified illustration of an anti-channeling plate.
Fig. 8 is a state before the specimen box is loaded into the main body high-pressure chamber module.
Detailed Description
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
as shown in FIG. 1, the roadway protection method for multi-seam gob-side entry retaining in a real ground stress environment comprises the following steps:
step one, preparing a sample;
preparing a coal sample, namely selecting 2 blocks of raw coal to respectively cut and polish into a cuboid test piece with 140mm multiplied by 400mm multiplied by 1000mm to simulate a coal bed, wherein the flatness of the end face of the cuboid test piece is controlled within +/-0.05 mm;
preparing sandstone: 3 sandstones are selected to be cut and polished into a cuboid test piece with the thickness of 40mm multiplied by 400mm multiplied by 1000mm to simulate a top-bottom plate rock stratum and a middle rock stratum, and the flatness of the end face of the cuboid test piece is controlled within +/-0.05 mm;
firstly, placing sandstone of a simulated bottom layer into the bottom of a test piece box body, uniformly coating high-strength epoxy resin adhesive on the upper surface of the sandstone, uniformly coating high-strength epoxy resin adhesive on the upper surface and the lower surface of a raw coal sample respectively, then respectively placing the raw coal sample into the test piece box to be compacted and attached with sandstone of a bottom plate, then placing an intermediate rock layer of which the upper surface and the lower surface are uniformly coated with the high-strength epoxy resin adhesive, and an upper coal layer, and finally placing sandstone of a simulated top plate layer into the test piece box;
hoisting the test piece box body to a transport frame;
step two, preparing a simulation system for the dynamic disaster prevention and control technology of the multi-field coupling coal rock mass;
the multi-field coupling coal and rock mass dynamic disaster prevention and control technology simulation system comprises a main body model and a transport frame; the main body model has a true triaxial simulation experiment function and comprises a true triaxial loading system and a test piece box in the first step, wherein the test piece box and the shell of the main body model are made of high-strength transparent glass, and a high-speed camera is arranged outside the main body model; the X direction is provided with an independent hydraulic loading device for pressurization, and the maximum loading pressure is 5000kN; the Y, Z hydraulic loading devices are respectively provided with 4 groups of independent hydraulic loading devices for pressurization, the maximum loading pressure of a single group of hydraulic loading devices is 3000kN, each group of hydraulic loading devices can be independently controlled, loading of different acting forces in the length direction of 1000mm is realized, and the triaxial stress state of the underground reservoir can be simulated more truly;
the test piece box is sent into a true triaxial loading system through a transfer frame, so that a stress loading cushion block of the test piece box body corresponds to a pressure head in the true triaxial loading system one by one;
thirdly, applying true triaxial prestress;
according to the ground stress of the stratum, a true triaxial loading system is utilized to apply the ground stress to the simulated stratum, in the process of loading the stress, a pressure head is firstly moved to enable the pressure head to be in contact with a loading cushion block, and a certain prestress is applied to achieve sigma x ＝σ y ＝σ z Then loading Z, Y, X stress in three directions one by one in a step-type mode to reach a preset ground stress value;
applying true triaxial mining stress;
loading the Z-direction force, wherein the loading is controlled by displacement loading or stress loading, the stress value of a Z-direction No. 4 loading device is changed to 6, 8 and 10MPa, and unloading is carried out until the coal seam roof is damaged, and sigma is maintained after the damage z4 The gob-side entry retaining device is unchanged so as to simulate the gob-side entry retaining effect of the gob-side entry retaining;
step five, starting a high-speed camera;
visually monitoring the whole loading process, and recording a gob-side entry retaining lane protection process of the goaf;
step six, other tests in the same group;
changing sandstone material, or changing true triaxial stress and stress loading rate, and repeating the first to fifth steps;
step seven, ending the test;
after the test is completed, the force load is required to be unloaded to zero, then the hydraulic system is switched to low pressure, the test piece is unloaded, the computer and the controller are closed, the power supply is cut off, and the test is finished.
As shown in fig. 2-3, the main body model of the multi-field coupling coal rock mass dynamic disaster prevention and control technology simulation system mainly comprises a main body high-pressure cavity module and a test piece box.
The shell 1 of the main body high-pressure cavity module is of a high-pressure closed pressure bin structure which is formed by combining an outer circle and an inner circle surrounded by bolts through a circular ring 3, a left circular end cover 4 and a right circular end cover 5. A front cushion block 2, a rear cushion block 9, an upper cushion block 10 and a lower cushion block 11 are respectively arranged on the front, the rear, the upper and the lower of the inner wall of the circular ring 3. The front cushion block 2, the rear cushion block 9, the upper cushion block 10 and the lower cushion block 11 enclose a rectangular cavity for the test piece box to be placed.
An axial hydraulic cylinder 6 is arranged on the left round end cover 4 in a penetrating way, and a seepage channel is arranged in the middle of the right round end cover 5 in a penetrating way.
The left round end cover 4 and the right round end cover 5 are respectively penetrated with a wire harness pipeline leading-out hole 7, a row of lifters 8 are arranged at the top of the lower cushion block 11 at left and right intervals, and the lifters 8 can protrude out of the lower cushion block 11 and also can sink into the lower cushion block 11. Each lifter 8 adopts a double-wheel structure which is arranged at intervals front and back and symmetrically, realizes front and back double support, and has balanced and stable stress. Each lifter 8 is driven by a separate hydraulic pressure, and all lifters 8 are controlled to synchronously lift and lower through a control system.
As shown in fig. 2-5, the test piece box is a rectangular test piece accommodating cavity surrounded by the left side plate 12, the bottom plate 13, the top plate 14, the right side plate 15, the front side plate 23 and the rear side plate 24 and combined with bolts, and the rectangular test piece accommodating cavity is collinear with the axial lead of the high-pressure closed pressure bin, so that the rectangular test piece is centered in the main body model. A left pressing plate 16 is arranged on the left side in the rectangular test piece accommodating cavity, a plurality of upper pressing plates 17 are arranged on the top left and right in sequence, and a plurality of front pressing plates 18 are arranged on the front left and right in sequence. The axial hydraulic cylinders 6 can penetrate through the left side plate 12 and are connected with the left pressing plate 16, each upper pressing plate 17 is connected with a top hydraulic cylinder 20 through an upper cushion block 19 penetrating through the top plate 14, the top hydraulic cylinder 20 is provided with a hydraulic piston 20a, the upper cushion block 19 is acted on through the hydraulic piston 20a, and then the upper pressing plate 17 applies load to the rectangular test piece. Each front platen 18 is connected to a lateral hydraulic cylinder 22 by a side block 21 mounted through a front side plate 23, the lateral hydraulic cylinder 22 also having a hydraulic piston, through which the side block 21 is acted upon by the hydraulic piston, and the rectangular test piece is loaded by the front platen 18.
Referring to fig. 2 to 6, a plurality of heating pipes 27 and temperature control probes 28 are installed in the openings of the upper platen 17, the front platen 18, the bottom plate 13, and the rear plate 24, and a plurality of ultrasonic probes 29 are installed in the openings of the upper platen 17, the front platen 18, the left platen 16, the bottom plate 13, the rear plate 24, and the right plate 15. A row of rollers 26 are mounted at left and right intervals on the bottom of the test piece box through a lining plate 25, and when the test piece box is pushed into the main body high-pressure cavity module, the lifter 8 is supported below the rollers 26.
Preferably, a high-frequency vibrator is arranged on the cavity of the axial hydraulic cylinder 6, high-speed vibration is generated under the action of a high-pressure air source, and high-frequency vibration force can be transmitted to the test piece right through the corresponding hydraulic cavity, the hydraulic piston and the left pressing plate 16.
The anti-channeling plates 30 corresponding to the upper pressing plates 17 one by one are arranged right above the bottom plate 13, a central air inlet hole 30a and a plurality of annular grooves 30b surrounding the central air inlet hole 30a are formed in the anti-channeling plates 30, and all the annular grooves 30b are communicated with the central air inlet hole 30a through communication grooves 30c which are distributed in a divergent mode, and an air inlet pipe transversely penetrates through the rear side wall of the test piece box and is connected to the bottom of the central air inlet hole 30 a. The annular grooves 30b are rectangular or circular and are equally spaced apart.
The air inlet pipe transversely passes through the rear side wall of the test piece box and is connected to the bottom of the central air inlet hole 30a, the ventilation partition plate 31 is arranged above the anti-channeling plate 30, the filter plates 32 are arranged at the left end and the right end of the test piece, and the sealing gaskets 33 are arranged on the upper side, the lower side, the front side and the rear side of the test piece.
The inner cavity of the test piece box can be provided with a rectangular test piece with the length of 1000 times the width of 400 times the height of 400mm, and the internal pressure resistance of the main body high-pressure cavity module is 10MPa.
Only one axial hydraulic cylinder 6 has a maximum loading pressure of 5000kN; four groups of top hydraulic cylinders 20 and side hydraulic cylinders 22 are respectively arranged, each group of hydraulic cylinders is provided with two parallel hydraulic loading systems for pressurizing, one of the hydraulic cylinders is a static load loading system, the other hydraulic loading system is a dynamic load loading system, the maximum loading pressure of a single group of hydraulic loading devices is 3000kN, each group of hydraulic loading systems is used for independently controlling one pressing plate and is arranged on the corresponding pressing plate in a left-right centering mode, and the axial hydraulic cylinders 6, the top hydraulic cylinders 20 and the side hydraulic cylinders 22 can be used for loading dynamic and static loads.
As shown in fig. 8, the multi-field coupling coal-rock mass dynamic disaster prevention and control technology simulation system comprises a main body model, a main body frame 37 for supporting the main body model, a transfer sliding rail 36, a test piece box lifting and conveying frame 34 and a right round end cover conveying frame 35. The specimen box lifting and lowering transfer frame 34 and the right round end cap transfer frame 35 are collectively referred to as a transfer frame.
The main body frame 37 is used for supporting a main body model, the main body frame 37 is of a rectangular frame structure, and the left end and the right end of the main body model extend out of the main body frame 37. The right side of main part frame 37 is provided with and transports slide rail 36, and transport slide rail 36 extends to the main part high pressure chamber module under, and transport slide rail 36's width is less than the interior empty width of main part frame 37. The transfer slide rail 36 is slidably provided with a specimen box lifting and transferring frame 34 and a right round end cover transferring frame 35, and the specimen box lifting and transferring frame 34 can perform lifting and transferring movements and is used for supporting the specimen box. The top of the right round end cover transferring frame 35 is arc-shaped and is used for supporting the right round end cover 5, the test piece box lifting transferring frame 34 just enables the test piece box to be horizontally pushed into the main body high-pressure cavity module after being lifted, and the top of the test piece box lifting transferring frame 34 is lower than the bottom of the main body high-pressure cavity module after being lowered, so that the test piece box lifting transferring frame slides into the lower part of the main body high-pressure cavity module, and the right round end cover transferring frame 35 can slide leftwards to a set position to install the right round end cover 5.
The main characteristics of the main body model are as follows:
(1) The shell of the main body high-pressure cavity module adopts a high-pressure sealing pressure bin with an outer circle and an inner circle, wherein the outer circle and the inner circle are surrounded by a circular ring, a left circular end cover and a right circular end cover which are combined with bolts, and the structure of the high-pressure sealing pressure bin is quite different from that of the traditional pressure bin with an outer square and an inner square which are surrounded by six plates; meanwhile, the test piece box is rectangular, so that the mounting of the test piece box is met, the front, rear, upper and lower cushion blocks with special shapes are creatively arranged on the front, rear, upper and lower sides of the inner wall of the high-pressure sealing pressure bin respectively, and a rectangular cavity for the test piece box to be placed is formed by the front, rear, upper and lower cushion blocks, so that a test piece box mounting environment with an outer circle and an inner side is formed, the internal pressure resistance is stronger, the sealing capability is better, the internal pressure resistance can be up to 10MPa, and a better test environment is provided for a lane protection simulation test of a multi-coal seam gob-side entry retaining in a real ground stress environment;
(2) The lifter is supported below the rollers, so that the test piece box can be pushed in and pulled out more easily and laborsaving, the automation degree of installation is improved, and the large-scale simulation test operation is easier and laborsaving;
(3) The upper pressing plate, the front pressing plate, the bottom plate and the rear side plate are provided with a plurality of heating pipes and temperature control probes, and the upper pressing plate, the front pressing plate, the left pressing plate, the bottom plate, the rear side plate and the right side plate are provided with a plurality of ultrasonic probes, so that a fractured rock mass seepage test under the three-dimensional stress-seepage-temperature multi-field coupling condition can be developed; and combine the anti-channeling board that sets up directly over the bottom plate, ventilative baffle is installed to the top of anti-channeling board, installs the filter in the left and right sides both ends of test piece, installs sealed pad around the upper and lower of test piece, can prevent the channeling, can guarantee again that the gas permeability is good to possess and filter and seal multiple effect.
Parameters of mining stress in a specific test scheme are set as follows:
Claims (5)
1. the roadway protection method for the multi-coal seam gob-side entry retaining in the real ground stress environment is characterized by comprising the following steps of:
step one, preparing a sample;
preparing a coal sample, namely selecting 2 blocks of raw coal to respectively cut and polish into a cuboid test piece simulation coal bed with 140mm multiplied by 400 multiplied by mm multiplied by 1000mm, wherein the flatness of the end face of the cuboid test piece simulation coal bed is controlled within +/-0.05 mm;
preparing sandstone: 3 sandstones are selected to be cut and polished into a cuboid test piece of 40mm multiplied by 400 multiplied by mm multiplied by 1000mm to simulate a top-bottom plate rock stratum and an intermediate rock stratum, and the flatness of the end face of the cuboid test piece is controlled within +/-0.05 mm;
firstly, placing sandstone of a simulated bottom layer into the bottom of a test piece box body, uniformly coating high-strength epoxy resin adhesive on the upper surface of the sandstone, uniformly coating high-strength epoxy resin adhesive on the upper surface and the lower surface of a raw coal sample respectively, then respectively placing the raw coal sample into the test piece box to be compacted and attached with sandstone of a bottom plate, then placing an intermediate rock layer of which the upper surface and the lower surface are uniformly coated with the high-strength epoxy resin adhesive, and an upper coal layer, and finally placing sandstone of a simulated top plate layer into the test piece box;
hoisting the test piece box body to a transport frame;
step two, preparing a simulation system for the dynamic disaster prevention and control technology of the multi-field coupling coal rock mass;
the multi-field coupling coal and rock mass dynamic disaster prevention and control technology simulation system comprises a main body model and a transport frame; the main body model has a true triaxial simulation experiment function and comprises a true triaxial loading system and a test piece box in the first step, wherein the test piece box and the shell of the main body model are made of high-strength transparent glass, and a high-speed camera is arranged outside the main body model; the X direction is provided with an independent hydraulic loading device for pressurization, and the maximum loading pressure is 5000kN; the Y, Z is pressurized by 4 groups of independent hydraulic loading devices in two directions, the maximum loading pressure of a single group of hydraulic loading devices is 3000kN, each group of hydraulic loading devices can be controlled independently, loading of different acting forces in the length direction of 1000mm is realized, and the triaxial stress state of the underground reservoir can be simulated more truly;
the test piece box is sent into a true triaxial loading system through a transfer frame, so that a stress loading cushion block of the test piece box body corresponds to a pressure head in the true triaxial loading system one by one;
thirdly, applying true triaxial prestress;
according to the ground stress of the stratum, a true triaxial loading system is utilized to apply the ground stress to the simulated stratum, in the process of loading the stress, a pressure head is firstly moved to enable the pressure head to be in contact with a loading cushion block, and a certain prestress is applied to achieveσ x = σ y = σ z Then loading Z, Y, X stress in three directions one by one in a step-type mode to reach a preset ground stress value;
applying true triaxial mining stress;
loading the Z-direction force, wherein the loading is displacement loading control or stress loading control, and the stress value of the Z-direction No. 4 loading device is changed to 6, 8,10 Unloading under the pressure of MPa until the roof of the coal bed is damaged, and maintaining after the damageσ z4 The gob-side entry retaining device is unchanged so as to simulate the gob-side entry retaining effect of the gob-side entry retaining;
step five, starting a high-speed camera;
visually monitoring the whole loading process, and recording a gob-side entry retaining lane protection process of the goaf;
step six, other tests in the same group;
changing sandstone material, or changing true triaxial stress and stress loading rate, and repeating the first to fifth steps;
step seven, ending the test;
after the test is finished, the force load is required to be unloaded to zero, then the hydraulic system is switched to low pressure, the test piece is unloaded, the computer and the controller are closed, the power supply is cut off, and the test is finished;
the main body model comprises a main body high-pressure cavity module and a test piece box, wherein a shell (1) of the main body high-pressure cavity module adopts a high-pressure closed pressure bin structure of an outer circle surrounded by a circular ring (3), a left circular end cover (4) and a right circular end cover (5) through bolts, a front cushion block (2), a rear cushion block (9), an upper cushion block (10) and a lower cushion block (11) are respectively arranged on the front, rear and lower sides of the inner wall of the circular ring (3), the front cushion block (2), the rear cushion block (9), the upper cushion block (10) and the lower cushion block (11) enclose a rectangular cavity for the test piece box to be placed in, an axial hydraulic cylinder (6) is arranged on the left circular end cover (4) in a penetrating manner, a seepage channel is arranged in the middle of the right circular end cover (5), wire harness pipeline leading-out holes (7) are respectively arranged on the left circular end cover (4) and the right circular end cover (5) in a penetrating manner, a row of lifters (8) are arranged at left and right intervals on the top of the lower cushion block (11), and the lifters (8) can protrude out of the lower cushion block (11) to be placed in the lower cushion block (11) at intervals;
the test piece box is a rectangular test piece accommodating cavity which is surrounded by a left side plate (12), a bottom plate (13), a top plate (14), a right side plate (15), a front side plate (23) and a rear side plate (24) through combining bolts, the axis of the rectangular test piece accommodating cavity and a high-pressure sealing pressure bin are collinear, a left pressure plate (16) is arranged on the left side in the rectangular test piece accommodating cavity, a plurality of upper pressure plates (17) and a plurality of front pressure plates (28) are arranged on the left side, the top of the rectangular test piece accommodating cavity in turn, a plurality of front pressure plates (6) are arranged on the left side and the right side, the axial hydraulic cylinders (6) can penetrate through the left side plate (12) and the left pressure plate (16), each upper pressure plate (17) is connected with the top hydraulic cylinder (20) through an upper cushion block (19) penetrating through the top plate (14), each front pressure plate (18) is connected with a lateral hydraulic cylinder (22) through a side cushion block (21) penetrating the front side plate (23), a plurality of heating pipes (27) and temperature control probes (28) are arranged on the left side and right side of the top pressure plate (18), the front pressure plate (13), the rear side plate (24) and the left side plate (16) are provided with a plurality of ultrasonic probes (29), a row of rollers (26) are arranged at left and right intervals at the bottom of the test piece box through a lining plate (25), and when the test piece box is pushed into the main body high-pressure cavity module, the lifter (8) is supported below the rollers (26);
just above bottom plate (13) be provided with upper pressure plate (17) one-to-one prevent channeling board (30), central inlet port (30 a) and a plurality of ring channel (30 b) around central inlet port (30 a) have been seted up on prevent channeling board (30), and all ring channel (30 b) and central inlet port (30 a) are through being the tie groove (30 c) intercommunication that divergently distributes, and the lateral wall of intake pipe transverse passing test piece case inserts the bottom of central inlet port (30 a), ventilative baffle (31) are installed to the top of prevent channeling board (30), install filter (32) at the left and right sides of test piece, install sealing pad (33) around about the test piece.
2. The roadway protection method for multi-seam gob-side entry retaining in a true ground stress environment according to claim 1, wherein the method comprises the following steps: only one axial hydraulic cylinder (6) has a maximum loading pressure of 5000kN; four groups of top hydraulic cylinders (20) and lateral hydraulic cylinders (22) are respectively arranged, each group of hydraulic cylinders is provided with two parallel hydraulic loading systems for pressurizing, one hydraulic loading system is a static load loading system, the other hydraulic loading system is a dynamic load loading system, the maximum loading pressure of a single group of hydraulic loading devices is 3000kN, each group of hydraulic loading systems is used for independently controlling one pressing plate and is arranged on the corresponding pressing plate in a left-right centering mode, and the axial hydraulic cylinders (6), the top hydraulic cylinders (20) and the lateral hydraulic cylinders (22) can all carry out dynamic and static load loading.
3. The roadway protection method for multi-seam gob-side entry retaining in a true ground stress environment according to claim 1, wherein the method comprises the following steps: the annular grooves (30 b) are rectangular or circular and are distributed at equal intervals.
4. The roadway protection method for multi-seam gob-side entry retaining in a true ground stress environment according to claim 1, wherein the method comprises the following steps: the main body frame (37) is used for supporting the main body model, the main body frame (37) is of a rectangular frame structure, the left end and the right end of the main body model extend out of the main body frame (37), a transfer sliding rail (36) is arranged on the right side of the main body frame (37), the transfer sliding rail (36) extends to the position right below the main body high-pressure cavity module, and the width of the transfer sliding rail (36) is smaller than the inner space width of the main body frame (37); a test piece box lifting and transporting frame (34) and a right round end cover transporting frame (35) are slidably arranged on the transporting slide rail (36), and the test piece box lifting and transporting frame (34) can perform lifting movement and is used for supporting the test piece box; the top of the right round end cover transferring frame (35) is arc-shaped and is used for supporting the right round end cover (5), the test piece box lifting transferring frame (34) can be just in time pushed into the main body high-pressure cavity module after being lifted, the top of the test piece box lifting transferring frame (34) is lower than the bottom of the main body high-pressure cavity module after being lowered, so that the test piece box lifting transferring frame can slide into the lower side of the main body high-pressure cavity module, and the right round end cover transferring frame (35) can slide leftwards to a set position to install the right round end cover (5).
5. The roadway protection method for multi-seam gob-side entry retaining in a true ground stress environment according to claim 1, wherein the method comprises the following steps: each lifter (8) adopts a double-support structure which is arranged at intervals and symmetrically, each lifter (8) adopts independent hydraulic drive, and all lifters (8) synchronously lift.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211668413.8A CN115950746B (en) | 2022-12-23 | 2022-12-23 | Roadway protection method for multi-coal seam gob-side entry retaining in real ground stress environment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211668413.8A CN115950746B (en) | 2022-12-23 | 2022-12-23 | Roadway protection method for multi-coal seam gob-side entry retaining in real ground stress environment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115950746A CN115950746A (en) | 2023-04-11 |
| CN115950746B true CN115950746B (en) | 2023-09-26 |
Family
ID=87288497
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211668413.8A Active CN115950746B (en) | 2022-12-23 | 2022-12-23 | Roadway protection method for multi-coal seam gob-side entry retaining in real ground stress environment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115950746B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106226502A (en) * | 2016-09-19 | 2016-12-14 | 山东大学 | Deep high-ground stress coal and rock dynamic disaster and displacement simulation pilot system and method |
| CN109142027A (en) * | 2018-08-20 | 2019-01-04 | 山东科技大学 | Working face driving causes Coal Outburst Visualization method |
| CN111175468A (en) * | 2020-03-09 | 2020-05-19 | 山东科技大学 | Pressure-relief and impact-prevention test method for water-injection-wetted coal rock under true three-dimensional stress |
| CN111175470A (en) * | 2020-03-09 | 2020-05-19 | 山东科技大学 | Test method for simulating spontaneous combustion and instability of coal body under true triaxial stress |
| CN111323307A (en) * | 2020-03-09 | 2020-06-23 | 山东科技大学 | Multi-coal-seam combined fracturing, pressure relief and extraction integrated test method |
| CN112081575A (en) * | 2020-09-10 | 2020-12-15 | 西南石油大学 | Multi-field coupling coal bed gas well surrounding rock deformation visual simulation device and method |
| US11151904B1 (en) * | 2020-04-16 | 2021-10-19 | University Of Science And Technology Beijing | Multi-functional stratigraphic structure model testing system and testing method |
| CN114062225A (en) * | 2021-11-30 | 2022-02-18 | 河南理工大学 | Low-permeability coal seam acidification permeability-increasing loaded coal body gas seepage multi-field coupling experiment system and experiment method |
-
2022
- 2022-12-23 CN CN202211668413.8A patent/CN115950746B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106226502A (en) * | 2016-09-19 | 2016-12-14 | 山东大学 | Deep high-ground stress coal and rock dynamic disaster and displacement simulation pilot system and method |
| CN109142027A (en) * | 2018-08-20 | 2019-01-04 | 山东科技大学 | Working face driving causes Coal Outburst Visualization method |
| CN111175468A (en) * | 2020-03-09 | 2020-05-19 | 山东科技大学 | Pressure-relief and impact-prevention test method for water-injection-wetted coal rock under true three-dimensional stress |
| CN111175470A (en) * | 2020-03-09 | 2020-05-19 | 山东科技大学 | Test method for simulating spontaneous combustion and instability of coal body under true triaxial stress |
| CN111323307A (en) * | 2020-03-09 | 2020-06-23 | 山东科技大学 | Multi-coal-seam combined fracturing, pressure relief and extraction integrated test method |
| US11151904B1 (en) * | 2020-04-16 | 2021-10-19 | University Of Science And Technology Beijing | Multi-functional stratigraphic structure model testing system and testing method |
| CN112081575A (en) * | 2020-09-10 | 2020-12-15 | 西南石油大学 | Multi-field coupling coal bed gas well surrounding rock deformation visual simulation device and method |
| CN114062225A (en) * | 2021-11-30 | 2022-02-18 | 河南理工大学 | Low-permeability coal seam acidification permeability-increasing loaded coal body gas seepage multi-field coupling experiment system and experiment method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115950746A (en) | 2023-04-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105758714B (en) | A kind of stress loading device | |
| CN111812021A (en) | Coal rock three-dimensional strain field visualization system and method under mining influence | |
| CN112269015A (en) | Inclined coal seam mining three-dimensional similarity test device with adjustable inclination angle of confined aquifer and test method | |
| CN111220523A (en) | Geothermal exploitation test method under simulated complex load condition | |
| CN111963118A (en) | Two-dimensional visual sand filling experiment model for simulating horizontal well exploitation | |
| CN111188622A (en) | Platform, system and method for simulating collapse of underground engineering surrounding rock dangerous stone | |
| CN116148075B (en) | High-stress soft rock stratum deformation simulation test method under mining stress | |
| WO2022134187A1 (en) | Rock true triaxial dynamic compression shear test apparatus and method in deep complex structure conditions | |
| CN115950746B (en) | Roadway protection method for multi-coal seam gob-side entry retaining in real ground stress environment | |
| CN112730809A (en) | Fluid-solid coupling similar test device and test method for pressure-bearing underwater mining | |
| CN116026698B (en) | Test method for roof collapse of goaf of coal bed under disturbance stress | |
| CN114397234A (en) | True triaxial gradient stress loading seepage test device for composite coal rock mass | |
| CN115979911B (en) | Fracture rock mechanical response simulation test method in dynamic and static load complex environment | |
| CN115950805B (en) | Test method for simulating multi-point complex seepage path in real ground stress environment | |
| CN116087468B (en) | Comprehensive test method for strength, strain and seepage of oil sand in high-temperature stress environment | |
| CN115977621B (en) | Physical simulation method for exploiting heavy oil reservoir through hydraulic communication of VHSD (very high-pressure reservoir) vertical well horizontal well | |
| CN116087457B (en) | Method for testing coal and gas outburst induced by graded dynamic load action | |
| CN117969277A (en) | True triaxial test method for full-process visualization of soft rock deformation under high-temperature stress environment | |
| CN116087458B (en) | Deep buried coal seam gas outburst test system | |
| CN116025346A (en) | Test piece box module for large-scale thickened oil exploitation test | |
| CN111198128B (en) | Integrated into one piece totally enclosed true triaxial test testing arrangement | |
| CN114563551A (en) | Dynamic load induced coal and gas outburst test method under seepage state | |
| CN116008084B (en) | Main body model for multi-field coupling coal rock mass dynamic disaster prevention and control simulation test | |
| CN116086974A (en) | Simulation test method for punching fracturing multiple coal beds under true triaxial stress | |
| CN116008083B (en) | Large-scale automatic true triaxial coal rock mass test piece simulation test system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |