CN102879549B - Three-way load large-scale three-dimensional analog simulation test system - Google Patents

Abstract

The invention discloses a three-dimensional loading large-scale three-dimensional similar simulation test system, which includes a test piece box and a reaction force system. The key lies in the flexible setting of the test piece box through the screw hole belt, so that the test piece box can be changed in different volumes, To meet different test requirements, the reaction system includes a concrete reaction pool located under the ground and a reaction frame fixed to the reaction pool. The present invention can simulate the complex distribution phenomenon of coal seam stress at different roof activity stages in the process of underground mining, and it is more convenient and effective to make test pieces of large dip angle mine seam, which can ensure that the rock mass exists in the three-dimensional stress during the whole mining process. Under the same conditions, the excavation of underground space under more working conditions can be studied, which reduces the height of the entire system above the surface, and the cost is lower and the system is more stable.

Description

Three-dimensional loading large-scale three-dimensional similar simulation test system

technical field

The invention relates to a simulation test system, in particular to a similar simulation test system for studying stress distribution of ore mass and rock mass.

Background technique

Similar material simulation test is a laboratory research method based on similarity theory and dimensional analysis, and is widely used in water conservancy, mining, geology, railway and other departments. The biggest feature of the simulation test is that the test conditions can be controlled and changed artificially, so as to determine the law of the influence of single or multiple factors on the mine pressure. The test effect is clear and intuitive, and the test period is short and the effect is quick. It has played an important role in the research of mining science. Huge effect. Even with the rapid development of numerical simulation and computing science of rock mechanics, similar material simulation test is still an irreplaceable research method in mining science research. It complements the increasingly mature numerical simulation and simulation, and helps humans understand and solve problems in mining science. play an important role.

Before the ore body is mined, the rock mass is in a state of equilibrium. When the ore body is mined, an underground space is formed, which destroys the original stress field of the rock mass, causes the stress redistribution of the rock mass, and continues until a new balance is formed in the rock mass. In the process of stress redistribution, the surrounding rock is deformed, moved, and destroyed, thereby exerting pressure on the working face, roadway and surrounding rock. Under the action of mine pressure, there will be a series of mechanical phenomena—mine pressure appearance, such as roof sinking, floor bulging, coal wall slabs, support deformation, rock formation movement, coal extrusion, etc. The overlying strata after mining can be divided into caving zone, fault zone and curved subsidence zone.

Although the three-dimensional similar simulation test system in the prior art has deepened the progress of underground excavation engineering research to a certain extent, it has the following shortcomings: 1) The model size is small, and the geometric ratio when doing simulation tests will be very small In practice, it is found that the geometric ratio of the model test is too small to reflect the impact of excavation; 2) The size of the model is fixed and cannot be adjusted, which will cause sometimes the geometric ratio is too small, and sometimes the space will be too large Waste of material; 3) The force direction is single, and it is difficult to achieve three-way loading; 4) Most of the rock mass deformation monitoring uses strain gauges, and the rock mass deformation data collection is not accurate enough; 5) The test piece box must be opened manually after the mine excavation Digging, which will cause unloading effect, which is inconsistent with the actual working conditions; 6) The process of loading the device is basically carried by hand, which is inconvenient to operate; 7) Most of the applied stress loading systems are manual, so the stress loading process cannot maintain a uniform speed , and its accuracy cannot be guaranteed. In addition, loading forms such as cyclic loading cannot be realized.

Therefore, those skilled in the art are committed to developing a large-scale three-dimensional similar simulation test system with variable model size, simple operation, and accurate and reliable three-way loading, as well as a test sample preparation method, a three-dimensional similar simulation test load simulation method, And a three-dimensional loading large-scale three-dimensional similar simulation test mining layer simulation method.

Contents of the invention

In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a three-dimensional loading large-scale three-dimensional similar simulation test system with variable model size, simple operation and accurate and reliable test, and a test sample preparation method, A three-dimensional similar simulation test load simulation method, and a three-dimensional loading large-scale three-dimensional similar simulation test production layer simulation method.

In order to achieve the above-mentioned first aspect of the invention, the present invention provides a three-dimensional loading large-scale three-dimensional similar simulation test system, including a test piece box and a reaction force system, the test piece box includes a base; the edge of the base is provided with The left screw hole band, the right screw hole band, the front screw hole band and the rear screw hole band constitute a square; the base is fixedly connected with a left side plate at the left screw hole band by bolts, The belt is fixedly connected to the front side plate by bolts;

At least one first middle screw hole band is arranged between the right screw hole band and the left screw hole band; between the rear screw hole band and the front screw hole band is provided with the first middle screw hole band. The number of hole belts corresponds to the second middle screw hole belt that is vertically connected; the connected first middle screw hole belt and the second middle screw hole belt form a square with the left screw hole belt and the right screw hole belt; the right screw hole belt The screw hole belt or any one of the first middle screw hole belts is fixedly connected with the right side plate by bolts; the rear screw hole belt connected to the right side plate or any one of the second middle screw hole belts The rear side plate is fixedly connected with bolts; the rear side plate is provided with sensor wiring holes; the outer side of the rear side plate is fixed with a first backing plate at intervals;

The inner side of the left plate is fixedly connected with a left pressure seat by bolts; the left plate is provided with a left pressure sleeve according to the equally divided area; The corresponding left pressure rod; the left pressure rod passes through the left pressure sleeve;

The inner side of the front side plate is fixedly connected with a front pressure seat by bolts; the front side plate is provided with a front pressure sleeve according to an evenly divided area; The corresponding front compression rod; the front compression rod passes through the front compression sleeve;

The left press seat is spaced apart from the front press seat;

The reaction force system includes a concrete reaction force pool located under the ground; the bottom of the reaction force pool is provided with a first reaction force seat fixedly connected to the reaction force pool; the right side of the first reaction force seat is provided with There is a second reaction force seat; the second reaction force seat is fixed to the bottom of the reaction force pool, and at the same time is fixedly connected to the first reaction force seat by bolts;

The reaction force pool is provided with a side bearing frame fixedly connected with the first reaction force seat on the left side of the test piece box, and close to the concrete wall surface; The left hydraulic cylinder whose position corresponds to the left pressure rod; the reaction force pool is provided with a reaction force frame connected with the second reaction force seat bolts on the right side of the test piece box; the reaction force frame It can be fixedly connected with the test piece box by bolts;

The front part of the first reaction seat is fixed with a front column; one end of the front column is close to the concrete wall of the reaction pool, and the other end is fixed with a number and position corresponding to the front pressure bar. front hydraulic cylinder;

The rear part of the first reaction seat is fixed with a rear column; one end of the rear column is close to the concrete wall of the reaction pool, and the other end is fixed with a number and position corresponding to the first backing plate. a second backing plate corresponding to and close to the first backing plate;

The front column and the rear column are connected as an integrated structure through the fixed beam above; the upper hydraulic cylinder opposite to the specimen box is evenly distributed on the beam;

The simulation test system also includes a pressure seat; when performing a similar simulation test, the pressure seat transmits the loading force of the upper hydraulic cylinder to similar materials in the test piece box.

In order to prevent the three-way force from interfering during the loading process, in the height direction, a first anti-interference seat in contact with the front press seat and the left press seat is placed at the corner of the front press seat and the left press seat; A second anti-interference seat is placed inside the left pressure seat; the first anti-interference seat and the second anti-interference seat are arranged at intervals.

Preferably, the end of the first anti-interference seat away from the left press seat has a wedge-shaped structure; the top end of the first anti-interference seat has a wedge-shaped structure; the end of the second anti-interference plate close to the front press seat is wedge-shaped structure.

In order to facilitate the movement of the test piece box, a rolling guide rail is provided on the first reaction force seat; the test piece box can be placed on the rolling guide rail; pull seats are provided on the left and right sides of the base; The left and right sides of the test piece box are provided with traction mechanisms corresponding to the pull seats.

Preferably, two pull seats are arranged at intervals on the left and right sides of the base; the traction mechanism includes a reducer; the reducer is connected to the first end of the first reel through a first coupling; the The second end of the first reel is connected with the second reel through the second coupling, the transmission shaft and the third coupling; The wire rope connected by the seat.

In order to simplify the operation, the front side of the second reaction force seat is provided with a first wire rope fixing seat that can fix the steel wire rope of the first reel; The second wire rope fixing seat of the wire rope of the second reel.

Preferably, the press seat includes an upper plate and a bottom plate, and the upper plate and the bottom plate are connected into one structure through a vertical plate; ribs are provided on the vertical plate.

For the convenience of making a test piece with an inclination angle ore layer, a third reaction force seat is provided on the right side of the second reaction force seat; the third reaction force seat is fixed with the bottom of the reaction force pool, and simultaneously with the The second reaction seat is fixedly connected by bolts;

The right end of the third reaction seat is provided with a first hinged seat and a second hinged seat at intervals; the right end of the base is provided with a third hinged seat and a second hinged seat which can be hinged with the first hinged seat and the second hinged seat respectively. Four hinged seats;

The reaction pool is provided with oil cylinder supports at the front and rear ends of the third reaction force seat close to the second reaction force seat; an oil cylinder is hinged on the oil cylinder support; the piston rod of the oil cylinder A thrust support is hinged at the end; the thrust support can be connected with the base of the test piece box.

In order to facilitate the simulation of coal seam excavation, at least one row of oil bag installation holes is correspondingly provided on the front side plate and the rear side plate.

In order to realize the invention objective of the second aspect of the present invention, the present invention provides a method for preparing a sample for a three-dimensional loading large-scale three-dimensional similar simulation test, comprising the following steps:

(1) Tilt the test piece box, and the inclination angle of the test piece box is equal to the inclination angle of the ore seam;

(2) Carry out numerical simulation of the rock formation pressure distribution law, and obtain the position of the pressure sensor at the stress measuring point of the prefabricated test piece according to the simulation result;

(3) According to the geometric similarity ratio, bulk density similarity ratio, stress similarity ratio and strength similarity ratio, the mechanical property parameters such as bulk density, compressive strength, and excavation speed of the model rock are calculated, and the river sand, gypsum, and calcium carbonate are used in different proportions. Stir evenly with an appropriate amount of water, make a number of standard specimens and air-dry them in a natural state, measure the uniaxial compressive strength of the standard specimens, and compare the compressive strength calculated according to the strength similarity ratio with a different ratio Comparison of serial uniaxial compressive strengths to obtain the best ratio of similar materials in each layer;

(4) According to the optimal ratio and bulk density of each layer, calculate the required mass of each layered material, weigh the mass of the corresponding ingredients, mix the ingredients evenly, then add an appropriate amount of water, and stir immediately to prevent condensation ; After stirring evenly, send the ingredients into the test piece box and tamp it; spread a layer of mica powder evenly on the surface between the layers of the simulated ore layer as the weak layer of the layer, and smooth the surface with a wall knife. Insert the measurement mark at the designated position of the layer; install each layer in order until all the rock layers are installed in the test piece box;

(5) In step (4), according to the results of step (2), sensors are arranged in the test piece, and an oil bag is set in the test piece to simulate the coal seam. dig;

(6) After the similar materials are dried, return the specimen box to the horizontal position.

Preferably, in order to better observe the deformation of the rock formation, since the udec software is especially suitable for simulating the response of the jointed rock system or the discontinuous block assembly system under static or dynamic load conditions, the deformation of the rock formation can be analyzed by using the udec software The numerical simulation is carried out regularly, and the cracks are extracted from the crack field formed by the numerical simulation to obtain the crack distribution, and the drilling positions are arranged on the test piece according to the extracted crack field for drilling.

In order to realize the invention object of the third aspect of the present invention, the present invention provides a kind of three-dimensional similar simulation test load simulation method, comprising the following steps:

(1) The up and down direction is the Z direction, the left and right direction is the X direction, and the front and rear direction is the Y direction. The force control method is used to load the horizontal loading pressure in the X direction, the horizontal loading pressure in the Y direction, and the vertical loading pressure in the Z direction. The loading sequence is :

a) Simultaneously load X-direction and Y-direction N (N is a natural number) seconds, and then load Z-direction N seconds;

b) repeat step a);

c) Simultaneously load X-direction and Y-direction 2N seconds, and then load Z-direction 2N seconds;

d) Repeat step c) until the three-way loading pressure reaches the predetermined value, which is the actual measured in-situ stress of the working condition;

In steps a) to d), the loading rate is constant;

(2) holding load;

(3) When the vertical loading pressure in the Z direction is ≥5kN, and the instantaneous drop force of the vertical loading pressure in the Z direction is ≥0.3kN, the three-way loading is switched to the displacement control mode.

Preferably, in step (1), the force loading speed range of the force control mode is 0.01kN/s-100kN/s, generally preferably 0.05kN/s.

In step (3), the loading speed range of the displacement control mode is 0.1mm/min-100mm/min, and generally preferably 0.1mm/min.

In order to realize the invention object of the fourth aspect of the present invention, the present invention provides a method for simulating the production layer of a three-dimensional loading large-scale three-dimensional similar simulation test, including the following steps:

(1) Make a rock formation test piece, and set a number of oil pockets in the test piece;

(2) The oil in the oil bag is pumped out by a micro-vacuum pump to form a production layer. The oil extraction rate is determined according to the aforementioned excavation rate. The excavation of the production layer is realized by pumping the oil in the oil bag, and the excavation speed is simulated by the oil pumping speed of the oil bag. For example, the actual excavation speed of a coal seam in a certain mine is 3.6m/d, according to the geometric similarity ratio α ₁ =100, the time similarity ratio The excavation speed of the model is calculated to be 0.25mm/min. Due to the different sizes of the oil pockets, the pumping speed range is: 0.01L/min-0.5L/min. The pumping speed is generally 0.025L/min-0.03L/min.

The beneficial effects of the present invention are:

(1) The present invention can truly simulate the three-dimensional stress state of the ground stress. When the model size is 3000mm×3000mm×3000mm, 9 jacks are arranged in the vertical direction (the loading area of each jack is 1000mm×1000mm), and 18 jacks are arranged in both horizontal directions. The cost of one jack (the loading area of each jack is 1000mm×500mm), so that the non-uniform loading of vertical stress and stress in two horizontal directions can be realized through multiple groups of hydraulic jacks, which can simulate different roof activity stages in the underground mining process. The complex distribution phenomenon of coal seam stress at that time.

(2) The size of the test piece of the present invention is variable, and a set of hardware systems can be used to simulate different coal seam conditions. For example, a 1000mm×1000mm×1000mm test piece can simulate roadway excavation; a 2000mm×2000mm×2000mm test piece can simulate the southwest region Thin coal seam situation; 3000mm×3000mm×3000mm test piece can simulate the thick coal seam situation in the north.

(3) The invention can adjust the angle of the test piece box, so when making the test pieces, the test piece box can be adjusted to the inclination angle of the ore seam to stack materials horizontally, and after the materials are dried, the test bench can be put back to the horizontal state, which is similar to the past It is more convenient and effective for the simulated test bench to pile up the ore seam with a large dip angle under horizontal conditions.

(4) The present invention can use the oil bag to simulate the mining layer, and extract the air in the oil bag to simulate the mining of the mining layer. This can ensure that the rock mass exists under the three-dimensional stress condition during the entire mining process.

(5) The load control method of the present invention is full closed-loop control of force and displacement, and the self-programming control mode of force and displacement, which is more flexible, smarter and more diverse than the loading method of similar simulation test devices in the past, and can study more processes Excavation of underground space under circumstances.

(6) Half of the test system is underground, which reduces the height of the entire system above the surface, and uses the underground reaction wall to reduce the cost and make the system more stable.

(7) The test piece transportation of the present invention is driven by a belt feeder, which saves time and effort.

Description of drawings

Fig. 1 is a schematic structural view of a specific embodiment of the present invention.

Fig. 2 is a partially enlarged view of IV in Fig. 1 .

FIG. 3 is a schematic top view of the structure in FIG. 1 .

FIG. 4 is an enlarged cross-sectional view along line E-E of FIG. 3 .

Fig. 5 is a left view structural diagram of Fig. 4 .

Fig. 6 is a left view structural diagram of Fig. 1 .

Fig. 7 is a partial enlarged view of III in Fig. 6 .

Fig. 8 is a schematic structural view of a test piece box in a specific embodiment of the present invention.

FIG. 9 is a left view structural diagram of FIG. 8 .

FIG. 10 is a schematic top view of the structure of FIG. 8 .

Fig. 11 is a partial enlarged view of position I in Fig. 10 .

Fig. 12 is a partially enlarged view of II in Fig. 10 .

Fig. 13 is a schematic structural view of a pressure seat in a specific embodiment of the present invention.

FIG. 14 is a schematic top view of the structure of FIG. 13 .

Fig. 15 is a left view structural diagram of Fig. 13 .

Fig. 16 is a schematic structural view of the traction mechanism in a specific embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

As shown in Figures 1 to 16, a three-dimensional loading large-scale three-dimensional similar simulation test system includes a specimen box and a reaction system. The test piece box includes a base 1, and the edge of the base 1 is provided with a left screw hole band 13, a right screw hole band 14, a front screw hole band 15 and a rear screw hole band 16 forming a square. The base 1 is fixedly connected with the left side plate 3 at the left screw hole band 13 by bolts, and is fixedly connected with the front side plate 5 at the front screw hole band 15 by bolts.

Between the right screw hole band 14 and the left screw hole band 13, two first middle screw hole bands 17 are arranged, and two screw hole bands respectively connected with the first middle screw hole bands are arranged between the rear screw hole band 16 and the front screw hole band 15. 17 vertically connected second middle screw hole bands 18, the first middle screw hole bands 17 and the second middle screw hole bands 18 and the left screw hole band 13 and the right screw hole band 14 form a square.

The right screw hole band 14 and the two first middle screw hole bands 17 can be fixedly connected to the right side plate 4 by bolts, and the rear screw hole band 16 connected with the right side plate 14 and the two second middle screw hole bands 18 Both can be fixedly connected to the rear side plate 6 by bolts.

In this embodiment, when the right side plate 4 is set on the right screw hole belt 14, and the rear side plate 6 is set on the rear screw hole belt 16, then each side plate and the base 1 can enclose a three-dimensional space of 3000mm×3000mm×3000mm; The right side plate 4 is set on the right first middle screw hole belt 17, and the rear side plate 6 is set on the rear second middle screw hole belt 18, then each side plate and the base 1 can be enclosed into a 2000mm×2000mm×2000mm Three-dimensional space; when the right side plate 4 is set on the left first middle screw hole belt 17, and the rear side plate 6 is set on the front second middle screw hole belt 18, then each side plate and the base 1 can be surrounded by a 1000mm× 1000mm×1000mm three-dimensional space.

In this embodiment, each side plate is a split structure that can be connected by bolts, so that the specimen boxes can be spliced into different sizes.

In other specific embodiments, the positions of the first middle screw hole band 17 and the second middle screw hole band 18 can be flexibly set according to needs, so that the specimen boxes can be spliced into other sizes or shapes.

The rear side plate 6 is provided with a sensor wiring hole 19 , and the outer side of the rear side plate 6 is fixed with a first backing plate 31 at intervals.

The inner side of the left side plate 3 is fixedly connected with a left pressure seat 7 by bolts, and the left side plate 3 is provided with a left pressure sleeve 9 according to an evenly divided area. Left pressure rod 8, left pressure rod 8 passes left pressure sleeve 9. As shown in FIG. 9 , the left side panel 3 is 3000mm×3000mm, which can be equally divided into nine areas of 1000mm×1000mm, each area is provided with two left pressure sleeves 9 .

The inner side of the front side plate 5 is fixedly connected with a front pressure seat 10 by bolts, and the front side plate 5 is provided with a front pressure sleeve 11 according to an evenly divided area; The front pressing rod 12; the front pressing rod 12 passes through the front pressing sleeve 11. As shown in FIG. 8 , the front side plate 5 is 3000mm×3000mm, which can be equally divided into nine areas of 1000mm×1000mm, each area is provided with two front pressure sleeves 11 .

The left press seat 7 is spaced apart from the front press seat 10.

The reaction force system comprises the concrete reaction force pool 23 under the ground, the bottom of the reaction force pool 23 is provided with the first reaction force seat 24a fixedly connected with the reaction force pool 23, and the right side of the first reaction force seat 24a is provided with a second The reaction force seat 24b and the second reaction force seat 24b are fixed to the bottom of the reaction force pool 23, and at the same time are fixedly connected to the first reaction force seat 24a by bolts. Stairs 56 connected to the ground are provided on both sides of the reaction force pool 23 , and various components in the reaction force pool 23 can be installed and maintained through the stairs 56 . the

The reaction force pool 23 is provided with a side bearing frame 26 fixedly connected with the first reaction force seat 24a on the left side of the test piece box, and close to the concrete wall. Rod 8 corresponds to the left hydraulic cylinder 27. The reaction force pool 23 is provided with a reaction force frame 28 bolted to the second reaction force seat 24b on the right side of the test piece box, and the reaction force frame 28 can be fixedly connected with the test piece box by bolts.

The front portion of the first reaction force seat 24a is fixed with a front column 29, and one end surface of the front column 29 is close to the concrete wall surface of the reaction force pool 23, and the other end surface is fixed with a number and a position corresponding to the front pressure rod 12. Cylinder 30.

The rear portion of the first reaction force seat 24a is fixed with a rear column 33, and one end surface of the rear column 33 is close to the concrete wall surface of the reaction force pool 23, and the other end surface is fixed with a number and a position corresponding to the first backing plate 31, and The second backing plate 32 can be in close contact with the first backing plate 31 .

The front column 29 and the rear column 33 are connected as an integral structure through the fixed beam 55 above, and the upper hydraulic cylinder 34 opposite to the specimen box is uniformly arranged on the beam 55 .

The simulation test system also includes a pressure seat 35, which transmits the loading force of the upper hydraulic cylinder 34 to similar materials in the test piece box when similar simulation tests are performed. The pressure seat 35 includes an upper plate 35a and a bottom plate 35b, the upper plate 35a and the bottom plate 35b are connected into one structure through a vertical plate 35c, and a rib plate 35d is arranged on the vertical plate 35c.

In the height direction, a first anti-interference seat 20 in contact with the front press seat 10 and the left press seat 7 is placed at the corner of the front press seat 10 and the left press seat 7, and a second anti-interference seat 20 is placed inside the left press seat 7. The seat 21, the first anti-interference seat 20 and the second anti-interference seat 21 are arranged at intervals.

The end of the first anti-interference seat 20 away from the left pressure seat 7 has a wedge-shaped structure; the top end of the first anti-interference seat 20 has a wedge-shaped structure;

A rolling guide rail 25 is arranged on the first reaction force seat 24a, and the test piece box can be placed on the rolling guide rail 25 .

Two pull seats 22 are arranged at intervals on the left and right sides of the base 1; traction mechanisms corresponding to the pull seats 22 are arranged on the left and right sides of the test piece box. The traction mechanism includes a speed reducer 36, the speed reducer 36 is connected with the first end of the first reel 38 through the first shaft coupling 37, and the second end of the first reel 38 passes through the second coupling 39, the transmission shaft 40 and the first end of the first reel 38. The third coupling 41 is coupled with the second drum 42 . The first reel 38 and the second reel 42 are wound with a wire rope 43 that can be connected with the pull seat 22 .

The front side of the second reaction force seat 24b is provided with the first steel wire rope fixing seat 44 that can fix the steel wire rope of the first reel 38; Two wire rope holders 45.

The right side of the second reaction force seat 24b is provided with a third reaction force seat 24c, and the third reaction force seat 24c is fixed to the bottom of the reaction force pool 23, and is fixedly connected with the second reaction force seat 24b by bolts simultaneously.

The right end of the third reaction force seat 24c is provided with a first hinged seat 46 and a second hinged seat 47 at intervals, and the right end of the base 1 is provided with a third hinged seat 48 and a third hinged seat 48 which can be hinged with the first hinged seat 46 and the second hinged seat 47 respectively. The fourth hinge seat 49.

The reaction force pool 23 is respectively provided with oil cylinder supports 51 at the front and rear ends of the third reaction force seat 24c near the second reaction force seat 24b, and an oil cylinder 52 is hinged on the oil cylinder support 51. The end of the piston rod 53 of the oil cylinder 52 is hinged with a thrust support 54, and the thrust support 54 can be connected with the base 1 of the test piece box.

A row of oil bag mounting holes 50 are correspondingly provided on the front side plate 5 and the rear side plate 6 .

The test system carries out the simulation test according to the following steps:

(1) Test piece box preparation: install the right side plate 4 on the right screw hole belt 14, and install the rear side plate 6 on the rear screw hole belt 16 to obtain a test piece box with a size of 3000mm×3000mm×3000mm; place the test piece The base 1 of the box is connected with the thrust support 54, and at the same time the first hinged seat 46 is hinged with the third hinged seat 48, the second hinged seat 47 is hinged with the fourth hinged seat 49; the test piece box is passed through the piston rod 53 of the oil cylinder 52 Jack up to the inclination angle θ of the ore seam required for the test, as shown in Figure 1. The specific size of the test piece box depends on the size of the test piece to be tested.

(2) Specimen preparation: comsol is based on the finite element method, and realizes the simulation of real physical phenomena by solving partial differential equations (single field) or partial differential equations (multiple fields). Science, porous media, structural mechanics, transmission phenomena, wave propagation and other fields have been widely used, so it is feasible to perform comsol simulation on the distribution of rock formation pressure field. Use the comsol numerical simulation software to numerically simulate the distribution of rock formation pressure, so that each pressure sensor can measure the stress distribution of the rock formation more accurately. Specific location; according to the geometric similarity ratio, bulk density similarity ratio, stress similarity ratio and strength similarity ratio, the mechanical property parameters such as bulk density, compressive strength, and excavation speed of the model rock are calculated, and the river sand, gypsum, and calcium carbonate are used in different proportions. Stir evenly with an appropriate amount of water, make a number of standard specimens and air-dry them in a natural state, measure the uniaxial compressive strength of the standard specimens, and compare the compressive strength calculated according to the strength similarity ratio with a different ratio By comparing the series of uniaxial compressive strengths, the best proportion of similar materials in each layer is obtained. According to the best proportion and bulk density of each layer, the required mass of each layered material is calculated, and the mass of the corresponding ingredients is weighed. Stir all the ingredients evenly, then add appropriate amount of water, and stir immediately to prevent condensation; after stirring evenly, put the ingredients into the test piece box and compact them; spread a layer of mica powder evenly on the surface between the layers of the simulated mine layer As the layered weak surface, smooth the surface with a wall knife, and at the same time insert a measuring mark at the designated position of each layer; install each layer according to the above steps in order, until all rock layers are installed in the test piece box; At the same time, the sensors are arranged according to the simulation results of the comsol numerical simulation software, and the oil pockets are set in the test piece to simulate the coal seam according to the positions of the installation holes 50 of each oil pocket, the thickness of the simulated coal seam is controlled by the amount of oil filling, and the opening of the coal seam is simulated by the oil drainage. Digging; after the similar material is dried, return the piston rod 53 of the oil cylinder 52, so that the test piece box is returned to the horizontal position.

On the other hand, udec is a tool that provides accurate and effective analysis for geotechnical engineering by using explicit problem-solving schemes. Explicit problem-solving schemes provide stable solutions for unstable physical processes and can simulate the failure process of objects. The software is especially It is suitable for simulating the response of jointed rock system or discontinuous block aggregate system under static or dynamic loading conditions. Using udec numerical simulation software to carry out numerical simulation of the deformation law of the rock formation, extract the cracks from the crack field formed by the udec numerical simulation software, obtain the distribution of cracks, and arrange the drilling positions on the test piece according to the extracted crack field for drilling.

(3) Loading: place a TV imager in the borehole; disassemble the base 1 and the thrust support 54 of the specimen box, and simultaneously disassemble the first hinged seat 46 and the third hinged seat 48, the second hinged seat 47 and the second hinged seat Four articulated seats 49; the test piece box is sent into the first reaction force seat 24a by the traction mechanism, and the test piece box is fixed; the reaction force frame 28 is installed; the up and down direction is the Z direction, the left and right direction is the X direction, and the front and rear direction is In the Y direction, the force control method is used to load the horizontal loading pressure in the X direction, the horizontal loading pressure in the Y direction, and the vertical loading pressure in the Z direction. The loading sequence is:

a) Simultaneously load the X and Y directions for 10 seconds, then load the Z direction for 10 seconds; the loading rate is constant at 0.05kN/s;

b) repeat step a);

c) Simultaneously load the X and Y directions for 20 seconds, then load the Z direction for 20 seconds; the loading rate is constant at 0.05kN/s;

d) Repeat step c) until the three-way loading pressure reaches a predetermined value, and the predetermined value is the ground stress measured on site under working conditions, which is 20KN in this embodiment;

e) holding load;

f) When the vertical loading pressure in the Z direction is ≥5kN, and the instantaneous drop force of the vertical loading pressure in the Z direction is ≥0.3kN, the three-way loading is switched to the displacement control mode, and the loading speed is 0.1mm/min.

(4) Excavation and observation: The excavation of the coal seam extracts the oil in the oil bag through the micro vacuum pump. Due to the formation of gobs during mining, the rock strata will be deformed or even destroyed under the action of in-situ stress. Through the data acquisition system, the stratum stress at different layers of the strata, the subsidence of each measuring point, the collapse height, fracture and separation of the overlying rock due to the in-situ stress (external force and self-gravity) during the mining process are collected; through drilling The hole TV imager observes the distribution range of cracks, the height of the cracks in the strata per unit thickness, the number of cracks per unit thickness, etc.

The oil in the oil bag is pumped out by a micro-vacuum pump to form a production layer. The oil extraction rate is determined according to the aforementioned excavation rate. The excavation of the production layer is realized by pumping the oil in the oil bag, and the excavation speed is simulated by the oil pumping speed of the oil bag. For example, the actual excavation speed of a coal seam in a certain mine is 3.6m/d, according to the geometric similarity ratio α ₁ =100, the time similarity ratio The model excavation speed is calculated to be 0.25mm/min. Due to the different sizes of the oil pockets, the oil pumping speed range is: 0.01L/min-0.5L/min, usually preferably 0.025L/min-0.03L/min. In this embodiment, the smoking speed is 0.028L/min.

In step (3), different loading methods and holding time can be set according to the needs of the research. If the relaxation of the rock mass is studied, the displacement control loading is used at the beginning to bring the displacement to a predetermined value.

In step (3), the time for the rock mass to fail and become unstable under the predetermined load due to the mine layer to be excavated varies according to the percentage of the predetermined load value reaching the peak stress that the rock mass can withstand after excavation, and the load remains stable during this period , until the rock mass loses stability.

In step (3), because the rock mass cannot bear the pre-determined load after the instability, the rock mass still has a certain bearing capacity. After switching to position loading, the stress-strain characteristics of the rock mass instability can be studied. It has certain guiding significance to guide engineering practice.

In this embodiment, according to the other two specific positions where the right side plate 4 and the rear side plate 6 are installed, a test piece box with a size of 1000mm×1000mm×1000mm or 2000mm×2000mm×2000mm can be obtained, but this does not affect the subsequent test operation . However, due to the smaller size of the test piece box, it may affect the loading of the hydraulic cylinder in the direction of smaller size, so the force transmission of the backing plate can be set in the corresponding direction to achieve basically the same technical effect.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims (9)

1. three-dimensional loads a large-scale three dimensional resemble simulation test system, comprises test piece box and counter force system, it is characterized in that:

Described test piece box comprises base (1); The edge of described base (1) is provided with and forms foursquare left screw band (13), right screw band (14), front screw band (15) and rear bolt hole band (16); Described base (1) has been bolted to connection left plate (3) at described left screw band (13) place, has been bolted to connection front side board (5) at described front screw band (15) place;

At least one first middle screw pore area (17) is provided with between described right screw band (14) and described left screw band (13); The second middle screw pore area (18) that is corresponding with described first middle screw pore area (17) quantity, vertical connection is provided with between described rear bolt hole band (16) with described front screw band (15); The the first middle screw pore area (17) connected and the second middle screw pore area (18) form square with described left screw band (13) and right screw band (14); Described right screw band (14) or arbitrary described first middle screw pore area (17) have been bolted to connection right plate (4); The described rear bolt hole band (16) connected with described right plate (14) or arbitrary described second middle screw pore area (18) have been bolted to connection back side panel (6); Described back side panel (6) is provided with sensor wiring hole (19); The outside spacers of described back side panel (6) is fixed with the first backing plate (31);

The inner side of described left plate (3) has been bolted to connection left wedge (7); Described left plate (3) is provided with left gland (9) by equal subregion; Described left wedge (7) is fixed with quantity and the position left depression bar (8) corresponding with described left gland (9); Described left depression bar (8) passes described left gland (9);

The inner side of described front side board (5) has been bolted to connection front wedge (10); Described front side board (5) is provided with front gland (11) by equal subregion; Described front wedge (10) is fixed with quantity and the position forward press (12) corresponding with described front gland (11); Described forward press (12) passes described front gland (11);

Described left wedge (7) and described front wedge (10) interval are arranged;

Described counter force system comprises and is positioned at underground concrete counter-force pond (23); The bottom of described counter-force pond (23) is provided with the first counter-force seat (24a) be fixedly connected with described counter-force pond (23); The right side of described first counter-force seat (24a) is provided with the second counter-force seat (24b); Fix at the bottom of described second counter-force seat (24b) and the pond of described counter-force pond (23), and be bolted to connection with described first counter-force seat (24a) simultaneously;

Described counter-force pond (23) is provided with in the left side of described test piece box and is fixedly connected with described first counter-force seat (24a), and near the side heavy frame (26) of concrete wall surface; Described side heavy frame (26) is fixed with quantity and the position left hydraulic cylinder (27) corresponding with described left depression bar (8); Described counter-force pond (23) is provided with on the right side of described test piece box and described second counter-force seat (24b) bolted reaction frame (28); Described reaction frame (28) can be bolted to connection with described test piece box;

The front portion of described first counter-force seat (24a) is fixed with front column (29); One end face of described front column (29) is near the concrete wall surface of described counter-force pond (23), and other end is fixed with quantity and the position front hydraulic cylinder (30) corresponding with described forward press (12);

The rear portion of described first counter-force seat (24a) is fixed with rear column (33); One end face of described rear column (33) near the concrete wall surface of described counter-force pond (23), other end be fixed with quantity and position corresponding with described first backing plate (31) and second backing plate (32) of described first backing plate (31) can be close to;

Described front column (29) and rear column (33) connect as one structure by the crossbeam (55) that top is fixing; Described crossbeam (55) is above uniform is provided with the upper hydraulic cylinder (34) relative with described test piece box;

Described three-dimensional loads large-scale three dimensional resemble simulation test system and also comprises the first wedge (35); When carrying out resemble simulation test, the loading force of described upper hydraulic cylinder (34) is passed on the analog material in described test piece box by described first wedge (35).

2. three-dimensional as claimed in claim 1 loads large-scale three dimensional resemble simulation test system, it is characterized in that: in the height direction, described front wedge (10) and the corner of described left wedge (7) are placed with the first anti-interference seat (20) contacted with left wedge (7) with described front wedge (10); The inner side of described left wedge (7) is placed with the second anti-interference seat (21); Described first anti-interference seat (20) and the second anti-interference seat (21) interval are arranged.

3. three-dimensional as claimed in claim 2 loads large-scale three dimensional resemble simulation test system, it is characterized in that: described first anti-interference seat (20) is wedge structure away from described left wedge (7) one end; The top of described first anti-interference seat (20) is wedge structure; Described second anti-interference plate (21) is wedge structure near described front wedge (10) one end.

4. three-dimensional as claimed in claim 1 loads large-scale three dimensional resemble simulation test system, it is characterized in that: described first counter-force seat (24a) is provided with rolling guide (25); Described test piece box can be placed on described rolling guide (25);

The left and right sides of described base (1) is provided with pulling seat (22); The left and right sides of described test piece box is provided with the haulage gear corresponding with described pulling seat (22).

5. three-dimensional as claimed in claim 4 loads large-scale three dimensional resemble simulation test system, it is characterized in that: the left and right sides of described base (1) is all arranged at intervals with two pulling seats (22); Described haulage gear comprises reductor (36); Described reductor (36) is connected by the first end of the first shaft coupling (37) with the first reel (38); Second end of described first reel (38) is connected with the second reel (42) by the second shaft coupling (39), transmission shaft (40) and the 3rd shaft coupling (41); Described first reel (38) with the second reel (42) is wound with the wire rope (43) that can be connected with described pulling seat (22).

6. three-dimensional as claimed in claim 5 loads large-scale three dimensional resemble simulation test system, it is characterized in that: the front side of described second counter-force seat (24b) is provided with the first wire rope holder (44) of the wire rope can fixing described first reel (38); The rear side of described second counter-force seat (24b) is provided with the second wire rope holder (45) of the wire rope can fixing described second reel (42).

7. three-dimensional as claimed in claim 1 loads large-scale three dimensional resemble simulation test system, it is characterized in that: described first wedge (35) comprises upper plate (35a) and base plate (35b), described upper plate (35a) and base plate (35b) connect as one structure by riser (35c); Described riser (35c) is provided with gusset (35d).

8. the three-dimensional as described in as arbitrary in claim 1 to 7 loads large-scale three dimensional resemble simulation test system, it is characterized in that:

The right side of described second counter-force seat (24b) is provided with the 3rd counter-force seat (24c); Fix at the bottom of described 3rd counter-force seat (24c) and the pond of described counter-force pond (23), and be bolted to connection with described second counter-force seat (24b) simultaneously;

The right-hand member of described 3rd counter-force seat (24c) is arranged at intervals with the first hinged seat (46) and the second hinged seat (47); The right-hand member of described base (1) arrange can respectively with described first hinged seat (46) and hinged the 3rd hinged seat (48) of the second hinged seat (47) and the 4th hinged seat (49);

Described counter-force pond (23) is respectively arranged with cylinder support (51) at described 3rd counter-force seat (24c) near the rear and front end of described second counter-force seat (24b) side; Described cylinder support (51) is hinged with oil cylinder (52); Piston rod (53) end of described oil cylinder (52) is hinged with thrust bearing (54); Described thrust bearing (54) can be connected with the base of described test piece box (1).

9. the three-dimensional as described in as arbitrary in claim 1 to 7 loads large-scale three dimensional resemble simulation test system, it is characterized in that: described front side board (5) and back side panel (6) are gone up correspondence and be provided with at least one row oil sac mounting hole (50).