CN111442979B - Model test system for static expansive force induced cracking soft rock - Google Patents

Abstract

The invention provides a model test system for soft rock splitting by static expansion force, which comprises an outer frame with a containing space, a model pool and a casting device, wherein the model pool is contained in the containing space and fixed on the outer frame, the casting device is communicated with the model pool and is used for injecting casting materials into the model pool, the casting materials are cured and formed in the model pool to form a rock mass model, the rock mass model comprises a rock mass model and a joint model which is dispersedly arranged in the rock mass model, a plurality of special-shaped holes are also arranged in the rock mass model, the special-shaped holes are formed by die casting of a special-shaped hole manufacturing device, the special-shaped holes are used for filling a static crushing agent, the model pool is made of transparent organic glass, and the casting materials are water-containing unsaturated polyester resin. The model test system for the static expansive force induced cracking soft rock can be used for conveniently watching the structural change in the model pool.

Description

A Model Test System for Soft Rock Fractured by Static Expansion Force

【Technical field】

The invention relates to the technical field of model test devices, in particular to a model test system for soft rock cracked by static expansion force.

【Background technique】

The traditional blasting method with the help of explosives releases a large amount of energy instantly, bringing huge destructive power. The blasting process is often accompanied by shock waves, flying dust and flying stones. When the blasting site is located in the city, the undesirable phenomena in the blasting process are sometimes unacceptable. In addition, when the blasting object is soft rock, the shock wave generated during the blasting process will change the stress state inside the rock mass, which will further develop the cracks inside the rock mass, reduce the integrity of the rock mass, and then weaken the overall strength of the rock mass. will cause malignant damage to the rock mass. These defects make the traditional blasting method subject to many restrictions, and the ordinary manual or mechanical excavation is too inefficient, which affects the construction progress. In response to these problems, static expansion cracking technology came into being. This construction method first uses static expansion cracking rock mass, and then uses air picks to disintegrate the rock mass, and the construction efficiency is greatly improved.

Static expansion cracking utilizes the expansion pressure generated by the volume expansion of the static crushing agent when it undergoes a hydration reaction to break concrete, rocks, etc. The static crushing agent is loaded into the pre-drilled blast hole, and the hydration reaction occurs under the action of the catalyst, and the volume expands after a certain period of time; due to the limitation of the hole wall, the expansion pressure can be generated, and the radial direction around the circular hole can be generated. When the tangential tensile stress is greater than the tensile strength of the broken object, the broken object will be placed on the hole wall. Cracks occur.

Static bursting has the advantages of safety and convenience, little impact on the environment, good rock breaking effect, and little influence on the deterioration of rock mass integrity. But there are still three main shortcomings: 1. The rock breaking time is long, the stress redistribution period in the surrounding area of the circular blasthole is long, and the stress change range is small, so that it generally takes 8 -10h; 2. The joint surface in the rock mass is not fully utilized to improve the rock breaking efficiency; 3. There is no written technical specification for the static bursting construction, and the on-site construction is highly subjective and the construction effect is poor. At the same time, there is no systematic study on the internal mechanism and development process of static expansion, the shape of cracks after static expansion, the influence of boundary conditions and blasthole shape on static expansion. In order to study and solve the above problems, it is necessary to carry out a large number of experiments; but if the field test is used, it will not only consume a large amount of materials, but also it is difficult to conduct enough experiments to ensure the rationality and integrity of the experimental results, and it is difficult to test the same object. Repeated experiments were carried out to explore the optimal construction method.

Therefore, it is necessary to provide a model test system for soft rock cracked by static expansion force to solve the above problems.

[Content of the invention]

The purpose of the present invention is to overcome the above technical problems and provide a model test system for soft rock cracked by static expansion force, which can easily observe the structural changes and strain changes in the rock mass model.

In order to achieve the above object, the present invention provides a model test system for soft rock cracked by static expansion force, including an outer frame with a receiving space, a model pool accommodated in the receiving space and fixed to the outer frame, and a model pool connected with the model pool. A casting device that communicates and is used to inject casting material into the model pool, the casting material is solidified and formed in the model pool to form a rock mass model, and the rock mass model includes a rock block model and is dispersed in the rock block model. The rock mass model is also provided with a plurality of special-shaped holes, the special-shaped holes are molded by the special-shaped hole making device, the special-shaped holes are used for filling static crushing agent, and the model pool is made of transparent made of plexiglass, and the casting material is a water-containing unsaturated polyester resin.

Preferably, the outer frame is in the form of a square frame as a whole, and the receiving space is formed inside the outer frame. The column of the top frame, the bottom frame is surrounded by four large square steel pipes connected end to end, the top frame is surrounded by four round steel tubes end to end, the column is a round steel pipe, and the inner Two spacers are welded evenly in the longitudinal direction and the transverse direction respectively, and the spacer bars arranged in the transverse direction and the spacer bars arranged in the longitudinal direction are perpendicular to each other.

Preferably, the model pool is carried on the bottom frame, and the model pool includes a bottom plate, a plurality of wall rings connected with the bottom plate, honeycomb columns installed on the wall rings, and a connection between the bottom plate and the The reaction force column of the wall ring, the bottom plate is a circular plate-like structure, the wall ring is a circular ring that matches the shape of the outer circumference of the bottom plate, and a plurality of the wall rings are along the shape of the model pool. The height direction is stacked in sequence, and the wall ring includes a common wall ring and a holed wall ring, the ordinary wall ring and the holed wall ring are stacked in sequence, and the holed wall ring is provided with a plurality of circular holes in the middle position of the height. The circular holes are evenly distributed along the circumference of the holed wall ring, the axial direction of the circular hole points to the axis of the holed wall ring, the honeycomb column is fixed in the circular hole, and the honeycomb column is insulated by heat insulation The honeycomb column is made of ceramics, and there are a plurality of small round holes evenly distributed inside the honeycomb column, and the small round holes communicate with the model pool and the outside world.

Preferably, the reaction force column is used to connect the bottom plate and the wall ring, the bottom plate is provided with at least two through holes in the height direction, and the reaction force column and the through holes are arranged in a one-to-one correspondence, The reaction column includes a concave column, a reaction plate and a bolt. The concave column has a U-shaped structure and includes a bottom wall and two side walls bent and extended from both ends of the bottom wall. The side walls are spaced in parallel to each other, the cross-sectional shape of the side walls matches the shape of the through holes, the bottom plate is supported on the bottom wall, and the wall ring is sandwiched between the two side walls , the inner side of the side wall is an arc surface, the shape of the arc surface matches the shape of the outer side arc surface of the wall ring, the top of the side wall is provided with a hole, and the two side walls are The holes are oppositely arranged, the reaction plate can penetrate into the two holes, the middle position of the reaction plate is provided with a threaded hole, and the bolt can pass through the threaded hole to abut the wall ring.

Preferably, the casting device includes a material barrel, a first rubber hose, an electric pump and a second rubber hose that are communicated in sequence, the material barrel contains an emulsion of water-unsaturated polyester resin, and the second The rubber hose extends from the top opening of the model pool to the bottom of the model pool along the inner wall of the model pool.

Preferably, the special-shaped hole extends straight downward from the upper end face of the rock mass model along the height direction of the rock mass model, and the special-shaped hole is in the shape of a triangular prism or a quadrangular prism.

Preferably, the special-shaped hole making device includes a large buckle, a chute, a small buckle and a special-shaped rod, the large buckle is correspondingly clamped on the top frame, and the two ends of the chute are respectively vertically welded to two The outer surface of the large buckle; the inside of the chute has a T-shaped guide rail, and the small buckle is welded with a T-shaped positioning post. sliding in the chute; the special-shaped rod is made of aluminum alloy, the upper part is a cylinder, and the lower part is a triangular prism or a quadrangular prism, and the special-shaped rod is fixed by tightening the wing nut of the small buckle.

Preferably, the joint model includes a plurality of joint model sheets spliced with each other and a plurality of hollow copper tubes connected to the joint model sheet, the joint model sheet includes a joint sheet and an unsaturated polyester resin reinforcement layer, and the The unsaturated polyester resin reinforcement layer covers both sides of the joint sheet, the hollow copper tube includes an input end and an output end, the input end is exposed outside the model pool, and the output end passes through the The small round holes of the honeycomb column are fixed with the joint model sheet.

Preferably, the model test system further includes a strain measuring device for measuring the strain value at the working surface of the special-shaped hole, the strain measuring device includes a sensing element and a signal receiving and processing instrument connected to the sensing element, The sensing element is arranged in the working surface of the special-shaped hole, the signal receiving and processing instrument is arranged outside the model pool, and the sensing element and the signal receiving and processing instrument are connected by wires.

Preferably, the model test system further includes a measurement and recording device, which is fixed on the outer frame and used to measure and record the test process of the model pool. The measurement and recording device includes a buckle, a movable Arm and measurement and recording equipment, the buckle is movably connected to the outer frame, the movable arm is a multi-section long arm, and the multi-section long arms are hinged to each other, and the measurement and recording device is fixed to the movable arm The measurement and recording device includes one or more of a laser displacement meter, a transmitting end and a receiving end of an ultrasonic measuring instrument, and a camera.

Compared with the related art, in the model test system for soft rock cracked by static expansion force provided by the present invention, the model pool is made of transparent plexiglass, and the casting material is water-containing unsaturated polyester resin, which can be easily observed. Structural changes in the rock mass model; by introducing a joint model, the on-site geological conditions can be more realistically restored; by setting a strain measuring device and a measuring recording device, the changes of physical quantities inside and outside the rock mass model can be measured, and the test process can be recorded; And through the cooperation of various subsystems, special-shaped holes with different shapes can be made, the internal mechanism of static expansion cracking can be studied, the optimization effect of different shapes and arrangements of special-shaped holes on static expansion cracking can be explored, and the utilization of In order to optimize the construction method of static expansion cracking, the optimal construction scheme is obtained through repeated tests, which provides a scientific basis for on-site construction. The model test system for soft rock cracked by static expansion force provided by the invention has powerful functions, wide application range, convenient operation, simple structure, and is convenient for popularization and use.

【Description of drawings】

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, under the premise of no creative work, other drawings can also be obtained from these drawings, wherein:

Fig. 1 is the structural representation of a kind of model test system of static expansion force cracking soft rock provided by the present invention;

Fig. 2 is the structural representation of the outer frame shown in Fig. 1;

Fig. 3 is the structural representation of the model pool shown in Fig. 1;

Fig. 4 is a schematic diagram of a partially exploded structure of the model pool shown in Fig. 3;

FIG. 5 is a schematic structural diagram of the honeycomb column shown in FIG. 3

Fig. 6 is the exploded structure schematic diagram of the reaction force column shown in Fig. 3;

Fig. 7 is the structural schematic diagram of the rock mass model shown in Fig. 1;

FIG. 8 is a schematic structural diagram of the special-shaped hole making device shown in FIG. 1;

Fig. 9 is the exploded structure schematic diagram of the special-shaped hole making device shown in Fig. 8;

Figure 10 is a schematic diagram of the structure of the joint model.

【Detailed ways】

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1 to FIG. 10 , the present invention provides a model test system 100 of soft rock cracked by static expansion force. The model test system 100 of soft rock cracked by static expansion force includes an outer frame 1 , a model pool 2 , Casting device 3 , rock mass model 4 , strain measurement device 5 and measurement recording device 6 .

The outer frame 1 has a square frame structure as a whole, and an accommodation space is formed inside the outer frame 1 . The outer frame 1 includes a bottom frame 11, a top frame 12 arranged parallel to the bottom frame 11 and spaced apart, and a column 13 connecting the bottom frame 11 and the top frame 12. The bottom frame 11 is made of four large square steel pipes. The top frame 12 is surrounded by four round steel pipes in turn, and the upright columns 13 are round steel pipes. Specifically, the bottom frame 11 , the top frame 12 and the uprights 13 are fixedly connected by welding, and the uprights 13 are arranged at the four corners of the bottom frame 11 and the top frame 12 . stable structure.

Two spacers 14 are welded evenly in the lateral and longitudinal directions inside the bottom frame 11 respectively, and the spacers 14 arranged in the transverse direction and the spacers 14 arranged in the longitudinal direction intersect with each other perpendicularly.

The model pool 2 is accommodated in the accommodating space and carried on the outer frame 1. Specifically, the model pool 2 is carried on the bottom frame 11, and the spacer 14 is the model pool 2. Good force support is provided, and at the same time, the model pool 2 can be separated from the ground by a certain space, which is convenient for wiring.

The model pool 2 includes a bottom plate 21 , a wall ring 22 , a honeycomb column 23 and a reaction force column 24 . The bottom plate 21 , the wall ring 22 and the reaction force column 24 are all made of transparent plexiglass material, so that the changes of the models in the model pool 2 can be observed intuitively.

The bottom plate 21 has a circular plate-like structure, and the bottom plate 21 is provided with through holes 210 along the height direction. The number of the through holes 210 is at least two. Preferably, in this embodiment, the through holes 210 are The number of the holes 210 is two, and the two through holes 210 are symmetrically arranged on opposite sides of the bottom plate 21 .

The wall ring 22 is fixed on the bottom plate 21. Specifically, the wall ring 22 is in the shape of a circular ring that matches the outer circumference of the bottom plate 21. The number of the wall ring 22 is multiple, a plurality of The wall rings 22 are stacked in sequence along the height direction of the model pool 2 . The wall ring 22 and the bottom plate 21 are fixedly connected by a matching structure of grooves and protrusions, and the installation is convenient and reliable. Similarly, grooves and protrusions are also used between the adjacent two wall rings 22. This type of connection is selected by conventional techniques in the field, and will not be described in detail in the present invention. Preferably, silicone gaskets are provided at the connection positions of the bottom plate 21 and the wall ring 22 and two adjacent wall rings 22, and the arrangement of the silicone gaskets can increase the sealing performance of each contact surface.

The wall ring 22 includes an ordinary wall ring 221 and a holed wall ring 222. The ordinary wall ring 221 and the holed wall ring 222 are stacked in sequence, that is, a holed wall ring 222 is arranged between the two ordinary wall rings 221. , a common wall ring 221 is arranged between the two wall rings 222 with holes. In this embodiment, the common wall ring 221 is located at the bottom of the wall ring 22, and the wall ring 222 with holes is located at the top.

The wall ring 222 with holes is provided with a plurality of circular holes 2220 at the middle position of the height. The plurality of circular holes 2220 are evenly distributed along the circumference of the wall ring 222 with holes. The axial direction of the circular holes 2220 points to the wall ring with holes. 222 axis. In this embodiment, the number of the circular holes 2220 is six, and in other embodiments, the number of the circular holes 2220 can also be adjusted according to requirements.

The honeycomb column 23 is fixed in the circular hole 2220, and the honeycomb column 23 is made of heat-insulating ceramics, which can avoid damage to the wall ring 222 with holes during the test. A plurality of small round holes are evenly distributed inside the honeycomb column 23 , and the small round holes communicate with the model pool 2 and the outside. In this embodiment, the number of the small circular holes is 19, and the diameter is 3 mm.

The reaction force column 24 is used to press the bottom plate 21 and the wall ring 22 to each other and fix them as a whole, so as to increase the tightness of the model pool 2 . The reaction force columns 24 are arranged in a one-to-one correspondence with the through holes 210 . The reaction force column 24 includes a concave column 241 , a reaction force plate 242 and a bolt 243 .

The concave column 241 has a U-shaped structure, and includes a bottom wall 2411 and two side walls 2412 bent and extended from both ends of the bottom wall 2411 , and the two side walls 2412 are parallel and spaced apart from each other. The cross-sectional shape of the side wall 2412 matches the shape of the through hole 210 . The bottom plate 21 is supported on the bottom wall 2411 , and the wall ring 22 is sandwiched between the two side walls 2412 . Preferably, the inner surface of the side wall 2412 is an arc surface, and the shape of the arc surface matches the arc shape of the outer surface of the wall ring 22 .

The top of the side wall 2412 is provided with a hole, and the holes on the two side walls 2412 are arranged opposite to each other. The reaction force plate 242 can be inserted into the hole, the middle position of the reaction force plate 242 is provided with a threaded hole, the bolt 243 is screwed into the threaded hole and abuts against the wall ring 22, and is tightened. The bolts 243 can generate axial pressure, thereby pressing the wall ring 22, so that the plurality of wall rings 22 and the wall rings 22 are tightly connected with the bottom plate 21 and are not easy to fall off.

The installation process of the model pool 2 is as follows: place the two concave columns 241 according to preset positions; place the bottom plate 21 so that the side walls 2412 of the concave columns 241 pass through the through holes 210 correspondingly. , until the bottom plate 21 abuts the bottom wall 2411; place a plurality of the wall rings 22 between the two side walls 2412 in turn, and rotate the wall rings 22 to a proper position; The plate 242 passes through the two holes in sequence; the bolts 243 are tightened to complete the installation of the model pool 2 .

The casting device 3 communicates with the model pool 2 for injecting casting material into the model pool 2 . The casting device 3 includes a material barrel 31 , a first rubber hose 32 , an electric pump 33 and a second rubber hose 34 that are communicated in sequence. The material bucket 31 contains a casting material, the casting material is a water-containing unsaturated polyester resin, and the water-containing unsaturated polyester resin is in an emulsified state in the material bucket 31 . The second rubber hose 34 extends from the top opening of the model pool 2 to the bottom of the model pool 2 along the inner wall of the model pool 2 , and the electric pump 33 can be activated to pump the material in the material bucket 31 . The aqueous unsaturated polyester resin emulsion is pumped into the model pool 2 . It should be noted that, during the injection process of the aqueous unsaturated polyester resin emulsion, the injection speed needs to be strictly controlled to avoid air mixing due to the violent flow of the aqueous unsaturated polyester resin emulsion.

After the casting material in the model pool 2 is solidified and formed, the rock mass model 4 is formed, and the rock mass model 4 is accommodated in the model pool 2 . The rock mass model 4 includes a rock block model 41 and joint models 42 distributed in the rock block model 41 .

The preparation process of the rock block model 41 is as follows: inject the water-containing unsaturated polyester resin emulsion into the model pool 2 through the casting device 3, and add an initiator and accelerator, and the water-containing unsaturated polyester resin The emulsion is solidified under the combined action of the initiator and the accelerator to form the rock block model 41 .

The solidification time of the rock block model 41 varies with the added amount of the initiator and the accelerator, and the added amount of the initiator and the accelerator can be adjusted to control the solidification time of the rock block model 41 . Preferably, in this embodiment, the initiator is dibenzoyl peroxide, and the accelerator is dimethylaniline.

The rock block model 41 can be solidified at room temperature, and it is transparent or translucent, and the change of static expansion inside the model can be observed clearly; the tensile strength of the rock block model 41 is the same as the The water content in the rock block model 41 is inversely proportional, and the mechanical parameters of the model can be controlled by controlling the water content of the rock block model 41 . It should be noted that, before filling the aqueous unsaturated polyester resin emulsion, a mold release agent needs to be smeared on the inner wall of the model pool 2 to facilitate taking out the model after the test.

Further, the rock mass model 4 is provided with a special-shaped hole 410, and the special-shaped hole 410 extends straight downward from the upper end face of the rock block model 41 along the height direction of the rock block model 41. The hole 410 is in the shape of a triangular prism or a quadrangular prism, and the height of the special-shaped hole 410 can be adjusted according to actual needs. The special-shaped hole 410 is used for filling static crushing agent. Preferably, the angle bisectors of the opposite prismatic corners of the lower part of the special-shaped hole 410 should overlap as much as possible, so as to make full use of the stress concentration at the sharp corners during the static expansion cracking process to achieve a better crushing effect.

The preparation process of the special-shaped hole 410 is as follows: the special-shaped hole making device is fixed on the outer frame 1, and then the casting material is directly filled into the model pool 2, and the water-containing unsaturated polyester resin is cured and formed. , and then demolding the special-shaped hole making device. By adjusting the shape, setting position and axial rotation angle of the special-shaped hole making device, the shape and arrangement of the special-shaped hole 410 can be changed, so as to explore the optimization effect of the special-shaped hole 410 with different shapes and arrangements on static bursting , the operation is simple and convenient, and can meet the needs of use under different conditions.

The special-shaped hole 410 is molded by the special-shaped hole making device 200 , and the special-shaped hole making device 200 includes a large buckle 201 , a chute 202 , a small buckle 203 and a special-shaped rod 204 . The large buckles 201 are correspondingly clamped on the top frame 12 , the two ends of the chute 202 are respectively vertically welded to the outer surfaces of the two large buckles 201 , and the two large buckles 201 are tightened. The wing nut can be fixed side by side on the top frame 12, and the position of the special-shaped rod 204 in the longitudinal direction can be determined by adjusting the position of the large buckle 201 on the top frame 12; There is a T-shaped guide rail inside the chute 202, and a T-shaped clamping post is welded on the small buckle 203. The clamping post slides in from one end of the chute 202, and can slide to any position in the chute, To determine the position of the special-shaped rod 204 in the lateral direction; the special-shaped rod 204 is made of aluminum alloy, the upper part is a cylinder with a length of 500mm, and the lower part is a triangular prism or a square prism with a length of 1000mm. By tightening the small buckle The wing nut of 203 fixes the special-shaped rod 204. Before fixing, the cylindrical part can be lifted up and down and rotated to any angle around the central axis to determine the vertical depth and rotation angle of the special-shaped rod 204; The angle bisectors of the sharp corners of the hole 410 should overlap as much as possible to make full use of the stress concentration at the sharp corners during the static expansion cracking process. Before fixing the special-shaped rod 204, a layer of mold release agent is coated on the prism surface of the lower part of the special-shaped rod 204, so as to facilitate the pulling out of the special-shaped rod 204 after the model is formed. After the aqueous unsaturated polyester resin emulsion is solidified, the small buckle 203 is loosened first, then the large buckle 201 is loosened, and then the large buckle 201, the chute 202, the small buckle 201, the The buckles 203 move backward together for a certain distance, and finally the special-shaped rod 204 is pulled out, and the special-shaped hole 410 is prepared.

The joint model 42 and the rock block model 41 together constitute the rock mass model 4 , and the joint model 42 includes a plurality of joint model pieces 421 spliced with each other and a plurality of hollow copper pieces connected with the joint model piece 421 . Tube 422.

The joint model sheet 421 includes a joint sheet and an unsaturated polyester resin reinforcement layer. The preparation process of the joint sheet is as follows: using the joint material in the on-site rock mass, grinding it into powder, pressing it into a 1 mm thick sheet, and cutting it into a suitable shape to make the joint sheet. The unsaturated polyester resin reinforcement layer covers both sides of the joint sheet, and after curing, the unsaturated polyester resin reinforcement layer can protect the joint sheet and keep the joint sheet intact.

The hollow copper tube 422 is connected to the joint model sheet 421. Specifically, the hollow copper tube 422 includes an input end and an output end. The input end is exposed outside the model pool 2, and the output end passes through. It is fixed to the joint model sheet 421 through the small round holes of the honeycomb column 25 . The fixing points of the hollow copper tubes 422 and the joint model piece 421 are evenly distributed on the joint model piece 421 . The direction and inclination of the joint model 4 are controlled by adjusting the protruding length and bending mode of different hollow copper tubes 422. Further, by rotating the holed wall ring 222, the spatial distribution position of the honeycomb column 25 can be changed, and the The direction of the joint model 42.

The part of the hollow copper pipe 422 exposed outside the model pool 2 needs to be reserved for a certain length, so that the rock model 4 can be pulled out after it is solidified. Further, the outer surface of the output end is coated with paraffin, and after the rock mass model 4 is cured, the part of the hollow copper tube 422 exposed outside the model pool 2 is heated. The temperature of the output end of the hollow copper tube 422 is rapidly increased, so that the paraffin is melted to form a lubricating layer, which can further facilitate the extraction of the hollow copper tube 422 .

While pulling out the hollow copper tube 422, the molten paraffin liquid is injected into the rock mass model 4 through the circular hole in the center of the hollow copper tube 422 to fill up the hollow copper tube 422 after the hollow copper tube 422 is pulled out. The remaining holes ensure the integrity and continuity of the model; the hollow copper tube 422 after being pulled out is filled with paraffin, but when the hollow copper tube 422 is heated next time, the solid paraffin in the tube can be converted into a liquid state, so paraffin is used. The filling test model has no effect on the repeated test; the tensile strength of the paraffin solid is relatively low, which can be basically consistent with the tensile strength of the rock mass model 4 .

The strain measuring device 5 is used to measure the strain value at the working surface of the special-shaped hole 410. The strain measuring device 5 includes a sensing element and a signal receiving and processing instrument connected to the sensing element. It is arranged in the action surface of the special-shaped hole 410, and the signal receiving and processing instrument is arranged outside the model pool 2. It should be noted that the action surface of the special-shaped hole 410 is located by the opposite sharp corners of the two special-shaped holes. The connecting plane is the working surface of the special-shaped hole. The sensing elements can be arranged in multiples, and one sensing element is used to measure the strain condition of a point. The sensing element and the signal receiving and processing instrument are connected by wires, and a plurality of wire holes for the wires to be routed are preset on the bottom plate 21 , and the wires pass through the wire holes and connect to the sensor. Component connection, use waterproof glue to seal the gap left by the wire passing through the wire hole. A plurality of the sensing elements can be arranged at different positions on the working surface of the special-shaped hole 410 , and the data measured by the sensing elements at different positions can fit the strain value of the entire working surface of the special-shaped hole 410 .

It should be noted that, the sensing element and the wire need to be put into the model pool 2 before the casting material is injected, and the sensing element and the wire need to be coated with a layer of strong toughness. The insulating paint not only enhances the bonding strength with the water-containing unsaturated polyester resin casting body, but also avoids the influence of the model material on the resistance strain effect of the sensing element 25 .

The measurement and recording device 6 is fixed to the outer frame 1 for measuring and recording the test process of the model pool 2. The measurement and recording device 6 includes a buckle 61, a movable arm 62 and a measurement and recording device 63. The buckle 61 is movably connected with the outer frame 1, and the installation position of the buckle 61 can be adjusted according to actual needs, which is convenient to use. The measurement recording device 6 can be provided in multiples, and the multiple measurement recording devices 6 are respectively arranged at each position of the outer frame 1 , so as to realize the omnidirectional measurement monitoring of the model pool 2 . The movable arm 62 is a multi-section long arm, and the multi-section long arms are hinged to each other. The measurement and recording device 63 is fixed at the end of the movable arm 62. The measurement and recording device includes a laser displacement meter, an ultrasonic measurement One or more of the transmitter and receiver of the instrument, and the camera. The ultrasonic measuring instrument judges the cracking situation inside the model through the time difference of receiving ultrasonic waves before and after the test; the laser displacement meter is used to measure the cracking data at the feature points on the top surface of the model during the static expansion cracking process; the camera is used to record the static expansion. Crack test process. Before carrying out the test, the movable arm 62 can be extended or retracted to move the measurement recording device 63 to an appropriate position; and the measurement recording device 63 can be rotated to point to an important monitoring target to improve the monitoring effect.

After the experiment is over, the rock mass model 4 in the model pool 2 can be chiseled and taken out, and the rock mass model 4 can continue to be used after melting, so as to realize multiple recycling and meet the needs of energy saving and environmental protection. The model pool 2 is disassembled and taken out, and each component is cleaned in preparation for the next round of tests.

Compared with the related art, in the model test system for soft rock cracked by static expansion force provided by the present invention, the model pool is made of transparent plexiglass, and the casting material is water-containing unsaturated polyester resin, which can be easily observed. Structural changes in the rock mass model; by introducing a joint model, the on-site geological conditions can be more realistically restored; by setting a strain measuring device and a measuring recording device, the changes of physical quantities inside and outside the rock mass model can be measured, and the test process can be recorded; And through the cooperation of various subsystems, special-shaped holes with different shapes can be made, the internal mechanism of static expansion cracking can be studied, the optimization effect of different shapes and arrangements of special-shaped holes on static expansion cracking can be explored, and the utilization of In order to optimize the construction method of static expansion cracking, the optimal construction scheme is obtained through repeated tests, which provides a scientific basis for on-site construction. The model test system for soft rock cracked by static expansion force provided by the invention has powerful functions, wide application range, convenient operation, simple structure, and is convenient for popularization and use. .

The above are only the embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, improvements can be made without departing from the inventive concept of the present invention, but these belong to the present invention. scope of protection.

Claims (4)

1. The model test system for the static expansion force induced cracking soft rock is characterized by comprising an outer frame with a containing space, a casting device which is contained in the containing space and fixed in a model pool of the outer frame and communicated with the model pool and used for injecting a casting material into the model pool, wherein the casting material is cured and formed in the model pool to form a rock mass model, the rock mass model comprises a rock mass model and a joint model which is dispersedly arranged in the rock mass model, a plurality of special-shaped holes are further formed in the rock mass model, the special-shaped holes are formed by die casting of a special-shaped hole manufacturing device, the special-shaped holes are used for filling a static crushing agent, the model pool is made of transparent organic glass, and the casting material is water-containing unsaturated polyester resin;

the outer frame is of a square frame structure integrally, the accommodating space is formed in the outer frame, the outer frame comprises a bottom frame, a top frame and a stand column, the top frame is arranged in parallel to the bottom frame at intervals, the stand column is connected with the bottom frame and the top frame, the bottom frame is formed by sequentially connecting four square steel pipes end to end, the top frame is formed by sequentially connecting four round steel pipes end to end, the stand column is a round steel pipe, two parting beads are uniformly welded in the bottom frame longitudinally and transversely, and the transversely arranged parting beads and the longitudinally arranged parting beads are mutually perpendicular and crossed;

the model pool is borne on the bottom frame and comprises a bottom plate, a plurality of wall rings connected with the bottom plate, honeycomb columns installed on the wall rings and reaction columns connected with the bottom plate and the wall rings, the bottom plate is of a circular plate-shaped structure, the wall rings are circular rings matched with the outer circumference of the bottom plate in shape, the wall rings are sequentially stacked along the height direction of the model pool and comprise common wall rings and perforated wall rings, the common wall rings and the perforated wall rings are sequentially stacked, a plurality of round holes penetrate through the perforated wall rings at the middle positions of the height, the round holes are uniformly distributed along the circumferences of the perforated wall rings, the axial directions of the round holes point to the axes of the perforated wall rings, the honeycomb columns are fixed in the round holes, the honeycomb columns are made of heat-insulating ceramics, and a plurality of small round holes are uniformly distributed in the honeycomb columns, the small round hole is communicated with the model pool and the outside;

the reaction column is used for connecting the bottom plate and the wall ring, at least two through holes are arranged in the bottom plate in a penetrating mode along the height direction, the reaction column and the through holes are arranged in a one-to-one correspondence mode, the reaction column comprises a concave column, a reaction plate and a bolt, the concave column is of a U-shaped structure and comprises a bottom wall and two side walls extending from two ends of the bottom wall in a bending mode, the two side walls are parallel to each other and spaced, the cross section shape of each side wall is matched with the shape of the through holes, the bottom plate is borne on the bottom wall, the wall ring is clamped between the two side walls, the inner side faces of the side walls are arc faces, the shape of the arc faces is matched with the shape of the arc faces of the outer side faces of the wall ring, holes are formed in the top ends of the side walls, the holes in the two side walls are arranged oppositely, the reaction plate can penetrate into the two holes, and threaded holes are formed in the middle positions of the reaction plate, the bolt can pass through the threaded hole and abut against the wall ring;

the special-shaped hole extends downwards from the upper end face of the rock mass model along the height direction of the rock mass model in a straight line mode, and the special-shaped hole is in a triangular prism shape or a quadrangular prism shape;

the special-shaped hole manufacturing device comprises a large buckle, a sliding chute, a small buckle and a special-shaped rod, the large buckle is correspondingly clamped on the top frame, and two ends of the sliding chute are respectively and vertically welded on the outer surfaces of the two large buckles; a T-shaped guide rail is arranged in the sliding groove, a T-shaped clamping column is welded on the small buckle, and the clamping column slides in from one end of the sliding groove and can slide in the sliding groove; the special-shaped rod is made of aluminum alloy, the upper part of the special-shaped rod is a cylinder, the lower part of the special-shaped rod is a triangular prism or a quadrangular prism, and the special-shaped rod is fixed by tightening a butterfly nut of the small buckle;

the joint model comprises a plurality of joint model pieces which are spliced with one another and a plurality of hollow copper pipes connected with the joint model pieces, each joint model piece comprises a joint piece and an unsaturated polyester resin reinforcing layer, the unsaturated polyester resin reinforcing layers cover two side faces of each joint piece, each hollow copper pipe comprises an input end and an output end, the input ends are exposed out of the model pool, and the output ends penetrate through small round holes of the honeycomb columns and are fixed with the joint model pieces.

2. The model testing system of claim 1, wherein said casting device comprises a material barrel containing an emulsion of an aqueous unsaturated polyester resin, a first rubber hose, an electric pump and a second rubber hose which are connected in series, said second rubber hose extending from the top opening of said model tank along the inner wall of said model tank into the bottom of said model tank.

3. The model testing system according to claim 1, further comprising a strain measuring device for measuring a strain value at the action surface of the shaped hole, wherein the strain measuring device comprises a sensing element and a signal receiving and processing instrument connected with the sensing element, the sensing element is disposed in the action surface of the shaped hole, the signal receiving and processing instrument is disposed outside the model cell, and the sensing element is connected with the signal receiving and processing instrument through a wire.

4. The model test system of claim 1, further comprising a measurement recording device fixed on the outer frame for measuring and recording the test process of the model pool, wherein the measurement recording device comprises a buckle, a movable arm and a measurement recording device, the buckle is movably connected with the outer frame, the movable arm is a multi-section long arm, the multi-section long arm is hinged to each other, the measurement recording device is fixed at the tail end of the movable arm, and the measurement recording device comprises one or more of a laser displacement meter, a transmitting end and a receiving end of an ultrasonic measuring instrument, and a camera.

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