Similar test block forming equipment for similar simulation experiment of roadway and manufacturing method of similar test block forming equipment

Abstract

The invention discloses similar test block forming equipment for a roadway similar simulation experiment and a manufacturing method. The similar test block forming equipment comprises a lower forming die, and an upper pressurizing die for pressurizing and forming a similar material in the lower die at a constant pressure is arranged above the lower forming die; and the pressurizing upper die is connected with a pressurizing control device for setting a critical pressure value during pressurizing according to mechanical parameters of the standard test block and setting a critical position to control the pressurizing upper die to move and pressurize. According to the forming equipment, similar materials are pressed and formed into required similar test blocks through the pressurizing upper die capable of providing constant pressure, so that the large mechanical property difference of the similar test blocks caused by inconsistent manual tamping mode and tamping force in the similar test block manufacturing process is avoided; therefore, the reliability and the accuracy of the experimental result of the similar simulation experiment are improved.

Description

[Technical field] The invention relates to the technical field of similar test blocks for similar simulation experiments, and in particular to a similar test block forming device and a manufacturing method for a tunnel similar simulation experiment. [Background technology] In recent years, as mining projects have gradually moved deeper, research on topics and projects related to surrounding rock support of deep tunnels needs to be carried out with the help of laboratories. In this type of research, due to the advantages of similar simulation model experiments such as low initial investment, realistic simulation process, and accurate simulation results, the use of similar simulation models for simulation experiments has excellent economy and research value. In similar simulation model experiments, the role of test blocks is extremely important, and their quality directly affects the quality of experimental data. Good test blocks can accurately reflect the on-site situation and feedback data that fits the actual situation. Therefore, in simulation research, the production of test blocks accounts for a large proportion of simulation work.

[0003] At present, test blocks are made manually, but due to the inconsistent material mixing method and mixing time when making test blocks manually, and the inconsistent manual compaction method and compaction strength when the test blocks are formed, the mechanical properties of the produced test blocks vary greatly. If test blocks with large discrete mechanical properties are used for experiments, it will inevitably greatly affect the results of subsequent similar simulation experiments. [Summary of the invention] In order to solve the technical problem that similar test blocks have large differences in mechanical properties due to artificial production, resulting in unreliable experimental results and low experimental accuracy in similar simulation experiments, the present invention proposes a similar test block forming device and a production method for a tunnel similar simulation experiment.

[0005] The present invention is achieved by the following technical solutions: A tunnel similarity simulation experiment specimen molding equipment is used for pressure molding similar materials selected and stirred according to the mechanical parameters of standard specimens, and is characterized in that it comprises a molding lower die, above which is provided a pressurizing upper die for pressurizing similar materials in the lower die, and the pressurizing upper die is connected to a pressurizing control device for setting a critical pressure value during pressurization and a critical position according to the mechanical parameters of the standard specimen to control its movement and pressurization.

[0006] In the tunnel similarity simulation test block forming device as described above, the mechanical parameters of the standard test block include bulk density, elastic modulus, Poisson's ratio, cohesion and internal friction angle.

[0007] In the tunnel similarity simulation experimental specimen forming equipment as described above, the pressurizing upper mold is provided with a pressurizing head for providing constant pressure, and the pressurizing upper mold is also provided with a displacement sensor for real-time monitoring the position of the pressurizing head and the position of similar materials in the forming lower mold, and a pressure sensor for real-time monitoring the pressure of the pressurizing head and setting a critical pressure value during pressurization.

[0008] In the tunnel similarity simulation experiment specimen forming equipment as described above, the lower forming mold is also connected to a conveying device for injecting similar materials in a material box into the lower forming mold, the conveying device includes a feed pump and a feed controller for controlling the feed pump to be turned on or off, the feed pump is connected to a feed pipe for injecting similar simulation experiment materials into the lower forming mold, the discharge end of the feed pipe is connected to a discharge head, and a rotary joint is provided between the discharge head and the feed pipe.

[0009] The tunnel similarity simulation experimental specimen forming equipment as described above also includes a stirring device for uniformly stirring similar materials, the stirring device includes a feed port and a discharging mechanism for controlling the discharging, a stirrer for uniformly stirring similar materials selected according to the mechanical parameters of the standard specimen according to a proportion is provided between the feed port and the discharging mechanism, the discharging mechanism includes a discharging baffle arranged below the stirrer and a hydraulic rod for controlling the rotation and discharging of the discharging baffle, one end of the discharging baffle is hinged to one end of the bottom of the stirrer, the other end of the discharging baffle is rotatable, the hydraulic rod is arranged at the bottom near the rotating end of the discharging baffle, and the rotating end of the discharging baffle is controlled by the hydraulic rod.

[0010] The tunnel similarity simulation experimental specimen forming equipment as described above also includes a transmission device for transmitting the evenly stirred similar materials to the material box, the transmission device includes a feed slide arranged at the feed place and a conveyor belt for conveying similar materials, the feed end of the conveyor belt is close to the bottom of the feed slide, the discharge end of the conveyor belt is connected to the material box, and the bottom of both ends of the conveyor belt is provided with a first adjustment seat and a second adjustment seat for adjusting the height difference of the conveyor belt, and the height of the first adjustment seat close to the side of the feed slide is higher than that of the second adjustment seat.

[0011] The tunnel similarity simulation test block forming equipment as described above also includes a control console for centrally controlling the operation of the pressure control device and the material feeding controller; The stirring device also includes a power mechanism for providing power to the stirrer and a stirring controller for controlling the operation of the power mechanism and the discharging mechanism; A partition is provided in the middle of the lower forming mold for dividing the lower forming mold into two equal parts; The feed inlet includes a solid material feed inlet and a liquid material feed inlet.

[0012] Another aspect of the present invention also provides a method for making similar test blocks for tunnel similarity simulation experiments using the above-mentioned forming equipment; The production method comprises the following steps: Step S1, drilling and coring the surrounding rock of the tunnel to make a standard test block; Step S2, using the MTS rock mechanics experimental system to measure rock mechanics parameters of the standard test block to obtain mechanical parameters of the standard test block; Step S3, selecting similar materials and determining the proportion of the similar materials according to the mechanical parameters obtained in step S2; Step S4, stirring the similar materials evenly according to the ratio determined in step S3 to prepare similar simulation experimental materials; Step S5, making common similar test blocks from the similar simulation experimental materials in step S4; Step S6, testing the prepared common similar test blocks, eliminating common similar test blocks with large error values, and obtaining qualified common similar test blocks that meet the standards; Step S7, randomly select 5 qualified common similar test blocks, and measure the average uniaxial compressive strength of the qualified common similar test blocks ; Step S8, making the remaining part of qualified common similar test blocks into pre-cracked common similar test blocks; Step S9, bonding the pre-cracked common similar test block obtained in step S8 to another part of the remaining qualified common similar test blocks to obtain a complete-cracked combined test block.

[0013] In the method for making similar test blocks for a tunnel similarity simulation experiment as described above, the step S4 further comprises the following steps: Step S41, dividing the material into solid material and liquid material according to the similar material ratio determined in step S3; Step S42, stirring the solid material in step S41 uniformly; Step S43, adding the evenly stirred solid material and liquid material into the stirrer; Step S44, the stirrer stirs at a preset speed, and after stirring for a preset time, the stirrer stops stirring.

[0014] In the method for making similar test blocks for a tunnel similarity simulation experiment as described above, the step S5 further comprises the following steps: Step S51, injecting similar simulation experimental materials into the molding lower mold; Step S52, when the displacement sensor detects that the similar simulation experimental material reaches the critical position in the lower molding die, the injection of the similar simulation experimental material is stopped; Step S53, the pressurized upper die is pressed downward, and when the pressure sensor detects that the pressure of the pressurizing head reaches a preset pressure P, the pressurized upper die stops descending and starts to rise to the initial position; Step S54, the displacement sensor determines whether the similar simulation experimental material at this time is below the critical line, if it is below the critical line, return to step S51, if it is not below the critical line, the common similar test block is completed; The method for making similar test blocks for a tunnel similarity simulation experiment as described above, the step S8 further comprises the following steps: Step S81, the pressurizing upper die performs uniaxial pressurization on the qualified common similar test block, and when the pressure value of the qualified common similar test block reaches a peak value, the pressurization is immediately stopped to obtain a pre-cracked common similar test block, and the uniaxial compressive strength of the pre-cracked common similar test block is recorded; Step S82, comparing the error between the uniaxial compressive strength of the pre-cracked common similar test block and the average uniaxial compressive strength of the qualified common similar test blocks obtained in step S7, if the error is less than 3%, then the pre-cracked common similar test block is retained, if the error is greater than 3%, then the pre-cracked common similar test block should be removed; Step S83, repeating steps S81 and S82 to make N pre-cracked common similar test blocks.

[0015] Compared with the prior art, the similar test block forming device and manufacturing method for tunnel similarity simulation experiment proposed by the present invention have the following beneficial effects: 1. The molding equipment proposed in the present invention pressurizes similar materials into required similar test blocks through a pressurized upper mold that can provide constant pressure, thereby avoiding large differences in mechanical properties of similar test blocks caused by inconsistent manual compaction methods and compaction strengths during the production of similar test blocks, thereby improving the reliability and accuracy of the experimental results of similar simulation experiments.

[0016] 2. The stirring device proposed in the present invention includes a stirring controller, which is used to centrally control the stirring and discharging of the stirrer, thereby helping to achieve more uniform stirring of similar simulation experimental materials. At the same time, the entire process is automated, avoiding large differences in the mechanical properties of similar test blocks caused by inconsistent methods and time of manual stirring of similar materials, thereby improving the reliability and accuracy of the experimental results of similar simulation experiments.

[0017] 3. The pressurized upper mold proposed in the present invention includes a displacement sensor and a pressure sensor. The displacement sensor can ensure that the size of the similar test block finally formed can meet the experimental requirements and improve the experimental accuracy of similar simulation experiments. The pressure sensor can ensure that the compressive strength and compression-tensile ratio of the manufactured similar test blocks are closest to those of the standard test blocks, thereby improving the quality consistency of the manufactured similar test blocks. The pressure of the pressure head and the downward pressure height can be accurately controlled by the displacement sensor and the pressure sensor, which can ensure that each similar test block manufactured is subjected to uniform pressure, thereby ensuring that the manufactured similar test blocks have consistent density and strength.

[0018] 4. The production method proposed in the present invention can produce a complete-broken combination similar test block, which can simulate the broken area and the complete area in the actual tunnel surrounding rock, so that the similar simulation experiment can be more in line with the actual tunnel surrounding rock, which helps to obtain more reliable and accurate experimental results.

Brief Description of the Drawings

[0020] Figure 1 It is a structural schematic diagram of a similar test block making device of the present invention; Figure 2 Another structural schematic diagram of a similar test block manufacturing device of the present invention; Figure 3 It is a schematic diagram of the structure of the stirring device of the present invention; Figure 4 It is another structural schematic diagram of a similar test block making device of the present invention; Figure 5 It is a schematic diagram of the lower mold structure of the present invention; Figure 6 It is a flow chart of the method for making similar test blocks for similar simulation experiments in tunnels of the present invention; Figure 7 is a detailed flow chart of step S4 of the present invention; Figure 8 is a detailed flow chart of step S5 of the present invention; Fig. 9 It is a detailed flow chart of step S8 of the present invention. [Specific implementation method] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] First embodiment: Please refer to Figures 1 to 5As shown, this embodiment proposes a tunnel similarity simulation test block molding device, including a molding lower die 31, a pressurizing upper die 32 for pressurizing and molding similar materials in the lower die at a constant pressure is provided above the molding lower die 31, and the pressurizing upper die 32 is connected to a pressurizing control device 33 for setting a critical pressure value during pressurization and a critical position to control its movement and pressurization according to the mechanical parameters of the standard test block. The molding device pressurizes and molds similar materials into the required similar test blocks through the pressurizing upper die 32 that can provide a constant pressure, thereby avoiding the large difference in mechanical properties of similar test blocks caused by inconsistent manual compaction methods and compaction strengths during the production of similar test blocks, thereby improving the reliability and accuracy of the experimental results of similar simulation experiments.

[0023] Furthermore, as a preferred embodiment of the present solution but not a limitation, the pressurizing upper mold 32 is provided with a pressurizing head 321 for providing constant pressure, and the pressurizing upper mold 32 is also provided with a displacement sensor 323 for real-time monitoring of the position of the pressurizing head 321 and the position of similar simulated experimental materials in the molding lower mold 31, and a pressure sensor 324 for real-time monitoring of the pressure of the pressurizing head 321 and setting a critical pressure value during pressurization.

[0024] In this embodiment, the displacement sensor can ensure that the size of the similar test block finally formed can meet the experimental requirements, thereby improving the experimental accuracy of the similar simulation experiment; the pressure sensor can ensure that the compressive strength and compression-tensile ratio of the manufactured similar test block are closest to those of the standard test block, thereby improving the quality consistency of the manufactured similar test blocks. The displacement sensor and the pressure sensor can also record the position and pressure value of the pressure head, so that a data table for manufacturing similar test blocks can be obtained, thereby analyzing the optimal position and pressure value for manufacturing the best similar test block from the data table; at the same time, the pressure of the pressure head and the downward pressure height can be accurately controlled by the displacement sensor and the pressure sensor, thereby ensuring that each manufactured similar test block is subjected to uniform pressure, thereby ensuring that the manufactured similar test blocks have consistent density and strength.

[0025] Further, as a preferred embodiment of the present invention but not a limitation, it also includes a stirring device 10 for stirring similar materials evenly, the stirring device 10 includes a feed port and a discharging mechanism 12 for controlling the discharging, a stirrer 13 for stirring similar materials selected according to the mechanical parameters of the standard test block evenly according to the proportion is provided between the feed port 11 and the discharging mechanism 12, the discharging mechanism 12 includes a discharging baffle 121 arranged below the stirrer 13 and a hydraulic rod 122 for controlling the discharging baffle 121 to rotate and discharge, one end of the discharging baffle 121 is hinged to one end of the bottom of the stirrer 13, and the other end of the discharging baffle 121 is rotatable, and when not discharging, the discharging baffle 121 can completely seal the bottom of the stirrer 13 so that similar materials will not leak out, and the hydraulic rod 122 is arranged at the bottom near the rotating end of the discharging baffle 121, and the rotating end of the discharging baffle 121 is controlled by the hydraulic rod 122; Among them, when there is no discharge, the hydraulic rod 122 extends to lift the discharge baffle 121 so that the discharge baffle 121 can seal the bottom of the agitator 13. When discharge is required, the hydraulic rod 122 retracts to make the discharge baffle 121 tilted at a certain angle. When the tilt angle is between 30° and 45°, the discharge effect is better.

[0026] In this embodiment, the stirring device stirs similar materials evenly in an automated manner, thereby avoiding the large differences in mechanical properties of similar test blocks caused by inconsistent methods and time of manual stirring of similar materials, thereby improving the reliability and accuracy of the experimental results of similar simulation experiments; In addition, one end of the discharge baffle can be rotated, which is easier to clean the inside of the mixer and less likely to cause blockage than the traditional discharge port. The discharge is controlled by the cooperation of the hydraulic rod and the discharge baffle, which can achieve precise control of the discharge and reduce material waste caused by improper discharge. The entire process can be automated, reducing the labor intensity of the staff and improving work efficiency. Furthermore, as a preferred embodiment of the present invention but not a limitation, the stirring device 10 also includes a power mechanism 14 for providing power to the stirrer 13 and a stirring controller 15 for controlling the operation of the power mechanism 14 and the discharging mechanism 12. The power mechanism 14 can be a pneumatic motor, a hydraulic motor or an electric motor. Preferably, the power mechanism 14 is an electric motor.

[0027] In this embodiment, the stirring controller is used to centrally control the stirring and discharging of the agitator, which helps to achieve more uniform stirring of similar materials. At the same time, the entire process is automated, and similar materials are stirred with precise stirring speed and stirring direction, which can avoid uneven stirring caused by human operation.

[0028] Further, as a preferred implementation manner of the present solution but not limiting, the feed port 11 includes a solid feed port 111 and a liquid feed port 112 .

[0029] In this embodiment, different similar materials are selected due to the different mechanical properties of the surrounding rocks of different on-site tunnels, and the feed ports are divided into solid feed ports and liquid feed ports to meet the different solid materials and liquid materials required to replace or add different similar materials; at the same time, the selection of similar materials usually requires adjusting the ratio between the materials to achieve the desired similar materials, so the separate feed ports can accurately control the amount of solid materials and liquid materials added.

[0030] Further, as a preferred embodiment of the present invention but not limiting, it also includes a transmission device 20 for transmitting the uniformly stirred similar materials to the material box 34, the transmission device 20 includes a feed slide 21 arranged at the feed position and a transmission belt 22 for transmitting similar materials, the feed end of the transmission belt 22 is close to the bottom of the feed slide 21, the discharge end of the transmission belt 22 is connected to the similar test block making device 30, and the bottoms of both ends of the transmission belt 22 are provided with a first adjustment seat 23 and a second adjustment seat 24 for adjusting the height difference of the transmission belt 22; Among them, the height of the first adjustment seat 23 close to the side of the feeding slide plate 21 is higher than that of the second adjustment seat 24 .

[0031] More preferably, the discharge end of the conveyor belt 22 may also be connected to a cache box (not shown) so that excess similar materials can be temporarily stored, providing a cache capacity for the production equipment, thereby improving the efficiency of the production equipment by temporarily storing materials during the production process.

[0032] In this embodiment, the design of the adjustment seat can flexibly adjust the inclination angle of the conveyor belt to adapt to similar materials with different viscosities and fluidities; transporting similar materials through the conveyor belt can reduce the time damage in the intermediate transportation links, improve production efficiency, and also realize batch production of similar test blocks.

[0033] Further, as a preferred embodiment of the present invention but not a limitation, the lower molding die 31 is also connected to a conveying device 35 for injecting similar materials in the material box 34 into the lower molding die 31, the conveying device 35 includes a feeding pump 351 and a feeding controller 352 for controlling the feeding pump 351 to be turned on or off, the feeding pump 351 is connected to a feeding pipe 353 for injecting similar materials into the lower molding die 32, the discharge end of the feeding pipe 353 is connected to a discharge head 354, a rotary joint 355 is provided between the discharge head 354 and the feeding pipe 353, so that the discharge head 354 is located above the lower molding die 32 during injection, and the discharge head 354 is located outside the lower molding die 32 when injection is completed; The height of the feed pipe 353 is higher than the height of the lower molding die 31 .

[0034] In this embodiment, the feed controller can control the opening or closing of the feed pump to achieve precise control of the injection amount of similar experimental materials; secondly, the entire process of injecting material into the molding mold is automated, which can avoid downtime caused by human operating errors and improve the production efficiency of the manufacturing equipment.

[0035] Further, as a preferred embodiment of the present invention but not limiting, a partition plate 311 is provided in the middle of the lower molding die 31 for dividing the lower molding die 31 into two equal parts, so that two similar test blocks with the same mechanical properties can be produced each time; In order to make the obtained similar test blocks more in line with the experimental standards, the lower molding die 31 is further provided with a critical scale 312, and the position of the critical scale is defined according to actual experimental requirements.

[0036] In this embodiment, the design of the partition allows two similar test blocks with the same mechanical properties to be produced each time, greatly improving production efficiency; a critical scale is provided on the lower molding die to ensure that the size of the similar test blocks produced can meet the experimental requirements, and the critical scale can also be used to accurately control the filling amount of the material.

[0037] Furthermore, as a preferred embodiment of the present invention but not limiting, it further includes a control console 30 for centrally controlling the operation of the pressurization control device 33 and the conveying device 35. Specifically, the control console 30 controls the on or off of the feed pump 351 by controlling the feed controller 352 , and the control console 30 also controls the rise or fall of the pressurized upper mold 32 by controlling the pressurization control device 33 .

[0038] In this embodiment, the design of the console can make the entire production process of the production equipment more efficient. At the same time, the console can also add a human-computer interaction function, so that the operator can directly set the critical pressure value and critical line position required by actual needs through the interactive interface of the console.

[0039] The working principle of this embodiment is as follows: The present invention provides a tunnel similarity simulation test block forming device, which firstly stirs the similar material evenly through a stirring device 10, and then pressurizes the similar material into a desired similar test block through a pressurized upper die 32 that can provide a constant pressure; Among them, the process of stirring similar materials is: the evenly stirred solid material and liquid material are added into the agitator 13 through the solid feed port 111 and the liquid feed port 112 of the stirring device 10 respectively, the stirring controller 15 controls the power mechanism 14 to start, so that the agitator 13 starts to stir the similar materials, the stirring controller 13 stirs according to the pre-set stirring speed and stirring time, and after the stirring is completed, the evenly stirred similar materials are transmitted to the material box 34 through the discharging mechanism 12.

[0040] The process of transmitting similar materials is as follows: the agitator 13 controls the hydraulic rod 122 to contract, and the discharge baffle 121 rotates and tilts downward at a certain angle, so that the evenly stirred similar materials can slide along the feed slide 21 of the transmission device 20 onto the conveyor belt 22. Since the height of the first adjustment seat 23 is higher than the height of the second adjustment seat 24, the conveyor belt 22 has a certain inclination angle, so that the evenly stirred similar materials can be transmitted to the material box 34.

[0041] The process of making similar test blocks is as follows: the control console 30 controls the material feeding controller 352 to turn on or off the material feeding pump 351, so that the uniformly stirred similar material can be injected into the molding lower mold 31 through the material feeding pipe 353 and the discharge head 354. When the displacement sensor 323 on the pressurized upper mold 32 detects that the uniformly stirred similar material reaches a predetermined critical scale 312, the injection is stopped. Then, the control console 30 controls the material feeding controller 352 to rotate the material feeding pipe 354 to the outside of the molding lower mold 31 to avoid pressurization. When the upper mold 32 is pressed down, the feed pipe 354 is crushed. At this time, the control console 30 controls the pressurizing control device 33 to realize the pressurizing upper mold 32 to press down and stir the similar materials evenly. When the pressure sensor 324 on the pressurizing upper mold 32 detects that the pressure value of the pressurizing head 321 reaches the preset pressure value P, it stops pressing down and starts to rise to the initial position; at this time, the displacement sensor 323 will monitor whether the position of the similar test block reaches the critical scale position. If not, the above operation process is repeated. If so, the similar test block is completed.

[0042] Second embodiment: Please refer to Figures 6 to 9 As shown, this embodiment proposes a method for making a similar test block for a tunnel similarity simulation experiment, including steps S1-S9, wherein: S1. Drill and core the surrounding rock of the tunnel to make standard test blocks.

[0043] Specifically, a drilling rig is used to drill and coring holes on the upper or lower wall of the tunnel, and the original rock drilled out is processed into standard test blocks with a diameter of 50 mm and a height of 100 mm.

[0044] S2. Use the MTS rock mechanics experimental system to measure the rock mechanics parameters of the standard test block to obtain the mechanical parameters of the standard test block.

[0045] Specifically, the mechanical parameters such as bulk density, elastic modulus, Poisson's ratio, cohesion and internal friction angle of the standard test block are measured by the MTS rock mechanics experimental system. In this embodiment, the mechanical parameters of the standard test block are measured as follows:

[0046] Among them, the MTS rock mechanics experimental system is a device used to test the mechanical properties and seepage characteristics of materials such as rocks and concrete under complex stress conditions. The MTS rock mechanics experimental system can realize the full process test of rock damage under complex coupling conditions such as high temperature and high pressure, seepage, and seismic dynamics, providing intuitive test data for the study of rock mechanics properties in mines.

[0047] In addition, due to the influence of factors such as the different geographical environments of mines and the different locations of surrounding rocks in the same mine tunnels, the mechanical parameters measured by the sampled standard test blocks will also be different.

[0048] S3. Select similar materials and determine the proportion of the similar materials according to the mechanical parameters obtained in step S2.

[0049] Specifically, the selection of similar materials usually adopts quartz sand, iron powder or barite powder as aggregate, gypsum, lime, cement and other materials as binder, and a small amount of regulator is added at the same time, and the ratio between the materials is adjusted to achieve similarity with various rock and soil materials.

[0050] In this embodiment, in order to obtain a similar test block with mechanical properties closest to the standard test block in step S2, this embodiment selects similar materials with quartz sand as aggregate and gypsum and cement as binders. After testing, when the proportion of the similar materials is as shown in the proportion table, the mechanical properties of the obtained similar test block are closest to those of the standard test block. Wherein, the ratio table is:

[0051] The mechanical parameters of similar materials composed according to the above ratio table are as follows:

[0052] In addition, since the standard test blocks will be affected by factors such as the different geographical environments of the mines and the different locations of the surrounding rocks of the tunnels in the same mine, the rock materials and mechanical properties of the obtained standard test blocks will be different, and the selection of the similar materials will also be different. Specifically, the selection and proportion of the similar materials should be determined based on the standard test blocks actually sampled.

[0053] S4. According to the similar material ratio determined in step S3, stir them evenly to prepare similar simulation experimental materials.

[0054] Specifically, the determined similar material ratio is divided into solid material and liquid material, and then the solid material is first stirred evenly, and then the solid material and the liquid material are mixed and stirred evenly by a stirring device to prepare similar simulation experimental materials used in the experiment.

[0055] Furthermore, as a preferred implementation mode of the present scheme but not limitation, the mixing of the solid material is to evenly mix similar materials selected in this embodiment with quartz sand as aggregate and gypsum and cement as binders, and the liquid material is water selected in this embodiment.

[0056] In this embodiment, before making similar simulation experimental materials, the solid materials are first stirred evenly to ensure the uniform distribution of various components in the solid materials and avoid local over-density or over-sparseness, so that the manufactured similar simulation experimental materials have the same and stable mechanical properties.

[0057] Further, as a preferred implementation of this solution but not limiting, step S4 includes steps S41-S45, wherein: S41, dividing the similar materials into solid materials and liquid materials according to the similar material ratio determined in step S3; S42, stirring the solid material in step S41 uniformly; S43, adding the evenly stirred solid material and liquid material into a stirrer; S44, the stirrer stirs at a preset speed, and after stirring for a preset time, the stirrer stops stirring.

[0058] Among them, in step S44, the stirrer stirs the similar simulation experiment materials at a preset speed and time, so that the similar test blocks produced are consistent, the difference in mechanical properties between similar test blocks is reduced, and the accuracy and reliability of the results of similar simulation experiments are improved.

[0059] In addition, before the similar simulation experimental materials are made into ordinary similar test blocks, the similar simulation experimental materials need to be left to stand for a period of time, which can cause the bubbles generated during the stirring process to burst, reduce the voids in the similar simulation experimental materials, and improve the density and strength of the similar simulation experimental materials. The best standing time is 30 seconds.

[0060] In this embodiment, the solid material and the liquid material are evenly stirred by a stirring device, and an automated stirring method is adopted instead of a manual stirring method, thereby avoiding the errors caused by the artificial production of similar simulation experimental materials, thereby greatly reducing the discreteness of the similar simulation experimental test blocks finally produced and improving the experimental accuracy of similar simulation experiments. At the same time, the automated stirring method also greatly reduces labor intensity and improves work efficiency.

[0061] S5. Make common similar test blocks with the similar simulation experimental materials in step S4.

[0062] Specifically, the similar simulation experimental materials in the molding lower mold are pressurized and molded by the pressurized upper mold. The pressurized upper mold is provided with a displacement sensor for real-time monitoring of the position of the pressurizing head and the position of the experimental material in the molding lower mold, and a pressure sensor for real-time monitoring of the pressurization pressure of the pressurizing head. The displacement sensor can ensure that the size of the final molded similar test block can meet the experimental requirements and improve the experimental accuracy of the similar simulation experiment; the pressure sensor can ensure that the compressive strength and compression-tensile ratio of the manufactured common similar test blocks are closest to those of the standard test blocks, while improving the quality consistency of the manufactured common similar test blocks; In addition, the displacement sensor and the pressure sensor can also record the position and pressure value of the pressure head, so that a data table for making similar test blocks can be obtained, and the best position and pressure value for making the best similar test block can be analyzed from the data table.

[0063] Further, as a preferred implementation manner of this solution but not limiting, step S5 includes steps S51-S55, wherein: S51, injecting similar simulation experimental materials into the molding lower mold; S52, when the displacement sensor detects that the similar simulation experimental material reaches the critical position in the lower molding die, the injection of the similar simulation experimental material is stopped; S53, the pressurized upper die is pressed downward, and when the pressure sensor detects that the pressure of the pressurizing head reaches a preset pressure P, the pressurized upper die stops descending and starts to rise to the initial position; S54, the displacement sensor determines whether the similar simulation experimental material at this time is below the critical line. If it is below the critical line, it returns to step S51. If it is not below the critical line, the production of the ordinary similar test block is completed.

[0064] Wherein, the critical line in step S52 is defined according to actual experimental requirements or actual size regulations; Specifically, the size of the forming lower die in this embodiment is a×a×L (length×width×height), where L > a, and 1.2a < L < 1.4a. The size requirement of the similar test block is a×a×a (length×width×height). Then the critical line is at the height of a in the forming lower die. Specifically, the demarcation of the critical line should be determined according to the height of the similar test block in the final test.

[0065] In addition, the forming lower die is provided with a partition that bisects it, so that 2 ordinary similar test blocks with the same mechanical properties can be made each time, greatly improving the production efficiency.

[0066] Further, as a preferred implementation manner rather than a limitation of this solution, the pressure P preset in step S53 is set according to the compressive strength of the standard test block; Among them, the compressive strength of the standard test block is generally between 20 MPa and 100 MPa, and the preset pressure value P is generally set between 0.3 MPa and 0.5 MPa. When the compressive strength of the standard test block is higher, the preset pressure value P will also increase relatively. Specifically, in this embodiment, the compressive strength of the standard test block is 30 MPa, and the preset pressure value P is 0.4 MPa.

[0067] In this embodiment, the pressure head presses the similar test block to form with a constant pressure P, which can avoid the uncertainty of the artificial ramming of the similar test block in terms of strength and orientation, greatly reducing the discreteness of the similar test block; at the same time, pressing and forming with a constant pressure P helps to reduce internal cracks or other defects caused by pressure fluctuations, thereby ensuring the integrity of the similar test block and improving the experimental accuracy of the similar simulation experiment.

[0068] S6. Detect the made ordinary similar test blocks, and eliminate the ordinary similar test blocks with large error values to obtain qualified ordinary similar test blocks that meet the standards.

[0069] Specifically, in order to make the mechanical properties of the finally obtained ordinary similar test blocks more consistent and make the error deviation of the final similar simulation experiment result smaller, it is necessary to detect the obtained ordinary similar test blocks and screen out the defective ordinary similar test blocks with large errors from the standard test block; Among them, the detection includes quality detection, dimension detection and wave velocity detection.

[0070] S7. Randomly select 5 qualified ordinary similar test blocks and measure the average uniaxial compressive strength of the qualified ordinary similar test blocks .

[0071] Specifically, apply pressure to the randomly selected qualified ordinary similar test blocks through the pressing upper die until the qualified ordinary similar test blocks are damaged, and record the pressure value of the pressure head at this time , and then the compressive strength of the qualified common similar test block is calculated by the compressive strength calculation formula, and the compressive strength calculation formula is:

[0072] Where i=1, 2, 3, 4, 5; S is the pressure-bearing area of ​​a qualified ordinary similar test block.

[0073] Among them, the compressive strength of the five qualified common similar test blocks ( , , , , ) and take the average value to obtain the average uniaxial compressive strength of qualified common similar test blocks ; It should be noted that if the compressive strength of one of the five qualified common similar test blocks has a large deviation, the qualified common similar test block with the large error should be eliminated.

[0074] S8. Make the remaining qualified common similar test blocks into pre-cracked common similar test blocks.

[0075] Specifically, the purpose of making pre-cracked ordinary similar test blocks is to simulate the crushing zone in the actual tunnel surrounding rock, so as to better simulate the conditions that the actual rock or concrete may encounter in the natural state, thereby improving the practical application value of the experimental results of similar simulation experiments.

[0076] Further, as a preferred implementation of this solution but not limiting, step S8 includes steps S81-S83, wherein: S81. The pressurized upper die is used to perform uniaxial pressurization on the qualified common similar test block. When the pressure value of the qualified common test block reaches the peak value, the pressurization is stopped immediately to obtain the pre-cracked common similar test block, and the uniaxial compressive strength of the pre-cracked common similar test block is recorded. ; S82. Compare the uniaxial compressive strength of the pre-cracked normal similar test block The average uniaxial compressive strength of the qualified common similar test blocks obtained in step S7 If the error is less than 3%, it will be retained. If the error is greater than 3%, the pre-cracked ordinary similar test block should be removed.

[0077] S83, repeat step S81 and step S82 to make N pre-cracked common similar test blocks.

[0078] Specifically, the uniaxial compressive strength of the pre-cracked common similar test block in step S82 is The average uniaxial compressive strength of the qualified common similar test blocks obtained in step S7 The error comparison is determined by the error calculation formula, which is:

[0079] Among them, if 3%, then the uniaxial compressive strength of the pre-cracked ordinary similar specimen is The average uniaxial compressive strength If the error is less than 3%, it is retained; 3%, if the error is greater than 3%, it should be removed.

[0080] In this embodiment, by screening out pre-cracked common similar test blocks with large errors, it can be ensured that the similar test blocks finally used for similar simulation experiments are closer to the tunnel surrounding rocks in the actual environment, making the experimental results more reliable and accurate.

[0081] S9, bonding the pre-cracked common similar test block obtained in step S8 with the remaining other qualified common similar test blocks to obtain a complete-cracked combined similar test block.

[0082] Specifically, the pre-cracked common similar test block is bonded to the qualified common similar test block by glue to obtain a complete-broken combined similar test block. In specific implementation, other methods such as adhesives can also be used for bonding.

[0083] In this embodiment, the intact-broken combination similar test blocks can simulate the broken areas and intact areas in the actual tunnel surrounding rock, so that the similar simulation experiment can be more in line with the actual tunnel surrounding rock, which helps to obtain more reliable and accurate experimental results.

[0084] Ordinary technicians in the relevant field should understand that the above is an implementation method provided in combination with specific content, and it is not considered that the specific implementation of the present invention is limited to these descriptions. At the same time, due to different industry naming, it is not limited to the above naming, nor is it limited to English naming. Any similarity or similarity with the method, structure, etc. of the present invention, or a number of technical deductions or substitutions made on the premise of the concept of the present invention, should be regarded as the protection scope of the present invention.

Claims

1. A tunnel similarity simulation test block molding equipment, used for pressurizing and molding similar materials selected and stirred according to the mechanical parameters of standard test blocks, characterized in that: The present invention comprises a molding lower die (31), wherein a pressurizing upper die (32) for pressurizing similar materials in the lower die is arranged above the molding lower die (31), and the pressurizing upper die (32) is connected to a pressurizing control device (33) for setting a critical pressure value during pressurization and a critical position according to mechanical parameters of a standard test block to control its movement and pressurization.

2. The tunnel similarity simulation test block forming equipment according to claim 1 is characterized in that: The mechanical parameters of the standard test block include bulk density, elastic modulus, Poisson's ratio, cohesion and internal friction angle.

3. The tunnel similarity simulation test block forming equipment according to claim 1 is characterized in that: The pressurizing upper die (32) is provided with a pressurizing head (321) for providing a constant pressure. The pressurizing upper die (32) is also provided with a displacement sensor (323) for real-time monitoring of the position of the pressurizing head (321) and the position of similar materials in the molding lower die (31), and a pressure sensor (324) for real-time monitoring of the pressure of the pressurizing head (321) and having a critical pressure value set during pressurization.

4. The tunnel similarity simulation test block forming equipment according to claim 1 is characterized in that: The lower molding die (31) is also connected to a conveying device (35) for injecting similar materials in a material box (34) into the lower molding die (31). The conveying device (35) comprises a feeding pump (351) and a feeding controller (352) for controlling the feeding pump (351) to be turned on or off. The feeding pump (351) is connected to a feeding pipe (353) for injecting similar simulated experimental materials into the lower molding die (32). The discharge end of the feeding pipe (353) is connected to a discharge head (354). A rotary joint (355) is provided between the discharge head (354) and the feeding pipe (353).

5. The tunnel similarity simulation test block forming equipment according to claim 1 is characterized in that: The invention also comprises a stirring device (10) for stirring similar materials uniformly, the stirring device (10) comprising a feed inlet (11) and a discharge mechanism (12) for controlling the discharge of materials, a stirrer (13) for stirring similar materials selected according to the mechanical parameters of a standard test block in accordance with a proportion and uniformly arranged between the feed inlet (11) and the discharge mechanism (12), the discharge mechanism (12) comprising a discharge baffle (121) arranged below the stirrer (13) and a hydraulic rod (122) for controlling the discharge baffle (121) to rotate and discharge materials, one end of the discharge baffle (121) being hinged to one end of the bottom of the stirrer (13), the other end of the discharge baffle (121) being rotatable, the hydraulic rod (122) being arranged at the bottom close to the rotation end of the discharge baffle (121), the rotation end of the discharge baffle (121) being controlled by the hydraulic rod (122).

6. The tunnel similarity simulation test block forming equipment according to claim 1 is characterized in that: It also includes a transmission device (20) for transmitting the uniformly stirred similar materials to the material box (34), the transmission device (20) includes a feed slide (21) arranged at the feed position and a transmission belt (22) for transmitting the similar materials, the feed end of the transmission belt (22) is close to the bottom of the feed slide (21), the discharge end of the transmission belt (22) is connected to the material box (34), and the bottom of both ends of the transmission belt (22) is provided with a first adjustment seat (23) and a second adjustment seat (24) for adjusting the height difference of the transmission belt (22), and the height of the first adjustment seat (23) close to the side of the feed slide (21) is higher than that of the second adjustment seat (24).

7. The tunnel similarity simulation test block forming equipment according to claim 5 is characterized in that: It also includes a control console (30) for centrally controlling the operation of the pressurization control device (33) and the material feeding controller (352); The stirring device (10) further comprises a power mechanism (14) for providing power to the stirrer (13) and a stirring controller (15) for controlling the operation of the power mechanism (14) and the discharging mechanism (12); A partition plate (311) is provided in the middle of the lower molding die (31) for dividing the lower molding die (31) into two equal parts; The feed inlet (11) comprises a solid material feed inlet (111) and a liquid material feed inlet (112).

8. A method for making a tunnel similarity simulation test block, characterized in that: The manufacturing method is implemented by the molding device according to any one of claims 1 to 7; The production method comprises the following steps: Step S1, drilling and coring the surrounding rock of the tunnel to make a standard test block; Step S2, using the MTS rock mechanics experimental system to measure rock mechanics parameters of the standard test block to obtain mechanical parameters of the standard test block; Step S3, selecting similar materials and determining the proportion of the similar materials according to the mechanical parameters obtained in step S2; Step S4, stirring the similar materials evenly according to the ratio determined in step S3 to prepare similar simulation experimental materials; Step S5, making common similar test blocks from the similar simulation experimental materials in step S4; Step S6, testing the prepared common similar test blocks, eliminating common similar test blocks with large error values, and obtaining qualified common similar test blocks that meet the standards; Step S7, randomly select 5 qualified common similar test blocks, and measure the average uniaxial compressive strength of the qualified common similar test blocks ; Step S8, making the remaining part of qualified common similar test blocks into pre-cracked common similar test blocks; Step S9, bonding the pre-cracked common similar test block obtained in step S8 to another part of the remaining qualified common similar test blocks to obtain a complete-cracked combined test block.

9. The method for making a tunnel similarity simulation test block according to claim 8, characterized in that: The step S4 further comprises the following steps: Step S41, dividing the material into solid material and liquid material according to the similar material ratio determined in step S3; Step S42, stirring the solid material in step S41 uniformly; Step S43, adding the evenly stirred solid material and liquid material into the stirrer; Step S44, the stirrer stirs at a preset speed, and after stirring for a preset time, the stirrer stops stirring.

10. The method for making a tunnel similarity simulation test block according to claim 8, characterized in that: The step S5 also includes the following: Step S51, injecting similar simulation experimental materials into the molding lower mold; Step S52, when the displacement sensor detects that the similar simulation experimental material reaches the critical position in the lower molding die, the injection of the similar simulation experimental material is stopped; Step S53, the pressurized upper die is pressed downward, and when the pressure sensor detects that the pressure of the pressurizing head reaches a preset pressure P, the pressurized upper die stops descending and starts to rise to the initial position; Step S54, the displacement sensor determines whether the similar simulation experimental material at this time is below the critical line, if it is below the critical line, return to step S51, if it is not below the critical line, the common similar test block is completed; The step S8 further comprises the following steps: Step S81, the pressurizing upper die performs uniaxial pressurization on the qualified common similar test block, and when the pressure value of the qualified common similar test block reaches a peak value, the pressurization is immediately stopped to obtain a pre-cracked common similar test block, and the uniaxial compressive strength of the pre-cracked common similar test block is recorded; Step S82, comparing the uniaxial compressive strength of the pre-cracked common similar test block with the average uniaxial compressive strength of the qualified common similar test blocks obtained in step S7 If the error is less than 3%, it will be retained. If the error is greater than 3%, the pre-cracked common similar test block should be removed. Step S83, repeating steps S81 and S82 to make N pre-cracked common similar test blocks.

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