A model test simulation tunnel step method excavation mold and its use method

Abstract

The present invention discloses a model test simulation tunnel step method excavation mold and a method of using the same, which belongs to the field of model test technology and solves the problem of low efficiency and precision of simulated step method excavation. The present invention is composed of eight sub-excavation modules, a data acquisition device, a monitoring sensor and a fastening device; the data acquisition device is composed of a data acquisition panel, a data cable and a data plug. The eight sub-excavation modules have fastening grooves and can be connected into an excavation footage section by a fastening device; a monitoring sensor is provided on the side wall of the excavation module, a data plug is provided at the center position of the front side, and a data interface is provided at the corresponding position of the rear side, and the two are connected end to end to transmit the monitoring data to the data acquisition device; there are disassembly holes on both sides of the data plug. The excavation module of the present invention is reduced in size according to a similar scale to the position and size of the on-site excavation, with a high degree of restoration, accurately reflecting the force characteristics of the surrounding rock during step method excavation, improving the test efficiency, and facilitating assembly and disassembly.

Description

Technical Field

[0001] The invention discloses a model test simulation tunnel step excavation mold and a use method thereof, which is particularly suitable for simulating the step excavation process of tunnels, tunnels and chambers in geomechanics model tests. The mold has convenient assembly and disassembly, accurate and stable test data, can improve the excavation test efficiency of the model test, and belongs to the field of model test technology. Background Art

[0002] In recent years, more and more geotechnical engineering researchers have used geomechanical model test technology to conduct research. Compared with research methods such as theoretical analysis and numerical simulation, model tests have the advantages of being intuitive, simple, and short in cycle. Using model tests, by controlling parameters and variables, the characteristics of surrounding rock pressure changes during the excavation of tunnels, lanes, underground chambers, etc. can be studied intuitively.

[0003] In order to meet the needs of economic development and people's production and life, the cross-sectional dimensions of tunnels, lanes, and underground chambers excavated in geotechnical engineering are constantly expanding, and the construction difficulty is becoming increasingly greater. At present, there are many feasible methods for excavating ultra-large cross-sectional tunnels, among which the most widely used is the step method. Under different geological conditions, the excavation footage and step sequence of the step method need to be determined according to the changes in surrounding rock pressure. Due to the complex geological conditions on site and the large cross-sectional dimensions, it is difficult to install a sufficient number of sensors for monitoring during the construction process, resulting in interruption and loss of collected data. The change in surrounding rock pressure is very critical to the safety of construction. The acquisition and early warning of surrounding rock pressure during step excavation are crucial to safe construction.

[0004] It is convenient and feasible to use geomechanical model tests to study the excavation of tunnels, lanes, and underground chambers. According to the similarity ratio of the model test, similar materials and loading equipment are used to simulate the geological and mechanical conditions of the tunnel prototype. The model is filled and the sensors are buried in the model test bench. After the material is air-dried, it is preloaded to balance the ground stress. Manual excavation is used to simulate the on-site excavation steps, so as to obtain the characteristics and laws of the surrounding rock pressure changes, and guide the on-site construction according to the test results.

[0005] At present, the common practice is to embed sensors around the model tunnel during the model filling process to monitor the pressure changes of the surrounding rock during the excavation process. However, some of the embedded sensors are easily damaged and fail during the model filling process, and during the loading process, the sensors will move with the compression of the filler and enter the excavation surface, seriously affecting the subsequent excavation and data collection. The step excavation method commonly used in geomechanical model tests is artificial step excavation, that is, using a special-shaped shovel to chisel, shovel, and cut the model tunnel face according to the step excavation steps, which has low work efficiency. Due to the large errors in manual operation, the tunnel often over-excavates or under-excavates, making it difficult to accurately reflect the actual tunnel excavation status, and thus it is impossible to collect and record the surrounding rock pressure changes when the tunnel is excavated using the step method, resulting in the meaninglessness of the model test.

[0006] Prior to the present invention, the invention with application number 2017104277233 provided a test device and test method for simulating surface deformation caused by step-method tunnel construction, which consisted of a box, three sets of propulsion models and a detection device. The box was provided with through holes, which could simulate the construction process of step-method tunnel construction causing surface deformation in the laboratory, so as to understand the influence of step-method tunnel construction on surface deformation. This patent simplifies the tunnel step excavation steps into 3 steps, which cannot restore the real tunnel excavation process in terms of quantity and form. Its tunnel module is large, and the friction resistance encountered during the propulsion process is large. There is no load applied to the top of the model tunnel, and the simulated geological conditions are single. The monitoring uses a mechanical micrometer, which requires manual reading, and the workload is large and the process is cumbersome.

[0007] The invention with patent number 2013105372256 provides a tunnel micro-step method process teaching simulation body. The simulation body tunnel is equipped with 4 process display sections that display the railway tunnel micro-step method process flow, a formal tunnel section display section and a tunnel portal display section. The process display section is cast with concrete and can be used for indoor railway teaching. However, this patent is large in size and can only be used for teaching demonstration. It cannot simulate and monitor the changes in surrounding rock pressure during tunnel excavation.

[0008] In view of this, it is necessary to invent a mold and a method of using the mold that can simulate the step method of tunnel excavation in a model test, so as to improve the excavation efficiency and monitoring accuracy of the model test tunnel. Summary of the invention

[0009] In view of the shortcomings of existing model tests simulating tunnel step excavation, the present invention provides a model test simulating tunnel step excavation mold and a use method thereof, which solves the monitoring and recording problems during model tests simulating tunnel step excavation, and improves excavation efficiency, monitoring accuracy and data accuracy.

[0010] The structure of a model test simulation tunnel step method excavation mold of the present invention is: composed of an excavation module, a data acquisition device, a monitoring sensor and a fastening device, the excavation module is composed of an arch excavation module, an arch step excavation module, a left wall excavation module, a center excavation module, a right wall excavation module, a left foot excavation module, a bottom plate excavation module and a right foot excavation module, the data acquisition device is composed of a data acquisition panel, a data line and a data plug. The fastening device is composed of a fastening groove and a fastener.

[0011] The excavation module is made of polytetrafluoroethylene. According to the different excavation positions of the tunnel using the step method, eight different sub-excavation modules are made, namely, the arch excavation module, the arch step excavation module, the left wall excavation module, the center excavation module, the right wall excavation module, the left foot excavation module, the bottom plate excavation module and the right foot excavation module.

[0012] The excavation module is composed of eight sub-excavation modules to form an excavation footage section. According to the similarity ratio requirements of the model test, the thickness of the excavation module is 5~15cm, the footage section width of the excavation module is 20~40cm, and the height is 30~40cm.

[0013] A data plug is provided at the center position of the front side of the excavation module, and the data plug can be connected to the data interface of the previous identical excavation module; a data interface is provided at the corresponding position on the rear side of the excavation module, which can be connected to the data plug of the subsequent identical excavation module or the data plug of the data acquisition device. The same modules are connected end to end to transmit the monitoring data to the data acquisition device.

[0014] The module side wall where the excavation module contacts the tunnel wall is provided with a monitoring sensor which can monitor the tunnel pressure and excavation time.

[0015] The data plug of the excavation module has a disassembly hole on both sides, which can be removed from the excavation footage section with the help of a disassembly tool to complete the excavation work.

[0016] The edge of the excavation module is provided with a fastening groove at the connection point with other modules, and the various excavation modules can be connected as a whole through fasteners to form an excavation advance section.

[0017] The vault excavation module is the vault part of the excavation module, which is semicircular in shape with a trapezoidal notch in the middle. Seven monitoring sensors are evenly distributed on the semicircular outer surface, which can monitor the pressure changes during excavation of the tunnel vault and waist. The vault excavation module has three fastening grooves, which are distributed on the upper side of the trapezoidal notch and at the two feet of the vault excavation module. A data plug is provided at the center position of the front side of the vault excavation module, and a data interface is provided at the corresponding position of the center of the rear side, and there is a disassembly hole on each side of the data plug.

[0018] The arch step excavation module is the lower connecting part of the arch crown excavation module, which is equivalent to the core soil part reserved for the first step in the step method, and has a trapezoidal shape; the arch step excavation module has two fastening grooves, which are distributed on the upper and lower sides of the arch step excavation module; a data plug is provided at the center position of the front side of the arch step excavation module, and a data interface is provided at the corresponding position of the center of the rear side, and there is a disassembly hole on each side of the data plug.

[0019] The left wall excavation module is the left wall part of the excavation module, which has a rectangular shape and has two monitoring sensors distributed on the left surface, which can monitor the pressure changes during the excavation of the left wall of the tunnel; the left wall excavation module has three fastening grooves, which are distributed on the upper, lower and right sides of the left wall excavation module; a data plug is provided at the center position of the front side of the left wall excavation module, and a data interface is provided at the corresponding position of the center of the rear side, and there is a disassembly hole on each side of the data plug.

[0020] The central excavation module is the central part of the excavation module, which is equivalent to the core soil part reserved for the second step in the step method. It has a rectangular shape and plays a connecting role. There is a fastening groove in the middle of each of the four sides of the central excavation module. A data plug is provided at the center position of the front side of the central excavation module, and a data interface is provided at the corresponding position of the rear center, which can record the excavation time of this module. There is a disassembly hole on each side of the data plug.

[0021] The right wall excavation module is the right wall part of the excavation module, which is symmetrical with the left wall excavation module about the axis of the tunnel. It has a rectangular shape and has two monitoring sensors distributed on the right surface, which can monitor the pressure changes during the excavation of the right wall of the tunnel; the right wall excavation module has three fastening grooves, distributed on the upper, lower and left sides of the right wall excavation module; a data plug is provided at the center position of the front side of the right wall excavation module, and a data interface is provided at the corresponding position of the center of the rear side, and there is a disassembly hole on each side of the data plug.

[0022] The left-foot excavation module is the left-foot part of the excavation module, which has a rectangular shape. Two monitoring sensors are distributed on the left and lower surfaces, which can monitor the pressure changes during excavation of the left wall and bottom plate of the tunnel; the left-foot excavation module has two fastening grooves, distributed on the upper and right sides of the left-foot excavation module; a data plug is provided at the center position of the front side of the left-foot excavation module, and a data interface is provided at the corresponding position of the center of the rear side, and there is a disassembly hole on each side of the data plug.

[0023] The bottom plate excavation module is the bottom plate part of the excavation module, which is equivalent to the core soil part reserved for the third step in the step method. It has a rectangular shape and five monitoring sensors are distributed on the lower surface to monitor the pressure changes during tunnel bottom plate excavation. The bottom plate excavation module has three fastening grooves, which are distributed on the left, top and right sides of the bottom plate excavation module. A data plug is provided at the center position of the front side of the bottom plate excavation module, and a data interface is provided at the corresponding position of the center of the rear side, with a disassembly hole on each side of the data plug.

[0024] The right-foot excavation module is the right-foot part of the excavation module, which is symmetrical with the left-foot excavation module about the axis of the tunnel. It has a rectangular shape and has two monitoring sensors distributed on the right and lower surfaces, which can monitor the pressure changes during excavation of the right wall and bottom plate of the tunnel; the right-foot excavation module has two fastening grooves, which are distributed on the upper and left sides of the right-foot excavation module; a data plug is provided at the center position of the front side of the right-foot excavation module, and a data interface is provided at the corresponding position of the center of the rear side, and there is a disassembly hole on each side of the data plug.

[0025] The data acquisition device is made of polytetrafluoroethylene with a thickness of 5 to 8 cm. Its appearance is the same as the cross-section of the excavation footage. Eight data plugs are arranged on its panel. There is a transmission circuit inside the panel, which can collect the data monitored and recorded by each excavation module. There is a data cable at the bottom of the data acquisition device, which can transmit the monitored and recorded data to the computer. The data plug is a square flat plug, which is connected to the data interface. Both have hot-swappable cables and circuits inside, which can transmit data. Unplugging the excavation module during power-on will not cause circuit short circuit and loss of monitoring data.

[0026] The monitoring sensor is a pressure sensor, which is distributed at the position where the surface of each excavation module contacts the surrounding rock of the tunnel, and monitors and records the excavation time and pressure changes of each excavation module during the excavation process.

[0027] The fastening device consists of a fastening groove and a fastener. The fastening groove is a semi-I-shaped opening set at different positions on each excavation module, with an opening width of 8~12mm. After the two fastening grooves are butt-jointed, they can be connected as a whole by the fastener.

[0028] The fastener is an I-shaped connector made of stainless steel, and its size matches the fastening groove. The fastener consists of an upper fastener, a lower fastener and a knob; the upper fastener and the lower fastener are both semi-I-shaped and connected together in the middle. The knob is a rotatable device in the middle of the fastener. The upper fastener and the lower fastener can be tightened toward the middle by turning clockwise with a cross screwdriver, and the upper fastener and the lower fastener can be loosened toward the middle by turning counterclockwise with a cross screwdriver; when the middle of the fastener is tightened, the various excavation modules are connected as a whole, and when the middle of the fastener is loosened, one or several excavation modules can be removed according to the needs of the excavation position.

[0029] The disassembly holes are openings on the surface of each excavation module. The diameter of the disassembly holes is 6-10 mm and the hole depth is 10-15 mm. There is a mortise structure inside the disassembly holes, so that the disassembly tools can be inserted into the disassembly holes and stuck in the mortise structure to remove the excavation module from the excavation footage section and complete the excavation work.

[0030] The present invention provides a method for using a model test simulation tunnel step method excavation mold, which specifically comprises the following steps:

[0031] (1) When the model platform is filled to the height of the tunnel floor, each excavation module is connected to an excavation footage section through fasteners. According to the excavation footage requirements of the model test, several excavation footage sections are assembled. The assembled excavation footage sections are connected through data plugs and data interfaces, and finally connected to the data acquisition device to form a tunnel excavation profile prefabricated model;

[0032] (2) Place the prefabricated model connected to the tunnel excavation contour at the tunnel excavation location, and continue to fill the model and compact and air-dry it. After the model is completed, connect the data cable to the laptop to monitor the changes in tunnel pressure when the model is loaded to the ground stress equilibrium;

[0033] (3) After the monitoring data is stable, excavate the model tunnel. Use a cross-shaped screwdriver to reversely rotate the knobs at the connection between the module to be excavated and other modules to loosen the upper and lower fasteners, and remove the fasteners.

[0034] (4) Use a disassembly tool to insert it into the disassembly hole, clamp the mortise structure, and remove the excavation module from the excavation section to complete the excavation work of the module;

[0035] (5) Repeat steps (3) and (4) according to the needs of the simulated excavation process until the tunnel is excavated in steps. After all the excavation work is completed, save the monitoring data and analyze the impact of each step excavation on the surrounding rock pressure of the tunnel.

[0036] The present invention provides a model test simulation tunnel step method excavation mold, each step of the tunnel step method excavation is made into a corresponding excavation module, each excavation module has a monitoring sensor to monitor and record the surrounding rock pressure and excavation time during excavation, each excavation module is connected by a fastener, and is easy to assemble and disassemble, and can quickly, efficiently and accurately simulate and monitor the surrounding rock pressure changes of the tunnel during the step method excavation process, and has the following advantages:

[0037] (1) The excavation module of the present invention is decomposed into eight excavation modules according to the different excavation positions of the tunnel step method. The position and size of each excavation module are reduced in scale according to the similar scale of the model test, and the degree of on-site restoration is high;

[0038] (2) The eight excavation modules of the present invention are connected by fasteners, and are flexible to assemble and disassemble, and have strong adaptability. When excavating, a single module can be used for excavation, or multiple modules can be used for excavation in combination, and the changing characteristics of surrounding rock pressure under different excavation steps such as two steps and three steps can be simulated;

[0039] (3) The monitoring sensors of the present invention are installed on the surface of each excavation module, instead of being buried inside the surrounding rock and transmitted through cables. Since the force is mutual, the pressure on the module surface is the surrounding rock pressure. The data monitoring, collection and transmission are stable, which can accurately reflect the force characteristics of the surrounding rock during step excavation and ensure the accuracy of the experimental results.

[0040] (4) Each excavation module of the present invention is made of polytetrafluoroethylene, which has the characteristics of light weight, high strength and insulation. The friction resistance between each excavation module is small, and it is easy to assemble and disassemble;

[0041] (5) Each excavation module of the present invention has high strength and does not deform under high confining pressure conditions. There is no over-excavation or under-excavation during disassembly and excavation, ensuring that the tunnel surface is straight;

[0042] (6) The modules and fasteners designed and manufactured by the present invention can be reused, and multiple model tests can be carried out to verify the test conclusions and better guide on-site construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of assembly and disassembly during excavation of the present invention.

[0044] Figure 2 The present invention shows a front view of an excavation section composed of eight excavation modules.

[0045] Figure 3 This is a front view of the eight excavation modules of the present invention after being disassembled.

[0046] Figure 4 This is a diagram of the data acquisition device of the present invention.

[0047] Figure 5 A three-dimensional view of the rear side after assembling each excavation module of the present invention.

[0048] Figure 6 This is a structural diagram of the fastener of the present invention.

[0049] Figure 7 It is a cross-sectional view of the left wall excavation module and the internal structure of the disassembly hole of the present invention.

[0050] Figure 8 This is a combined three-dimensional diagram of the cross sections of several excavation advances of the present invention.

[0051] Fig. 9This is the excavation diagram of the first step arch excavation module of the first frame in the step method excavation process simulated by the present invention.

[0052] Fig.10 This is a diagram of the excavation of the second frame first step arch module and the excavation of the left and right side wall modules of the first frame second step in the simulated step method excavation process of the present invention.

[0053] Fig.11 This is the excavation diagram of the third first step vault module in the simulated step method excavation process of the present invention.

[0054] Fig.12 This is a diagram of the simultaneous excavation of the first three steps in the step method excavation process simulated by the present invention.

[0055] In the figure: 1—excavation module; 11—vault excavation module; 12—arch step excavation module; 13—left wall excavation module; 14—center excavation module; 15—right wall excavation module; 16—left foot excavation module; 17—bottom plate excavation module; 18—right foot excavation module; 2—data acquisition device; 21—data acquisition panel; 22—data line; 23—data plug; 24—data interface; 3—monitoring sensor; 4—fastening device; 41 fastening groove; 42—fastener; 421—upper fastener; 422—lower fastener; 423—knob 423; 5—disassembly hole. DETAILED DESCRIPTION

[0056] The present invention provides a model test simulating tunnel step method excavation mold. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the specific implementation mode of the present invention is described in detail below in conjunction with the accompanying drawings.

[0057] like Figures 1 to 7 As shown, a model test simulation tunnel step method excavation mold of the present invention is composed of an excavation module 1, a data acquisition device 2, a monitoring sensor 3 and a fastening device 4. The excavation module 1 is composed of an arch excavation module 11, an arch step excavation module 12, a left wall excavation module 13, a center excavation module 14, a right wall excavation module 15, a left foot excavation module 16, a bottom plate excavation module 17 and a right foot excavation module 18. The data acquisition device 2 is composed of a data acquisition panel 21, a data line 22 and a data plug 23. The fastening device 4 is composed of a fastening groove 41 and a fastener 42.

[0058] like Figure 2 , 3As shown, the excavation module 1 is made of polytetrafluoroethylene. According to the different excavation positions of the tunnel using the step method, eight different sub-excavation modules are made, namely, the arch excavation module 11, the arch step excavation module 12, the left wall excavation module 13, the center excavation module 14, the right wall excavation module 15, the left foot excavation module 16, the bottom plate excavation module 17 and the right foot excavation module 18.

[0059] like Figure 2 As shown, the excavation module 1 is composed of eight sub-excavation modules to form an excavation footage section. According to the similarity scale requirements of the model test, the thickness of the excavation module 1 is 5~15cm, the footage section width of the excavation module 1 is 20~40cm, and the height is 30~40cm.

[0060] A data plug 23 is provided at the center position of the front side of the excavation module 1, and the data plug 23 can be connected to the data interface 24 of the previous identical excavation module 1; a data interface 24 is provided at the corresponding position on the rear side of the excavation module 1, which can be connected to the data plug 23 of the subsequent identical excavation module 1 or the data plug 23 of the data acquisition device 2. The same modules are connected end to end to transmit the monitoring data to the data acquisition device 2.

[0061] The module side wall of the excavation module 1 in contact with the tunnel wall is provided with a monitoring sensor 3 which can monitor the tunnel pressure and excavation time.

[0062] The data plug 23 of the excavation module 1 has a disassembly hole 5 on both sides, which can be removed from the excavation section with the help of a disassembly tool to complete the excavation work.

[0063] A fastening groove 41 is provided at the edge of the excavation module 1 where it is connected to other modules, and each excavation module 1 can be connected as a whole through a fastener 42 to form an excavation advance section.

[0064] The vault excavation module 11 is the vault part of the excavation module 1, and has a semicircular shape with a trapezoidal notch in the middle. Seven monitoring sensors 3 are evenly distributed on the semicircular outer surface, which can monitor the pressure changes during excavation of the tunnel vault and waist. The vault excavation module 11 has three fastening grooves 41, which are distributed on the upper side of the trapezoidal notch and at the two feet of the vault excavation module 11. A data plug 23 is provided at the center position of the front side of the vault excavation module 11, and a data interface 24 is provided at the corresponding position of the rear center, and there is a disassembly hole 5 on each side of the data plug 23.

[0065] The arch step excavation module 12 is the lower connecting part of the arch crown excavation module 11, which is equivalent to the core soil part reserved for the first step in the step method, and has a trapezoidal shape; the arch step excavation module 12 has two fastening grooves 41, which are distributed on the upper and lower sides of the arch step excavation module 12; a data plug 23 is provided at the center position of the front side of the arch step excavation module 12, and a data interface 24 is provided at the corresponding position of the center of the rear side, and there is a disassembly hole 5 on each side of the data plug 23.

[0066] The left wall excavation module 13 is the left wall part of the excavation module 1, and has a rectangular shape. Two monitoring sensors 3 are distributed on the left surface, which can monitor the pressure changes during the excavation of the left wall of the tunnel; the left wall excavation module 13 has three fastening grooves 41, which are distributed on the upper side, lower side and right side of the left wall excavation module 13; a data plug 23 is provided at the center position of the front side of the left wall excavation module 13, and a data interface 24 is provided at the corresponding position of the rear center, and there is a disassembly hole 5 on each side of the data plug 23.

[0067] The central excavation module 14 is the central part of the excavation module 1, which is equivalent to the core soil part reserved for the second step in the step method. It has a rectangular shape and plays a connecting role. There is a fastening groove 41 in the middle of each of the four sides of the central excavation module 14. A data plug 23 is provided at the center position of the front side of the central excavation module 14, and a data interface 24 is provided at the corresponding position of the rear center, which can record the excavation time of this module. There is a disassembly hole 5 on each side of the data plug 23.

[0068] The right wall excavation module 15 is the right wall part of the excavation module 1, which is symmetrical with the left wall excavation module 13 about the axis of the tunnel, and has a rectangular shape. Two monitoring sensors 3 are distributed on the right surface, which can monitor the pressure changes during the excavation of the right wall of the tunnel; the right wall excavation module 15 has three fastening grooves 41, which are distributed on the upper side, lower side and left side of the right wall excavation module 15; a data plug 23 is provided at the center position of the front side of the right wall excavation module 15, and a data interface 24 is provided at the corresponding position of the center of the rear side, and there is a disassembly hole 5 on each side of the data plug 23.

[0069] The left-foot excavation module 16 is the left-foot part of the excavation module 1, and has a rectangular shape. Two monitoring sensors 3 are distributed on the left and lower surfaces, which can monitor the pressure changes during excavation of the left wall and bottom plate of the tunnel; the left-foot excavation module 16 has two fastening grooves 41, which are distributed on the upper and right sides of the left-foot excavation module 16; a data plug 23 is provided at the center position of the front side of the left-foot excavation module 16, and a data interface 24 is provided at the corresponding position of the rear center, and there is a disassembly hole 5 on each side of the data plug 23.

[0070] The bottom plate excavation module 17 is the bottom plate part of the excavation module 1, which is equivalent to the core soil part reserved for the third step in the step method. It has a rectangular shape and five monitoring sensors 3 are distributed on the lower surface to monitor the pressure changes during the excavation of the tunnel bottom plate; the bottom plate excavation module 17 has three fastening grooves 41, which are distributed on the left side, top side and right side of the bottom plate excavation module 17; a data plug 23 is provided at the center position of the front side of the bottom plate excavation module 17, and a data interface 24 is provided at the corresponding position of the rear center, and there is a disassembly hole 5 on each side of the data plug 23.

[0071] The right-foot excavation module 18 is the right-foot part of the excavation module 1, which is symmetrical with the left-foot excavation module 16 about the axis of the tunnel, and has a rectangular shape. Two monitoring sensors 3 are distributed on the right and lower surfaces, which can monitor the pressure changes during excavation of the right wall and bottom plate of the tunnel; the right-foot excavation module 18 has two fastening grooves 41, which are distributed on the upper and left sides of the right-foot excavation module 18; a data plug 23 is provided at the center position of the front side of the right-foot excavation module 18, and a data interface 24 is provided at the corresponding position of the rear center, and there is a disassembly hole 5 on each side of the data plug 23.

[0072] like Figure 4 As shown, the data acquisition device 2 is made of polytetrafluoroethylene with a thickness of 5 to 8 cm. Its appearance is the same as the cross-section of the excavation footage. Eight data plugs 23 are arranged on its panel. There is a transmission circuit inside the panel, which can collect the data monitored and recorded by each excavation module 1. There is a data line 22 at the bottom of the data acquisition device 2, which can transmit the monitored and recorded data to the computer; the data plug 23 is a square flat plug, which is connected to the data interface 24. Both have hot-swappable cables and circuits inside, which can transmit data. Unplugging the excavation module 1 during the power-on process will not cause a circuit short circuit and loss of monitoring data.

[0073] like Figure 5 As shown, the monitoring sensor 3 is a pressure sensor, which is distributed at the position where the surface of each excavation module 1 contacts the surrounding rock of the tunnel, and monitors and records the excavation time and pressure changes of each excavation module 1 during the excavation process.

[0074] like Figure 6 As shown, the fastening device 4 consists of a fastening groove 41 and a fastener 42. The fastening groove 41 is a semi-I-shaped opening set at different positions on each excavation module 1, and the opening width is 8~12mm. After the two fastening grooves 41 are connected, they can be connected as a whole by the fastener 42.

[0075] The fastener 42 is an I-shaped connector made of stainless steel, and its size matches the fastening groove 41. The fastener 42 consists of an upper fastener 421, a lower fastener 422 and a knob 423; the upper fastener 421 and the lower fastener 422 are both semi-I-shaped and connected together in the middle. The knob 423 is a rotatable device in the middle of the fastener 42. The upper fastener 421 and the lower fastener 422 can be tightened toward the middle by rotating clockwise with a cross screwdriver, and the upper fastener 421 and the lower fastener 422 can be loosened toward the middle by rotating counterclockwise with a cross screwdriver; when the middle of the fastener 42 is tightened, the excavation modules 1 are connected as a whole, and when the middle of the fastener 42 is loosened, one or several excavation modules 1 can be removed according to the needs of the excavation position.

[0076] like Figure 7 As shown, the disassembly hole 5 is an opening on the surface of each excavation module 1, the diameter of the disassembly hole 5 is 6~10mm, the hole depth is 10~15mm, and there is a mortise structure inside the disassembly hole 5, so that the disassembly tool can be inserted into the disassembly hole 5 and clamped in the mortise structure, so as to remove the excavation module 1 from the excavation footage section and complete the excavation work.

[0077] like Figures 8 to 12 As shown, the present invention provides a method for using a model test simulation tunnel step method excavation mold, which specifically includes the following steps:

[0078] (1) When the model platform is filled to the height of the tunnel floor, each excavation module 1 is connected to form an excavation footage section through a fastener 42. According to the excavation footage requirements of the model test, several excavation footage sections are assembled, and the assembled excavation footage sections are connected through a data plug 23 and a data interface 24, and finally connected to the data acquisition device 2 to form a tunnel excavation profile prefabricated model;

[0079] (2) Place the prefabricated model connected to the tunnel excavation contour at the tunnel excavation location, continue to fill the model and compact and air-dry it, and after the model is completed, connect the data cable 22 to the laptop to monitor the changes in tunnel pressure when the model is loaded to the ground stress equilibrium;

[0080] (3) After the monitoring data is stable, excavation of the model tunnel is carried out. The knob 423 at the connection between the module to be excavated and other modules is rotated in the opposite direction using a cross-shaped screwdriver to loosen the upper fastener 421 and the lower fastener 422, and the fastener 42 is removed;

[0081] (4) Using a disassembly tool, insert it into the disassembly hole 5, clamp the mortise structure, and remove the excavation module 1 from the excavation footage section to complete the excavation work of the module;

[0082] (5) Repeat steps (3) and (4) according to the needs of the simulated excavation process until the tunnel is excavated in steps. After all the excavation work is completed, save the monitoring data and analyze the impact of each step excavation on the surrounding rock pressure of the tunnel.

Claims

1. A model test simulation tunnel step method excavation mold, characterized by: It consists of several excavation modules, data acquisition devices, monitoring sensors and fastening devices; the data acquisition device consists of a data acquisition panel, a data cable and a data plug; the fastening device consists of a fastening groove and a fastener; the excavation module is made of polytetrafluoroethylene and is divided into eight different sub-excavation modules according to the step excavation position, namely, the arch excavation module, the arch step excavation module, the left wall excavation module, the center excavation module, the right wall excavation module, the left foot excavation module, the bottom plate excavation module and the right foot excavation module; a data plug is provided at the front center of the sub-excavation module, and the data plug is connected to the data of the previous excavation module. The eight sub-excavation modules are connected by the data interface of the same sub-excavation module; a data interface is provided at the corresponding position on the rear side of the sub-excavation module, which can be connected with the data plug of the same sub-excavation module of the next excavation module or the data plug of the data acquisition device; a fastening groove is provided at the edge of the sub-excavation module and the connection with other sub-excavation modules, and the eight sub-excavation modules are connected as a whole by fasteners to form an excavation footage section. According to the excavation footage requirements of the model test, several excavation modules are assembled into several excavation footage sections; the data acquisition device is made of polytetrafluoroethylene, with a thickness of 5~8cm, and its appearance is consistent with the excavation footage The cross-section is the same. Eight data plugs are arranged on the data acquisition panel. There is a transmission circuit inside the data acquisition panel, which can collect the data monitored and recorded by each sub-excavation module. There is a data cable at the bottom of the data acquisition device. The data plug is a square flat plug, which is connected to the data interface. There are cables and circuits with hot-swap functions inside the two. There is a disassembly hole on each side of the data plug of the sub-excavation module. The disassembly hole is an opening on the surface of each sub-excavation module, located on both sides of the data plug. The diameter of the disassembly hole is 6~10mm, and the hole depth is 10~15mm. There is a mortise structure inside the disassembly hole, so that the disassembly tool can be inserted from the disassembly hole. The mortise structure is stuck, and the sub-excavation module is removed from the excavation footage section; the monitoring sensor is a pressure sensor, which is distributed at the position where the surface of each sub-excavation module contacts the surrounding rock of the tunnel; the fastening groove is a semi-I-shaped opening set at different positions on each sub-excavation module, and the opening width is 8~12mm; the fastener is an I-shaped connector made of stainless steel, and its size matches the fastening groove, and the fastener consists of an upper fastener, a lower fastener and a knob; the upper fastener and the lower fastener are both semi-I-shaped, connected together in the middle, and the knob is located at the connection between the two, and the direction of rotation of the knob determines the working state of the fastener.

2. The method for using a model test simulation tunnel step excavation mold according to claim 1, characterized in that: The specific steps include: (1) When the model platform is filled to the height of the tunnel floor, the eight sub-excavation modules are connected to form an excavation footage section through fasteners. According to the excavation footage requirements of the model test, several excavation footage sections are assembled, and the assembled excavation footage sections are connected through data plugs and data interfaces, and finally connected to the data acquisition device to form a tunnel excavation profile prefabricated model; (2) Place the prefabricated model connected to the tunnel excavation contour at the tunnel excavation location, and continue to fill the model and compact and air-dry it. After the model is completed, connect the data cable to the laptop to monitor the changes in tunnel pressure when the model is loaded to the ground stress equilibrium; (3) After the monitoring data is stable, excavation of the model tunnel is carried out. Use a cross-shaped screwdriver to reversely rotate the knobs at the connection between the sub-excavation module to be excavated and other sub-excavation modules to loosen the upper fasteners and the lower fasteners, and remove the fasteners; (4) Use a disassembly tool to insert into the disassembly hole, clamp the mortise structure, and remove the sub-excavation module from the excavation footage section to complete the excavation work of the sub-excavation module; (5) Repeat steps (3) and (4) according to the needs of the simulated excavation process until the tunnel is excavated in steps. After all the excavation work is completed, save the monitoring data and analyze the impact of each step excavation on the surrounding rock pressure of the tunnel.

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