A physical model test excavation device and method for water-rich porous rock masses

Abstract

This invention provides a physical model test excavation device and method for water-rich porous rock masses, relating to the field of underground engineering simulation testing. Addressing the current difficulty in accurately simulating water inrush or instability at the tunnel face, this invention precisely controls the water pressure within the cavity using a controller, solving the problem of existing equipment's inability to accurately control water head changes during excavation, thus improving the reliability of experimental results. Furthermore, by precisely controlling the water pressure and tunneling pressure, the model tunnel boring machine adopts a tunneling method closer to actual engineering. Through precise control of the cutterhead's tunneling speed and force, as well as the support effect of the sleeve on the excavated area, it can simulate water inrush or instability at the tunnel face caused by over-excavation, simulating the mechanism of water inrush or instability at the tunnel face caused by over-excavation in actual engineering, thereby improving the realism of the simulation.

Description

Technical Field

[0001] This invention relates to the field of underground engineering simulation testing, specifically to a physical model test excavation device and method for water-rich porous rock masses. Background Technology

[0002] In the fields of geological engineering and mining engineering, accurately simulating the excavation process of water-rich porous rock masses is crucial for studying rock mass stability and groundwater flow. However, existing physical model testing methods face numerous challenges in simulating rock mass excavation under water-rich conditions. Traditional manual excavation and fully open excavation methods have limitations in controlling surrounding rock deformation, resulting in excessively small excavation scales. A high geometric similarity ratio of the surrounding rock further exacerbates the challenge of mechanical similarity ratios, imposing stringent requirements on the proportions of similar materials.

[0003] Chinese Patent (Publication No. CN 117191442 A) discloses a test device for simulating shield tunnel construction in water-rich karst areas. This device can simulate shield tunnel construction under different groundwater levels and karst cave parameters (size, shape, location, and filling degree), and monitor the surrounding rock mechanical properties and ground settlement during shield tunnel construction under corresponding conditions. This provides a certain indoor model test basis for studying the impact of shield tunnel construction in water-rich karst areas. However, existing methods for addressing water inrush or instability at the excavation face during excavation often employ a retreat method, which differs significantly from the water inrush or instability mechanisms caused by over-excavation in actual engineering. Furthermore, existing equipment struggles to accurately control water head changes during excavation, affecting the reliability of experimental results. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a physical model test excavation device and method for water-rich porous rock masses. By precisely controlling the water pressure within the cavity through a controller, the invention solves the problem of existing equipment's difficulty in accurately controlling water head changes during excavation, thereby improving the reliability of experimental results. Furthermore, by precisely controlling the water pressure and tunneling pressure, the model tunnel boring machine adopts a tunneling method that more closely resembles that in actual engineering projects. By precisely controlling the excavation speed and force of the cutterhead, as well as the support effect of the sleeve on the excavated area, the invention can simulate the phenomenon of water inrush or instability at the tunnel face caused by over-excavation, thus simulating the mechanism of water inrush or instability at the tunnel face caused by over-excavation in actual engineering projects and improving the realism of the simulation.

[0005] The first objective of this invention is to provide a physical model test excavation device for water-rich porous rock masses, employing the following scheme:

[0006] include:

[0007] The model test chamber has an internal cavity filled with a material similar to water-rich porous rock mass. The cavity is connected to a water source through a water supply pipe. A water pressure monitoring element is installed inside the cavity to obtain the water pressure inside the cavity and send it to the controller.

[0008] The model tunnel boring machine is equipped with a cutterhead and a sleeve. The sleeve contains a muck discharger and a main shaft that drives the cutterhead. The outer shell of the model test chamber has an excavation opening for the model tunnel boring machine to pass through. The cutterhead passes through the excavation opening and extends into the cavity. One end of the sleeve extends into the cavity and forms support for the excavation area of ​​the cutterhead. An earth pressure monitoring element is installed on the cutterhead to acquire the earth pressure at the working face and send it to the controller. The controller is used to control the water pressure in the cavity and the cutterhead excavation pressure.

[0009] Furthermore, a waterproof mechanism is provided between the excavation opening and the sleeve. The outer ring of the waterproof mechanism is fixed to the model test box corresponding to the excavation opening, and a sliding seal is formed between the inner ring of the waterproof mechanism and the outer circumferential wall of the sleeve.

[0010] Furthermore, the waterproofing mechanism is a double-layer annular sealing ring, with the outer ring of the double-layer annular sealing ring installed on the excavation opening and sealed by fasteners.

[0011] Furthermore, the outer diameter of the cutterhead is larger than the outer diameter of the sleeve. When the cutterhead is driven to dig upward in the axial direction, a gap can be formed between the cutterhead and the sleeve in the axial direction, so that the cutterhead and the sleeve are in an unsupported state.

[0012] Furthermore, the main shaft and the sleeve are coaxially distributed, the lead wire connected to the earth pressure detection element is led out through the pre-reserved opening in the center of the main shaft, and a sealing layer is coated on the outer circumference of the sleeve.

[0013] Furthermore, the spindle is connected to an axial force monitoring element and a torque monitoring element, which are respectively connected to a controller to acquire the axial force and torque when the cutter head is driven and send them to the controller. The controller can adjust the operating status of the spindle and the cutter head.

[0014] Furthermore, the water source is a water supply component, and a valve is installed on the water supply pipe, which is connected to a controller.

[0015] A second objective of this invention is to provide a method for operating a physical model test excavation device for water-rich porous rock masses as described in the first objective, comprising:

[0016] The cutterhead and part of the sleeve of the model shield machine are inserted into the cavity through the excavation opening. The cavity of the model test box is filled with water-rich porous rock-like material. The cavity is connected to a water supply pipe and a water pressure monitoring element is installed.

[0017] Water is injected into the cavity and the set water pressure is maintained. After the set saturation period, the model shield machine is used to excavate the water-rich porous rock mass similar material.

[0018] By collecting parameters during excavation, the internal seepage and geostress variation patterns of similar materials with water-rich porous rock masses during the excavation process were obtained.

[0019] Furthermore, when filling water-rich porous rock mass with similar material to the cutterhead height, the cutterhead is sealed with moist clay, and then the filling and compaction continue in layers to the set height.

[0020] Furthermore, when filling water-rich porous rock mass with similar materials, multiple water pressure monitoring elements are installed inside the cavity and connected to the controller respectively.

[0021] Compared with the prior art, the advantages and positive effects of this invention are:

[0022] (1) To address the problem that it is difficult to accurately simulate water inrush or instability at the tunnel face, the water pressure inside the cavity is precisely controlled by the controller, which solves the problem that existing equipment cannot accurately control the water head changes during excavation, thus improving the reliability of the experimental results. Furthermore, by precisely controlling the water pressure and tunneling pressure, the model tunnel boring machine adopts a tunneling method that is closer to that in actual engineering. By precisely controlling the tunneling speed and force of the cutterhead, as well as the support effect of the sleeve on the excavation area, the phenomenon of water inrush or instability at the tunnel face caused by over-excavation can be simulated, thus simulating the mechanism of water inrush or instability at the tunnel face caused by over-excavation in actual engineering, thereby improving the realism of the simulation.

[0023] (2) Earth pressure monitoring elements were installed on the model tunnel boring machine to monitor changes in earth pressure at the tunnel face in real time. The data was sent to the controller in real time, and the controller then adjusted the water pressure and tunneling pressure based on the monitoring data to achieve more accurate simulation and control. By collecting and analyzing data such as water pressure, earth pressure, and ground settlement during the model test, a deeper understanding of the mechanical characteristics and ground response during the construction of shield tunnels in water-rich karst areas can be obtained. This helps to evaluate the effectiveness of different construction strategies and provides useful guidance for actual engineering projects. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the physical model test excavation device for water-rich porous rock mass in Embodiments 1 and 2 of the present invention.

[0026] Figure 2 This is a schematic diagram of the model tunnel boring machine and the model test box in Embodiments 1 and 2 of the present invention.

[0027] Figure 3 This is a schematic diagram of the top plate of the model test chamber in Embodiments 1 and 2 of the present invention.

[0028] Among them, 10, model test box; 20, model tunnel boring machine; 101, top plate; 102, water pressure monitoring element; 103, flange connection; 104, water supply assembly; 105, water supply pipe; 106, first bolt; 107, second bolt; 108, outlet; 109, inlet; 201, cutterhead; 202, sleeve; 203, slag discharger; 204, slag bin; 205, partition plate; 206, earth pressure monitoring element; 301, waterproofing mechanism; 302, moist clay seal; 401, water-rich porous rock mass similar material. Detailed Implementation

[0029] Example 1

[0030] In a typical embodiment of the present invention, such as Figures 1-3 As shown, a physical model test excavation device for water-rich porous rock masses is presented.

[0031] Existing methods for handling water inrush or instability at the tunnel face during excavation often employ a retreat mechanism, which differs significantly from the actual mechanisms of water inrush or instability caused by over-excavation in engineering projects. Furthermore, existing equipment struggles to precisely control water head changes during excavation, impacting the reliability of experimental results. Therefore, this embodiment provides a physical model test excavation device for water-rich porous rock masses. By precisely controlling water pressure and tunneling pressure, the model tunnel boring machine 20 employs a tunneling method closer to that in actual engineering projects. Through precise control of the cutterhead 201's tunneling speed and force, and the support effect of the sleeve 202 on the excavated area, the device can simulate water inrush or instability at the tunnel face caused by over-excavation, thus simulating the actual mechanisms of water inrush or instability caused by over-excavation in engineering projects and improving the realism of the simulation.

[0032] The following is a detailed description of the physical model test excavation device for water-rich porous rock masses, with reference to the accompanying drawings. For example... Figure 1 As shown, the physical model test excavation device for water-rich porous rock mass mainly includes a simulation test chamber and a model tunnel boring machine 20. A cavity is formed inside the model test chamber 10, which can be filled with a material 401 similar to water-rich porous rock mass. This cavity can be connected to a water source through a water supply pipe 105 to simulate a groundwater environment. A water pressure monitoring element 102 is installed inside the cavity to acquire water pressure data and send the data to a controller.

[0033] like Figure 3As shown, the water source is located outside the model test chamber 10. The water source uses a water supply component 104, such as a combination of a water pump and a water tank. The water pump draws water from the tank and then injects it into the chamber via a water supply pipe 105, adjusting the water pressure within the chamber to provide different hydrostatic pressures to the water-rich porous rock-like material 401. A water pressure monitoring element 102 monitors the water pressure changes within the model test chamber 10 in real time and adjusts the water supply component 104 according to the set hydrostatic pressure. In this embodiment, the water pressure monitoring element 102 can be a water pressure sensor, which can be placed not only at the top of the chamber but also at other locations within the chamber to meet monitoring needs at multiple locations.

[0034] In this embodiment, the water supply component 104 provides hydrostatic pressure with different gradients within 10MPa. The water supply pipe 105 can be a high-pressure explosion-proof hose. The water inlet 109 is installed at the top plate 101 of the model test chamber 10 using a flange connector 103. The top plate 101 of the model test chamber 10 is connected to the lower body of the model test chamber 10 through the flange face. A sealing gasket is placed between the flange faces and fixed by the first bolt 106 and the second bolt 107. Waterproof material is coated on the outside of the connection. The water supply pipe 105 is connected to the cavity through the water inlet 109.

[0035] A valve is installed on the water supply pipe 105. The valve can be a solenoid valve or the like. It is connected to a controller, which can control the opening and closing of the water supply and the water flow rate.

[0036] The data of the water pressure monitoring element 102 is transmitted via wire. A high-quality silicone sealing ring is used at the connection between the signal line of the water pressure monitoring element 102 and the model test box 10. A waterproof wire sheath is placed between the signal line and the silicone sealing ring.

[0037] like Figure 2 As shown, the model tunnel boring machine 20 can simulate the tunneling process of a tunnel boring machine in water-rich porous rock. The model tunnel boring machine 20 is equipped with a cutterhead 201 and a sleeve 202. The cutterhead 201 is used to excavate the rock mass, and the sleeve 202 houses a muck discharger 203 and the main shaft that drives the cutterhead 201. The outer shell of the model test chamber 10 has an excavation opening through which the model tunnel boring machine 20 passes. The cutterhead 201 passes through the excavation opening and extends into the cavity. One end of the sleeve 202 extends into the cavity and forms support for the excavation area of ​​the cutterhead 201. An earth pressure monitoring element 206 is installed on the cutterhead 201 to acquire the earth pressure at the working face and send it to the controller. The controller is used to control the water pressure inside the cavity and the tunneling pressure of the cutterhead 201. The main shaft of the model tunnel boring machine 20 is controlled by the controller to adjust the tunneling pressure.

[0038] The controller can receive data from the water pressure monitoring element 102 and the earth pressure monitoring element 206, and control the water pressure inside the cavity and the tunneling pressure of the model shield machine 20 accordingly. By precisely controlling these parameters, various working conditions during shield tunnel construction in actual engineering can be simulated more accurately.

[0039] By more realistically simulating the mechanisms of water inrush or instability at the tunnel face and changes in hydraulic head, the accuracy of simulation for shield tunnel construction in water-rich karst areas has been improved. Precise control of experimental conditions makes the experimental results more reliable, providing a more solid indoor model test foundation for studying the impact of shield tunnel construction in water-rich karst areas.

[0040] like Figure 2 As shown, the waterproofing mechanism 301 is located between the excavation opening and the sleeve 202 to prevent moisture from seeping into the interior of the model test chamber 10 from the excavation opening. The outer ring of the waterproofing mechanism 301 is fixed to the model test chamber 10 corresponding to the excavation opening. A sliding seal is formed between the inner ring of the waterproofing mechanism 301 and the outer circumferential wall of the sleeve 202 to ensure that the waterproofing effect is maintained even when the sleeve 202 moves.

[0041] The waterproofing mechanism 301 employs a double-layer annular sealing ring, enhancing the reliability and durability of the seal. The outer ring of the double-layer annular sealing ring is installed at the excavation opening using fasteners, ensuring a tight seal. Fasteners can be bolts, screws, or other similar components. After securing with fasteners, sealant can be applied to both the installation locations of the double-layer annular sealing ring and the fasteners to achieve a final seal.

[0042] In addition, at the starting position of the tunneling, the sealing plate 302 is wrapped with moist clay to provide internal waterproofing during the saturation process of the water-rich porous rock mass similar material 401.

[0043] The cutter head 201 can be a scraper-type cutter head 201 with a diameter of 30cm. Different opening ratios can be selected, including 20%, 40% and 60%. The upper limit of the torque of the cutter head 201 is set to 1000Nm to ensure cutting of water-rich porous rock masses.

[0044] The outer diameter of the cutterhead 201 is larger than the outer diameter of the sleeve 202. When the cutterhead 201 is driven to excavate axially, an axial gap is formed between the cutterhead 201 and the sleeve 202, creating an unsupported state between them. Specifically, the diameter of the cutterhead 201 is slightly larger than that of the sleeve 202 to ensure smooth jacking of the sleeve 202 during excavation. The cutterhead 201 can advance independently by a maximum of 6cm, creating an unsupported state between it and the sleeve 202.

[0045] The main shaft and sleeve 202 are coaxially distributed. The lead wire connecting the earth pressure detection element passes through the pre-drilled hole in the center of the main shaft and leads out. The outer circumference of sleeve 202 is coated with a sealing layer. Sleeve 202 is 1m long and made of stainless steel. The sealing layer is Vaseline evenly applied to the outer wall of sleeve 202, which is used for timely support of the surrounding rock during excavation and jacking. The main shaft is located at the center of sleeve 202 and is driven by the reduction transmission device at the rear of sleeve 202 to advance the overall model shield machine 20.

[0046] The earth pressure monitoring element 206 is an earth pressure sensor for the cutterhead 201, located at the center of the front side of the cutterhead 201. The signal line is led out from the center of the main shaft and connected to the control via a wireless transmission device to realize the real-time monitoring function of earth pressure at the face of the cutterhead 201 during tunneling.

[0047] The slag discharger 203 is spiral-shaped and located slightly below the inside of the sleeve 202. A partition 205 is installed between it and the cutterhead 201. The slag discharger 203 passes under the partition 205 and is positioned behind the cutterhead 201. The slag discharger 203 has a diameter of 6 cm and a length of 1 m, and is used to promptly discharge the slag cut by the cutterhead 201 during excavation. A slag chamber 204 is set between the partition 205 and the cutterhead 201. The amount of slag remaining in the slag chamber 204 is controlled by adjusting the slag discharge speed of the slag discharger 203, thereby controlling the magnitude of the support force in front of the cutterhead 201.

[0048] The main shaft is equipped with axial force monitoring elements and torque monitoring elements. The axial force monitoring element can be an axial force sensor, and the torque monitoring element can be a torque sensor. These elements are connected to the controller. The controller can acquire axial force and torque data when the cutterhead 201 is driven, and adjust the operating status of the main shaft and cutterhead 201 based on this data to achieve precise control of the tunneling process.

[0049] An earth pressure monitoring element 206 was installed on the model tunnel boring machine 20 to monitor changes in earth pressure at the tunnel face in real time. The data was sent to the controller in real time, which then adjusted the water pressure and tunneling pressure based on the monitoring data to achieve more accurate simulation and control. By collecting and analyzing data such as water pressure, earth pressure, and ground settlement during the model test, a deeper understanding of the mechanical properties and ground response during the construction of shield tunnels in water-rich karst areas can be obtained. This helps to evaluate the effectiveness of different construction strategies and provides useful guidance for actual engineering projects.

[0050] Example 2

[0051] In another typical embodiment of the present invention, such as Figures 1-3 As shown, a working method of a physical model test excavation device for water-rich porous rock mass is given, which utilizes the physical model test excavation device for water-rich porous rock mass as described in Example 1.

[0052] A working method for a physical model test excavation device for water-rich porous rock masses includes:

[0053] The cutterhead 201 and part of the sleeve 202 of the model shield machine 20 penetrate into the cavity through the excavation opening. The cavity of the model test box 10 is filled with water-rich porous rock-like material 401. The cavity is connected to the water supply pipe 105 and a water pressure monitoring element 102 is installed.

[0054] Water is injected into the cavity and the set water pressure is maintained. After the set saturation period, the model shield machine 20 is used to excavate the water-rich porous rock mass similar material 401.

[0055] By collecting parameters during excavation, the internal seepage and geostress variation patterns of water-rich porous rock mass similar material 401 were obtained during the excavation process.

[0056] Specifically, in combination Figures 1-3 The working method of the physical model test excavation device for water-rich porous rock masses includes the following steps:

[0057] Step 1: After the model box and the model tunnel boring machine 20 are connected by the waterproof mechanism 301, the rock sample is filled to the height of the cutterhead 201. The cutterhead 201 is then sealed with moist clay, and the filling and compaction are continued in layers to the specified height.

[0058] Step 2: When filling the rock sample, internal pressure sensors can be installed at the designated locations. After filling is completed, the top plate 101 is covered and fixed on the upper rock sample. All sensors are led out through the reserved holes of the top plate 101 and waterproof measures are taken.

[0059] Step 3: Connect the water inlet pipe to the model test chamber 10, and continuously inject water into the model test chamber 10 at the specified water pressure until the pressure remains constant for a long period of time;

[0060] Step 4: After 5 days of saturation, set the tunneling parameters (including cutterhead 201 rotation speed, tunneling speed, and muck ejector 203 rotation speed) and begin excavating the water-rich porous rock mass;

[0061] Step 5: Observe the changes in the readings of each monitoring element during the excavation process to obtain the internal seepage and geostress variation patterns of the water-rich porous rock mass during the excavation process.

[0062] The connection points between the model test chamber 10 and the water supply component 104, the monitoring element, and the model tunnel boring machine 20 are sealed in different ways to meet the requirement of no water leakage or pressure relief after the water pressure is applied to the model test chamber 10. In particular, the double-layer sealing ring design at the connection with the model tunnel boring machine 20 also meets the sealing requirements during the movement of the sleeve 202.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A physical model test excavation device for water-rich porous rock masses, characterized in that, include: The model test chamber has an internal cavity filled with a material similar to water-rich porous rock mass. The cavity is connected to a water source through a water supply pipe. A water pressure monitoring element is installed inside the cavity to obtain the water pressure inside the cavity and send it to the controller. The model tunnel boring machine is equipped with a cutterhead and a sleeve. The sleeve contains a slag discharger and a main shaft that drives the cutterhead. The outer shell of the model test chamber has an excavation opening for the model tunnel boring machine to pass through. The cutterhead passes through the excavation opening and extends into the cavity. One end of the sleeve extends into the cavity and forms support for the excavation area of ​​the cutterhead. An earth pressure monitoring element is installed on the cutterhead to acquire the earth pressure at the working face and send it to the controller. The controller is used to control the water pressure in the cavity and the cutterhead excavation pressure. When the cutterhead is driven to excavate axially, it can create an axial gap between the cutterhead and the sleeve, thus creating an unsupported state between the cutterhead and the sleeve. A valve is installed on the water supply pipe, and the valve is connected to the controller.

2. The physical model test excavation device for water-rich porous rock masses as described in claim 1, characterized in that, A waterproof mechanism is provided between the excavation opening and the sleeve. The outer ring of the waterproof mechanism is fixed to the model test box corresponding to the excavation opening, and a sliding seal is formed between the inner ring of the waterproof mechanism and the outer circumferential wall of the sleeve.

3. The physical model test excavation device for water-rich porous rock masses as described in claim 2, characterized in that, The waterproofing mechanism is a double-layer annular sealing ring. The outer ring of the double-layer annular sealing ring is installed on the excavation opening and sealed by fasteners.

4. The physical model test excavation device for water-rich porous rock masses as described in claim 1, characterized in that, The outer diameter of the cutter head is larger than the outer diameter of the sleeve.

5. The physical model test excavation device for water-rich porous rock masses as described in claim 4, characterized in that, The main shaft and the sleeve are coaxially distributed. The lead wire connecting the earth pressure detection element passes through the pre-reserved opening in the center of the main shaft and is led out. The outer circumference of the sleeve is coated with a sealing layer.

6. The physical model test excavation device for water-rich porous rock masses as described in claim 4 or 5, characterized in that, The spindle is equipped with an axial force monitoring element and a torque monitoring element, which are respectively connected to the controller. These elements are used to acquire the axial force and torque during the drive of the cutter head and send them to the controller. The controller can adjust the operating status of the spindle and the cutter head.

7. The physical model test excavation device for water-rich porous rock masses as described in claim 1, characterized in that, The water source is a water supply component.

8. A method for operating a physical model test excavation device for water-rich porous rock masses, utilizing the physical model test excavation device for water-rich porous rock masses as described in any one of claims 1-7, characterized in that, include: The cutterhead and part of the sleeve of the model shield machine are inserted into the cavity through the excavation opening. The cavity of the model test box is filled with water-rich porous rock-like material. The cavity is connected to a water supply pipe and a water pressure monitoring element is installed. Water is injected into the cavity and the set water pressure is maintained. After the set saturation period, the model shield machine is used to excavate the water-rich porous rock mass similar material. By collecting parameters during excavation, the internal seepage and geostress variation patterns of similar materials with water-rich porous rock masses during the excavation process were obtained.

9. The working method of the physical model test excavation device for water-rich porous rock mass as described in claim 8, characterized in that, When filling water-rich porous rock mass with similar material to the cutterhead height, seal the cutterhead with moist clay, and then continue filling and compacting in layers to the set height.

10. The working method of the physical model test excavation device for water-rich porous rock mass as described in claim 8, characterized in that, When filling water-rich porous rock mass with similar materials, multiple water pressure monitoring elements are installed in the cavity and connected to the controller respectively.

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