Rock-soil monitoring method and device for internal cavity of three-dimensional similar simulation test

Abstract

The invention relates to a rock-soil monitoring method and device for an internal cavity of a three-dimensional similar simulation test, and discloses a rock-soil monitoring method for realizing multi-point adjustable layout and stable installation in the cavity through a frame assembly, realizing self-adaptive fitting with a sample, continuous pre-tightening compensation and multi-parameter synchronous acquisition through a monitoring assembly, and combining integrated wiring and sealing protection. The rock-soil monitoring method and the rock-soil monitoring device for the internal cavity in the three-dimensional similar simulation test are used for realizing deep stable monitoring of a sample which cannot be perforated. The device is characterized in that the device comprises a frame assembly and a monitoring assembly, the frame assembly provides stable supporting and adjustable monitoring point arrangement for the monitoring assembly, the monitoring assembly achieves multi-parameter synchronous collection and sample accurate monitoring, and the frame assembly is composed of a stable cross beam and two vertical guide rails fixed to the bottom faces of the two ends of the stable cross beam; a sliding adjusting block is arranged on each vertical guide rail in a sliding mode along the height, and an integrated threading pipe is arranged on the outer side of the frame.

Description

Technical Field

[0001] This invention relates to a method and device for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test. It is a device for real-time, multi-parameter, fitted monitoring of soil and rock in the internal cavity of a three-dimensional similarity simulation test, belonging to the field of similarity model experiment technology. Specifically, it relates to a method and device for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test. This is achieved through a frame assembly that enables adjustable and stable installation at multiple points within the cavity; through a monitoring assembly that achieves adaptive fitting with the sample, continuous pre-tightening compensation, and synchronous acquisition of multiple parameters; and combined with integrated wiring and sealing protection, enabling deep and stable monitoring of non-perforated samples. Background Technology

[0002] In three-dimensional similarity model tests for geotechnical engineering, parameters such as stress, strain, displacement, deformation, earth pressure, and water content around the internal cavity soil and rock are crucial for assessing structural stability and revealing evolutionary patterns. Current testing and monitoring typically employ a single type of sensor to acquire a single physical quantity, or distribute multiple sensors at different locations for separate data collection and comparative analysis. However, due to inconsistent spatial locations of sensor measurement points, poor synchronization of data acquisition links and time, and a lack of methods to link water content to mechanical quantities, it is often difficult to achieve coordinated acquisition of strain information and data such as pressure and water content at the same monitoring point. This leads to unstable inferences about stress-strain relationships, increased data interpretation bias, and difficulty in forming reliable evolutionary patterns and early warning criteria. To obtain data that more closely reflects the actual stress state, some approaches involve pre-embedding sensors during sample preparation or installing probes through holes in the sample. Other approaches use external rigid probes or fixed supports to support the sample for measurement. However, in three-dimensional similarity simulation experiments, soil and rock samples are often pre-prepared square samples and are not allowed to be drilled. At the same time, the internal cavity is open at the front and back, and the only places that can be installed are the left and right sides and the top. Traditional pre-embedding or drilling methods are difficult to implement or may damage the integrity and similarity of the sample. Fixed probe schemes are not easy to achieve accurate layout and repeated positioning at multiple heights and multiple points. Installation deviations can easily introduce measurement errors, making it difficult to meet the needs of deep and accurate monitoring of the internal cavity.

[0003] Publication No. CN116577480A discloses a three-dimensional loading similar material test system for simulating underground rock and soil disasters, including a base plate; a model box is fixedly connected to the surface of the base plate; an end cover plate is fixedly connected to one end of the model box; servo actuators are arranged in a rectangular array on both sides, the top, and the end away from the end cover plate of the model box; a rectangular pressure plate is provided at the end of the servo actuators; a box seat is provided on the surface of the base plate and at the bottom inside the model box; a drive shaft is arranged in a linear array between the two ends inside the box seat; two adjacent drive shafts are connected to each other by a drive belt at one end of the box seat; a flipping platform is arranged in a linear array between the two sides of the upper surface of the box seat. The above system mainly uses the servo actuator array to load the model box, and the test data acquisition focuses on loading control and overall response. It is difficult to form a synchronous closed loop of strain-soil pressure-moisture content at the same monitoring point, which is not conducive to establishing a highly consistent evolution law and early warning criteria. Summary of the Invention

[0004] To improve the above situation, the present invention provides a method and device for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test. This method and device achieves adjustable and stable installation of multiple points within the cavity through a frame component, adaptive fitting with the sample, continuous pre-tightening compensation, and synchronous acquisition of multiple parameters through a monitoring component, and integrates wiring and sealing protection to achieve deep stability monitoring of non-perforated samples.

[0005] The method and device for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test according to the present invention are implemented as follows: The monitoring device for the internal cavity of a three-dimensional similarity simulation test includes a frame assembly and a monitoring assembly. The frame assembly provides stable support and adjustable monitoring point layout for the monitoring assembly. The monitoring assembly realizes simultaneous acquisition of multiple parameters and accurate monitoring of the sample. The frame assembly consists of a stable crossbeam and two vertical guide rails fixed to the bottom surfaces at both ends. Each vertical guide rail has a sliding adjustment block that slides along its height. An integrated conduit is installed on the outside of the frame. The monitoring component includes a fine-tuning screw, a torque transmission ring fixed to the screw, an open cylindrical sleeve coaxially arranged, and a disc spring assembly located between the two and sleeved on the screw. The open cylindrical sleeve is connected to a monitoring connector via a ball joint structure. The monitoring connector has a mating surface, on which a soil pressure sensor and a moisture meter are flushly embedded. The monitoring connector has a stepped mounting cavity, within which an elastic measuring component is fixed. An optical fiber strain gauge is mounted on its back. The sensor and resistance strain gauge are included. The monitoring assembly comprises three sets, each corresponding to one of the two vertical guide rails and one of the stabilizing crossbeams of the frame assembly. The frame assembly has an overall U-shaped structure. In the set of monitoring components corresponding to the vertical guide rails, one end of the fine-tuning screw extends inward from the outside of the U-shaped structure of the frame assembly, passing through a sliding adjustment block, and is threadedly connected to the sliding adjustment block. Multiple monitoring components in this set correspond one-to-one with the sliding adjustment block. In the set of monitoring components corresponding to the stabilizing crossbeam, one end of the fine-tuning screw extends vertically downward from the outside of the U-shaped structure of the frame assembly, passing through the stabilizing crossbeam to the other end, and is threadedly connected to the stabilizing crossbeam. Preferably, the number of monitoring components corresponding to the stabilizing beam is 1-3. The frame components include a stabilizing crossbeam, vertical guide rails, sliding adjustment blocks, and integrated conduit. A vertical guide rail is fixed to the bottom surface near both ends of the stabilizing beam. The stabilizing beam and the two vertical guide rails together form a U-shaped frame structure. Preferably, the vertical guide rail adopts a composite guide structure of T-groove + dovetail guide surface, and a height scale line is provided on the side of the vertical guide rail facing away from the U-shaped inner cavity. A set of sliding adjustment blocks is slidably installed on each vertical guide rail along its length. Preferably, each group of sliding adjustment blocks has 2 to 4 blocks, and the number of sliding adjustment blocks on the two vertical guide rails is the same and they correspond one-to-one in the height direction. An integrated conduit assembly is located on the side of the U-shaped frame facing away from the U-shaped inner cavity. Preferably, the integrated conduit assembly includes two vertical branch conduits fixedly disposed on the outer sides of the two vertical guide rails, and a horizontal main conduit fixedly disposed on the outer side of the stable crossbeam, wherein the upper ends of the two vertical branch conduits are connected to the horizontal main conduit. The monitoring components include a torque transmission ring, an open cylindrical sleeve, a disc spring assembly, a monitoring connector, a soil pressure sensor, a moisture meter, a stepped mounting cavity, an elastic measuring component, a fiber optic strain sensor, and a resistance strain gauge. The torque transmission ring is sleeved on the threaded section near the inner end of the fine-tuning screw, and its inner ring surface is fixedly connected to the side of the fine-tuning screw. The open end is sleeved on the other end of the fine-tuning screw near the inner side and is coaxial with it. Preferably, the other end of the open cylindrical sleeve is an arc-shaped end. Preferably, the inner wall of the open cylindrical sleeve is provided with a low-friction bushing. The disc spring assembly is fitted onto the fine-tuning screw and positioned between the torque transmission ring and the open cylindrical sleeve. Both ends of the disc spring assembly abut against the corresponding end faces of the torque transmission ring and the open cylindrical sleeve. The monitoring connector is connected to the arc-shaped end of the open cylindrical sleeve via a ball joint structure. A soil pressure sensor and a moisture meter are embedded in the mating surface of the monitoring joint facing the soil sample. Both the soil pressure sensor and the moisture meter are embedded and flush with the mating surface. Preferably, the bonding surface is covered with a wear-resistant thin layer, which is a replaceable wear-resistant force-transmitting layer, and a through-measuring window is provided in the corresponding area of ​​the soil pressure sensor and the moisture meter. Preferably, the moisture meter is a non-invasive moisture content sensor. The monitoring connector has a stepped mounting cavity on its mating side facing the soil and rock sample. The stepped mounting cavity includes a stepped positioning surface at the opening on the mating side and a back cavity space inside it. The elastic measuring component is disposed within the stepped mounting cavity and fixed at the stepped positioning surface. Preferably, the periphery of the elastic measuring component is pressed and fixed at the step positioning surface by a pressure ring, pressure cap, or slot structure. Preferably, the outer surface of the elastic measuring component forms the mating surface of the monitoring connector, or is flush with the mating surface, or is slightly convex relative to the mating surface. Preferably, the elastic measuring component is a diaphragm, a thin plate, or an elastic pressure plate. The fiber optic strain sensor is disposed within the stepped mounting cavity and fixed to the back of the elastic measuring component. Preferably, the back of the elastic measuring component has at least one shallow groove for receiving a sensor, the fiber optic strain sensor is embedded in the shallow groove and fixed with adhesive, and its outer side is protected by a cover strip or potting layer. Preferably, the fiber optic strain sensor is a fiber optic grating strain sensor, and at least two FBG grating measurement points are integrated on the same fiber. The at least two FBG measurement points are distributed circumferentially and / or radially on the elastic measuring component. The resistance strain gauge is disposed within the stepped mounting cavity and attached to the back of the elastic measuring component. Preferably, the resistance strain gauge is attached to the central region of the elastic measuring component or a predetermined stress-sensitive region. Preferably, the resistance strain gauges are arranged in a bridge of two or four gauges, and are potted or treated with a three-proof coating within the back cavity. One end of the flexible sheath is sealed to the outlet of the monitoring connector via a sealed outlet connector. The other end of the flexible sheath passes through a sealed inlet port located on a vertical guide rail or a stable crossbeam and extends into an integrated conduit. The sensor cable or optical fiber of the monitoring connector is threaded through the flexible sheath. Preferably, the flexible sheath has a bending allowance between the monitoring connector and the integrated conduit. This invention also relates to a method for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test, the monitoring method comprising the following steps: (1) Fix the frame assembly to the left and right mounting surfaces and the top mounting surface of the internal cavity of the three-dimensional similar model test, so that the U-shaped frame structure formed by the stable crossbeam and the two vertical guide rails is aligned with the working area inside the cavity. (2) Based on the test monitoring location, adjust the height of each sliding adjustment block on the two vertical guide rails so that the sliding adjustment blocks on both sides correspond one-to-one in the height direction. Use the height scale line on the outside of the vertical guide rails to complete the left and right alignment. Then lock the sliding adjustment blocks to complete the height layout of the monitoring points. (3) The sensor lines corresponding to each monitoring connector are uniformly organized and introduced into the integrated conduit. The outgoing end of each monitoring connector first enters the flexible sheath. One end of the flexible sheath is sealed to the monitoring connector through the sealed outgoing connector, and the other end passes through the sealed inlet of the integrated conduit and extends into the integrated conduit. The electrical signal lines (corresponding to the soil pressure sensor, moisture meter, and resistance strain gauge) and the optical fiber lines (corresponding to the optical fiber strain sensor) are laid out in sections in the integrated conduit. After ascending along the vertical branch channel and merging into the horizontal main channel, they are led out from the main outgoing end to the sealed junction box or data acquisition system to reduce crosstalk and meet the minimum bending radius requirement of the optical fiber. (4) The prefabricated square similar material soil sample is laid in the U-shaped frame structure, and the front and rear partitions are installed at the front and rear openings of the cavity to complete the sealing. The front partition can be equipped with an observation window to observe the condition of the sample. (5) Rotate the fine-tuning screws of each monitoring component so that the monitoring joints gradually approach and adhere to the surface of the soil and rock sample after automatic alignment via the ball joint structure. Continue fine-tuning until the disc spring assembly generates a preset compression amount to form a stable pre-tightening force, so that the soil pressure sensor and moisture meter at the contact surface remain flush and adhered, and effective measurement is achieved through the through-measuring window of the wear-resistant force transmission layer. At the same time, the elastic measuring component in the stepped mounting cavity generates measurable micro-deformation under pressure, thereby enabling the fiber optic strain sensor and resistance strain gauge on its back to enter the effective measurement state. (6) After the bonding and pre-tightening are completed, zero-point acquisition and calibration are performed on the soil pressure sensor, moisture meter, fiber optic strain sensor, and resistance strain gauge. The zero-point acquisition and calibration uses the stable state of bonding and pre-tightening as the initial reference to eliminate the initial pressure and initial strain bias introduced by the compression pre-tightening of the disc spring group. Subsequently, the pressure increment, strain increment, and moisture content change relative to the zero point are output and analyzed during the test, thereby ensuring that the measurement results reflect the true evolution response of the soil and rock sample during the loading / disturbance process, without being interfered with by the pre-tightening state of the disc spring group. At the same time, the elastic compensation provided by the disc spring group can maintain the continuous bonding of the monitoring joint and reduce signal jumps and loss caused by delamination. Then, the test is started and multi-parameter data are collected simultaneously. The fiber optic strain sensor is used to obtain the distributed strain information of the elastic measuring component, the resistance strain gauge is used to obtain the local micro-strain information, the soil pressure sensor is used to obtain the contact pressure information, and the moisture meter is used to obtain the moisture content information. The mechanical response is corrected and interpreted based on the moisture content. (7) After the test, stop collecting data, rotate the fine adjustment screw in the opposite direction to release the preload, so that the monitoring connector is separated from the sample, remove the front and rear partitions, take out the sample, and inspect and maintain the wear-resistant force transmission layer, the through-measuring window and the conduit assembly to prepare for the next test. Beneficial effects

[0006] First, it can simultaneously collect soil pressure, water content, FBG distributed strain and local micro-strain of resistance strain gauges at the same monitoring point, and use water content to correct the mechanical response. The data dimensions are more complete and the accuracy is higher, which is conducive to establishing more reliable evolution laws and early warning criteria.

[0007] 2. By using a U-shaped frame to install and adjust the distribution of points on the left, right and top, and with the help of screw rods for measurement, deep monitoring of the internal cavity can be completed without drilling holes in the prefabricated square soil and rock sample.

[0008] 3. After passing through a flexible sheath, the cable / fiber enters the integrated conduit for full-enclosed protection, and is further protected by sealing, waterproofing and anti-corrosion treatment, which significantly reduces the risk of signal instability or failure caused by wear, water ingress and corrosion. Attached Figure Description

[0009] Figure 1 This is a three-dimensional structural diagram of the soil and rock monitoring device for the internal cavity of the three-dimensional similarity simulation test of the present invention; Figure 2 This is a three-dimensional structural diagram of the soil and rock monitoring device for the internal cavity of the three-dimensional similarity simulation test of the present invention, which only shows the structure of the monitoring components; Figure 3 This is a three-dimensional structural diagram of the soil and rock monitoring device for the internal cavity of the three-dimensional similarity simulation test of the present invention, which only shows the structure of the monitoring components; Figure 4This is a three-dimensional structural diagram of the internal cavity soil and rock monitoring device of the present invention under working conditions in a three-dimensional similarity simulation test. Attached Figure

[0010] The components are: vertical guide rail (1), fine-tuning screw (2), sliding adjustment block (3), torque transmission ring (4), stabilizing crossbeam (5), monitoring connector (6), open cylindrical sleeve (7), disc spring assembly (8), integrated conduit (9), flexible sheath (10), moisture meter (11), elastic measuring component (12), soil pressure sensor (13), resistance strain gauge (14), stepped mounting cavity (15), and fiber optic strain sensor (16). Detailed Implementation

[0011] The method and device for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test according to the present invention are implemented as follows: The three-dimensional similarity simulation test internal cavity soil and rock monitoring device of the present invention includes a frame assembly and a monitoring assembly. The frame assembly consists of a stable crossbeam and two vertical guide rails fixed to the bottom surfaces at both ends. Each vertical guide rail has a sliding adjustment block that slides along its height. An integrated conduit is provided on the outside of the frame. The monitoring component includes a fine-tuning screw, a torque transmission ring fixed to the screw, an open cylindrical sleeve coaxially arranged, and a disc spring assembly located between the two and sleeved on the screw. The open cylindrical sleeve is connected to the monitoring connector via a ball joint structure. The monitoring connector has a mating surface, and a soil pressure sensor and a moisture meter are flush-mounted on the mating surface. The monitoring connector has a stepped mounting cavity, and an elastic measuring component is fixed inside the mounting cavity. A fiber optic strain sensor and a resistance strain gauge are provided on its back. The monitoring component has three sets, which are respectively connected to the two vertical guide rails (1) and the stable crossbeam of the frame assembly. Corresponding to beam (5), the frame assembly has an overall U-shaped structure. One end of the fine-tuning screw (2) in a set of monitoring components corresponding to the vertical guide rail (1) extends inward from the outside of the U-shaped structure of the frame assembly through the sliding adjustment block (3) and is threadedly connected to the sliding adjustment block (3). Multiple monitoring components in this set correspond one-to-one with the sliding adjustment block (3). One end of the fine-tuning screw (2) in a set of monitoring components corresponding to the stabilizing beam (5) extends vertically downward from the outside of the U-shaped structure of the frame assembly through the stabilizing beam (5) to the other end and is threadedly connected to the stabilizing beam (5). The frame assembly provides stable support and adjustable monitoring point layout for the monitoring components. The monitoring components realize multi-parameter synchronous acquisition and accurate monitoring of samples. Preferably, the number of monitoring components corresponding to the stabilizing beam (5) is 1-3. The frame components include a stabilizing crossbeam (5), a vertical guide rail (1), a sliding adjustment block (3), and an integrated conduit. A vertical guide rail (1) is fixedly placed on the bottom surface near both ends of the stabilizing beam (5). The stabilizing beam (5) and the two vertical guide rails (1) together form a U-shaped frame structure. Preferably, the vertical guide rail (1) adopts a composite guide structure of T-groove + dovetail guide surface, and a height scale line is provided on the side of the vertical guide rail (1) facing away from the U-shaped inner cavity. A set of sliding adjustment blocks (3) are slidably set on each vertical guide rail (1) along its length direction. Preferably, the number of sliding adjustment blocks (3) in each group is 2 to 4, and the number of sliding adjustment blocks (3) on the two vertical guide rails (1) is the same and they correspond one-to-one in the height direction. An integrated conduit (9) is disposed on the side of the U-shaped frame facing away from the U-shaped inner cavity. Preferably, the integrated conduit (9) includes two vertical branch conduits fixedly installed on the outer sides of the two vertical guide rails (1), and a horizontal main conduit fixedly installed on the outer side of the stable crossbeam (5), wherein the upper ends of the two vertical branch conduits are connected to the horizontal main conduit. The monitoring components include a torque transmission ring (4), an open cylindrical sleeve (7), a disc spring assembly (8), a monitoring connector (6), a soil pressure sensor (13), a moisture meter (11), a stepped mounting cavity (15), an elastic measuring component (12), a fiber optic strain sensor (16), and a resistance strain gauge (14). The torque transmission ring (4) is sleeved on the threaded section near the inner end of the fine-tuning screw (2), and its inner ring surface is fixedly connected to the side of the fine-tuning screw (2). The open end is sleeved on the other end of the fine-tuning screw (2) near the inner side and is coaxial with it. Preferably, the other end of the open cylindrical sleeve (7) is an arc-shaped end. Preferably, the inner wall of the open cylindrical sleeve (7) is provided with a low-friction bushing. The disc spring assembly (8) is fitted onto the fine-tuning screw (2) and located between the torque transmission ring (4) and the open cylindrical sleeve (7). The two ends of the disc spring assembly (8) respectively abut against the corresponding end faces of the torque transmission ring (4) and the open cylindrical sleeve (7). The monitoring connector (6) is connected to the arc-shaped end of the open cylindrical sleeve (7) via a ball joint structure. The soil pressure sensor (13) and moisture meter (11) are embedded in the mating surface of the monitoring connector (6) facing the soil sample. Both the soil pressure sensor (13) and the moisture meter (11) are embedded and flush with the mating surface. Preferably, the bonding surface is covered with a wear-resistant thin layer, which is a replaceable wear-resistant force-transmitting layer, and a through-measuring window is provided in the corresponding area of ​​the earth pressure sensor (13) and the moisture meter (11). Preferably, the moisture meter (11) is a non-invasive moisture content sensor. The monitoring connector (6) has a stepped mounting cavity (15) on its mating side facing the soil and rock sample. The stepped mounting cavity (15) includes a stepped positioning surface at the opening on the mating side and a back cavity space inside it. The elastic measuring component (12) is disposed within the stepped mounting cavity (15) and fixed at the stepped positioning surface. Preferably, the periphery of the elastic measuring component (12) is pressed and fixed at the step positioning surface by a pressure ring, pressure cap, or slot structure. Preferably, the outer surface of the elastic measuring component (12) forms the mating surface of the monitoring connector (6), or is flush with the mating surface, or is slightly convex relative to the mating surface. Preferably, the elastic measuring component (12) is a diaphragm, a thin plate, or an elastic pressure plate. The fiber optic strain sensor (16) is disposed within the stepped mounting cavity (15) and fixed to the back of the elastic measuring component (12). Preferably, the elastic measuring component (12) has at least one shallow groove for receiving a sensor on its back side, the fiber optic strain sensor (16) is embedded in the shallow groove and fixed with adhesive, and its outer side is protected by a cover strip or potting layer. Preferably, the fiber optic strain sensor (16) is a fiber optic grating strain sensor, and at least two FBG grating measurement points are integrated on the same fiber. The at least two FBG measurement points are distributed circumferentially and / or radially on the elastic measuring component (12). The resistance strain gauge (14) is disposed in the stepped mounting cavity (15) and attached to the back of the elastic measuring component (12). Preferably, the resistance strain gauge (14) is attached to the central region of the elastic measuring component (12) or a predetermined stress-sensitive region. Preferably, the resistance strain gauges (14) are arranged in a bridge of two or four pieces, and are potted or treated with three-proof coating in the back cavity. One end of the flexible sheath (10) is sealed to the outlet of the monitoring connector (6) through a sealed outlet connector. The other end of the flexible sheath (10) passes through the sealed inlet on the vertical guide rail (1) or the stable crossbeam (5) and extends into the integrated conduit (9). The sensor cable or optical fiber of the monitoring connector (6) is threaded through the flexible sheath (10). Preferably, the flexible sheath (10) has a bending allowance between the monitoring connector (6) and the integrated conduit (9). Furthermore, preferably, the surface of the fine-tuning screw (2) is provided with a scale for observing the preload state of the disc spring assembly. Preferably, the normal stiffness of the disc spring assembly (8) is at least 10 times the stiffness of the soil in the rock mass sample. This invention also relates to a method for monitoring soil and rock in the internal cavity of a three-dimensional similarity simulation test, the monitoring method comprising the following steps: (1) Fix the frame assembly to the left and right mounting surfaces and the top mounting surface of the internal cavity of the three-dimensional similar model test, so that the U-shaped frame structure formed by the stable crossbeam (5) and the two vertical guide rails (1) is aligned with the experimental area inside the cavity. (2) Based on the test monitoring location, adjust the height of each sliding adjustment block (3) on the two vertical guide rails (1) so that the sliding adjustment blocks (3) on both sides correspond one-to-one in the height direction, and use the height scale line on the outside of the vertical guide rails (1) to complete the left and right alignment. Then lock the sliding adjustment blocks (3) to complete the height layout of the monitoring points. (3) Organize the sensor lines corresponding to each monitoring connector (6) and introduce them into the integrated conduit (9). The outgoing end of each monitoring connector (6) first enters the flexible sheath (10). One end of the flexible sheath (10) is sealed to the monitoring connector (6) through the sealed outgoing connector, and the other end passes through the sealed inlet of the integrated conduit (9) and extends into the integrated conduit (9). The electrical signal lines (corresponding to the soil pressure sensor (13), moisture meter (11), and resistance strain gauge (14)) and the optical fiber lines (corresponding to the optical fiber strain sensor (16)) are laid out in sections in the integrated conduit (9), and after going up along the vertical branch channel and merging into the horizontal main channel, they are led out from the main outgoing end to the data acquisition system to reduce crosstalk and meet the minimum bending radius requirement of the optical fiber. (4) The prefabricated square similar material soil sample is laid in the U-shaped frame structure, and the front and rear partitions are installed at the front and rear openings of the cavity to complete the sealing. The front partition can be equipped with an observation window to observe the condition of the sample. (5) Rotate the fine-tuning screws (2) of each monitoring component so that the monitoring connector (6) gradually approaches and adheres to the surface of the soil and rock sample after automatic alignment by the ball joint structure. Continue fine-tuning until the disc spring group (8) generates a preset compression amount to form a stable pre-tightening force. That is, the disc spring group is pressed to the limit to form a rigid support for the monitoring connector (6), so that the soil pressure sensor (13) and the moisture meter (11) at the contact surface remain flush and adhere to each other and achieve effective measurement through the through-measuring window of the wear-resistant force transmission layer. At the same time, the elastic measuring component (12) in the stepped installation cavity (15) generates measurable micro-deformation under pressure, so that the fiber optic strain sensor (16) and the resistance strain gauge (14) on its back enter the effective measurement state. (6) After the bonding and pre-tightening are completed, zero-point acquisition and calibration are performed on the soil pressure sensor (13), moisture meter (11), fiber optic strain sensor (16), and resistance strain gauge (14). The zero-point acquisition and calibration is based on the stable state of bonding and pre-tightening as the initial reference, which is used to eliminate the initial pressure and initial strain bias introduced by the compression pre-tightening of the disc spring assembly (8). Subsequently, the output and analysis during the test are the pressure increment, strain increment, and moisture content change relative to the zero point, so as to ensure that the measurement results reflect the true evolution response of the soil and rock sample during the loading / disturbance process, and not... The pre-tightening state of the disc spring assembly (8) will interfere with the signal. At the same time, the elastic compensation provided by the disc spring assembly (8) can maintain the continuous fit of the monitoring joint (6), reducing signal jumps and loss caused by the gap. Then, the test is started and multi-parameter data are collected simultaneously. Among them, the fiber optic strain sensor (16) is used to obtain the distributed strain information of the elastic measuring component (12), the resistance strain gauge (14) is used to obtain the local micro-strain information, the soil pressure sensor (13) is used to obtain the contact pressure information, and the moisture meter (11) is used to obtain the moisture content information. The mechanical response is corrected and interpreted according to the moisture content. (7) After the test, stop collecting data, rotate the fine adjustment screw (2) in the opposite direction to release the preload, so that the monitoring connector (6) is separated from the sample, remove the front and rear partitions, take out the sample, and inspect and maintain the wear-resistant force transmission layer, the through-measuring window and the conduit assembly to prepare for the next test. The frame assembly has an overall U-shaped structure design, which can be stably installed and arranged with the internal cavity open at the front and back and only the left and right sides and the top can be installed, and provides multi-directional contact monitoring channels for the soil and rock samples from the side and top. The vertical guide rail (1) adopts a composite guide design of T-groove + dovetail guide surface and is set with height scale line, which can improve the guiding accuracy and repeat positioning consistency of the sliding adjustment block (3) movement, and realize the rapid reproduction of the monitoring point height and the left and right alignment. The design of the two vertical guide rails (1) with the same number of sliding adjustment blocks (3) and corresponding one-to-one in the height direction can realize the left and right symmetrical / same height comparison points, which is convenient for obtaining horizontal comparison data and reducing the point layout error; The design of the fine-tuning screw (2) threaded advance and the disc spring group (8) pre-tightening compensation can achieve stable contact of the monitoring joint (6) without opening the sample, and provide elastic following for sample creep / micro-displacement, reducing voiding and data jumps; The monitoring connector (6) is designed to be connected to the open cylindrical sleeve (7) through a ball joint structure, which can automatically compensate for unevenness of the sample surface and installation angle, reduce off-center load and stress concentration, and improve the bonding reliability and measurement consistency. The integrated conduit (9) is located on the side of the U-shaped frame facing away from the U-shaped inner cavity. The integrated conduit (9) includes two vertical branch conduits fixedly installed on the outer side of the two vertical guide rails (1) and a horizontal main conduit fixedly installed on the outer side of the stable crossbeam (5). The design that the upper ends of the two vertical branch conduits are connected to the horizontal main conduit can orderly collect and centrally lead out the cables of each monitoring point, reduce cable wear, tangling and interference, and improve the wiring protection and maintenance convenience. The goal is to achieve adjustable and stable installation of multiple points within the cavity through the frame components, adaptive fit with the sample, continuous pre-tightening compensation, and synchronous acquisition of multiple parameters through the monitoring components, and to achieve deep stability monitoring of non-perforated samples by combining integrated wiring and sealing protection.

[0012] Other similar embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art that are not disclosed herein.

[0013] It should be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connect," and "link" should be interpreted broadly. For example, they can refer to fixed connections such as folded edges, rivets, pins, adhesives, and welds; detachable connections such as threaded connections, snap-fit ​​connections, and hinges; integral connections; electrical connections; direct connections; or indirect connections via an intermediate medium; or internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0014] The above embodiments are preferred embodiments of the present invention. Due to space limitations, the applicant has not used other embodiments, but this is not intended to limit the scope of the present invention. Any person skilled in the art can make some modifications without departing from the scope of the present invention; that is, all equivalent modifications made in accordance with the present invention should be covered by the scope of the present invention.

Claims

1. A soil and rock monitoring device for an internal cavity in a three-dimensional similarity simulation test, comprising a frame assembly and a monitoring assembly, characterized in that: The frame assembly provides stable support and adjustable monitoring point layout for the monitoring component. The monitoring component enables simultaneous acquisition of multiple parameters and precise monitoring of samples. The frame assembly consists of a stable crossbeam and two vertical guide rails fixed to the bottom surfaces at both ends. Each vertical guide rail has a sliding adjustment block that slides along its height. An integrated conduit is installed on the outside of the frame. The monitoring component includes a fine-tuning screw, a torque transmission ring fixed to the screw, an open cylindrical sleeve coaxially arranged, and a disc spring assembly located between the two and sleeved on the screw. The open cylindrical sleeve is connected to the monitoring connector via a ball joint structure. The monitoring connector has a mating surface, on which a soil pressure sensor and a moisture meter are flushly embedded. The monitoring connector has a stepped mounting cavity, in which an elastic measuring component is fixed. A fiber optic strain sensor and a resistance strain gauge are installed on its back. The monitoring component has three sets, corresponding to the two vertical guide rails and the stable crossbeam of the frame assembly, respectively.

2. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 1, characterized in that... The frame assembly has an overall U-shaped structure. One end of the fine-tuning screw in a set of monitoring components corresponding to the vertical guide rail extends inward from the outside of the U-shaped structure of the frame assembly through the sliding adjustment block and is threadedly connected to the sliding adjustment block. Multiple monitoring components in this set correspond one-to-one with the sliding adjustment blocks. One end of the fine-tuning screw in a set of monitoring components corresponding to the stabilizing beam extends vertically downward from the outside of the U-shaped structure of the frame assembly through the stabilizing beam to the other end and is threadedly connected to the stabilizing beam. The number of monitoring components in the set corresponding to the stabilizing beam is 1-3.

3. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 1, characterized in that... The frame assembly includes a stabilizing crossbeam, vertical guide rails, sliding adjustment blocks, and an integrated conduit. A vertical guide rail is fixedly placed on the bottom surface near both ends of the stabilizing crossbeam. The stabilizing crossbeam and the two vertical guide rails together form a U-shaped frame structure. A set of sliding adjustment blocks is slidably arranged on each vertical guide rail along its length. The integrated conduit assembly is located on the side of the U-shaped frame facing away from the U-shaped inner cavity.

4. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 1, characterized in that... The monitoring assembly includes a torque transmission ring, an open cylindrical sleeve, a disc spring assembly, a monitoring connector, an earth pressure sensor, a moisture meter, a stepped mounting cavity, an elastic measuring component, a fiber optic strain sensor, and a resistance strain gauge. The torque transmission ring is fitted onto the threaded section near the inner end of the fine-tuning screw, with its inner ring surface fixedly connected to the side of the fine-tuning screw. The open end is fitted onto the other end of the fine-tuning screw near the inner side and is coaxially arranged with it. The disc spring assembly is fitted onto the fine-tuning screw and located between the torque transmission ring and the open cylindrical sleeve. The two ends of the disc spring assembly respectively abut against the corresponding end faces of the torque transmission ring and the open cylindrical sleeve. The monitoring connector is connected to the arc-shaped end of the open cylindrical sleeve through a ball joint structure. The earth pressure sensor and moisture meter are embedded in the contact surface of the monitoring connector facing the soil sample. Both the earth pressure sensor and the moisture meter are... The monitoring connector is flush with the mating surface and features an embedded installation. A stepped mounting cavity is provided on the mating side facing the soil sample. The stepped mounting cavity includes a stepped positioning surface at the opening on the mating side and a back cavity space inside it. An elastic measuring component is disposed within the stepped mounting cavity and fixed at the stepped positioning surface. A fiber optic strain sensor is disposed within the stepped mounting cavity and fixed to the back of the elastic measuring component. A resistance strain gauge is disposed within the stepped mounting cavity and attached to the back of the elastic measuring component. One end of a flexible sheath is sealed to the outlet of the monitoring connector via a sealed cable outlet connector. The other end of the flexible sheath passes through a sealed cable inlet located on a vertical guide rail or a stable crossbeam and extends into an integrated conduit. The sensor cable or optical fiber of the monitoring connector is threaded through the flexible sheath.

5. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 3, characterized in that... The vertical guide rail adopts a composite guide structure of T-groove + dovetail guide surface, and a height scale line is set on the side of the vertical guide rail facing away from the U-shaped inner cavity. The number of sliding adjustment blocks in each group is 2 to 4, and the number of sliding adjustment blocks on the two vertical guide rails is the same and they correspond one-to-one in the height direction.

6. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 3, characterized in that... The integrated conduit assembly includes two vertical branch conduits fixedly installed on the outer sides of the two vertical guide rails, and a horizontal main conduit fixedly installed on the outer side of the stable crossbeam, wherein the upper ends of the two vertical branch conduits are connected to the horizontal main conduit.

7. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 4, characterized in that... The other end of the open cylindrical sleeve is an arc-shaped end. The inner wall of the open cylindrical sleeve is provided with a low-friction bushing. The contact surface is covered with a wear-resistant thin layer. The wear-resistant thin layer is a replaceable wear-resistant force transmission layer. A through-measuring window is provided in the corresponding area of ​​the soil pressure sensor and the moisture meter. The moisture meter is a non-invasive moisture content sensor.

8. The soil and rock monitoring device for an internal cavity of a three-dimensional similarity simulation test according to claim 4, characterized in that... The periphery of the elastic measuring component is pressed and fixed at the step positioning surface by a pressure ring, pressure cap or slot structure. The outer surface of the elastic measuring component forms the mating surface of the monitoring connector or is flush with the mating surface or slightly convex relative to the mating surface. The elastic measuring component is a diaphragm, thin plate or elastic pressure plate. The flexible sheath reserves bending allowance between the monitoring connector and the integrated conduit. The resistance strain gauge is attached to the middle area of ​​the elastic measuring component or the preset stress-sensitive area. The resistance strain gauge is a two- or four-piece structure arranged in a bridge and is potted or treated with three-proof coating in the back cavity.

9. A three-dimensional similarity simulation test internal cavity soil and rock monitoring device according to claim 4, characterized in that... At least one shallow groove for receiving sensors is opened on the back of the elastic measuring component. The fiber optic strain sensor is embedded in the shallow groove and fixed by adhesive. A cover strip or potting layer is provided on its outside for protection. The fiber optic strain sensor is a fiber optic grating strain sensor, and at least two FBG grating measurement points are integrated on the same fiber. The at least two FBG measurement points are distributed circumferentially and / or radially on the elastic measuring component.

10. A three-dimensional similarity simulation test internal cavity soil and rock monitoring device according to claim 1, characterized in that... The method for monitoring soil and rock conditions inside a three-dimensional similarity simulation test cavity includes the following steps: (1) Fix the frame assembly to the left and right mounting surfaces and the top mounting surface of the internal cavity of the three-dimensional similar model test, so that the U-shaped frame structure formed by the stable crossbeam and the two vertical guide rails is aligned with the working area inside the cavity. (2) Based on the test monitoring location, adjust the height of each sliding adjustment block on the two vertical guide rails so that the sliding adjustment blocks on both sides correspond one-to-one in the height direction. Use the height scale line on the outside of the vertical guide rails to complete the left and right alignment. Then lock the sliding adjustment blocks to complete the height layout of the monitoring points. (3) The sensor lines corresponding to each monitoring connector are uniformly organized and introduced into the integrated conduit. The outgoing end of each monitoring connector first enters the flexible sheath. One end of the flexible sheath is sealed to the monitoring connector through the sealed outgoing connector, and the other end passes through the sealed inlet of the integrated conduit and extends into the integrated conduit. The electrical signal lines (corresponding to the soil pressure sensor, moisture meter, and resistance strain gauge) and the optical fiber lines (corresponding to the optical fiber strain sensor) are laid out in sections in the integrated conduit. After ascending along the vertical branch channel and merging into the horizontal main channel, they are led out from the main outgoing end to the sealed junction box or data acquisition system to reduce crosstalk and meet the minimum bending radius requirement of the optical fiber. (4) The prefabricated square similar material soil sample is laid in the U-shaped frame structure, and the front and rear partitions are installed at the front and rear openings of the cavity to complete the sealing. The front partition can be equipped with an observation window to observe the condition of the sample. (5) Rotate the fine-tuning screws of each monitoring component so that the monitoring joints gradually approach and adhere to the surface of the soil and rock sample after automatic alignment via the ball joint structure. Continue fine-tuning until the disc spring assembly generates a preset compression amount to form a stable pre-tightening force, so that the soil pressure sensor and moisture meter at the contact surface remain flush and adhered, and effective measurement is achieved through the through-measuring window of the wear-resistant force transmission layer. At the same time, the elastic measuring component in the stepped mounting cavity generates measurable micro-deformation under pressure, thereby enabling the fiber optic strain sensor and resistance strain gauge on its back to enter the effective measurement state. (6) After the bonding and pre-tightening are completed, zero-point acquisition and calibration are performed on the soil pressure sensor, moisture meter, fiber optic strain sensor, and resistance strain gauge. The zero-point acquisition and calibration uses the stable state of bonding and pre-tightening as the initial reference to eliminate the initial pressure and initial strain bias introduced by the compression pre-tightening of the disc spring group. Subsequently, the pressure increment, strain increment, and moisture content change relative to the zero point are output and analyzed during the test, thereby ensuring that the measurement results reflect the true evolution response of the soil and rock sample during the loading / disturbance process, without being interfered with by the pre-tightening state of the disc spring group. At the same time, the elastic compensation provided by the disc spring group can maintain the continuous bonding of the monitoring joint and reduce signal jumps and loss caused by delamination. Then, the test is started and multi-parameter data are collected simultaneously. The fiber optic strain sensor is used to obtain the distributed strain information of the elastic measuring component, the resistance strain gauge is used to obtain the local micro-strain information, the soil pressure sensor is used to obtain the contact pressure information, and the moisture meter is used to obtain the moisture content information. The mechanical response is corrected and interpreted based on the moisture content. (7) After the test, stop collecting data, rotate the fine adjustment screw in the opposite direction to release the preload, so that the monitoring connector is separated from the sample, remove the front and rear partitions, take out the sample, and inspect and maintain the wear-resistant force transmission layer, the through-measuring window and the conduit assembly to prepare for the next test.

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