Tunnel deformation monitoring device

Abstract

The utility model discloses a tunnel deformation monitoring device which solves the problem that in the prior art, surrounding rock deformation is difficult to monitor when high-stress soft rock is faced in TBM method construction. The deformation monitoring device comprises a protective shell and a monitoring mechanism which is detachably connected with the protective shell, the protection shell is filled with a protection medium, the monitoring mechanism comprises a hollow rod body, N elastic bodies are arranged on the hollow rod body, N is larger than or equal to 2, and sensors used for monitoring deformation of the elastic bodies are arranged on the elastic bodies and / or the hollow rod body. The protective shell protects the monitoring mechanism and can be retained in surrounding rock after detection is completed, and concrete can be repoured into the protective shell to achieve an anchoring effect; the monitoring mechanism can be efficiently recycled; the plurality of elastomers are matched with the corresponding sensors to perform multi-site monitoring, so that the monitoring range is widened, the detection precision is improved, the deformation rate in the soft rock large deformation tunnel construction process is effectively predicted, and the large deformation tunnel construction safety is further improved.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, and in particular to a tunnel surrounding rock monitoring device. Background Technology

[0002] Large deformation of surrounding rock has always been a global challenge in tunnel construction in high-stress areas. Currently, scholars both domestically and internationally have conducted relevant research on large deformation of tunnel surrounding rock. These scholars have mainly defined large deformation of tunnel surrounding rock from both qualitative and quantitative perspectives. The qualitative perspective includes the mechanical mechanisms and failure characteristics of large deformation, while the quantitative perspective includes other indicators such as tangential strain density, allowable deformation, relative deformation, critical burial depth, the ratio of uniaxial compressive strength to Young's modulus, and the strength-stress ratio.

[0003] Existing qualitative indicators can only determine the risk of large deformation. Quantitative indicators are mainly based on the drill-and-blast method and can only determine the relative deformation amount, not the deformation rate, which has significant limitations in TBM construction. Existing technologies, such as the large deformation tunnel relief anchor bolt with measuring surrounding rock pressure (application publication number CN 110195608 A), can determine the surrounding rock pressure between the surrounding rock and the initial support by measuring the compression of the tower spring during the deformation process; however, it only detects the surrounding rock pressure in the initial stage of anchor bolt support and cannot detect the surrounding rock pressure during tunneling or in the later stages of support. Furthermore, anchor bolt testing is often a disposable consumable in current field construction, which cannot be recycled and results in high consumption. Utility Model Content

[0004] To address the shortcomings in the aforementioned background technology, this utility model proposes a tunnel deformation monitoring device, which solves the problem of difficulty in monitoring surrounding rock deformation when facing high-stress soft rock in TBM construction.

[0005] The technical solution of this utility model is implemented as follows: A tunnel deformation monitoring device includes a protective shell and a monitoring mechanism detachably connected to the protective shell. The protective shell is filled with a protective medium. The monitoring mechanism includes a hollow rod disposed within the protective shell, with N elastic bodies (N≥2) mounted on the hollow rod. Sensors for monitoring the deformation of the elastic bodies are mounted on the elastic bodies and / or the hollow rod. The protective shell protects the monitoring mechanism and can remain in the surrounding rock after testing. Concrete can be re-filled inside for anchoring. The monitoring mechanism senses the deformation and pressure of the surrounding rock through the elastic bodies, while the sensors record the deformation and pressure and transmit the signals to a host computer, achieving the monitoring purpose and predicting the deformation rate during the construction of soft rock tunnels with large deformation.

[0006] In a further preferred embodiment, the open end of the protective shell is detachably connected to an end cover plate. The hollow rod is vertically confined within the protective shell by the end cover plate. An optical fiber is installed inside the hollow rod, and the sensor is connected to a data storage module mounted on the end cover plate via the optical fiber. The end cover plate not only seals the protective shell but also secures the hollow rod, ensuring its stable placement within the protective shell.

[0007] Further preferably, the protective shell has a positioning sleeve inside its top, with the top of the hollow rod located inside the positioning sleeve; a sleeve is provided on the end cover plate, the outer wall of the sleeve has external threads, and the lower inner wall of the protective shell has internal threads, with the internal threads of the protective shell engaging with the external hole of the outer wall of the sleeve. The protective shell is threadedly connected to the sleeve on the end cover plate, enabling quick assembly and disassembly of the monitoring mechanism and the protective shell.

[0008] Further preferably, the lower part of the hollow rod body is provided with an external thread, and the inner wall of the sleeve is provided with an internal thread. The external thread of the hollow rod body mates with the internal thread of the inner wall of the sleeve. The hollow rod body and the sleeve are threadedly connected, which realizes the detachability of the hollow rod body and the end cover plate, and at the same time realizes the adjustment and locking of the length of the hollow rod body within the protective shell.

[0009] Further preferably, the protective shell is a metal shell, with the hollow rod coaxially arranged with the protective shell, and the outer wall of the protective shell is provided with external threads or anti-slip textures to increase friction. The metal shell can withstand a certain force from the surrounding rock to protect the monitoring mechanism. When the surrounding rock undergoes large deformation, the metal shell undergoes corresponding deformation, which in turn causes the internal elastic body to undergo elastic deformation, and the sensor monitors the magnitude of this deformation.

[0010] Further preferably, the end cover plate is provided with a filling hole, and the filling hole is provided with a sealing plug; the filling hole is used for filling and discharging non-Newtonian fluid protective media.

[0011] Further optimization involves N elastic bodies evenly distributed axially on the hollow rod, with adjacent elastic bodies positioned at a certain angle. That is, the N elastic bodies face different directions to detect deformation of the surrounding rock in different orientations. The protective medium is a non-Newtonian fluid.

[0012] In a further preferred embodiment, the hollow rod body has N radial through holes, and N elastic bodies are correspondingly arranged in the N radial through holes, with both ends of the elastic bodies extending out of the corresponding radial through holes.

[0013] More preferably, the elastic body is a spring body, and the sensor is a strain sensor or fiber optic sensor mounted on the spring body.

[0014] More preferably, the elastic body is a rubber body, and the sensor is a strain sensor or an optical fiber sensor mounted on the spring body.

[0015] The beneficial effects of this utility model are as follows: The protective shell of this utility model not only protects the monitoring mechanism but also remains in the surrounding rock after testing. The interior can be re-filled with concrete for anchoring; the monitoring mechanism can be efficiently recycled; and construction costs are reduced. The shell is filled with a non-Newtonian fluid protective medium, which protects the sensor from strong impacts from the surrounding rock, preventing sensor failure due to rock deformation; this also improves monitoring accuracy. Multiple elastic bodies, in conjunction with corresponding sensors, enable multi-point monitoring, increasing the monitoring range and further improving detection accuracy. This allows for effective prediction of deformation rates during the construction of large deformation tunnels in soft rock, thereby improving the safety of large deformation tunnel construction.

[0016] This invention is a device for advanced drilling layout and large deformation monitoring based on the actual excavation disturbance situation of the TBM construction method. It can not only monitor the range of excavation disturbance stress, but also quantitatively predict the deformation convergence rate of large deformation in soft rock based on the changing trend of the large deformation displacement monitoring gauge at different distances from the working face. This solves the problem of difficult monitoring of surrounding rock deformation when facing high-stress soft rock in the existing TBM construction method. Attached Figure Description

[0017] To more clearly illustrate the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the internal structure of this utility model. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Example 1, such as Figure 1 As shown, it should be noted that in soft rock tunnel construction, the TBM's excavation capacity is limited, and the gap between the shield and the surrounding rock is small. Therefore, the TBM is highly sensitive to the rate of large deformation in soft rock during construction, and is prone to jamming accidents. Thus, predicting the deformation rate during the construction of soft rock tunnels with large deformation is crucial for safe construction in the large deformation sections.

[0021] This embodiment of a tunnel deformation monitoring device includes a protective shell 1 and a monitoring mechanism detachably connected to the protective shell 1. The protective shell protects the monitoring mechanism, and the detachable connection allows the monitoring mechanism to be removed from the shell after monitoring, while the protective shell remains in the surrounding rock. The shell can be re-filled with concrete for anchoring. The monitoring mechanism is also highly recyclable. The protective shell 1 is filled with a protective medium 5, preferably a non-Newtonian fluid. Non-Newtonian fluids such as mud fill the protective shell, providing protection against strong impacts from the surrounding rock and preventing sensor damage from rock deformation. The monitoring mechanism includes a hollow rod 2 inside the protective shell 1. The hollow rod is designed to hold optical fibers, wires, etc., preventing wires from being exposed to the non-Newtonian fluid medium. The hollow rod 2 has N elastic bodies 3, where N ≥ 2. Sensors 4 for monitoring the deformation of the elastic bodies 3 are provided on the elastic bodies 3 and / or the hollow rod 2. The sensors correspond one-to-one with the elastic bodies, and N elastic bodies form at least N strain receiving points, improving detection accuracy. When the surrounding rock undergoes large deformation, the protective shell produces corresponding deformation, which in turn causes elastic deformation of the internal elastic bodies. The sensors monitor the magnitude of this deformation, and the deformation rate is predicted during the construction of large deformation tunnels in soft rock through a host computer, thereby improving the safety of large deformation tunnel construction.

[0022] Example 2: A tunnel deformation monitoring device includes a protective shell 1 and a monitoring mechanism detachably connected to the protective shell 1. The protective shell protects the monitoring mechanism, and the detachable connection allows the monitoring mechanism to be removed from the shell after monitoring, while the protective shell remains in the surrounding rock. The shell can be re-filled with concrete for anchoring. The monitoring mechanism is also highly recyclable. In this example, the protective shell 1 is filled with a non-Newtonian fluid protective medium 5, such as mud, which protects the sensor from deformation and damage when subjected to strong impacts from the surrounding rock. The monitoring mechanism includes a hollow rod 2 inside the protective shell 1. The hollow rod is designed to hold optical fibers, wires, etc., preventing the wires from being exposed to the non-Newtonian fluid medium. N elastic bodies 3 (N≥2) are mounted on the hollow rod 2, and sensors 4 for monitoring the deformation of the elastic bodies 3 are mounted on the elastic bodies 3 and / or the hollow rod 2. The sensors correspond one-to-one with the elastic bodies, and N elastic bodies form at least N strain receiving points, improving detection accuracy. When the rock undergoes large deformation, the protective shell produces corresponding deformation, which in turn causes the internal elastic bodies to undergo elastic deformation. The sensors monitor the magnitude of this deformation, and the deformation rate during the construction of large deformation tunnels in soft rock is predicted through a host computer, thereby improving the safety of large deformation tunnel construction.

[0023] In this embodiment, the protective shell is a cylindrical structure with one open end. An end cover plate 6 is detachably connected to the open end of the protective shell 1. The end cover plate seals the protective shell 1 and provides support for the hollow rod. Specifically, the hollow rod 2 is vertically confined within the protective shell 1 by the end cover plate 6, ensuring its stability within the shell. An optical fiber 7 is installed inside the hollow rod 2 to prevent leakage and potential entanglement or interference. In this embodiment, the sensor 4 is connected to a data storage module 8 mounted on the end cover plate 6 via the optical fiber 7. Multiple grating sensors are connected in series via the internal optical fiber of the rod, transmitting data to the data storage module. The data storage module can be linked to a host computer for data transmission. The host computer calculates and compares the data to predict the deformation rate during the construction of a soft rock tunnel with large deformation, thereby improving construction safety.

[0024] In this embodiment, a positioning sleeve 9 is provided inside the top of the protective shell 1. The positioning sleeve is a bushing structure, and the top of the hollow rod 2 is located inside the positioning sleeve 9. The positioning sleeve serves to position and support the hollow rod from the top. In this embodiment, a sleeve 61 is provided on the end cover plate 6. The sleeve is fixed at the center of the end cover plate. The outer wall of the sleeve 61 has external threads, and the lower inner wall of the protective shell 1 has internal threads. The internal threads of the protective shell 1 are threaded into the outer hole of the sleeve 61. The protective shell is threadedly connected to the sleeve on the end cover plate, realizing quick assembly and disassembly of the monitoring mechanism and the protective shell.

[0025] Example 3: A tunnel deformation monitoring device. Based on Example 2, the hollow rod 2 in this example has an external thread at its lower part, and the inner wall of the sleeve 61 has an internal thread. The external thread of the hollow rod 2 mates with the internal thread of the inner wall of the sleeve 61. The hollow rod and the sleeve are threadedly connected, enabling the hollow rod and the end cover plate to be detachable, and simultaneously allowing for adjustment and locking of the length of the hollow rod within the protective housing. It should be noted that the hollow rod can also be connected and fixed to the sleeve using a locking buckle or a pin.

[0026] In this embodiment, the protective shell 1, as a preferred option, is a metal shell. The metal shell can withstand a certain force from the surrounding rock, protecting the monitoring mechanism. When the surrounding rock undergoes large deformation, the metal shell deforms accordingly, causing the internal elastic body to elastically deform. The sensor monitors the magnitude of this deformation. Commonly used materials for the metal shell include 345MPa, 420MPa, and 500MPa steel. The hollow rod 2 is coaxially aligned with the protective shell 1, and the outer wall of the protective shell 1 has external threads or anti-slip textures to increase friction. The entire monitoring structure is housed within the metal protective shell. The threaded design on the outside of the protective shell increases friction with the surrounding rock, facilitating stable anchoring later. After monitoring is completed, the end cover can be removed, the monitoring mechanism disassembled and recycled, and inserted into a new protective shell, achieving efficient recycling of the monitoring mechanism. The metal protective shell remains inside the borehole, and its interior can be refilled with concrete for anchoring.

[0027] In this embodiment, the end cover plate 6 is provided with a filling hole, and a sealing plug is provided on the filling hole. The filling hole is used for filling and discharging non-Newtonian fluid protective media. Before monitoring, it is used to fill the housing with non-Newtonian fluid and seal it with the sealing plug; after monitoring, the sealing plug is opened and the non-Newtonian fluid in the housing is released, which facilitates the safe removal of the monitoring mechanism.

[0028] Example 4: A tunnel deformation monitoring device. Based on Example 3, in this example, N elastic bodies 3 are evenly distributed axially on a hollow rod 2. Taking N=5 as an example, adjacent elastic bodies 3 are set at a certain angle; that is, the N elastic bodies face different directions to detect the deformation of the surrounding rock in different orientations. The specific installation method of the elastic bodies is as follows: N radial through holes 21 are opened on the hollow rod 2. Again, taking N=5 as an example, 5 elastic bodies 3 are correspondingly set in 5 radial through holes 21. The elastic body 3 corresponds one-to-one with the radial through hole, and both ends of the elastic body 3 extend out of the corresponding radial through hole 21 to form 2N monitoring receiving points. For each elastic body, both ends can receive deformation pressure, improving monitoring accuracy.

[0029] In this embodiment, the elastic body 3 is a spring, and the sensor 4 is a strain gauge sensor or a fiber optic sensor mounted on the spring. A strain gauge sensor uses strain gauges attached to the surface of the spring or related areas. When the spring is subjected to external force and deforms, the strain gauges deform accordingly, and their resistance changes. A Wheatstone bridge circuit is used to convert the resistance change into an electrical signal, thereby measuring the spring's deformation and force. A fiber optic sensor utilizes the optical properties of optical fibers to detect the spring's deformation and force. For example, a fiber Bragg grating sensor detects a change in the wavelength of the reflected light when the spring deforms under force; this change in wavelength is used to measure the deformation and force.

[0030] Example 5: A tunnel deformation monitoring device. Based on Example 3, this example differs from Example 4 in that the elastic body 3 is a rubber body, and the sensor 4 is a strain gauge sensor or fiber optic sensor mounted on the rubber body. The strain gauge sensor uses strain gauges attached to the surface or relevant parts of the rubber body. When the rubber body is subjected to external force and deforms, the strain gauges deform accordingly, and their resistance changes. A Wheatstone bridge circuit is used to convert the resistance change into an electrical signal, thereby measuring the deformation and force on the rubber body. The fiber optic sensor utilizes the optical properties of optical fibers to detect the deformation and force on the rubber body. For example, a fiber Bragg grating sensor detects the change in the wavelength of the reflected light when the rubber body deforms under force; this change in wavelength is used to measure the deformation and force.

[0031] The specific application process of this tunnel deformation monitoring device in tunnel construction is as follows:

[0032] First, use an anchor drilling machine to drill holes, with the drilling depth consistent with the length of the tunnel support anchor bolts;

[0033] Next, the dust and cement slurry inside the borehole are cleaned, and the deformation monitoring device is inserted into the borehole. The large deformation monitoring device has an elastic structure and can capture the shrinkage of the rock and soil under large deformation. A deformation monitoring device is arranged at approximately 2m intervals along the tunnel axis, and the large deformation monitoring devices are connected by a grating.

[0034] Secondly, inject cement grout or non-shrinkage expansion mortar around the deformation monitoring device and fill the hole completely to make it firm. During grouting, ensure that the grout is uniform and avoid water or other liquids accumulating in the hole.

[0035] Finally, the TBM begins construction. As the tunnel is excavated, the rock mass in front of the tunnel face experiences stress adjustments within a certain range due to the excavation disturbance stress. Installing the equidistant monitoring device of this invention not only monitors the range of excavation disturbance stress but also quantitatively predicts the deformation convergence rate of soft rock based on the changing trends of large deformation displacement monitoring gauges at different distances from the tunnel face. This provides a basis for TBM construction in compressive, large deformation soft rock masses.

[0036] After monitoring is completed, the sealed end can be removed, and the metal protective shell can remain in the borehole to act as an anchor. The monitoring device can then be dismantled, recycled, and inserted into a new protective shell, thus achieving efficient recycling of the monitoring device.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A tunnel deformation monitoring device, characterized in that: It includes a protective shell (1) and a monitoring mechanism that can be detachably connected to the protective shell (1); the protective shell (1) is filled with a protective medium (5), and the monitoring mechanism includes a hollow rod (2) disposed in the protective shell (1), and N elastic bodies (3) are provided on the hollow rod (2), where N≥2, and sensors (4) for monitoring the deformation of the elastic bodies (3) are provided on the elastic bodies (3) and / or the hollow rod (2).

2. The tunnel deformation monitoring device according to claim 1, characterized in that: The protective shell (1) has an end cover plate (6) detachably connected to its open end. The hollow rod (2) is vertically limited inside the protective shell (1) by the end cover plate (6). An optical fiber (7) is provided inside the hollow rod (2). The sensor (4) is connected to the data storage module (8) set on the end cover plate (6) through the optical fiber (7).

3. The tunnel deformation monitoring device according to claim 2, characterized in that: The protective shell (1) has a positioning sleeve (9) inside its top end, and the top of the hollow rod (2) is located inside the positioning sleeve (9); the end cover plate (6) has a sleeve (61), the outer wall of the sleeve (61) has an external thread, the lower inner wall of the protective shell (1) has an internal thread, and the internal thread of the protective shell (1) is threaded with the outer hole of the outer wall of the sleeve (61).

4. The tunnel deformation monitoring device according to claim 3, characterized in that: The hollow rod (2) has an external thread at the bottom and an internal thread on the inner wall of the sleeve (61). The external thread of the hollow rod (2) is engaged with the internal thread on the inner wall of the sleeve (61).

5. The tunnel deformation monitoring device according to claim 3 or 4, characterized in that: The protective shell (1) is a metal shell, the hollow rod (2) is coaxially arranged with the protective shell (1), and the outer wall of the protective shell (1) is provided with external threads or anti-slip patterns to increase friction.

6. The tunnel deformation monitoring device according to claim 5, characterized in that: The end cover plate (6) is provided with an injection hole, and the injection hole is provided with a sealing plug.

7. The tunnel deformation monitoring device according to any one of claims 1 to 4 and 6, characterized in that: N elastic bodies (3) are evenly distributed along the axial direction on the hollow rod (2), with a certain angle between adjacent elastic bodies (3); the protective medium (5) is a non-Newtonian fluid.

8. The tunnel deformation monitoring device according to claim 7, characterized in that: The hollow rod (2) has N radial through holes (21) and N elastic bodies (3) are respectively arranged in the N radial through holes (21), and the two ends of the elastic bodies (3) extend out of the corresponding radial through holes (21).

9. The tunnel deformation monitoring device according to claim 8, characterized in that: The elastic body (3) is a spring body, and the sensor (4) is a strain sensor or fiber optic sensor mounted on the spring body.

10. The tunnel deformation monitoring device according to claim 8, characterized in that: The elastic body (3) is a rubber body, and the sensor (4) is a strain sensor or fiber optic sensor mounted on the spring body.

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