Shallow-buried tunnel surrounding rock stability monitoring device

Abstract

The utility model discloses a shallow-buried tunnel surrounding rock stability monitoring device which comprises a plurality of first monitoring assemblies which are arranged on the inner wall of a tunnel at intervals along the contour line of a construction section to be detected, any first monitoring assembly comprises a first detection rod, the first detection rod penetrates through a first detection hole preset in a tunnel supporting layer, and the bottom end of the first detection rod is anchored into a surrounding rock layer; the shell is of a cylindrical structure with a T-shaped cross section and two closed ends, the tail part of the shell is sleeved in the first detection hole in a matched manner and is in sliding connection with the first detection rod, and the head part of the shell covers an orifice of the first detection hole; the elastic element is fixedly connected with the pressure sensor located at the head of the shell and the first detection rod; and the second monitoring assembly is arranged to be used for monitoring the ground surface settlement amount above the first monitoring assembly. According to the utility model, the stability of the surrounding rock near the section of the current tunnel is judged through the measured values of the two monitoring assemblies arranged inside and outside the tunnel, and the comprehensiveness and accuracy of the stability monitoring of the surrounding rock are greatly improved while the monitoring efficiency is ensured.

Description

Technical Field

[0001] This utility model relates to the field of tunnel monitoring technology. More specifically, this utility model relates to a device for monitoring the stability of surrounding rock in shallow-buried tunnels. Background Technology

[0002] During tunnel construction, processes such as blasting and excavation can significantly impact the stability of the tunnel and surrounding rock, easily causing tunnel deformation, surface subsidence, and other problems, posing substantial safety risks. This is especially true for shallow-buried tunnels, where the shallow depth of the tunnel construction makes it easier for the underlying tunnel construction to affect the stability of the rock mass and soil layers across the entire height above, leading to ground subsidence, tunnel collapses, and other accidents, posing significant safety risks to surface facilities, the tunnel itself, and the construction workers within. Conventional methods for monitoring the stability of tunnel surrounding rock mainly include internal tunnel deformation detection. This involves setting up multiple monitoring points on the tunnel's internal structure and using a total station to measure the displacement of each monitoring point, thereby obtaining the deformation at the current construction section and using this as a basis for judging the stability of the surrounding rock. However, total stations require manual point-by-point monitoring, resulting in low detection efficiency. Furthermore, the real-time nature and accuracy of the detection data are insufficient due to limitations imposed by the tunnel construction structure and environmental influences, making significant measurement errors likely.

[0003] To address the aforementioned issues, it is necessary to design a monitoring device for the stability of surrounding rock in shallow tunnels, which can improve the comprehensiveness and accuracy of measurements while ensuring monitoring efficiency. Utility Model Content

[0004] The purpose of this invention is to provide a shallow-buried tunnel surrounding rock stability monitoring device. By using the measurement values ​​of two monitoring components set inside and outside the tunnel, the stability of the surrounding rock near the current tunnel cross section can be determined together. This avoids the problems of inconvenient total station degrees and insufficient accuracy caused by the tunnel structure and limited field of vision. While ensuring monitoring efficiency, it greatly improves the comprehensiveness and accuracy of surrounding rock stability monitoring.

[0005] To achieve these objectives and other advantages according to this utility model, a shallow-buried tunnel surrounding rock stability monitoring device is provided, comprising:

[0006] Multiple first monitoring components are spaced apart on the inner wall of the tunnel along the outline of the construction section to be measured. Each first monitoring component includes a first detection rod that passes through a pre-set first detection hole on the tunnel support layer and has its bottom end anchored into the surrounding rock layer; a shell that is a cylindrical structure with a T-shaped cross-section and closed at both ends, the tail of the shell fitting inside the first detection hole and the tail end slidingly connected to the first detection rod, and the head of the shell fixedly covering and sealing the opening of the first detection hole; a pressure sensor that is disposed opposite to the first detection rod on the inner side wall of the head of the shell; and an elastic element that is fixedly connected to the pressure sensor and the outer end of the first detection rod along the length direction of the first detection rod.

[0007] Multiple second monitoring components are spaced apart on the ground above the tunnel along the tunnel width direction and are located in the same vertical plane as the multiple first monitoring components. Each second monitoring component is configured to monitor the ground subsidence at the corresponding location.

[0008] Preferably, in the shallow-buried tunnel surrounding rock stability monitoring device, the first monitoring component further includes multiple anchors, which are spaced apart along the outer periphery of the head of the shell, and any anchor passes through the head of the shell along the axial direction of the first detection hole and is anchored into the tunnel support layer.

[0009] Preferably, in the shallow-buried tunnel surrounding rock stability monitoring device, the first detection rod and the first detection hole are coaxially arranged, and the axes of the first detection rod and the first detection hole are perpendicular to the surface of the tunnel support layer at the corresponding installation position.

[0010] Preferably, in the shallow-buried tunnel surrounding rock stability monitoring device, the bottom end of the first detection rod is a conical tip.

[0011] Preferably, in the shallow-buried tunnel surrounding rock stability monitoring device, the top of the first detection rod is provided with a grouting port, and the bottom of the first detection rod is provided with multiple grout outlets at intervals, each grout outlet being connected to the grouting port through a grouting channel inside the first detection rod.

[0012] Preferably, in the shallow-buried tunnel surrounding rock stability monitoring device, the second monitoring component includes a second detection rod that passes through a pre-set second detection hole on the ground and has its bottom end anchored into the stratum below the second detection hole, with the top end of the second detection rod extending upwards out of the second detection hole; a first filling layer that is circumferentially disposed on the outside of the segment of the second detection rod located within the second detection hole and forms an annular casting layer; a second filling layer that fills the space between the first filling layer and the second detection hole and forms an annular casting layer; and a reflector that is fixed to the top of the outer wall of the second detection rod, the three-dimensional coordinates of which are measured by a total station positioned relative to one side of the second detection rod.

[0013] Preferably, in the shallow-buried tunnel surrounding rock stability monitoring device, the first filling layer is filled with concrete, and the second filling layer is filled with a mixture of cement and clay.

[0014] This utility model has at least the following beneficial effects:

[0015] This invention uses measurements from two monitoring components installed inside and outside the tunnel to jointly determine the stability of the surrounding rock near the current tunnel cross-section. The first monitoring component inside the tunnel uses an elastic element and a pressure sensor to automatically measure the disturbance of the surrounding rock, avoiding the problems of inconvenient total station readings and insufficient accuracy caused by the tunnel structure and limited field of vision. The second monitoring component outside the tunnel assists in judging the disturbance of the underground surrounding rock by measuring the surface settlement in the same vertical plane. While ensuring monitoring efficiency, this invention greatly improves the comprehensiveness and accuracy of surrounding rock stability monitoring.

[0016] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the first monitoring component of a shallow-buried tunnel surrounding rock stability monitoring device according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the arrangement structure of the second monitoring component of the shallow-buried tunnel surrounding rock stability monitoring device described in the above embodiments;

[0019] Figure 3 This is a schematic diagram of the structure of the second monitoring component in the above embodiment.

[0020] Explanation of reference numerals in the attached figures:

[0021] 11. First detection rod; 12. Housing; 13. Pressure sensor; 14. Elastic element; 15. Anchor; 2. Second monitoring component; 21. Second detection rod; 22. First filling layer; 23. Second filling layer; 24. Reflector; 3. Tunnel support layer; 4. Surrounding rock layer; 5. Stratum; 6. Tunnel. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0023] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this utility model, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] like Figure 1-3 As shown, this utility model provides a shallow-buried tunnel surrounding rock stability monitoring device, comprising:

[0025] Multiple first monitoring components are spaced apart on the inner wall of the tunnel along the outline of the construction section to be measured. Each first monitoring component includes a first detection rod 11, which passes through a pre-set first detection hole on the tunnel support layer 3 and has its bottom end anchored into the surrounding rock layer 4; a housing 12, which is a cylindrical structure with a T-shaped cross-section and closed at both ends. The tail of the housing 12 fits inside the first detection hole and its tail end is slidably connected to the first detection rod 11. The head of the housing 12 is fixedly covered and closed on the opening of the first detection hole; a pressure sensor 13 is disposed opposite to the first detection rod 11 on the inner side wall of the head of the housing 12; and an elastic element 14 is fixedly connected to the outer end of the pressure sensor 13 and the first detection rod 11 along the length direction of the first detection rod 11.

[0026] Multiple second monitoring components 2 are arranged at intervals on the ground above the tunnel along the tunnel width direction and are located in the same vertical plane as the multiple first monitoring components. Each second monitoring component is configured to monitor the ground subsidence at the corresponding location.

[0027] In the above technical solution, the first monitoring component and the second monitoring component 2 are arranged on the same vertical plane (where the tunnel cross-section is located). Each first monitoring component is used to measure the surrounding rock condition near the current tunnel cross-section from inside the tunnel 6, and each second monitoring component is used to indirectly measure the surrounding rock condition near the current tunnel cross-section from outside the tunnel 6 (the ground surface). Although there is a certain (height) distance between the ground and the tunnel, for shallow-buried tunnel construction sections, the settlement data of the ground surface extending upward along the current tunnel cross-section can also reflect the stability of the surrounding rock near the tunnel cross-section. In actual construction, the first monitoring component and the second monitoring component have the same measurement frequency. The staff can comprehensively judge the stability of the surrounding rock at the current tunnel cross-section by combining the monitoring results of the first monitoring component and the second monitoring component. For example, when the monitoring value of any first monitoring component or second monitoring component exceeds its preset allowable displacement (or pressure) range, it is judged that the stability of the surrounding rock in that direction is insufficient, and measures need to be taken for reinforcement.

[0028] Specifically, after the support layer construction is completed, the first monitoring component is installed. A first detection hole is pre-set at the installation position of the first monitoring component. The housing can fit into and seal the first detection hole from the outside, thereby forming an independent and sealed detection space inside the housing, unaffected by the external environment, based on the first detection hole. One end of the first detection rod is located inside the detection space, and the other end (sliding) extends out of the tail end (bottom end) of the housing and enters the surrounding rock layer and is fixed thereto. When the surrounding rock layer is disturbed, the disturbance can be fed back by the displacement of the first detection rod in the detection space. An elastic element and a pressure sensor are also provided between the first detection rod and the head of the housing. The reading of the pressure sensor can not only reflect the pressure change in the surrounding rock layer, but also calculate the deformation of the elastic element based on the elastic coefficient, thereby reflecting the magnitude of the disturbance in the surrounding rock layer. The elastic element can be a spring. The head of the housing is fixed at the opening of the first detection hole. This isolates the housing from interference from the support structure, creating an independent detection space for the first detection rod. Furthermore, it allows the housing to form a relatively stable integral connection with the tunnel support, providing a stable reference surface for the detection stroke of the first detection rod and ensuring the accuracy of the detection data. When arranging the first monitoring components, avoid the steel frame and areas of voided backfill. The monitoring points should be placed between two steel frames, and the bottom of the first detection rod should be driven into the surrounding rock to a depth of no less than 30 cm.

[0029] like Figure 2As shown, the multiple second monitoring components 2 are symmetrically arranged on both sides of the tunnel centerline, except for the location at the tunnel centerline. The distance between the two outermost second monitoring components is not less than H0 + B, where H0 is the tunnel burial depth and B is the tunnel design width. The distance between two adjacent second monitoring components can be controlled between 2m and 5m, and the spacing can be appropriately shortened near the tunnel centerline. The influence of surface settlement data measured by the second monitoring components at different locations on the stability of the surrounding rock in different areas around the tunnel cross-section can be determined based on the tunnel stress analysis structure, and the control threshold of each second monitoring component can be set accordingly. The second monitoring components can be conventional vertical displacement monitoring devices (such as hydrostatic levels).

[0030] The pressure sensor, the second monitoring component, and the controller are electrically connected. The controller is used to receive detection data from the first and second monitoring components and summarize and analyze them. Construction personnel can combine the internal and external monitoring data to jointly determine the stability of the surrounding rock at the current location.

[0031] This invention uses measurements from two monitoring components, one inside and one outside the tunnel, to jointly determine the stability of the surrounding rock near the current tunnel cross-section. The first monitoring component inside the tunnel uses an elastic element and a pressure sensor to automatically measure the disturbance of the surrounding rock, avoiding the problems of inconvenient total station readings and insufficient accuracy caused by the tunnel structure and limited field of vision. The second monitoring component outside the tunnel assists in judging the disturbance of the underground surrounding rock by measuring the surface settlement in the same vertical plane, which greatly improves the comprehensiveness and accuracy of the surrounding rock stability monitoring. Moreover, surface measurements are not easily limited by the field of vision and environment, and the total station readings are accurate and convenient, without affecting the original efficiency of the surrounding rock stability monitoring.

[0032] In another technical solution, the shallow-buried tunnel surrounding rock stability monitoring device further includes a plurality of anchors 15, which are spaced apart along the outer periphery of the head of the housing 12. Any anchor 15 passes through the head of the housing 12 along the axial direction of the first detection hole and is anchored into the tunnel support layer 3.

[0033] The anchor can be an anchor rod. The corresponding position of the housing head has a pre-set installation hole. After the first detection rod and the housing are installed, the anchor rod is passed through the corresponding installation hole and anchored into the tunnel support layer.

[0034] In another technical solution, in the shallow-buried tunnel surrounding rock stability monitoring device, the first detection rod 11 and the first detection hole are coaxially arranged, and the axes of the first detection rod 11 and the first detection hole are both perpendicular to the surface of the tunnel support layer 3 at the corresponding installation position. This ensures the monitoring sensitivity of the first monitoring component and the reliability of the measurement data.

[0035] In another technical solution, the bottom end of the first detection rod 11 of the shallow buried tunnel surrounding rock stability monitoring device is a conical tip, which facilitates the smooth passage of the first detection rod through the bottom of the first detection hole and into the interior of the surrounding rock layer.

[0036] In another technical solution, the shallow-buried tunnel surrounding rock stability monitoring device has a grouting port at the top of the first detection rod 11 and multiple grout outlets at intervals at the bottom of the first detection rod 11. Each grout outlet is connected to the grouting port through a grouting channel inside the first detection rod 11.

[0037] Specifically, during the installation of the shallow-buried tunnel surrounding rock stability monitoring device, the bottom end of the first detection rod is first passed through the first detection hole and inserted into the surrounding rock layer. Then, grout is injected into the surrounding rock layer through the grouting port and grouting channel to fill the gaps in the surrounding rock layer generated during the anchoring of the first detection rod, and to solidify and connect the first detection rod with the surrounding rock layer as one unit. Then, the shell and elastic elements are installed to enclose the first detection rod in the isolated detection space and detect its displacement to reflect the disturbance of the surrounding rock.

[0038] In another technical solution, the shallow-buried tunnel surrounding rock stability monitoring device includes a second monitoring component 2 comprising a second detection rod 21 that passes through a pre-set second detection hole on the ground and has its bottom end anchored into the stratum 5 below the second detection hole, with the top end of the second detection rod 21 extending upwards out of the second detection hole; a first filling layer 22 that is circumferentially disposed outside the segment of the second detection rod 21 located within the second detection hole and forms an annular casting layer; a second filling layer 23 that fills the space between the first filling layer 22 and the second detection hole and forms an annular casting layer; and a reflector 24 that is fixed to the top of the outer wall of the second detection rod 21, the three-dimensional coordinates of which are measured by a total station positioned relative to one side of the second detection rod 21.

[0039] The above technical solution provides an implementable surface settlement monitoring structure. By detecting the displacement (change in height coordinates) of the reflector using a total station, the displacement of the second detection rod as the ground settles can be measured. The first filling layer is a concrete pouring layer, used to connect the second detection rod to the ground structure at the bottom of the borehole. The second filling layer is a cement and clay grouting layer, used to further integrate the second detection rod, the first filling layer, and the surrounding ground structure. Therefore, when the ground structure changes, the settlement can be accurately reflected by the displacement of the end of the second detection rod extending from the detection borehole.

[0040] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A device for monitoring the stability of surrounding rock in shallow-buried tunnels, characterized in that, include: Multiple first monitoring components are spaced apart on the inner wall of the tunnel along the outline of the construction section to be measured. Each first monitoring component includes a first detection rod that passes through a pre-set first detection hole on the tunnel support layer and has its bottom end anchored into the surrounding rock layer; a shell that is a cylindrical structure with a T-shaped cross-section and closed at both ends, the tail of the shell fitting inside the first detection hole and the tail end slidingly connected to the first detection rod, and the head of the shell fixedly covering and sealing the opening of the first detection hole; a pressure sensor that is disposed opposite to the first detection rod on the inner side wall of the head of the shell; and an elastic element that is fixedly connected to the pressure sensor and the outer end of the first detection rod along the length direction of the first detection rod. Multiple second monitoring components are spaced apart on the ground above the tunnel along the tunnel width direction and are located in the same vertical plane as the multiple first monitoring components. Each second monitoring component is configured to monitor the amount of ground subsidence at the corresponding location.

2. The shallow-buried tunnel surrounding rock stability monitoring device as described in claim 1, characterized in that, The first monitoring component also includes a plurality of anchors spaced apart along the outer periphery of the head of the housing, with any anchor passing through the head of the housing along the axial direction of the first detection hole and anchored into the tunnel support layer.

3. The shallow-buried tunnel surrounding rock stability monitoring device as described in claim 1, characterized in that, The first detection rod and the first detection hole are coaxially arranged, and the axes of the first detection rod and the first detection hole are perpendicular to the surface of the tunnel support layer at the corresponding installation position.

4. The shallow-buried tunnel surrounding rock stability monitoring device as described in claim 1, characterized in that, The bottom end of the first detection rod is a tapered tip.

5. The shallow-buried tunnel surrounding rock stability monitoring device as described in claim 1, characterized in that, The top of the first detection rod is provided with a grouting port, and the bottom of the first detection rod is provided with multiple grout outlets at intervals. Each grout outlet is connected to the grouting port through a grouting channel inside the first detection rod.

6. The shallow-buried tunnel surrounding rock stability monitoring device as described in claim 1, characterized in that, The second monitoring component includes a second detection rod that passes through a pre-set second detection hole in the ground and has its bottom end anchored into the stratum below the second detection hole, with the top end of the second detection rod extending upwards out of the second detection hole; a first filling layer that is circumferentially disposed on the outside of the segment of the second detection rod located in the second detection hole and forms an annular casting layer; a second filling layer that fills the space between the first filling layer and the second detection hole and forms an annular casting layer; and a reflector that is fixed to the top of the outer wall of the second detection rod, the three-dimensional coordinates of which are measured by a total station positioned relative to one side of the second detection rod.

7. The shallow-buried tunnel surrounding rock stability monitoring device as described in claim 6, characterized in that, The first filling layer is filled with concrete, and the second filling layer is filled with a mixture of cement and clay.

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