Tunnel engineering interlayer yielding support deformation stress sensing and grading evaluation method

Abstract

The application discloses a tunnel engineering interlayer yielding support deformation stress sensing and grading evaluation method, comprising the following steps: S1, acquiring the profile surface of the initial support or the first layer support of the double-layer lining structure; S2, monitoring the radial deformation of the interlayer yielding support structure in real time, and synchronously monitoring the radial pressure and tangential pressure of the surrounding rock at the place; S3, on the basis of the profile surface, drawing smooth and continuous curves of the deformation and stress sensing results of each measuring point based on the Kriging interpolation method; S4, calculating the overall deformation and stress mean value, deviation and dispersion of each measuring point of the section, and grading evaluating and early warning the service performance of the tunnel interlayer yielding support structure. The application can realize unmanned remote monitoring during the service of the tunnel, avoids the secondary lining slotting and slotting and the damage to the interlayer waterproof structure caused by the physical and mechanical monitoring mode, and simultaneously avoids the damage and failure problems of the traditional physical compression sensor under the condition of non-uniform deformation of the buffer layer.

Description

Technical Field

[0001] This invention relates to the field of deformation stress perception and assessment in inter-layer pressure relief support for tunnel engineering. More specifically, this invention relates to a method for sensing and classifying deformation stress in inter-layer pressure relief support for tunnel engineering. Background Technology

[0002] Addressing the challenges of safe construction and long-term performance maintenance of tunnel support structures in complex geological conditions, especially in high-stress soft rock formations with large deformation, the yielding support structure, compared to the traditional rigid support's principle of limiting surrounding rock deformation, allows the surrounding rock to release ground pressure through moderate and controllable deformation. This achieves coordinated deformation between the support structure and the surrounding rock, thereby reducing the load on the support structure, improving the internal force distribution, and is increasingly valued by industry professionals. Interlayer buffer support, as a typical yielding structure, primarily absorbs the deformation pressure of the surrounding rock through the compressive deformation of buffer materials or structures arranged between layers, thus alleviating the load on the support structure. Effective perception of the deformation stress state of interlayer buffer support is a crucial basis for evaluating its service performance. Interlayer buffer support has a typical yielding plateau section, and the mechanical properties of this section differ significantly under different confining pressure conditions. Existing technologies use destructive methods, such as drilling holes in the secondary lining for monitoring, which can easily damage the tunnel's waterproofing layer during construction. Furthermore, since large deformations in soft rock tunnels often exhibit non-uniform characteristics, focusing solely on the radial deformation of the interlayer buffer support structure lacks the correction of the stress state of the interlayer relief support structure for the deformation evolution of the buffer layer, which is insufficient to effectively assess the service performance of the interlayer relief support structure. Therefore, how to achieve deformation stress perception and analysis of the interlayer relief support structure has become a critical challenge that industry professionals urgently need to address. Summary of the Invention

[0003] To achieve these objectives and other advantages according to the present invention, a preferred embodiment of the present invention provides a method for sensing and classifying the deformation stress of inter-layer relief support in tunnel engineering, comprising the following steps: S1. Obtain the outline of the first layer of support in the initial support or double-layer lining structure; S2. Monitor the radial deformation of the interlayer pressure relief support structure in real time, and simultaneously monitor the radial and tangential pressure of the surrounding rock at that location; S3. Based on the obtained outline of the initial support or the first layer of support of the double-layer lining structure, draw a smooth and continuous curve of the deformation and stress sensing results of each measuring point on a proportional scale using the Kriging interpolation method. S4. Calculate the overall deformation and stress mean, deviation and dispersion of each measuring point of the cross section; combine the allowable bearing capacity of the lining structure and the allowable deformation of the interlayer pressure relief support structure to conduct a graded evaluation and early warning of the service performance of the tunnel interlayer pressure relief support structure.

[0004] Preferably, in step S2, an ultrasonic transceiver unit and a two-dimensional compressive stress sensor are installed by pre-reserving slots inside the interlayer pressure relief support structure; the ultrasonic transceiver unit is used to monitor the radial deformation of the interlayer pressure relief support structure, and the two-dimensional compressive stress sensor is used to monitor the radial and tangential pressure of the surrounding rock.

[0005] Preferably, the ultrasonic transceiver unit includes an excitation end and a receiving end, wherein the excitation end is close to the side of the lining structure, and the receiving end is close to the side of the initial support or the first layer support of the double-layer lining structure; and a groove base is formed by carving a groove of 2-3cm on the initial support or the first layer support of the double-layer lining structure to fix the receiving end.

[0006] Preferably, the two-dimensional compressive stress sensor is embedded in the center of the interlayer pressure relief support structure, and the distance between it and the ultrasonic transceiver unit is not less than 20cm.

[0007] Preferably, after obtaining the contour surface in step S1, the layout of the measuring points is determined according to the actual deformation of the contour surface: no less than 8 measuring points are set for each tunnel cross section, and they are evenly arranged along the tunnel contour line at the arch crown, left arch waist, right arch waist, left end point of the arching line, right end point of the arching line, center of the invert arch, and both sides of the center of the invert arch; the circumferential spacing between adjacent measuring points is 3~4m; for local protruding deformation parts on the contour surface, the circumferential spacing between measuring points is increased to 2~3m.

[0008] Preferably, in step S3, the deformation sensing results of each measuring point include radial deformation and tangential deformation, and the stress sensing results of each measuring point include radial pressure, tangential pressure and longitudinal pressure; the deformation sensing results are plotted on the inner side of the contour surface to form a deformation curve, and the stress sensing results are plotted on the outer side of the contour surface to form a stress curve.

[0009] Preferably, the overall cross-sectional deformation, mean stress, deviation, and dispersion of each measuring point in step S4 specifically include the following calculations: Average compressive deformation: ,in Here, n represents the compression deformation value at each measuring point, and n is the number of measuring points. Let the variance of compression deformation be: ,in Here, n represents the deformation value under pressure at each measuring point, and n is the number of measuring points. To ensure the average compressive deformation; Let the compressive deformation dispersion be: Residual deformation at measuring point: ,in The design allows for compressive deformation. Let the compressive stress be averaged: ,in Here, n represents the stress value at each measuring point, and n is the number of measuring points. Let the compressive stress variance be: Let the compressive stress dispersion be: .

[0010] Preferably, the allowable deformation dispersion The larger the value, the more uneven the deformation of the interlayer pressure-relief support structure on that cross section; the aforementioned pressure-relief stress dispersion The larger the value, the more uneven the stress distribution on the cross section of the interlayer pressure relief support structure.

[0011] Preferably, the graded evaluation in step S4 includes a deformation failure evaluation of a single measuring point: based on The results divide the residual yield deformation level into three levels: low, medium, and high, corresponding to ratio ranges of 0~0.3, 0.3~0.7, and 0.6~1.0, respectively. When the ratio is 0, the interlayer yield support structure at the measuring point is judged to have failed due to deformation.

[0012] Preferably, the graded assessment in step S4 further includes stress failure assessment of a single measuring point: when the radial or tangential pressure of the surrounding rock obtained by real-time monitoring reaches or exceeds the allowable bearing capacity of the lining structure, it is determined that the interlayer pressure relief support structure at the measuring point has failed under stress; and if any measuring point is determined to be deformed or stressed, it is determined that the interlayer pressure relief support effect at the measuring point has failed.

[0013] The present invention has at least the following beneficial effects: (1) This invention provides a method for sensing the stress of the pressure relief deformation of the buffer layer support structure. The actual compression thickness of the buffer layer is calculated based on the change in the ultrasonic time history caused by the change in the density after the buffer compression deformation. The thickness of the buffer layer under the current stress state and the remaining pressure relief deformation are sensed and predicted by a two-dimensional stress sensor. This method can realize unmanned remote monitoring during the tunnel service period, avoid the secondary lining slotting and groove leaving caused by physical and mechanical monitoring methods and the damage to the interlayer waterproof structure. At the same time, it avoids the problem of damage and failure of traditional physical compression sensors under non-uniform deformation conditions of the buffer layer.

[0014] (2) Considering that the compressive deformation of the buffer layer support changes with the stress field, traditional monitoring and evaluation only rely on the amount of compressive deformation without considering the correction of the stress field, which will lead to incorrect judgments on the service performance of the buffer layer structure. This invention establishes 7 evaluation indicators based on the deformation and stress test results and gives the criteria for judging deformation and stress failure. It quantitatively evaluates the service performance of the buffer layer structure from two dimensions: deformation and stress. The curves of deformation and stress test results at each measuring point can intuitively show the overall bearing state of the tunnel.

[0015] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the arrangement of deformation and stress measuring points in the tunnel buffer layer support structure of the present invention.

[0017] Figure 2 This is a graph showing the deformation and stress curves of the measuring points of the tunnel buffer layer support structure in this invention. Detailed Implementation

[0018] 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.

[0019] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious modifications will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0020] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., 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 invention 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, the above terms should not be construed as limiting this invention.

[0021] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0022] like Figure 1 As shown, a preferred embodiment of the present invention provides a method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering, comprising the following steps: S1. Obtain the outline of the first layer of support for the initial support 1 or the double-layer lining structure. S2. Monitor the radial deformation of the interlayer pressure relief support structure in real time, and simultaneously monitor the radial and tangential pressure of the surrounding rock at that location; S3. Based on the obtained outline of the initial support or the first layer of support of the double-layer lining structure, draw a smooth and continuous curve of the deformation and stress sensing results of each measuring point on a proportional scale using the Kriging interpolation method. S4. Calculate the overall deformation and stress mean, deviation and dispersion of each measuring point of the cross section; combine the allowable bearing capacity of the lining structure and the allowable deformation of the interlayer pressure relief support structure to conduct a graded evaluation and early warning of the service performance of the tunnel interlayer pressure relief support structure.

[0023] The aforementioned technical solution enables real-time monitoring of radial deformation of the interlayer pressure-bearing support structure and synchronous monitoring of radial and tangential pressure on the surrounding rock without damaging the tunnel's waterproof structure. The smooth, continuous curve plotted using the Kriging interpolation method visually displays the continuous distribution of deformation and stress across the entire cross-section, overcoming the limitation of discrete measuring points in reflecting local abrupt changes. By calculating the overall statistical indicators of the cross-section and combining them with allowable values ​​for graded evaluation, the service performance of the pressure-bearing support structure can be quantitatively assessed.

[0024] In the above technical solution, step S1 is performed first. After the tunnel excavation is completed, initial support is installed. Once the initial support has stabilized, technicians use a 3D cross-section scanner to scan a cross section at regular intervals along the longitudinal direction of the tunnel. For a double-layer lining structure, the same operation is performed after the first layer of lining is installed to obtain the outline of the first layer of lining. This is usually done using a total station or laser scanner, serving as a reference surface for subsequent analysis.

[0025] Then, step S2 is performed to monitor the radial deformation of the interlayer pressure relief support structure 3 in real time, and simultaneously monitor the radial and tangential pressure of the surrounding rock at that location. During the construction of the interlayer pressure relief support structure, the corresponding monitoring element 2 is installed in the target monitoring section according to the preset layout plan. The monitoring element 2 is located in the buffer layer 4 between the initial support 1 and the secondary lining 3. The buffer layer is filled with buffer material. The signal transmission line of the monitoring element needs to be concealed along the tunnel outline to avoid damage during the construction of the support structure and the operation and maintenance of the tunnel. This process continuously collects the radial deformation data generated by the interlayer pressure relief support structure during its service life 24 hours a day, and simultaneously collects the radial and tangential pressure data of the surrounding rock acting on the support structure at the same monitoring location.

[0026] Next, step S3 involves data processing using Kriging interpolation. Specifically, the collected discrete measurement point data is spatially interpolated using the Kriging interpolation algorithm. Based on the obtained initial support or first-layer support profile of the double-layer lining structure, this algorithm proportionally plots a smooth, continuous curve showing the deformation and stress perception results at each measurement point. This visualization method transforms the originally discrete numbers into intuitive graphics, allowing technicians to immediately identify the distribution trends of deformation and stress, rather than simply focusing on isolated numerical values.

[0027] Finally, step S4 automatically calculates the overall deformation and average stress of the cross-section, as well as the deviation of each measuring point from the average, and simultaneously calculates the dispersion index of each measuring point. These statistical parameters reflect the uniformity of stress on the support structure. Based on the calculation results, and combined with the pre-set allowable bearing capacity of the lining structure and the allowable deformation of the interlayer pressure relief support structure, the system classifies and determines the service performance of the tunnel's interlayer pressure relief support structure. When the calculated parameters exceed the preset threshold, the system triggers the corresponding warning level, thereby achieving dynamic management of the tunnel's safety status.

[0028] The present invention also provides the following technical solution: In step S2, an ultrasonic transceiver unit and a two-dimensional compressive stress sensor are installed by reserving a slot inside the interlayer pressure relief support structure; the ultrasonic transceiver unit is used to monitor the radial deformation of the interlayer pressure relief support structure, and the two-dimensional compressive stress sensor is used to monitor the radial pressure and tangential pressure of the surrounding rock.

[0029] To achieve precise monitoring of the deformation of the support structure and the surrounding rock pressure, the above implementation scheme employs a technique of pre-reserving slots within the interlayer pressure-relief support structure. During construction, when pouring or installing the interlayer pressure-relief support structure, specific sized channels or grooves are pre-reserved within the structure according to predetermined monitoring points. Subsequently, ultrasonic transceiver units and two-dimensional compressive stress sensors are installed within these pre-reserved slots. The main function of the ultrasonic transceiver unit is to monitor the radial deformation of the interlayer pressure-relief support structure using the propagation characteristics of sound waves; while the two-dimensional compressive stress sensor is specifically used to sense and record the radial and tangential pressures applied by the surrounding rock at that location. This embedded installation method not only protects the sensors from damage caused by the external construction environment but also ensures a tight connection between the sensors and the support structure, thereby obtaining the most accurate and sensitive monitoring data.

[0030] The present invention also provides the following technical solution: the ultrasonic transceiver unit includes an excitation end and a receiving end, wherein the excitation end is close to the side of the lining structure, and the receiving end is close to the side of the initial support or the first layer support of the double-layer lining structure; and a groove base is formed by carving a groove of 2-3cm on the initial support or the first layer support of the double-layer lining structure for fixing the receiving end.

[0031] The above embodiments further refine the structural layout of the ultrasonic transceiver unit and its working process in specific implementation. The ultrasonic transceiver unit consists of two parts: an excitation end and a receiving end. In terms of installation orientation, the excitation end is located near the lining structure, while the receiving end is located near the initial support or the first layer support of the double-layer lining structure. This layout utilizes the propagation characteristics of sound waves in different media. By measuring the time difference or phase difference of sound wave propagation between the excitation end and the receiving end, the thickness change of the interlayer pressure-bearing support structure, i.e., radial deformation, can be accurately inverted. To ensure that the receiving end remains stable under complex stress environments and does not shift or fall off, this embodiment specifically designs a grooved treatment on the surface of the first layer support of the initial support or double-layer lining structure. In specific operation, a groove with a depth of 2 to 3 cm is carved into the support layer using a special tool to form a stable grooved base, in which the receiving end is firmly fixed. This mechanical fixing method combines physical embedding and structural support, greatly improving the long-term stability and anti-interference capability of the monitoring system.

[0032] The present invention also provides the following technical solution, wherein the two-dimensional compressive stress sensor is embedded in the center of the interlayer pressure relief support structure, and the distance between it and the ultrasonic transceiver unit is not less than 20cm.

[0033] In the above technical solution, the two-dimensional compressive stress sensor is embedded at the geometric center of the interlayer pressure relief support structure. Placing the sensor at the center ensures it can uniformly sense stress transmission from all directions, avoiding measurement errors caused by edge effects. To prevent signal interference or stress concentration in the physical structure between the sensor and the ultrasonic transceiver unit, this embodiment explicitly stipulates that the linear distance between the two-dimensional compressive stress sensor and the ultrasonic transceiver unit must be no less than 20 centimeters. This distance parameter was obtained through extensive experimental verification, ensuring that the two sensors operate independently and without interference, while also ensuring a high degree of spatial consistency in the data they monitor, thus truly reflecting the overall stress and deformation of the cross-section.

[0034] The present invention also provides the following technical solution: after obtaining the contour surface in step S1, the layout position of the measuring points is determined according to the actual deformation of the contour surface: no less than 8 measuring points are set in each tunnel cross section, and are evenly arranged along the tunnel contour line at the arch top, left arch waist, right arch waist, left end point of the arching line, right end point of the arching line, center of the invert arch, and both sides of the center of the invert arch; the circumferential spacing between adjacent measuring points is 3~4m; for local protruding deformation parts on the contour surface, the circumferential spacing of the measuring points is increased to 2~3m.

[0035] After obtaining the tunnel profile in step S1, the above implementation scheme does not arbitrarily place measuring points, but determines their specific locations based on the actual deformation of the profile. Specifically, each tunnel cross-section must have at least eight measuring points. These points need to be evenly distributed along the tunnel profile, with specific locations including: the arch crown, left arch waist, right arch waist, left end point of the arching line, right end point of the arching line, center of the invert, and both sides of the invert center. This comprehensive point placement strategy covers the most complex and easily deformable key parts of the tunnel. In terms of circumferential spacing, the distance between adjacent measuring points is generally controlled within the range of 3 to 4 meters. However, this implementation scheme also considers special cases, namely, when there are locally protruding deformed areas on the profile, in order to capture the deformation characteristics of this area more precisely, the circumferential spacing of the measuring points needs to be increased, reducing it to 2 to 3 meters. This method of combining widespread placement with focused density ensures both the breadth of monitoring and the accuracy of monitoring key areas.

[0036] The present invention also provides the following technical solution: in step S3, the deformation sensing results of each measuring point include radial deformation and tangential deformation, and the stress sensing results of each measuring point include radial pressure, tangential pressure and longitudinal pressure; the deformation sensing results are plotted on the inner side of the contour surface to form a deformation curve, and the stress sensing results are plotted on the outer side of the contour surface to form a stress curve.

[0037] In practice, the calculated deformation sensing results are plotted on the inner side of the contour surface. By connecting the deformation values ​​of each measuring point, a smooth deformation curve is formed. This curve visually displays the changing trend of the internal shape of the support structure. Simultaneously, the stress sensing results are plotted on the outer side of the contour surface, forming a stress curve. This method of plotting on both the inner and outer sides allows technicians to easily compare the correspondence between "structural shape changes" and "external load distribution" when reviewing the drawings, greatly improving the efficiency and intuitiveness of data analysis.

[0038] The present invention also provides the following technical solution, wherein the overall cross-sectional deformation, mean stress, deviation, and dispersion of each measuring point in step S4 specifically include the following calculations: Average compressive deformation: ,in Here, n represents the compression deformation value at each measuring point, and n is the number of measuring points. Let the variance of compression deformation be: ,in Here, n represents the deformation value under pressure at each measuring point, and n is the number of measuring points. To ensure the average compressive deformation; Let the compressive deformation dispersion be: Residual deformation at measuring point: ,in The design allows for compressive deformation. Let the compressive stress be averaged: ,in Here, n represents the stress value at each measuring point, and n is the number of measuring points. Let the compressive stress variance be: Let the compressive stress dispersion be: .

[0039] The present invention also provides the following technical solution, wherein the allowable compression deformation dispersion The larger the value, the more uneven the deformation of the interlayer pressure-relief support structure on that cross section; the aforementioned pressure-relief stress dispersion The larger the value, the more uneven the stress distribution on the cross section of the interlayer pressure relief support structure.

[0040] The above-mentioned technical solution can identify potential risks of deformation incoordination and local stress concentration in the support structure in advance by accurately judging the degree of uneven deformation and stress. This provides an accurate basis for timely implementation of corresponding reinforcement measures on site, effectively avoiding engineering accidents such as local deformation instability and structural collapse caused by the continuous aggravation of uneven deformation and stress in the support structure. It also significantly improves the long-term stability and safety of the inter-layer pressure relief support system in tunnels.

[0041] In practical implementation, the dispersion of compressive deformation and the dispersion of compressive stress are two key evaluation indicators. When the dispersion of compressive stress is small, it means that the difference between the stress values ​​at various measuring points within the cross-section is small, and the stress values ​​at all measuring points are concentrated near the average compressive stress of the cross-section. The surrounding rock pressure borne by the interlayer compressive support structure within the entire cross-section is basically consistent, and the support structure exhibits a uniform stress state with good stress distribution uniformity. As the dispersion of compressive stress gradually increases, it means that the difference between the stress values ​​at various measuring points within the cross-section gradually increases. The stress values ​​at some measuring points are much greater than the overall average of the cross-section, while the stress values ​​at some measuring points are much less than the overall average of the cross-section. The distribution range of stress values ​​gradually expands, and there are significant differences in the surrounding rock pressure borne by different locations of the interlayer compressive support structure within the entire cross-section. The degree of stress non-uniformity gradually increases, and stress concentration begins to appear in local locations. When the compressive stress dispersion value reaches a high level, it indicates that there are significant differences in stress values ​​at various measuring points within the cross-section. The surrounding rock pressure at local locations is much higher than at other locations, and obvious local stress concentration areas appear in the support structure. The stress distribution is extremely uneven, and local locations of the support structure are subjected to pressure far exceeding the overall average level, posing a risk of localized crushing and structural failure. After completing the corresponding analysis, the dispersion values ​​at different monitoring times are compared to analyze the changing trends of deformation and stress dispersion. If the dispersion value shows a continuously increasing trend, it indicates that the unevenness of deformation and stress in the support structure within the cross-section is continuously intensifying, requiring close monitoring and follow-up.

[0042] The present invention also provides the following technical solution, wherein the graded evaluation in step S4 includes the deformation failure evaluation of a single measuring point: according to The results divide the residual yield deformation level into three levels: low, medium, and high, corresponding to ratio ranges of 0~0.3, 0.3~0.7, and 0.6~1.0, respectively. When the ratio is 0, the interlayer yield support structure at the measuring point is judged to have failed due to deformation.

[0043] When the calculated residual yield deformation level ratio is between 0 and 0.3, the residual yield deformation level of the measuring point is classified as low, indicating that the support structure at this location has consumed more than 70% of the designed yield deformation, with less than 30% remaining. The yielding function of the support structure has been largely utilized, and the margin for further deformation is small, requiring close monitoring. When the calculated residual yield deformation level ratio is between 0.3 and 0.7, the residual yield deformation level of the measuring point is classified as medium, indicating that the support structure at this location has consumed between 30% and 70% of the designed yield deformation, with between 30% and 70% remaining. The yielding function of the support structure is functioning normally, with sufficient deformation margin remaining, and monitoring can be carried out at the normal monitoring frequency. When the calculated residual yield deformation level ratio is within the range of 0.6 to 1.0, the residual yield deformation level of the measuring point is classified as high-level, indicating that the support structure at this measuring point has consumed less than 40% of the designed yield deformation, and the remaining yield deformation space exceeds 60%. The yield function of the support structure is basically not utilized, and there is still a very sufficient deformation margin. Monitoring can be carried out at the normal monitoring frequency. After completing the level classification, deformation failure is judged. The judgment criteria strictly follow the preset threshold. When the calculated residual yield deformation level ratio is 0, it means that the actual yield deformation value of the support structure at this measuring point is equal to the designed yield deformation. The design yield deformation space of the support structure has been completely exhausted, and it can no longer absorb the deformation energy released by the surrounding rock through its own compression deformation. The preset yield support function is completely lost. At this time, the interlayer yield support structure at this measuring point is directly judged to have deformed and failed. For measuring points judged to have deformed and failed, they are immediately marked, and their location, monitoring time, actual deformation value and design threshold are recorded, and they are simultaneously included in the risk warning list.

[0044] The present invention also provides the following technical solution, wherein the graded assessment in step S4 further includes stress failure assessment of a single measuring point: when the radial or tangential pressure of the surrounding rock obtained by real-time monitoring reaches or exceeds the allowable bearing capacity of the lining structure, the interlayer pressure relief support structure at that measuring point is determined to have failed stress; and, if any measuring point is determined to have either deformation failure or stress failure, the interlayer pressure relief support effect at that measuring point is deemed to have failed. In other words, for the same measuring point, as long as the measuring point is determined to have either deformation failure or stress failure, regardless of whether the other assessment result is in a safe state, the interlayer pressure relief support effect at that measuring point is directly deemed to have failed. That is to say, when a measuring point exhibits deformation failure, even if its stress value does not exceed the allowable bearing capacity, the support effect is deemed to have failed; when a measuring point exhibits stress failure, even if its deformation amount does not reach the deformation failure threshold, the support effect is deemed to have failed; only when neither the deformation assessment nor the stress assessment of the measuring point is deemed to have failed is the interlayer pressure relief support effect at that measuring point deemed to be effective.

[0045] Although embodiments of the present invention 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 the present invention. 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, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering, characterized in that, Includes the following steps: S1. Obtain the outline of the first layer of support in the initial support or double-layer lining structure; S2. Monitor the radial deformation of the interlayer pressure relief support structure in real time, and simultaneously monitor the radial and tangential pressure of the surrounding rock at that location; S3. Based on the obtained outline of the initial support or the first layer of support of the double-layer lining structure, draw a smooth and continuous curve of the deformation and stress sensing results of each measuring point on a proportional scale using the Kriging interpolation method. S4. Calculate the overall deformation and stress mean, deviation and dispersion of each measuring point of the cross section; combine the allowable bearing capacity of the lining structure and the allowable deformation of the interlayer pressure relief support structure to conduct a graded evaluation and early warning of the service performance of the tunnel interlayer pressure relief support structure.

2. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 1, characterized in that, In step S2, an ultrasonic transceiver unit and a two-dimensional compressive stress sensor are installed by pre-reserving slots inside the interlayer pressure relief support structure. The ultrasonic transceiver unit is used to monitor the radial deformation of the interlayer pressure relief support structure, and the two-dimensional compressive stress sensor is used to monitor the radial and tangential pressure of the surrounding rock.

3. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 2, characterized in that, The ultrasonic transceiver unit includes an excitation end and a receiving end, wherein the excitation end is close to the side of the lining structure, and the receiving end is close to the side of the initial support or the first layer support of the double-layer lining structure; and a groove base with a groove of 2-3cm is engraved on the initial support or the first layer support of the double-layer lining structure to fix the receiving end.

4. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 2, characterized in that, The two-dimensional compressive stress sensor is embedded in the center of the interlayer pressure relief support structure, and the distance between it and the ultrasonic transceiver unit is not less than 20cm.

5. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 1, characterized in that, After obtaining the profile surface in step S1, the location of the measuring points is determined according to the actual deformation of the profile surface: no less than 8 measuring points are set for each tunnel cross section, and they are evenly distributed along the tunnel profile line at the top of the arch, the left arch waist, the right arch waist, the left end point of the arching line, the right end point of the arching line, the center of the invert arch, and both sides of the center of the invert arch; the circumferential spacing between adjacent measuring points is 3~4m; for local protruding deformation parts on the profile surface, the circumferential spacing between measuring points is increased to 2~3m.

6. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 1, characterized in that, In step S3, the deformation sensing results of each measuring point include radial deformation and tangential deformation, and the stress sensing results of each measuring point include radial pressure, tangential pressure and longitudinal pressure; the deformation sensing results are plotted on the inner side of the contour surface to form a deformation curve, and the stress sensing results are plotted on the outer side of the contour surface to form a stress curve.

7. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 1, characterized in that, The overall cross-sectional deformation, mean stress, deviation, and dispersion of each measuring point mentioned in step S4 specifically include the following calculations: Average compressive deformation: ,in Here, n represents the compression deformation value at each measuring point, and n is the number of measuring points. Let the variance of compression deformation be: ,in Here, n represents the deformation value under pressure at each measuring point, and n is the number of measuring points. To ensure the average compressive deformation; Let the compressive deformation dispersion be: Residual deformation at measuring point: ,in The design allows for compressive deformation. Let the compressive stress be averaged: ,in Here, n represents the stress value at each measuring point, and n is the number of measuring points. Let the compressive stress variance be: Let the compressive stress dispersion be: .

8. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 7, characterized in that, The pressure deformation dispersion The larger the value, the more uneven the deformation of the interlayer pressure-relief support structure on that cross section; the aforementioned pressure-relief stress dispersion The larger the value, the more uneven the stress distribution on the cross section of the interlayer pressure relief support structure.

9. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 7, characterized in that, The graded assessment described in step S4 includes the deformation failure assessment of a single measuring point: based on The results divide the residual yield deformation level into three levels: low, medium, and high, corresponding to ratio ranges of 0~0.3, 0.3~0.7, and 0.6~1.0, respectively. When the ratio is 0, the interlayer yield support structure at the measuring point is judged to have failed due to deformation.

10. The method for sensing and classifying the deformation stress of inter-layer pressure relief support in tunnel engineering according to claim 1, characterized in that, The graded assessment in step S4 also includes stress failure assessment of individual measuring points: when the radial or tangential pressure of the surrounding rock obtained by real-time monitoring reaches or exceeds the allowable bearing capacity of the lining structure, the stress failure of the interlayer pressure relief support structure at that measuring point is determined; and if any measuring point is determined to be deformed or stressed, the interlayer pressure relief support effect at that measuring point is deemed to have failed.

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