Method for Evaluating Soundness of Tunnel Support Works and Soundness Evaluation System

Abstract

To provide a soundness evaluation method and a soundness evaluation system for tunnel shoring that can properly evaluate soundness of each excavation stage of shoring for supporting a tunnel.SOLUTION: There is provided a soundness evaluation method for tunnel shoring that specifies stress of shoring constructed as a tunnel excavated and evaluates soundness of the shoring, and the soundness evaluation method for tunnel shoring has: an A process of imaging set measurement positions of shoring by a three-dimensional laser scanner 10 to acquire three-dimensional coordinates in each excavation stage of a tunnel, and specifying a displacement quantity at a measurement position of each excavation stage and also specifying an increment displacement quantity after the excavation stage progresses; a B process of generating, by computer, a shoring model M related to the shoring and imparting the increment displacement quantity to the shoring model M to calculate stress generated in the shoring model M for each excavation stage; and a C process of evaluating soundness of the shoring based upon the calculated stress of each excavation stage.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a method for evaluating the soundness of tunnel support works and a soundness evaluation system.

Background Art

[0002] In the construction of mountain tunnels, in order to grasp the properties (or state, behavior, etc.) of the ground, face observations are generally carried out, and in-pit measurements are also generally carried out to measure the deformation or stress state of the support works and the ground. The tunnel construction management method is carried out, for example, by setting management reference values for in-pit displacement using the direct strain method or the like, measuring the in-pit displacement at any time as excavation progresses, and comparing the measured values with the management reference values. However, the setting of management reference values for in-pit displacement using the direct strain method is for the purpose of ensuring the stability of the ground and does not evaluate the soundness of the support works that support the tunnel. By appropriately evaluating the soundness of the support works for each excavation stage of the tunnel, tunnel construction with high construction safety can be realized.

[0003] Here, Patent Document 1 proposes a method for predicting the final displacement amount of a tunnel, which provides a method for predicting the displacement amount of a mountain tunnel at a tunnel site. Specifically, a three-dimensional finite element method simulation analysis reflecting the excavation progress is performed by a three-dimensional finite element method model arbitrarily set as a standard model, and for each ground type, support structure, and excavation method, a relational expression between the initial displacement velocity and the ground stiffness ratio of each measurement point and at least a relational expression between the final displacement amount and the ground stiffness ratio are obtained in a first step, and after the excavation of the tunnel, initial displacement velocity data of each measurement point is obtained by measurement with a 3D laser scanner installed in front of the face in a second step, and the ground stiffness ratio of the excavation site is calculated by fitting it to the relational expression between the initial displacement velocity and the ground stiffness ratio obtained in the first step, and a final displacement amount prediction method having a third step of calculating the final displacement amount of each measurement point based on the relational expression between the final displacement amount and the ground stiffness ratio.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2016-121487 Summary of the Invention Problems to be Solved by the Invention

[0005] The prediction method described in Patent Document 1 predicts the final displacement amount of a tunnel, and as described above, does not evaluate the soundness of a support structure for supporting the tunnel at each excavation stage.

[0006] An object of the present invention is to provide a soundness evaluation method and a soundness evaluation system for a tunnel support structure that can appropriately evaluate the soundness of a support structure for supporting a tunnel at each excavation stage. Means for Solving the Problems

[0007] To achieve the above object, one aspect of the soundness evaluation method for a tunnel support structure according to the present invention is a soundness evaluation method for a tunnel support structure that specifies the stress of a support structure constructed as the tunnel is excavated and evaluates the soundness of the support structure, comprising: at each excavation stage of the tunnel, imaging the set measurement position of the support structure with a three-dimensional laser scanner to obtain three-dimensional coordinates, specifying the displacement amount at the measurement position at each excavation stage, and specifying the incremental displacement amount when the excavation stage progresses, step A; in a computer, creating a support structure model for the support structure, and calculating the stress generated in the support structure model at each excavation stage by applying the incremental displacement amount to the support structure model, step B; and step C of evaluating the soundness of the support structure based on the calculated stress at each excavation stage.

[0008] According to this aspect, for each tunneling stage using a three-dimensional laser scanner, the three-dimensional coordinates of the measurement positions of the temporary support are obtained to identify the displacement amount, and after identifying the incremental displacement amount when the tunneling stage progresses, the incremental displacement amount is applied to the temporary support model, and the stress generated in the temporary support model for each tunneling stage is calculated to evaluate the soundness of the temporary support, whereby the soundness of the temporary support for each tunneling stage can be appropriately evaluated. Here, the three-dimensional coordinates of the three-dimensional laser scanner can be obtained by traversing surveying or the like, and the three-dimensional coordinates at the measurement positions of the temporary support are identified by the three-dimensional laser scanner having the three-dimensional coordinates. By applying a three-dimensional laser scanner, it is unnecessary to install measuring instruments at various measurement positions on the temporary support, and rapid displacement measurement at each measurement position becomes possible. In the conventional stress measurement of the temporary support, stress meters are attached to various parts of the temporary support and stress meters are embedded in the sprayed concrete (secondary spraying), so stress measurement at various measurement positions of the temporary support is impossible, and it is also impossible to change the measurement position opportunely. Furthermore, since the stress meters installed on the temporary support are basically left (buried) inside the secondary spraying, there are various problems such as the installation of stress meters being time-consuming and the stress measurement being costly. By applying a three-dimensional laser scanner, all these problems can be solved. By applying the incremental displacement amount when the tunneling stage progresses to the temporary support model created by a computer and performing stress analysis, the stress generated throughout the temporary support can be accurately identified by inverse analysis of the support stress. Here, the temporary support model includes a two-dimensional beam spring model, a two-dimensional or three-dimensional FEM (Finite Element Method) analysis model, etc.

[0009] Also, another aspect of the method for evaluating the soundness of tunnel temporary supports according to the present invention is In the step B, The temporary support includes sprayed concrete and a steel temporary support, The temporary support model includes a sprayed concrete model and a steel temporary support model, Calculate the stress at each excavation stage of the sprayed concrete model and the steel support model, In the C process, Characterized by evaluating the soundness of each of the sprayed concrete and the steel support.

[0010] According to this aspect, by specifying the displacement amount at the measurement positions of the sprayed concrete and the steel support included in the support, and the incremental displacement amount when the excavation stage progresses, and specifying the stress actually generated in each support by inverse analysis of each support stress, the soundness of each support can be appropriately evaluated. Therefore, for example, when the generated stresses of both the sprayed concrete and the steel support are greater than their respective yield strengths, etc., countermeasures such as reviewing the specifications of both supports will be taken. When only the steel support is inappropriate, countermeasures can be taken only for the steel support. Here, when the soundness of the sprayed concrete is evaluated as insufficient, there is a risk of cracks and peeling of the sprayed concrete. When the soundness of the steel support is evaluated as insufficient, there is a risk of deformation and buckling of the steel support.

[0011] Another aspect of the method for evaluating the soundness of a tunnel support according to the present invention is In the B process, Create the support model as a three-dimensional model, Characterized by applying the incremental displacement amount to the support model in a surface manner.

[0012] According to this aspect, by applying the incremental displacement amount to the three-dimensional model (such as a FEM analysis model) of the support in a surface manner, a more accurate analysis result can be obtained, and the soundness of the support can be evaluated more precisely.

[0013] Another aspect of the method for evaluating the soundness of a tunnel support according to the present invention is A D process of setting the allowable strain at the time of damage of the support from a plurality of tunnel construction cases where damage of the support has been confirmed, and Furthermore, there is an E step of setting the management reference value of the support work by multiplying the excavation radius of the tunnel to be managed by the allowable strain. In the C step, in addition to evaluating the soundness of the support work based on the stress calculated for each excavation stage, the soundness of the support work is evaluated by comparing the management reference value with the displacement amount at the measurement position for each excavation stage.

[0014] According to this aspect, in addition to evaluating the soundness based on the stress of the support work for each excavation stage, by performing an evaluation of soundness based on the comparison between the measured value regarding the displacement amount of the support work and the management reference value, for example, when both evaluations are favorable, it is determined that the support work is sound, and when at least one of the evaluations is unfavorable, it is determined that the support work is not sound, thereby enabling a more reliable evaluation of soundness. Also, in this aspect, the allowable strain at the time of damage to the support work is set from a plurality of tunnel construction cases where damage to the support work has been confirmed, and the management reference value of the support work is set by multiplying the allowable strain by the excavation radius of the tunnel to be managed, thereby enabling the setting of a management reference value for evaluating the soundness of the support work that reflects the strain at the time of damage to the support work and the scale (excavation radius) of the tunnel to be managed. Then, by comparing this management reference value with the measured value regarding the displacement amount of the support work accompanying the excavation of the tunnel and determining the suitability of the support work, the soundness of the support work can be appropriately evaluated.

[0015] Here, the "plurality of tunnel construction cases" includes tunnel construction cases in which damage to the support work has been confirmed and published by the Japan Tunneling Technology Association, the Japan Society of Civil Engineers, etc., in addition to the past tunnel construction achievements held by construction companies. The support work includes shotcrete, steel support work, rock bolts, etc., and the "damage to the support work" includes, as described above, cracks and peeling of shotcrete, deformation and buckling of steel support work, deformation of washer plates of rock bolts, and breakage of rock bolts.

[0016] As the strain at the time of damage to the support work (the displacement amount of the support work (or tunnel wall surface) / the excavation radius of the tunnel), for example, 2% or less (about 1 to 2%) can be set.

[0017] Also, one aspect of the tunnel support work soundness evaluation system according to the present invention is A tunnel support work soundness evaluation system that specifies the stress of the support work constructed along with the excavation of the tunnel and evaluates the soundness of the support work, having a three-dimensional laser scanner and an evaluation device, The three-dimensional laser scanner For each excavation stage of the tunnel, images the set measurement position of the support work with a three-dimensional laser scanner to obtain three-dimensional coordinates, The evaluation device A displacement amount specifying unit that specifies the displacement amount at the measurement position for each excavation stage and specifies the incremental displacement amount when the excavation stage progresses, A stress calculation unit that creates a support work model related to the support work and calculates the stress generated in the support work model for each excavation stage by applying the incremental displacement amount to the support work model, And an evaluation unit that evaluates the soundness of the support work based on the calculated stress for each excavation stage.

[0018] According to this aspect, for each excavation stage of the tunnel, three-dimensional coordinates of the measurement position of the support work are obtained using a three-dimensional laser scanner to specify the displacement amount, and in the evaluation device, the incremental displacement amount when the excavation stage progresses is specified. By applying the incremental displacement amount to the created support work model and calculating the stress generated in the support work model for each excavation stage to evaluate the soundness of the support work, the soundness of the support work for each excavation stage can be appropriately evaluated.

[0019] Also, in another aspect of the tunnel support work soundness evaluation system according to the present invention, The evaluation device A storage unit that stores a plurality of tunnel construction cases in which damage to the support work has been confirmed, An allowable strain setting unit that sets an allowable strain at the time of damage to the support based on the plurality of tunnel construction cases, and further includes a management reference value setting unit that sets a management reference value for the support by multiplying the allowable strain by the excavation radius of the tunnel to be managed, In the evaluation unit, in addition to evaluating the soundness of the support based on the calculated stress for each excavation stage, the soundness of the support is evaluated by comparing the management reference value with the displacement amount at the measurement position for each excavation stage. It is characterized by that.

[0020] According to this aspect, in addition to the evaluation of the soundness based on the stress of the support for each excavation stage, by performing the evaluation of the soundness based on the comparison between the measured value related to the displacement amount of the support and the management reference value, a more reliable soundness evaluation can be realized.

Effect of the Invention

[0021] According to the soundness evaluation method and soundness evaluation system of the tunnel support of the present invention, the soundness of the support for supporting the tunnel can be appropriately evaluated for each excavation stage.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0023] Hereinafter, a soundness evaluation system and a soundness evaluation method for tunnel support work according to an embodiment will be described with reference to the accompanying drawings. In the present specification and the drawings, substantially the same components may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0024] [Soundness Evaluation System for Tunnel Support Work According to the Embodiment] First, with reference to FIGS. 1 to 6, an example of a soundness evaluation system for tunnel support work according to an embodiment will be described. Here, FIG. 1 is an overall configuration diagram showing an example of a soundness evaluation system for tunnel support work according to the embodiment. FIG. 2 is a diagram showing an example of the hardware configuration of a computer constituting the soundness evaluation system, and FIG. 3 is a diagram showing an example of the functional configuration of an evaluation device constituting the soundness evaluation system.

[0025] The soundness evaluation system 100 is a soundness evaluation system that identifies the stress of the support work constructed along with the excavation of the tunnel and evaluates the soundness of the support work.

[0026] The soundness evaluation system 100 includes a three-dimensional laser scanner 10 and an evaluation device 20. In the example shown in the figure, the soundness evaluation system 100 is configured such that the three-dimensional laser scanner 10 and the evaluation device 20 are connected via a network 30 so as to be able to transmit and receive measurement data. Here, the three-dimensional laser scanner 10 and the evaluation device 20 may be connected by wire to perform data transmission and reception instead of being connected via the network 30.

[0027] The three-dimensional laser scanner 10 irradiates lasers at a plurality of measurement positions set for the scaffolder, receives the reflected lasers, and acquires the three-dimensional coordinates of the measurement positions. More precisely, the three-dimensional coordinates of the three-dimensional laser scanner 10 are specified by traversing surveying or the like, and the three-dimensional coordinates of a plurality of measurement positions of the scaffolder are specified by the three-dimensional laser scanner 10 having the three-dimensional coordinates.

[0028] The evaluation device 20 has various functions as shown in FIG. 3, and the details thereof will be described below. Both the three-dimensional laser scanner 10 and the evaluation device 20 are configured by a computer. However, in the following description with reference to FIG. 2, the evaluation device 20 will be taken up and described.

[0029] The personal computers constituting the evaluation device 20 include a CPU (Central Processing Unit) 21, a main storage device 22, an auxiliary storage device 23, a communication IF 24, and an input / output IF (interface) 25 that are interconnected by a connection bus 26. The main storage device 22 and the auxiliary storage device 23 are recording media readable by a computer. Note that the above-described components may be provided individually, or some of the components may not be provided.

[0030] The CPU 21 is also called an MPU (Microprocessor) or a processor. The CPU 21 may be a single processor or a multi-processor. The CPU 21 is a central arithmetic processing unit that controls the entire evaluation device 20. The CPU 21, for example, expands a program stored in the auxiliary storage device 23 so that it can be executed in the working area of the main storage device 22, and controls peripheral devices through the execution of the program, thereby providing a function that meets a predetermined purpose.

[0031] The main memory device 22 stores computer programs executed by the CPU 21, data processed by the CPU 21, and the like. The main memory device 22 includes, for example, a flash memory, a RAM (Random Access Memory), and a ROM (Read Only Memory). The auxiliary storage device 23 reads and writes various programs and various data to and from a recording medium, and is also called an external storage device. The auxiliary storage device 23 stores, for example, an OS (Operating System), various programs, various tables, and the like. The OS includes, for example, a communication interface program that transfers data to and from external devices connected via the communication IF 24. External devices such as the evaluation device 20 include a three-dimensional laser scanner 10, a host computer in the department to which the measurer belongs, and smartphones, tablets, etc. carried by other measurers.

[0032] The auxiliary storage device 23 is used, for example, as a storage area that supplements the main memory device 22, and stores computer programs executed by the CPU 21, data processed by the CPU 21, and the like. The auxiliary storage device 23 is a silicon disk including a non-volatile semiconductor memory (flash memory, EPROM (Erasable Programmable ROM)), a hard disk drive (HDD) device, a solid state drive device, or the like. Further, as the auxiliary storage device 23, a drive device for a removable recording medium such as a CD drive device, a DVD drive device, and a BD drive device is exemplified, and as the removable recording medium, a CD, a DVD, a BD, a USB (Universal Serial Bus) memory, an SD (Secure Digital) memory card, etc. are exemplified.

[0033] The input / output IF 25 is an interface that inputs and outputs data to and from devices connected to the evaluation device 20. For example, input devices such as a keyboard, a pointing device such as a touch panel or a mouse, and a microphone are connected to the input / output IF 25. The evaluation device 20 receives operation instructions and the like from an operator who operates the input device via the input / output IF 25.

[0034] In addition, devices such as display devices such as liquid crystal panels (LCD: Liquid Crystal Display) and organic EL panels (EL: Electroluminescence), and output devices such as printers and speakers are connected to the input / output IF25. In the evaluation device 20, the stress calculation results and soundness evaluation results of the support work for each of the plurality of excavation stages are displayed at any time.

[0035] The communication IF24 is an interface with the network to which the evaluation device 20 is connected. The communication IF24 receives measurement values by the three-dimensional laser scanner 10 via various networks such as public networks such as the Internet, wireless networks such as mobile phone networks, dedicated networks such as VPN (Virtual Private Network), and LAN (Local Area Network), and transmits data related to the stress calculation results and soundness evaluation results of the support work to a host computer or the like. Here, an LPWA wireless communication module and a communication antenna or the like may be connected to the communication IF24. The LPWA wireless communication module is a device that realizes LPWA wireless communication (wireless transmission), and is, for example, an electronic component in which a wireless chip and peripheral circuits are mounted on a small substrate. The main communication methods (communication protocols) of LPWA include Sigfox, LoRaWAN (Long Range Wide Area Network), NB-IoT, etc. For example, it is preferable to apply LoRaWAN, which does not require a license and can install a private base station in a mine even in mountainous areas where mobile phone communication waves are difficult to reach, and can construct a low-cost communication system. LoRaWAN is a communication method that uses the ISM band in the 920 MHz band and enables long-distance communication even with a low output of 13 dBm or less, and adopts LoRa modulation.

[0036] As shown in FIG. 3, the evaluation device 20 provides various functions of at least the communication unit 202, displacement amount specifying unit 204, stress calculation unit 206, evaluation unit 208, allowable strain setting unit 210, management reference value setting unit 212, display unit 214, and storage unit 216 by executing a program by the CPU 21. Here, at least a part of the above processing functions may be provided by a DSP (Digital Signal Processor), GPU (Graphics Processing Unit), etc. Similarly, at least a part of the above processing functions may be a dedicated LSI (large scale integration) such as an FPGA (Field-Programmable Gate Array), a numerical calculation processor, an image processing processor, or other digital circuits.

[0037] In the communication unit 202, measurement data (measurement values) regarding the three-dimensional coordinates at each measurement position of the support work transmitted from the three-dimensional laser scanner 10 are received at any time and stored in the storage unit 216 at any time.

[0038] The displacement amount specifying unit 204 specifies the displacement amount for each excavation stage at each measurement position based on the three-dimensional coordinates and the coordinate change amount at a plurality of measurement positions of the support work measured for each excavation stage, and specifies the incremental displacement amount when the excavation stage advances at each measurement position of each support work. For example, by measuring the three-dimensional coordinates of a plurality of measurement positions of a steel support work built at intervals of several meters for each of a plurality of excavation stages, the incremental displacement amount for each excavation stage is specified.

[0039] The stress calculation unit 206 creates a support work model regarding the support work, and calculates the stress generated in the support work model for each excavation stage by applying the incremental displacement amount to the support work model.

[0040] Here, FIG. 4 is a diagram showing an example of display on the display unit 214 when an incremental displacement amount is applied as a forced displacement to the FEM analysis model of the support work. The support work model M in the illustrated example is a two-dimensional or three-dimensional FEM analysis model, and is a model diagram when an incremental displacement amount is forcibly loaded on the support work model M having a horseshoe-shaped cross section.

[0041] Here, when the formwork includes shotcrete and steel formwork, the formwork model M becomes a superposed beam model of the shotcrete model and the steel formwork model. For the steel formwork model, ν (Poisson's ratio), E (Young's modulus), A (cross-sectional area), I (second moment of area), etc. are set according to its specifications. For the shotcrete model, ν, E, A, etc. are set according to its specifications. Note that for shotcrete, since its Young's modulus E changes with the age of the material, assumptions are necessary, and for the cross-sectional area A, assumptions considering the unevenness of the thickness are also necessary.

[0042] When creating a three-dimensional FEM analysis model (three-dimensional model), by applying a surface incremental displacement to the three-dimensional formwork model, more accurate stress analysis results can be obtained.

[0043] As shown in FIG. 4, by applying an incremental displacement as a forced displacement to the formwork model M, the stress generated in the formwork model is calculated as shown in FIG. 5. In the illustrated example, in the steel formwork model of the formwork model M, a maximum bending stress of 274 N / mm 2 is generated.

[0044] The storage unit 216 stores, for example, the yield strength data of steel formwork (e.g., 400 N / mm 2 ). In the evaluation unit 208, the calculated maximum bending stress of 274 N / mm 2 is compared with the yield strength: 400 N / mm 2 to evaluate the soundness of the steel formwork. In this example, since the maximum generated bending stress is less than or equal to the yield strength, it is evaluated as having soundness.

[0045] The storage unit 216 stores a plurality of tunnel construction cases where formwork damage has been confirmed.

[0046] Here, FIG. 6 shows an example of a tunnel construction case. More specifically, it is a table summarizing construction cases based on past construction records.

[0047] Figure 6 shows the overburden, geology, deformation position of the support member (support work), face separation, tunnel equivalent radius (for example, the radius when simulating a horseshoe-shaped tunnel as a circle), support pattern (support work pattern) at the time of deformation, and measured displacement for 26 cases from Tunnel A to Tunnel Z. The "circumferential strain" in the right column is calculated from the tunnel equivalent radius and the measured displacement. Note that the "circumferential strain" refers to the radial strain at multiple locations (crown, inner space, wall surface) in the circumferential direction of the tunnel. In addition, there are construction cases based on the construction achievements summarized by the present inventors other than the examples shown in Figure 6, but Figure 6 shows one example of them.

[0048] Here, the calculation method of the circumferential strain: εt (%) is a method of dividing the measured displacement of the tunnel (radial displacement): Ur (m) by the tunnel excavation radius (or equivalent radius, unit: m): R and multiplying by 100.

[0049] Note that although not shown in the figure, the construction cases include cases described in known literature. Examples of this known literature include construction cases described in the Japan Tunnel Engineering Society; Tunnel and Underground, the Japan Society of Civil Engineers: Proceedings of the Tunnel Engineering Research Symposium, and the Japan Tunnel Engineering Society: Construction Experience Symposium.

[0050] In the allowable strain setting unit 210, the allowable strain at the time of damage to the support work is set in the range of, for example, 1% to 2% based on the above-mentioned multiple construction cases. Here, by setting the allowable strain to 2%, the management reference value on the dangerous side based on the tunnel construction case can be set, and by setting the allowable strain to 1%, the management reference value on the safe side based on the tunnel construction case can be set. The allowable strain setting unit 210 may automatically set an appropriate allowable strain for the tunnel to be managed in the range of about 1% to 2%, or the allowable strain set by the construction manager or the like in the range of about 1% to 2% may be input to the allowable strain setting unit 210.

[0051] Further, for example, a safety factor may be further considered for a strain of 1%, and by considering the safety factor, a management reference value on the safer side can be set. Here, as the safety factor, about 1.1 to 1.5 can be set. For example, when a safety factor of 1.25 is expected for a strain of 1%, the allowable strain is set to 0.8%.

[0052] The management reference value setting unit 212 sets the management reference value of the support by multiplying the allowable strain set by the allowable strain setting unit 210 by the excavation radius of the tunnel to be managed.

[0053] In addition to evaluating the soundness of the support based on the calculated stress for each excavation stage as described above, the evaluation unit 208 also evaluates the soundness of the support by comparing the set management reference value with the displacement amount at the measurement position for each excavation stage.

[0054] And, for example, by the two-stage soundness evaluation of the support, it can be determined that the support is sound when both soundness evaluations are passed. Also, when at least one of the soundness evaluations is not passed, it is determined that the support is not sound, and countermeasures are considered and implemented.

[0055] The evaluation device 20 in the illustrated example has a two-stage soundness evaluation function for the support. However, for example, it may be in a form that does not include the allowable strain setting unit 210 and the management reference value setting unit 212. In this form, the soundness of the support is evaluated based only on the calculated stress for each excavation stage.

[0056] According to the soundness evaluation system 100, using the three-dimensional laser scanner 10, the three-dimensional coordinates of the measurement position of the support are acquired for each excavation stage of the tunnel to specify the displacement amount. In the evaluation device 20, the incremental displacement amount when the excavation stage progresses is specified, the incremental displacement amount is applied to the created support model M, and the stress generated in the support model M for each excavation stage is calculated to evaluate the soundness of the support, whereby the soundness of the support for each excavation stage can be appropriately evaluated.

[0057] In addition, by applying the three-dimensional laser scanner 10, it is unnecessary to install measuring instruments at various measurement positions in the supporting work, and rapid displacement measurement at each measurement position becomes possible.

[0058] [Method for Evaluating the Soundness of Tunnel Supporting Work According to the First Embodiment] Next, with reference to FIG. 7, an example of a method for evaluating the soundness of tunnel supporting work according to the first embodiment will be described. Here, FIG. 7 is a flowchart of an example of a method for evaluating the soundness of tunnel supporting work according to the first embodiment.

[0059] This soundness evaluation method is an evaluation method for specifying the stress of the supporting work constructed along with the excavation of the tunnel and evaluating the soundness of the supporting work.

[0060] First, for each excavation stage of the tunnel, the set measurement positions of the supporting work are imaged by a three-dimensional laser scanner to obtain three-dimensional coordinates (step S10).

[0061] Then, the displacement amount at the measurement position for each excavation stage is specified, and the incremental displacement amount when the excavation stage progresses is specified (step S12). Above, steps S10 and S12 are collectively referred to as process A.

[0062] Next, on a computer, a supporting work model related to the supporting work is created, and by applying the incremental displacement amount to the supporting work model, the stress generated in the supporting work model for each excavation stage is calculated (step S14, process B).

[0063] Next, based on the calculated stress for each excavation stage, the soundness of the supporting work is evaluated (step S16, process C).

[0064] As a result of the soundness evaluation of the supporting work, for example, if the stress exceeds the yield strength, it is considered that the supporting work is not sound, and some countermeasures are considered and implemented (step S18). On the other hand, if the stress is below the yield strength, it can be evaluated that the current supporting work is sound.

[0065] [Method for Evaluating Soundness of Tunnel Support Work According to the Second Embodiment] Next, with reference to FIG. 8, an example of a method for evaluating the soundness of tunnel support work according to the second embodiment will be described. Here, FIG. 8 is a flowchart of an example of a method for evaluating the soundness of tunnel support work according to the second embodiment.

[0066] In FIG. 8, the flowchart in the left column is basically the same as the flowchart shown in FIG. 7. By this flowchart in the left column, the soundness evaluation of the first-stage support work is performed (step S16).

[0067] On the other hand, in FIG. 8, in the flowchart in the right column, first, the allowable strain at the time of damage to the support work is set from a plurality of tunnel construction cases where damage to the support work has been confirmed. The allowable strain is preferably set in the range of about 1% to 2%. When a safety factor is further considered, a more safety-side allowable strain is set (step S20, D process).

[0068] Next, by multiplying the allowable strain by the excavation radius of the tunnel to be managed, the management reference value for the support work is set (step S22, E process).

[0069] Next, for each excavation stage of the tunnel, the set measurement position of the support work is imaged by a three-dimensional laser scanner to obtain three-dimensional coordinates (step S24), and by comparing the management reference value with the displacement amount at the measurement position for each excavation stage, the soundness evaluation of the second-stage support work is performed (step S26, C process).

[0070] Finally, it is determined whether at least one of the results of the soundness evaluations of the first-stage and second-stage support works is sound (step S30). When both are evaluated as not sound, consideration and implementation of some countermeasures are carried out (step S18). On the other hand, when either one is evaluated as sound, or both are evaluated as sound, it can be evaluated that the current support work is sound.

[0071] According to this soundness evaluation method, it is possible to achieve a more accurate soundness evaluation of tunnel support work.

[0072] In addition, other embodiments in which other components are combined with the configurations and the like described in the above embodiments may be possible, and the present invention is not limited to the configurations shown here at all. In this regard, it is possible to make changes without departing from the gist of the present invention, and it can be appropriately determined according to the application form.

Explanation of Signs

[0073] 10: Three-dimensional laser scanner 20: Evaluation device 30: Network 100: Soundness evaluation system for tunnel support work (soundness evaluation system) 202: Communication unit 204: Displacement amount specifying unit 206: Stress calculation unit 208: Evaluation unit 210: Allowable strain setting unit 212: Management reference value setting unit 214: Display unit 216: Storage unit M: Support work model

Claims

1. A method for evaluating the soundness of tunnel support works, which identifies the stress of the support works constructed along with the excavation of a tunnel and evaluates the soundness of the support works, comprising: In each excavation stage of the tunnel, imaging the set measurement positions of the support works with a three-dimensional laser scanner to obtain three-dimensional coordinates, identifying the displacement amount at the measurement positions for each excavation stage, and identifying the incremental displacement amount when the excavation stage progresses, step A; In a computer, creating a support work model related to the support works, and calculating the stress generated in the support work model for each excavation stage by applying the incremental displacement amount to the support work model, step B; Based on the calculated stress for each excavation stage, evaluating the soundness of the support works, step C, characterized by comprising the above steps, a method for evaluating the soundness of tunnel support works.

2. In the above step B, The support works include shotcrete and steel support works, The support work model includes a shotcrete model and a steel support work model, Calculating the stress for each excavation stage of each of the shotcrete model and the steel support work model, In the above step C, Evaluating the soundness of each of the shotcrete and the steel support works, characterized by the method for evaluating the soundness of tunnel support works according to Claim 1.

3. In the above step B, Creating the support work model as a three-dimensional model, Characterized by applying the incremental displacement amount to the support work model in a surface manner, the method for evaluating the soundness of tunnel support works according to Claim 1 or 2.

4. Step D of setting the allowable strain at the time of damage of the support works from a plurality of tunnel construction cases where damage to the support works has been confirmed; Further comprising step E of setting the management reference value of the support works by multiplying the excavation radius of the tunnel to be managed by the allowable strain; In the above step C, in addition to evaluating the soundness of the support works based on the calculated stress for each excavation stage, evaluating the soundness of the support works by comparing the management reference value with the displacement amount at the measurement positions for each excavation stage, characterized by the method for evaluating the soundness of tunnel support works according to any one of Claims 1 to 3.

5. A system for evaluating the soundness of tunnel support works, which identifies the stress of the support works constructed along with the excavation of a tunnel and evaluates the soundness of the support works, comprising: It has a three-dimensional laser scanner and an evaluation device, The three-dimensional laser scanner For each excavation stage of the tunnel, images the measurement position of the set support work by the three-dimensional laser scanner to obtain three-dimensional coordinates, The evaluation device A displacement amount specifying unit that specifies the displacement amount at the measurement position for each excavation stage and specifies the incremental displacement amount when the excavation stage progresses; A stress calculation unit that creates a support work model for the support work and calculates the stress generated in the support work model for each excavation stage by applying the incremental displacement amount to the support work model; A tunnel support work soundness evaluation system, characterized by having an evaluation unit that evaluates the soundness of the support work based on the calculated stress for each excavation stage.

6. The evaluation device A storage unit that stores a plurality of tunnel construction cases in which damage to the support work has been confirmed; An allowable strain setting unit that sets an allowable strain at the time of damage to the support work based on the plurality of tunnel construction cases; It further has a management reference value setting unit that sets a management reference value for the support work by multiplying the excavation radius of the tunnel to be managed by the allowable strain, In the evaluation unit, in addition to evaluating the soundness of the support work based on the calculated stress for each excavation stage, the soundness of the support work is evaluated by comparing the management reference value with the displacement amount at the measurement position for each excavation stage. The tunnel support work soundness evaluation system according to claim 5, characterized in that.

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