Ground measurement system and its installation method

Abstract

To provide a natural ground measurement system and its installation method capable of eliminating labor and danger associated with wiring, curing, and maintenance of wired cables, and without limitations on measurement locations.SOLUTION: A natural ground measurement system 100 that measures quantitative data as a mountain tunnel 10 is excavated comprises at least one sensor 80 installed in a wall 13 of the mountain tunnel 10 or in a steel shoring 22 supporting the wall 13, a first communication device 32 that transmits measurement data acquired by the sensor 80, a second communication device 61 that is arranged closer to a wellhead 12 than the first communication device 32 and receives measurement data wirelessly transmitted from the first communication device 32. All or part of the first communication device 32 is accommodated in a recess 22d on the wellhead 12 side formed by a web 22c and flanges 22a and 22b of the steel shoring 22 made of H-section steel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ground measurement system and its installation method. By law Regarding. [Background technology]

[0002] In the construction of mountain tunnels, B-measurements are carried out with the primary purpose of reflecting the results in the design and construction, depending on the ground conditions and design content. This B-measurement is intended to determine the appropriateness of the support materials and construction methods used, as well as to ensure rational and economical implementation of the design and construction of the tunnel further inside. This B-measurement includes underground displacement measurement, steel support stress measurement, shotcrete stress measurement, and rock bolt axial force measurement, and all of these are performed using special sensors to obtain quantitative data (measurement data) to evaluate the current ground conditions and, further, to evaluate future ground conditions as excavation progresses. For example, Patent Document 1 proposes a method for predicting ground conditions that enables highly accurate prediction of the ground conditions ahead of the tunnel face by accurately identifying horizontal internal displacement in addition to tunnel settlement. Specifically, in the method, a plurality of inclinometers are installed at intervals in the axial direction of the tunnel in the tunnel arch section of a tunnel with a cross-sectional shape that includes at least a semicircular section, measurement data from each inclinometer is acquired, the amount of change in inclination angle is calculated from the measurement data from adjacent inclinometers, and the ground conditions ahead of the tunnel face are predicted based on the calculation results. The inclinometers are installed at an angle of 55 to 65 degrees from the spring line, with the intersection of the horizontal spring line and the vertical center line as the center. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-61080 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the construction of mountain tunnels, the mainstream method for collecting measurement data measured by sensors is the wired collection method, in which data is collected from the sensors via wired cables to a data logger or a PC (personal computer). However, there are issues such as the time and effort required to install wired cables inside the tunnel, to protect them from flying blasting stones, and to secure a power source, and the danger involved in wiring work near the tunnel face. Furthermore, it has become standard practice these days to set up a system in which data is constantly transferred from the data loggers mentioned above to a PC located in a guardhouse outside the mine via a communication cable (maximum communication distance, for example, 1.2 km), and the data can then be accessed at any time from the PC via LAN at the work site office. However, as there are also sites where LAN cables are laid directly inside the mine or Wi-Fi (registered trademark) access points are installed, maintaining and managing the communication cables (to prevent damage) has become an issue.

[0005] The wired data collection method described above requires workers and managers to have access to the vicinity of the measurement location during installation and construction. Because various vehicles and construction personnel pass through the tunnel, it is necessary to select a time and measurement location that will not interfere with construction. In other words, since there are concerns about skin slippage at the face when the measurement location is near the tunnel face, it is desirable for safety reasons to set the measurement location at a location some distance from the tunnel face. However, given that measurements close to the face are ideal for evaluating the properties of the ground ahead, measuring the ground at a location some distance from the tunnel face can lead to a decrease in the accuracy of the property evaluation.

[0006] The present invention provides a ground measurement system and its installation method that can eliminate the labor and danger associated with wiring, protection, and maintenance of wired cables, does not limit measurement locations, and can quickly feed back measurement data to subsequent mountain tunnel construction. The law It is intended to provide. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the natural ground measurement system according to the present invention is to A ground measurement system that measures quantitative data as a mountain tunnel is excavated, At least one sensor installed on the tunnel wall of the mountain tunnel or on a steel support supporting the tunnel wall; a first communicator that transmits measurement data acquired by the sensor; a second communication device disposed closer to the wellhead than the first communication device and configured to receive the measurement data wirelessly transmitted from the first communication device; The steel support is formed from H-shaped steel, and all or part of the first communication device is housed in a recess on the tunnel entrance side formed by a web and a flange.

[0008] According to this aspect, measurement data acquired by the sensor is transmitted from the first communication device to the second communication device installed on the mineshaft side, thereby eliminating the trouble and danger associated with wiring, protection, and maintenance of wired cables and eliminating limitations on measurement locations. Furthermore, by accommodating the first communication device in a recess on the mineshaft side formed by the web and flange of the steel support structure made of H-shaped steel, even if the first communication device is installed near the mineshaft face, it is possible to protect the first communication device from flying blasting stones and the like without taking any special protective measures.

[0009] The first communication device is installed by fitting all or part of it into the recess on the entrance side of the H-shaped steel beam and spraying shotcrete (secondary shotcrete) around the first communication device.

[0010] In another aspect of the natural ground measurement system according to the present invention, The present invention is characterized in that all or part of a unit body that integrates the first communication device and a data logger that accumulates the measurement data acquired from the sensor is housed in the recess.

[0011] According to this embodiment, by using a compact unit (for example, a configuration in which the entire unit is contained in a single housing) in which the first communication device and data logger are integrated, the unit, which can both store and transmit measurement data from the sensor, can be easily accommodated in the recess on the mine entrance side of the steel support.

[0012] In another aspect of the natural ground measurement system according to the present invention, The first communication device is characterized by including an LPWA wireless communication module and a communication antenna that transmits the measurement data to the second communication device.

[0013] According to this aspect, the first communication unit is equipped with an LPWA wireless communication module, and by transmitting measurement data (quantitative data) to the second communication device installed at the tunnel entrance, long-distance wireless communication in mountain tunnels can be achieved with low power consumption, which makes it possible to quickly feed back the measurement data to subsequent mountain tunnel construction. Here, LPWA (Low Power Wide Area) refers to a wireless communication method that enables wide-area data communication and low power consumption (for example, a communication method using the 920 MHz ISM (Industrial Scientific and Medical Band)). Note that in this specification, "long-distance communication" means wireless communication of measurement data over a distance of, for example, 100 m or more.

[0014] The measurement data received by the second communication device is transmitted, for example, via a network, to a PC or server device in the work site office, or to user terminals (smartphones, tablets, personal computers, etc.) carried by people involved in the construction (construction manager, personnel in charge of the construction company's head office or branch, construction contractors, etc.). By applying LPWA wireless communication, the number of second communication devices installed in the tunnel can be reduced, and depending on the length of the mountain tunnel, for example, it may be possible to transmit measurement data measured by the sensor to a server device, etc. via a network with only one second communication device.

[0015] The measurement data transmitted to the server device is then transmitted via the server device to user terminals owned by multiple construction personnel, allowing the multiple user terminals to share the measurement data simultaneously and in real time. Furthermore, at least one of the server device and the user terminal determines the ground conditions and / or ground evaluation (such as the hardness or softness of the ground, the stability or instability of the ground, and the appropriateness of the support pattern) based on the measurement data. This allows multiple user terminals to quickly determine the current ground conditions and the appropriateness of the support pattern originally planned based on the hardness or softness of the ground. Furthermore, if the current ground conditions are worse (e.g., softer) than those initially planned, the support pattern can be quickly revised, enabling construction management that ensures high construction safety even in the event of a sudden change in ground conditions.

[0016] In another aspect of the natural ground measurement system according to the present invention, The present invention is characterized in that at least an elastic protective material is disposed on the outside of the first communication device or the unit body, and shotcrete is applied to the outside of the elastic protective material.

[0017] According to this aspect, at least an elastic protective material is arranged on the outside of the first communication device or the unit body, and sprayed concrete is applied to the outside of the elastic protective material, thereby preventing the sprayed concrete from coming into direct contact with the unit body, for example. Furthermore, since the unit body is protected by the elastic protective material, when removing it from the installation location and relocating it to another location, the unit body can be easily taken out by removing the elastic protective material. Here, "at least elastic protective material is provided" includes a form in which only elastic protective material is provided, as well as a form in which elastic protective material and a fixing jig, etc. are provided.

[0018] Here, the elastic protective material is preferably a member made of resin or foamed resin, which has a certain degree of rigidity and elasticity and is relatively easy to remove.

[0019] In another aspect of the natural ground measurement system according to the present invention, The sensor is characterized by including at least one of an underground displacement meter, a rock bolt axial force meter, a shotcrete stress meter, and a steel support stress meter.

[0020] According to this embodiment, by applying various sensors, highly accurate B measurement can be achieved, and the current nature of the ground can be evaluated, and furthermore, the future nature of the ground as excavation progresses can be evaluated.

[0021] Furthermore, one aspect of the support unit according to the present invention is A support unit constituting a ground measurement system that measures quantitative data as a mountain tunnel is excavated, A steel support made of H-shaped steel is attached to the primary spraying surface of the primary spraying applied to the side surface of the excavated face and the side surface of the primary spraying applied to the side surface; A wire mesh or support rod attached to the steel support; a sensor installed on the wire mesh or the support rod; The device is characterized by having a first communication device, the whole or part of which is housed in a recess on the wellhead side formed by the web and flange of the H-shaped steel, or a unit body in which the first communication device is integrated with a data logger that accumulates measurement data obtained from the sensor.

[0022] According to this aspect, by applying a support unit that integrates a steel support made of H-shaped steel, a wire mesh or support rod, a sensor, and a first communication device or unit body that is housed in a recess on the tunnel entrance side of the H-shaped steel, it becomes possible to simultaneously install sensors, communication devices, data loggers, etc. when erecting the steel support, thereby enabling efficient installation of a ground measurement system.

[0023] Furthermore, one aspect of the method for installing a natural ground measurement system according to the present invention is to: A method for installing a ground measurement system that measures quantitative data as a mountain tunnel is excavated, comprising: Process A involves erecting a support unit in which a wire mesh or support rod is attached to a steel support made of H-shaped steel against the primary sprayed surface of the primary sprayed applied to the side of the excavated face and side of the mountain tunnel, and at least one of a shotcrete stress meter and a steel support stress meter included in a sensor is installed on the wire mesh or support rod, and a first communication device that transmits measurement data acquired by the sensor, or all or part of a unit body integrating the first communication device and a data logger, is housed in a recess on the tunnel entrance side formed by the web and flange of the H-shaped steel; A process B in which a secondary spraying is carried out so as to entrain the sensor; The method is characterized by having a step C of disposing a second communication device closer to the entrance of the well than the first communication device, for receiving the measurement data wirelessly transmitted from the first communication device.

[0024] According to this aspect, a sensor is pre-installed via wire mesh or support rods on a steel support made of H-shaped steel, and a first communication device or a unit integrating the first communication device and a data logger is pre-installed in a recess on the wellhead side of the H-shaped steel. After erecting the support unit, secondary spraying is performed to encase the sensor, thereby enabling efficient installation of a ground measurement system. This installation method is for when both or either one of a shotcrete stress meter and a steel support stress meter that can be attached to the steel support via wire mesh or support rods is a sensor.

[0025] Another aspect of the method for installing a natural ground measurement system according to the present invention is to A method for installing a ground measurement system that measures quantitative data as a mountain tunnel is excavated, comprising: A process A involves erecting a support unit that houses a first communication device that transmits measurement data acquired by a sensor, or all or part of a unit body that integrates the first communication device and a data logger, in a recess on the tunnel entrance side formed by the web and flange of a steel support made of H-shaped steel, relative to the primary spraying surface of the primary spraying applied to the excavated face and side of the mountain tunnel; Process B: Secondary spraying is performed up to the flange or its vicinity on the inside of the H-shaped steel tunnel; Process C involves drilling holes from the secondary spraying to the natural ground and installing an underground displacement meter or rock bolt axial force meter included in the sensor in the drilled hole; The method is characterized by including a step D of disposing a second communication device closer to the entrance of the well than the first communication device, the second communication device receiving the measurement data wirelessly transmitted from the first communication device.

[0026] According to this aspect, after erecting a shoring unit that already houses a first communication device or a unit body integrating a first communication device and a data logger into a recess on the tunnel entrance side of a steel shoring made of H-shaped steel, secondary spraying is performed, and a hole is drilled from the secondary spraying to the natural ground to install an underground displacement meter or a rock bolt axial force meter in the drilled hole, thereby achieving efficient installation of a natural ground measurement system. This installation method is an installation method when the underground displacement meter or rock bolt axial force meter to be installed in the hole drilled in the natural ground is used as the sensor.

[0027] In another aspect of the method for installing a natural ground measurement system according to the present invention, In the step B, at least an elastic protective material is disposed on the outside of the first communication device or the unit body, and shotcrete is applied to the outside of the elastic protective material; When carrying out step A on the side constructed by the next excavation, the elastic protective material is removed, thereby removing the first communication device or the unit body already installed in the recess from the recess, and replacing it in the recess of the steel support to be installed later.

[0028] According to this embodiment, for example, by placing elastic protective material on the outside of the unit body and applying sprayed concrete to the outside of the elastic protective material, when carrying out process A on the side constructed by the next excavation, the unit body installed in the recess can be removed from the recess by removing the elastic protective material, and can be repurposed by being placed in the recess of the next support to be installed. [Effects of the Invention]

[0029] The ground measurement system of the present invention and its installation method By law This makes it possible to provide a ground measurement system that eliminates the hassle and danger associated with wiring, covering, and maintaining wired cables, does not restrict measurement locations, and can quickly provide feedback on measurement data for subsequent mountain tunnel construction. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 2 is a plan view showing an example of the natural ground measurement system and the shoring unit according to the embodiment. [Figure 2] FIG. 2 is a view taken along the line II-II in FIG. 1, showing an example of the placement of sensors and data loggers. [Figure 3] 1 is an overall block diagram of an example of a natural ground measurement system according to an embodiment. FIG. [Figure 4] FIG. 4 is an enlarged view of part IV in FIG. 1, showing an example of an installation configuration of a sensor and a unit body. [Figure 5] 10A and 10B are diagrams illustrating other examples of the installation configuration of the sensor and the unit body. [Figure 6A] FIG. 5 is a process diagram illustrating the installation method of the natural ground measurement system according to the first embodiment, illustrating a method for forming the installation configuration shown in FIG. 4. [Figure 6B] FIG. 6B is a process diagram illustrating the installation method of the natural ground measurement system according to the first embodiment, following FIG. 6A. [Figure 6C] FIG. 6B is a process diagram illustrating the installation method of the natural ground measurement system according to the first embodiment. [Figure 7A] FIG. 6 is a process diagram illustrating a method for installing the natural ground measurement system according to the second embodiment, illustrating a method for forming the installation configuration shown in FIG. 5. [Figure 7B] FIG. 7B is a process diagram illustrating the installation method of the natural ground measurement system according to the second embodiment, following FIG. 7A. [Figure 7C] FIG. 7B is a process diagram illustrating the installation method of the natural ground measurement system according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, a natural ground measurement system, an installation method thereof, and a shoring unit according to an embodiment will be described with reference to the accompanying drawings. Note that in this specification and the drawings, substantially identical components will be designated by the same reference numerals, and redundant explanations may be omitted.

[0032] [Ground measurement system and shoring unit according to the embodiment] First, an example of a ground measurement system and a shoring unit according to an embodiment will be described with reference to Figures 1 to 5. Here, Figure 1 is an overall configuration diagram showing an example of a ground measurement system and a shoring unit according to an embodiment, Figure 2 is a view taken along the line II-II in Figure 1 and shows an example of the installation of each sensor and data logger, and Figure 3 is an overall block diagram of an example of a ground measurement system according to an embodiment.

[0033] The illustrated natural ground measurement system 100 is applied to a mountain tunnel. A mountain tunnel 10 is constructed by drilling a charge hole in a tunnel face 11 using a drilling machine such as a jumbo drill, and then loading the hole with dynamite and detonating it. Note that mountain tunnels may also be constructed by mechanical excavation (not shown) using a free-face boring machine or a breaker.

[0034] After the tunnel has been extended to a predetermined length by blasting or other means, the natural ground in the area enclosed by the two-dot chain line V in Figure 1 is excavated forward, and new steel supports 22 (steel arch supports) and shotcrete are installed on the tunnel wall 13. A primary spraying 21 of concrete, for example, about 5 cm to 15 cm thick, is applied to the surface of the tunnel wall 13, and mirror spraying 21A is applied to the tunnel face 11. After that, steel supports 22 made of H-shaped steel or the like are installed at predetermined intervals in the direction of excavation to protect the tunnel wall. After that, a secondary spraying 23 of concrete, for example, about 5 cm to 20 cm thick, is applied so as to encase the steel supports 22.

[0035] The primary spraying 21 and secondary spraying 23 are carried out by bringing a concrete mixer truck into the tunnel and spraying the concrete with a sprayer. After the secondary spraying 23 is carried out, rock bolts (not shown) are installed as needed. These rock bolts are made of steel bars, for example, about 2 to 6 meters long, and are used to support the tensile force caused by deformation of the ground G toward the inside of the tunnel, thereby suppressing deformation of the tunnel wall 13.

[0036] The natural ground measurement system 100 is a system that measures quantitative data as the mountain tunnel 10 is excavated. The natural ground measurement system 100 has at least one sensor 80 installed on the tunnel wall 13 of the mountain tunnel 10 or on the steel support 22 that supports the tunnel wall 13, a first communicator 32 (see FIG. 3 ) that transmits the measurement data acquired by the sensor 80, and a second communicator 61 that is disposed closer to the tunnel entrance 12 than the first communicator 32 and receives the measurement data wirelessly transmitted from the first communicator 32.

[0037] 3, a data logger 31 and a first communicator 32 are integrated to form a unit body 30. The data logger 31 supplies an applied voltage, performs A / D conversion of a signal from a sensor 80, and stores the digital value after A / D conversion. In the data logger 31, the signal from the sensor 80 is converted into a digital value via A / D conversion, and the converted digital data is stored. The stored data is then transmitted via a communication antenna 33 provided in the first communicator 32.

[0038] The first communicator 32 is a slave device of an LPWA (wireless communication module) that conforms to the LoRa Private standard.

[0039] On the other hand, the communication base station 60 (base station) has a second communication device 61 equipped with a communication antenna 63 and a tablet PC 62 built in, and the tablet PC 62 is also a component of the natural ground measurement system 100. The tablet PC 62 is connected to a LAN via WiFi or a wired connection, and data files stored in the storage device (memory) of the tablet PC 62 are shared on the network, allowing data to be acquired in real time from the work site office, etc.

[0040] The interior of mountain tunnel 10 is filled with various (mainly metal) obstacles such as heavy machinery, center carts, and steel soundproof doors, creating an environment in which radio waves are attenuated, but in principle, long-distance communication of approximately 1 to 2 km is possible when transmitting and receiving measurement data using an LPWA wireless system. Therefore, in the natural ground measurement system 100, the second communication device 61 is installed, for example, at a position several hundred meters or more away from the sensor 80 near the tunnel face 11, and thereafter, the system is constructed so that measurement data is transmitted to the second communication device 61 closest to the tunnel entrance 12, which is connected to an external network, without being relocated.

[0041] According to the ground measurement system 100, the measurement data acquired by the sensor 80 is transmitted from the first communication device 32 to the second communication device 61 arranged on the tunnel entrance 12 side, thereby eliminating the effort and danger associated with wiring, protection, and maintenance of wired cables and eliminating limitations on measurement locations.

[0042] Returning to Fig. 1, a unit body 30 equipped with a first communication device 32 is accommodated in a recess 22d formed by a web 22c, an upper flange 22a, and a lower flange 22b of a steel support 22 made of H-shaped steel and located near the working face 11 and susceptible to flying blasting stones. The recess 22d is located on the side of the wellhead 12 opposite the working face 11. In addition to the illustrated example, the unit body 30 may be accommodated in the recess 22d on the side of the wellhead 12 of two or more steel supports 22 located near the working face 11. In addition, although the illustrated example shows a configuration in which the entire unit body 30 is completely accommodated in the recess 22d, the unit body 30 may also be accommodated in the recess 22d in a manner in which part of the unit body 30 protrudes from the recess 22d.

[0043] The sensor 80 shown in Fig. 1 is a shotcrete stress meter 80A. The unit body 30 and the shotcrete stress meter 80A are attached to a common wire mesh 50. Although not shown in the figure, a steel support rod may be used instead of the wire mesh 50.

[0044] More specifically, as shown in Figure 4, an elastic protective material 41 such as a hard sponge is arranged on the outside of the unit body 30, an L-shaped fixing jig 43 is fixed to the web 22c of the steel support 22 with a tapping screw 48, a support plate 42 such as a polycarbonate plate is fixed to the fixing jig 43 with a fixing bolt 44, and the underside of the elastic protective material 41 is covered by the support plate 42.

[0045] The shotcrete stress meter 80A and the data logger 31 of the unit body 30 are wired via a data cable 39.

[0046] As will be explained in detail below, the steel support 22 is erected with the wire mesh 50 secured to it with wire or the like, and the shotcrete stress meter 80A and the data logger 31 of the unit body 30 wired to it. The wire mesh 50 protrudes slightly toward the front of the tunnel from the steel support 22 already erected one bay before, and the newly installed wire mesh 50 is firmly fixed in place by tying it to the protruding part with binding wire or the like. After the steel support 22 is erected, the secondary spraying 23 is applied, and the steel support 22, wire mesh 50, shotcrete stress meter 80A, elastic protective material 41, and unit body 30 are caught up in the secondary spraying 23.

[0047] Also, although not shown in the figures, instead of the support plate 42 such as a polycarbonate plate, a non-metallic mesh net may be arranged and high-early-strength mortar or the like may be applied from below by a plasterer, or it may be covered with a thin layer of sprayed concrete.

[0048] As shown in Figure 2, multiple types of sensors 80 are installed inside the tunnel wall 13 and natural ground G of the mountain tunnel 10. Here, a single 4-channel data logger 30 is connected to the shotcrete stress meter 80A and the steel support stress meter 80B. A single 6-channel data logger 30 is also connected to each of the rock bolt axial force meter 80C and the underground displacement meter 80D. For the steel support stress meter 80B, a cable is routed to the unit body 30 (before erection on site) along the recess 22d in the web. Furthermore, multi-channel data loggers can also be manufactured and used.

[0049] In the installation example shown in Figure 2, four types of sensors 80 are installed near the center line CL in the cross section of the mountain tunnel 10, and four types of sensors 80 are installed above and below the left and right sides of the spring line SL. The sensors 80 include a shotcrete stress meter 80A (circle in the figure), a steel support stress meter 80B (square in the figure), a rock bolt axial force meter 80C (triangle in the figure), and an underground displacement meter 80D (star in the figure).

[0050] As shown in FIG. 2, the number of channels varies depending on the type of sensor, and a unit 30 including a data logger 31 is installed to correspond to each number of channels.

[0051] When the sensor 80 is an underground displacement meter 80D, the installation configuration is as shown in Fig. 5. After the secondary spraying 23 is applied, a borehole B is drilled from the secondary spraying 23 to the ground G to install a part of the underground displacement meter 80D, and since a part of the underground displacement meter 80D is exposed on the inner wall surface of the tunnel, an excavation G1 is made in advance into the ground G at the installation location to keep this exposed part within the tunnel cross section, and the primary spraying 21 is applied to the surface of that excavation.

[0052] By constructing the secondary spraying 23 along the longitudinal line of the excavation G1, a depression 23a is formed in the secondary spraying 23 at the location where the underground displacement meter 80D is installed.

[0053] The unit body 30 is accommodated in a recess 22d on the mine entrance 12 side of the steel support 22, and an elastic protective material 41 such as a hard sponge is arranged on the outside of the unit body 30. An L-shaped fixing jig 43 is fixed to the web 22c of the steel support 22 with a tapping screw 48, and a support plate 42 such as a polycarbonate plate is fixed to the fixing jig 43 with a fixing bolt 44, and the underside of the elastic protective material 41 is covered by the support plate 42.

[0054] A separate elastic protective material 41 is disposed on the underside of the underground displacement meter 80D, and the underside of the elastic protective material 41 is covered with a backing plate 42. A support steel member 47 fixed to the bottom flange 22b of the steel support 22 supports the underside of the backing plate 42. The gap between the top surface of the backing plate 42 and the secondary spraying 23 is filled with urethane foam 45.

[0055] As shown in Figure 5, by providing a recess 23a in the secondary spray 23 and accommodating the underground displacement meter 80D and its supporting members in the recess 23a, it is possible to prevent these from protruding (or protruding significantly) into the interior of the tunnel.

[0056] Furthermore, in either the form shown in Figure 4 or Figure 5, part or all of the unit body 30 equipped with the first communication device 32 and the data logger 31 is housed in the recess 22d on the mine entrance 12 side of the steel support 22, so that even if the unit body 30 is installed near the working face 11, the unit body 30 can be protected from blasting stones, etc. without taking any special protective measures.

[0057] [Installation method of natural ground measurement system according to the embodiment] First Embodiment Next, an example of a method for installing the natural ground measurement system according to the first embodiment will be described with reference to Fig. 6A to Fig. 6C and Fig. 4. Here, Fig. 6A to Fig. 6C are process diagrams illustrating the method for installing the natural ground measurement system according to the first embodiment, and are diagrams illustrating a method for forming the installation configuration shown in Fig. 4.

[0058] To form the installation configuration shown in Figure 4, first, as shown in Figure 6A, the unit body 30 is placed in the recess 22d on the tunnel entrance 12 side of the steel support 22, and the wire mesh 50 is fixed to the upper flange 22a with wire or the like, and the sprayed concrete stress meter 80A and the data logger 31 of the unit body 30 are wired via a data cable 39.

[0059] Here, support rods (support steel materials) or the like may be used instead of the wire mesh 50. The sprayed concrete stress meter 80A is installed by attaching strain gauges to two surfaces (the face 11 side and the tunnel mouth 12 side) of the web 22c, and is wired to the unit body 30 along the recess 22d of the web 22c.

[0060] An elastic protective material 41 such as a hard sponge is arranged on the outside of the unit body 30, an L-shaped fixing jig 43 is screwed to the web 22c of the steel support 22, a support plate 42 such as a polycarbonate plate is fixed to the fixing jig 43 with fixing bolts 44, and the underside of the elastic protective material 41 is covered with the support plate 42 to form a support unit 70.

[0061] The formed support unit 70 is erected in the X1 direction so that the back of the wire mesh 50 abuts the primary spraying surface 21a of the primary spraying 21, thereby forming the state before the secondary spraying construction shown in Figure 6B.

[0062] Here, a wire mesh 50 protrudes slightly toward the front of the tunnel from the steel support structure 22 that has already been erected, and the newly installed wire mesh 50 is firmly fixed by tying it to the protruding part of this wire mesh 50 with a binding wire 51 (this is process A).

[0063] Next, as shown in Figure 6C, secondary spraying 23 is applied, so that the steel support structure 22, wire mesh 50, sprayed concrete stress meter 80A, elastic protective material 41, and unit body 30 are encased in secondary spraying 23 (this is process B).

[0064] In parallel with the above-described step B, or before or after step B, the second communication device 61 is disposed closer to the wellhead 12 than the first communication device 32 (this is step C).

[0065] According to the installation method shown in the figure, when installing the sprayed concrete stress meter 80A to be buried in the secondary spraying 23, the sprayed concrete stress meter 80A is installed in advance via a wire mesh 50 on the steel support 22 made of H-shaped steel, and after the support unit 70, in which the unit body 30 is already housed, is erected in the recess 22d on the tunnel entrance 12 side of the H-shaped steel 22, the secondary spraying 23 is constructed so as to encase the sprayed concrete stress meter 80A, thereby enabling efficient installation of the ground measurement system 100 when using the concrete stress meter 80A (and / or steel support stress meter) as a sensor.

[0066] Furthermore, when the unit body 30 is removed and moved to another installation location, the receiving plate 42 is removed and the elastic protective material 41 is pulled out to form a removal space, which makes it possible to easily remove the unit body 30.

[0067] Second Embodiment Next, an example of an installation method for the natural ground measurement system according to the second embodiment will be described with reference to Fig. 7A to Fig. 7C and Fig. 5. Here, Fig. 7A to Fig. 7C are process diagrams illustrating the installation method for the natural ground measurement system according to the second embodiment, and are diagrams illustrating a method for forming the installation configuration shown in Fig. 5.

[0068] To form the installation configuration shown in FIG. 5, first, as shown in FIG. 7A, a digging G1 is formed in the natural ground G at the installation position of the sensor 80D.

[0069] Next, the unit body 30 is placed in the recess 22d on the mine entrance 12 side of the steel support 22, an elastic protective material 41 such as a hard sponge is placed on the outside of the unit body 30, an L-shaped fixing jig 43 is screwed to the web 22c of the steel support 22, a support plate 42 such as a polycarbonate plate is fixed to the fixing jig 43 with fixing bolts 44, and the underside of the elastic protective material 41 is covered with the support plate 42 to form the support unit 70A.

[0070] The formed support unit 70A is erected in the X2 direction so that the back surface of the upper flange 22a of the steel support 22 abuts against the primary spraying surface 21a of the primary spraying 21 (this is process A).

[0071] As shown in FIG. 7B, after erecting the shoring unit 70A, the secondary spraying 23 is applied up to the vicinity of the shoring unit 70A.

[0072] By this secondary spraying 23, a depression 23a is formed at a position corresponding to the excavation G1 (this is step B).

[0073] Next, as shown in Figure 7C, in the depression 23a, a borehole B is formed by drilling from the secondary spraying 23 to the natural ground G, and an underground displacement meter 80D is installed from the borehole B to the inner surface of the depression 23a of the secondary spraying 23, thereby forming the installation configuration shown in Figure 5.

[0074] Next, as shown in Figure 5, a separate elastic protective material 41 is placed on the underside of the underground displacement meter 80D, and the underside of the elastic protective material 41 is covered with a backing plate 42. Then, a support steel member 47 is fixed to the bottom flange 22b of the steel support 22 to support the underside of the backing plate 42. The gap between the top surface of the backing plate 42 and the secondary spraying 23 is filled with urethane foam 45 (this is process C). The above series of processes can also be applied in the case where a rock bolt axial force meter 80C is installed instead of the underground displacement meter 80D shown in the figure.

[0075] In parallel with the above-described step C, or before or after step C, the second communication device 61 is disposed closer to the wellhead 12 than the first communication device 32 (this is step D).

[0076] According to the installation method shown in the figure, after erecting the support unit 70A, which already houses the unit body 30, into the recess 22d on the tunnel entrance 12 side of the steel support 22 made of H-shaped steel, the secondary spraying 23 is applied, a hole is drilled from the secondary spraying 23 to the ground G, and the underground displacement meter 80D is installed in the drilled hole, thereby realizing efficient installation of the ground measurement system 100 when the underground displacement meter 80D is used as a sensor.

[0077] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0078] 10: Mountain Tunnel 11: Cutting edge 12: Wellhead 13: Pit wall 21: Primary spraying 21a: Primary spray surface 22: Steel shoring (H-beam) 22a: Upper flange (flange) 22b: Lower flange (flange) 22c:Web 22d: Recess 23: Secondary spraying 23a: Depression 30: Unit body 31: Data logger 32: First communication device (LPWA slave device) 33: Communication antenna 39: Data cable 41: Elastic protective material (hard sponge) 42: Support plate 43: Fixture 44: Fixing bolt 45: Urethane foam 47: Support steel 48: Tapping screw 50: Wire mesh 51: Binding wire 60: Communication base station 61:Second communication device 62: Tablet PC 63: Communication antenna 70, 70A: Shoring unit 80: Sensor 80A: Shotcrete stress meter (sensor) 80B: Steel support stress meter (sensor) 80C: Rock bolt axial force meter (sensor) 80D: Underground displacement meter (sensor) 100: Ground measurement system G: Ground G1:Digging B: Borehole

Claims

1. A ground measurement system that measures quantitative data as a mountain tunnel is excavated, At least one sensor installed on the tunnel wall of the mountain tunnel or on a steel support supporting the tunnel wall; a first communicator that transmits measurement data acquired by the sensor, and a data logger that accumulates the measurement data acquired from the sensor; a second communication device that is disposed at a position closer to the mine entrance than the first communication device and that can be connected to an external network, receives the measurement data wirelessly transmitted from the first communication device, and transmits the measurement data via the network to a computer outside the mine; the first communication device and the data logger are all or partly housed in a recess on the wellhead side formed by a web and a flange of the steel support formed by H-shaped steel, and the first communication device and the data logger can be removed from the recess in which they are housed and relocated to a recess of another steel support for reuse; an elastic protective material is disposed outside the first communication device and the data logger; a fixing jig is fixed to the steel support; a backing plate is removably fixed to the fixing jig; the underside of the elastic protective material is covered by the backing plate; and shotcrete is applied to the outside of the elastic protective material; A ground measurement system characterized in that, when the first communication device and the data logger are replaced and reused, the support plate is removed from the fixing jig, the elastic protective material is pulled out, and the first communication device and the data logger are pulled out from the recess.

2. 2. The natural ground measurement system according to claim 1, wherein the first communication device comprises an LPWA wireless communication module and a communication antenna that transmits the measurement data to the second communication device.

3. 3. The ground measurement system according to claim 1, wherein the sensor includes at least one of an underground displacement meter, a rock bolt axial force meter, a shotcrete stress meter, and a steel support stress meter.

4. A method for installing a ground measurement system that measures quantitative data as a mountain tunnel is excavated, comprising: Process A involves erecting a support unit in relation to the primary sprayed surface of the primary sprayed concrete applied to the excavated face and sides of the mountain tunnel, in which a wire mesh or support rod is attached to a steel support made of H-shaped steel, at least one of a shotcrete stress meter and a steel support stress meter included in a sensor is installed on the wire mesh or support rod, and a recess on the tunnel entrance side formed by the web and flange of the H-shaped steel contains a first communication device that transmits measurement data acquired by the sensor, and all or part of a data logger that stores the measurement data acquired from the sensor; A process B in which a secondary spraying is performed so as to entrain the sensor; and a step C of disposing a second communication device at a position closer to the mine entrance than the first communication device and connectable to an external network, the second communication device receiving the measurement data wirelessly transmitted from the first communication device and transmitting the measurement data via the network to a computer outside the mine, When carrying out the step A on the side surface constructed by the next excavation, the first communication device and the data logger are removed from the recess in which they are housed and are relocated to a recess in a steel support to be installed later for reuse, In the step B, an elastic protective material is disposed outside the first communication device and the data logger, a fixing jig is fixed to the steel support, a support plate is removably fixed to the fixing jig, the underside of the elastic protective material is covered with the support plate, and shotcrete is applied to the outside of the elastic protective material. A method for installing a ground measurement system, characterized in that, in order to relocate and reuse the first communication device and the data logger when carrying out step A on the side constructed by the next excavation, the support plate is removed from the fixing jig, the elastic protective material is pulled out, the first communication device and the data logger are pulled out from the recess, and the first communication device and the data logger are relocated and reused in a recess of a steel support to be installed later.

5. A method for installing a ground measurement system that measures quantitative data as a mountain tunnel is excavated, comprising: Process A involves erecting a support unit that houses a first communication device that transmits measurement data acquired by a sensor and all or part of a data logger that stores the measurement data acquired from the sensor, in a recess on the tunnel entrance side formed by the web and flange of a steel support made of H-shaped steel, relative to the primary spraying surface of the primary spraying applied to the side of the excavated face and side of the mountain tunnel; Process B: Secondary spraying is performed up to the flange of the H-shaped steel on the inside of the tunnel or its vicinity; Process C involves drilling holes from the secondary spraying to the natural ground and installing an underground displacement meter or rock bolt axial force meter included in the sensor in the drilled holes; and a step D of disposing a second communication device at a position closer to the entrance of the mine than the first communication device and connectable to an external network, the second communication device receiving the measurement data wirelessly transmitted from the first communication device and transmitting the measurement data via the network to a computer outside the mine, When carrying out the step A on the side surface constructed by the next excavation, the first communication device and the data logger are removed from the recess in which they are housed and are relocated to a recess in a steel support to be installed later for reuse, In the step B, an elastic protective material is disposed outside the first communication device and the data logger, a fixing jig is fixed to the steel support, a support plate is removably fixed to the fixing jig, the underside of the elastic protective material is covered with the support plate, and shotcrete is applied to the outside of the elastic protective material. A method for installing a ground measurement system, characterized in that, in order to relocate and reuse the first communication device and the data logger when carrying out step A on the side constructed by the next excavation, the support plate is removed from the fixing jig, the elastic protective material is pulled out, the first communication device and the data logger are pulled out from the recess, and the first communication device and the data logger are relocated and reused in a recess of a steel support to be installed later.

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