Estimation method and system for stagnant water area in tunnel pit

Abstract

To accurately estimate a stagnant water area and stagnant water amount in a tunnel pit at a low cost even in a simple configuration.SOLUTION: An estimation method for a stagnant water area includes steps of: selecting an upstream sensor and a downstream sensor installed at two places of an upstream side and a downstream side, respectively, apart from each other in a water flow direction among sensors installed in an oblique tunnel pit; measuring a water level with the sensors at the upstream side and the downstream side; and estimating that a stagnant water area is created between the two places where the upstream sensor and the downstream sensor are installed where a time difference between when the upstream sensor measured the water level which has reached a first threshold value and when the downstream sensor measured the water level which has reached a second threshold value is a specific minimum value or more and a specific maximum value or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method and system for estimating a waterlogging area in a tunnel pit.

Background Art

[0002] Conventionally, water flows into a tunnel pit, which is a structure, depending on the situation. By guiding the inflowing water through a pipeline and draining it, the environment inside the tunnel pit can be appropriately maintained.

[0003] However, if the pipeline used for drainage inside the tunnel pit is blocked for some reason, water temporarily stagnates, and so-called waterlogging occurs. And if the area where water has stagnated, that is, the waterlogging area, is large, the tunnel pit will be flooded. If a person is in the tunnel pit when it is flooded, safety problems will occur.

[0004] In structures such as roads, technologies for detecting the occurrence of waterlogging and flooding have already been proposed (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the conventional technology estimates the flooded area of a road using a waterlogging sensor installed on a sidewalk and three-dimensional information of the road, or measures the waterlogging level around a vehicle using a radio wave sensor installed on a vehicle such as an automobile, and cannot be used for estimating or measuring the waterlogging area in a tunnel pit.

[0007] Here, an object is to provide a method and a system for estimating a water stagnation area in a tunnel excavation face that can solve the problems of the conventional technology, has a low cost and a simple configuration, and can accurately estimate the water stagnation area and the amount of stagnant water in the tunnel excavation face.

Means for Solving the Problem

[0008] Therefore, in the method for estimating the water stagnation area in the tunnel excavation face, a step of selecting an upstream sensor and a downstream sensor, which are respectively installed at two positions on the upstream side and the downstream side that are separated from each other with respect to the water flow direction, from among the sensors installed in the inclined excavation face of the tunnel; a step of measuring the water level by the upstream sensor and the downstream sensor; when it is measured that the water level has reached a first threshold value by the upstream sensor, and when it is measured that the water level has reached a second threshold value by the downstream sensor, if the time difference between them is equal to or greater than a predetermined minimum value and equal to or less than a predetermined maximum value, a step of estimating that a water stagnation area has occurred between the two positions where the upstream sensor and the downstream sensor are installed, are included.

[0009] In another method for estimating the water stagnation area in the tunnel excavation face, further, a step of estimating the amount of stagnant water between the two positions where the upstream sensor and the downstream sensor are installed, by multiplying the sum of the height difference between the two positions where the upstream sensor and the downstream sensor are installed and the water depth measured by the upstream sensor, by the area obtained by projecting the cross-section of the excavation face at the position where the downstream sensor is installed onto a horizontal plane, is included.

[0010] In still another method for estimating the water stagnation area in the tunnel excavation face, further, a step of estimating the inflow amount of water flowing into the two positions where the upstream sensor and the downstream sensor are installed, based on the water flow rate measured by the upstream sensor, is included.

[0011] In still another method for estimating the water stagnation area in the tunnel excavation face, further, the predetermined minimum value and the predetermined maximum value of the time difference are set in advance for each position where the upstream sensor and the downstream sensor are installed.

[0012] In still another method for estimating the stagnant water area in a tunnel pit, further, the sensor is a water gusher that can directly measure the water level and the flow velocity at the water surface to obtain the flow rate.

[0013] In still another method for estimating the stagnant water area in a tunnel pit, further, the sensor can directly measure the water levels and the flow velocities at the water surfaces of the open water channel and the closed water channel to obtain the flow rate, and the water level in the state where the sensor is submerged can be set as a threshold value.

[0014] In a system for estimating the stagnant water area in a tunnel pit, a sensor installed in the sloping tunnel pit, including at least an upstream sensor and a downstream sensor respectively installed at two locations on the upstream side and the downstream side spaced apart from each other with respect to the direction of water flow, a measuring unit that measures the water level by the upstream sensor and the downstream sensor, and when it is measured that the water level has reached a first threshold value by the upstream sensor and when it is measured that the water level has reached a second threshold value by the downstream sensor, a first estimating unit that estimates that a stagnant water area has occurred between the two locations where the upstream sensor and the downstream sensor are installed if the time difference is equal to or greater than a predetermined minimum value and equal to or less than a predetermined maximum value.

[0015] In another system for estimating the stagnant water area in a tunnel pit, further, a second estimating unit that estimates the amount of stagnant water between the two locations where the upstream sensor and the downstream sensor are installed by multiplying the sum of the height difference between the two locations where the upstream sensor and the downstream sensor are installed and the water depth measured by the upstream sensor by the area obtained by projecting the cross-section of the tunnel pit at the location where the downstream sensor is installed onto a horizontal plane.

[0016] In still another system for estimating the stagnant water area in a tunnel pit, further, a third estimating unit that estimates the inflow amount of water flowing into the two locations where the upstream sensor and the downstream sensor are installed based on the water flow rate measured by the upstream sensor.

Advantages of the Invention

[0017] According to the present disclosure, it is possible to accurately estimate the stagnant water area and the amount of stagnant water in the tunnel shaft while having a low-cost and simple configuration.

Brief Description of the Drawings

[0018]

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Embodiments for Carrying Out the Invention

[0019] Hereinafter, the present embodiment will be described in detail with reference to the drawings.

[0020] FIG. 1 is a block diagram showing the functional configuration of a tunnel pit water storage area estimation system in the present embodiment.

[0021] In the figure, reference numeral 50 denotes a tunnel pit water storage area estimation system in the present embodiment, which is a kind of computer system used to accurately estimate the water storage area and the amount of water stored in the tunnel pit.

[0022] In the example shown in the figure, the tunnel pit water storage area estimation system 50 includes a water gusher 51, an arithmetic unit 52, a communication device 53, and a receiving device 54.

[0023] The water gusher 51, also referred to as a flow meter, is a sensor that directly measures the water level and the flow velocity at the water surface to obtain the water flow rate. Further, it is desirable that the water gusher 51 has a mechanism that outputs a change in the observation data after being submerged compared to the observation data immediately before being submerged when it itself is submerged.

[0024] The arithmetic unit 52 is a kind of computer including arithmetic elements such as a CPU and an MPU, storage devices such as a magnetic disk and a semiconductor memory, input devices such as a keyboard, a mouse, and a touch panel, display devices such as a CRT and a liquid crystal display, a communication interface, etc. The computer may be, for example, a personal computer, a workstation, a server, a tablet computer, etc., but any type of computer that operates according to a program such as application software installed in the storage device is acceptable, and it may be a single computer or a group of computers in which a plurality of computers are communicably connected by a network. Then, the arithmetic unit 52 is communicably connected to the spring water meter 51, receives the observation data which is the output signal of the spring water meter 51, and executes data processing of the observation data.

[0025] Furthermore, the communication device 53 is a kind of communication modem connected to the arithmetic unit 52, converts the output signal of the arithmetic unit 52 into a communication signal composed of an electrical signal or an optical signal according to various communication protocols, and transmits it to a receiving device 54 connected to the communication network via a communication network composed of a wired or wireless public line or a dedicated line. Note that the communication device 53 may be integrated with the arithmetic unit 52 or may be a separate device from the arithmetic unit 52.

[0026] Furthermore, the receiving device 54 is a kind of computer equipped with arithmetic elements such as a CPU and an MPU, storage devices such as a magnetic disk and a semiconductor memory, input devices such as a keyboard, a mouse, and a touch panel, display devices such as a CRT and a liquid crystal display, a communication interface, and the like. This computer can be, for example, a personal computer, a workstation, a server, a tablet computer, etc., but any type of computer that operates according to a program such as application software installed in the storage device is acceptable, and it can be a single computer or a group of computers in which multiple computers are communicably connected via a network. Then, the receiving device 54 executes data processing based on the communication signal received from the communication device 53 via the communication network, and outputs the water stagnation area and the amount of stagnant water in the tunnel pit as processing results.

[0027] In the present embodiment, it is assumed that there are a plurality of water gush meters 51 as sensors, which are installed at a plurality of locations in the tunnel pit. Among the sensors installed in the inclined pit of the tunnel 10 described later, the upstream sensor and the downstream sensor installed at two locations on the upstream side and the downstream side that are separated from each other in the direction of water flow are selected. Also, the arithmetic device 52 and the communication device 53 may be single or plural, but it is desirable that they be arranged in a place not too far from the water gush meter 51. Furthermore, the receiving device 54 may be plural, but is usually single, and it is desirable that it be arranged at a monitoring center, an administrative office, etc. that monitors the state of the tunnel 10.

[0028] Note that in the tunnel pit water stagnation area estimation system 50, one or two or more water gush meters 51 are connected to one arithmetic device 52, one or two or more arithmetic devices 52 are connected to one communication device 53, and one or two or more communication devices 53 are connected to one receiving device 54.

[0029] From a functional perspective, the tunnel in-pit water stagnation area estimation system 50 in this embodiment is a sensor installed in the inclined in-pit of the tunnel 10, and includes at least a sensor including an upstream sensor and a downstream sensor installed at two locations on the upstream side and the downstream side that are separated from each other with respect to the direction of water flow, a measurement unit that measures the water level by the upstream sensor and the downstream sensor, and when it is measured that the water level has reached a first threshold value by the upstream sensor, and when it is measured that the water level has reached a second threshold value by the downstream sensor, if the time difference between them is equal to or greater than a predetermined minimum value and equal to or less than a predetermined maximum value, it is desirable that it includes a first estimation unit that estimates that a water stagnation area has occurred between the two locations where the upstream sensor and the downstream sensor are installed.

[0030] The tunnel in-pit water stagnation area estimation system 50 may further include a second estimation unit that estimates the amount of stagnant water between the two locations where the upstream sensor and the downstream sensor are installed by multiplying the sum of the height difference between the two locations where the upstream sensor and the downstream sensor are installed and the water depth measured by the upstream sensor by the area of the cross-section of the in-pit at the location where the downstream sensor is installed projected onto a horizontal plane.

[0031] Furthermore, the tunnel in-pit water stagnation area estimation system 50 may further include a third estimation unit that estimates the inflow amount of water flowing into the area between the two locations where the upstream sensor and the downstream sensor are installed based on the water flow rate measured by the upstream sensor.

[0032] Next, the installation state of the water gushing meter 51 in the tunnel in-pit will be described.

[0033] FIG. 2 is a schematic cross-sectional view of a tunnel pit in the present embodiment, FIG. 3 is a schematic longitudinal-sectional view of the tunnel pit in the present embodiment, FIG. 4 is a schematic cross-sectional view of the tunnel pit under normal conditions in the present embodiment, FIG. 5 is a first schematic cross-sectional view when water stagnation occurs due to an obstacle in the tunnel pit in the present embodiment, and FIG. 6 is a second schematic cross-sectional view when water stagnation occurs due to an obstacle in the tunnel pit in the present embodiment. In FIGS. 4 to 6, (a) is a schematic longitudinal-sectional view, and (b) is a schematic cross-sectional view at the location where the water gushing meter is installed.

[0034] In the figures, reference numeral 10 denotes a tunnel as a structure in the present embodiment, which may be a railway tunnel, a road tunnel, or a tunnel of any type and structure. For the sake of explanation here, the case where the tunnel 10 is the Seikan Tunnel that connects Honshu and Hokkaido and is a railway undersea tunnel will be described.

[0035] As described in the section of "Background Art", when abnormal water gushing occurs for some reason in the tunnel pit and furthermore, a situation where drainage is difficult due to an obstacle occurs, a water stagnation area is generated. In the case of the Seikan Tunnel, since water gushes down from the main pit during work due to its structure, there may be safety problems during passenger guidance.

[0036] In the figures, reference numeral 14 denotes water, reference numeral 14a denotes the water surface, reference numeral 15 denotes an obstacle generated for some reason, which obstructs the flow of water 14. Also, reference numeral 11 denotes the main pit of the tunnel 10, reference numeral 12 denotes the work pit of the tunnel 10, and reference numeral 13 denotes a cross-passage connecting the main pit 11 and the work pit 12.

[0037] In this embodiment, as shown in FIGS. 4 to 6, the water level of the water 14 flowing directly below two water gages 51 installed at two adjacent locations in the tunnel 10 and the flow velocity of the water surface 14a are directly measured to obtain the flow rate. The two water gages 51 are respectively installed at two locations on the upstream side and the downstream side spaced apart from each other with respect to the flow direction of the water 14 in the inclined tunnel 10. The stagnant water refers to the water 14 staying at a certain location in the tunnel 10. The stagnant water does not necessarily occur at the lowest location, but is caused by an obstacle 15 generated for some reason, so it is necessary to consider the possibility of occurring at any location.

[0038] As shown in FIG. 3, a plurality of (three in the example shown in FIG. 3) pumping pumps for draining the water 14 such as the groundwater gushing in are provided in the tunnel 10. Further, water gages 51 are respectively installed at a plurality of locations (locations indicated by M1 to M16, TP1 to 3, TS1 to 3, YP1 to 3, and YS1 to 3 in the example shown in FIG. 3) in the tunnel 10.

[0039] As described above, the water gage 51 is also called a flow meter, and is a sensor that directly measures the water level and the flow velocity at the water surface 14a to obtain the flow rate of the water 14. As the water gage 51, a commercially available general one can be used. For example, a planar antenna radio level meter MRF-10, a radio level meter KRG-10, a radio level meter LRG-10, a throw-in type water level meter PL-200, etc. manufactured by Tokyo Keiki Co., Ltd. can be used.

[0040] Next, the operation of the stagnant water area determination process for determining the stagnant water area in the tunnel pit by the tunnel pit stagnant water area estimation system 50 in this embodiment will be described.

[0041] FIG. 7 is a flowchart showing the operation of the stagnant water area determination process in this embodiment.

[0042] As shown in the figure, the stagnant water area determination process includes the operations of steps S1 to S3. In the tunnel pit stagnant water area estimation system 50 in the present embodiment, each operation of steps S1 to S3 and the overall operation of the stagnant water area determination process may be performed independently by the arithmetic unit 52 or the communication device 53, or may be performed by two or more of the water gushing meter 51, the arithmetic unit 52, the communication device 53, and the receiving device 54 cooperating with each other.

[0043] After starting the stagnant water area determination process, first, in step S1, the tunnel pit stagnant water area estimation system 50 determines whether a stagnant water area has occurred, that is, performs a stagnant water area occurrence determination. And when it is estimated that no stagnant water area has occurred, that is, when there is no determination of the occurrence of a stagnant water area, the stagnant water area determination process is terminated. On the other hand, when it is estimated that a stagnant water area has occurred, that is, when there is a determination of the occurrence of a stagnant water area, the process proceeds to step S2.

[0044] And in step S2, the tunnel pit stagnant water area estimation system 50 estimates the stagnant water area.

[0045] Subsequently, in step S3, the tunnel pit stagnant water area estimation system 50 estimates the amount of stagnant water and the amount of inflow water in the stagnant water occurrence section. And the tunnel pit stagnant water area estimation system 50 stores the estimation result of the stagnant water area and the estimation result of the amount of stagnant water in the stagnant water occurrence section in the storage device provided in the arithmetic unit 52 or the receiving device 54, and terminates the stagnant water area determination process.

[0046] Next, the flowchart will be described. Step S1 The tunnel pit stagnant water area estimation system 50 performs a stagnant water area occurrence determination. If there is a determination of the occurrence of a stagnant water area, the process proceeds to step S2. If there is no determination of the occurrence of a stagnant water area, the process is terminated. Step S2 The tunnel pit stagnant water area estimation system 50 estimates the stagnant water area. Step S3 The tunnel pit stagnant water area estimation system 50 estimates the amount of stagnant water and the amount of inflow water in the stagnant water occurrence section and terminates the process.

[0047] Next, the operation of determining the occurrence of a water stagnation area in step S1 will be described.

[0048] FIG. 8 is a cross-sectional view of a water channel for explaining the alarm threshold of the water gusher in the present embodiment, FIG. 9 is a table showing an example of determining the occurrence of a water stagnation area in the present embodiment, FIG. 10 is a table showing an example of the time difference for determining the occurrence of a water stagnation area in the present embodiment, and FIG. 11 is a flowchart showing the operation of a subroutine for determining the occurrence of a water stagnation area in the present embodiment. In FIGS. 8 and 9, (a) shows the case where the water channel is an open water channel, and (b) shows the case where the water channel is a closed water channel.

[0049] Here, as shown in FIG. 8, the thresholds at which the water gusher 51 outputs an alarm are an 80[%] alarm corresponding to the water level reaching 80[%] of the upper end of the water channel, a 90[%] alarm corresponding to the water level reaching 90[%] of the upper end of the water channel, a 100[%] alarm corresponding to the water level reaching the upper end of the water channel, an action limit water depth corresponding to the water level reaching 30 [cm] above the floor surface, a trigger corresponding to the water level reaching the lower surface of the water gusher 51 soon, that is, the state where the sensor is submerged, and a sensor submergence corresponding to the water level reaching the lower surface of the water gusher 51, that is, the state where the sensor is submerged. Six types are set.

[0050] The action limit water depth is the water depth at which walking becomes difficult when the water depth (water level) from the floor surface reaches 30 [cm] during flooding of the underground space. The water depth of 30 [cm] is defined in "Ministry of Land, Infrastructure, Transport and Tourism, Explanation of the Guidelines for Flood Control Measures in Underground Spaces <Technical Data> 1.5.1 Limiting Conditions when Evacuating Flooded Corridors, Rooms, etc., Page G-11".

[0051] When the water gusher 51 is used alone, only the water levels corresponding to the 80[%] alarm and the 90[%] alarm are used as the thresholds for outputting an alarm. That is, in the water gusher alone process where the water gusher 51 is used alone, an alarm is output when the water level reaches the threshold of the 80[%] alarm or the 90[%] alarm.

[0052] In the standing water area generation determination process in this embodiment, as shown in FIGS. 4 to 6, based on the outputs of two water gages 51 installed at two locations in the tunnel 10 of the tunnel, the generation of a standing water area is determined. Here, the water gage 51 installed on the upstream side in the tunnel (the left side in FIGS. 4(a), 5(a), and 6(a)) is referred to as the upstream sensor, and the water gage 51 installed on the downstream side in the tunnel (the right side in FIGS. 4(a), 5(a), and 6(a)) is referred to as the downstream sensor for explanation.

[0053] When the water channel of the tunnel in-pit standing water area estimation system 50 is an open water channel, for example, as shown in the table of FIG. 9(a), when the water level at the upstream sensor reaches the action limit water depth, trigger, and sensor immersion threshold values, and the water level at the downstream sensor reaches the sensor immersion threshold value, it can be determined that the generation of a standing water area is estimated.

[0054] In addition, when the water channel of the tunnel in-pit standing water area estimation system 50 is a closed water channel, for example, as shown in the table of FIG. 9(b), when the water level at the upstream sensor reaches the trigger and sensor immersion threshold values, and the water level at the downstream sensor reaches the sensor immersion threshold value, it can be determined that the generation of a standing water area is estimated.

[0055] In the table shown in FIG. 9, the difference between the case where the water channel is an open water channel and the case where it is a closed water channel is only that the action limit water depth is not included in the alarm level (threshold value) of the upstream sensor in the case of a closed water channel.

[0056] Regarding the combination of the alarm levels of the upstream sensor and the downstream sensor for determining that the occurrence of a stagnant water area is estimated, if necessary, the example settings shown in the tables of FIGS. 9(a) and (b) can be changed. For example, in the example shown in the table of FIG. 9(a), it is determined that the occurrence of a stagnant water area is estimated when the water level in the upstream sensor is equal to or higher than the action limit water depth and the water level in the downstream sensor reaches the threshold of sensor submersion. However, this can be changed to determine that the occurrence of a stagnant water area is estimated when the water level in the downstream sensor is equal to or higher than the water level corresponding to the 80 [%] alarm. However, if it is changed in this way, although the occurrence of a stagnant water area can be estimated earlier, the possibility of false alarms also increases. Therefore, the alarm levels of the upstream sensor and the downstream sensor for determining that the occurrence of a stagnant water area is estimated need to be set appropriately.

[0057] Furthermore, the tunnel in-pit stagnant water area estimation system 50 determines whether the occurrence of a stagnant water area is estimated based on the time difference, that is, performs the determination of the occurrence of a stagnant water area based on the time difference.

[0058] When it is determined that the occurrence of a stagnant water area is estimated based on the outputs of the two water gages 51 installed at two locations in the tunnel 10 of the tunnel, that is, when performing the stagnant water area determination by two sensors, it is necessary to determine the event based on the time when the threshold of each sensor is exceeded. In order to obtain the time difference between the time when it is detected that the water level has reached a predetermined threshold in one sensor (upstream sensor) and the time when it is detected that the water level has reached a predetermined threshold in the other sensor (downstream sensor), it is necessary to set the distance between the sensors and the maximum or minimum value of the inflowing water volume.

[0059] Here, the case where the tunnel 10 is the Seikan Tunnel will be described. The maximum inflow water volume (Q1) and the minimum inflow water volume (Q2) shall be as follows. Maximum inflow water volume (Q1): Approximately 85 [t / min] (the flow rate at the time of the water gushing accident during the construction of the Seikan Tunnel.) Minimum inflow rate (Q2): Obtained from the normal flow rate (for example, use the average value of the measured water inflow of the Seikan Tunnel in 2020).

[0060] Based on this, the time difference between each sensor (water inflow meter 51) in the Seikan Tunnel summarized is shown in Fig. 10.

[0061] For example, when the downstream sensor determines that the water level has reached the threshold of sensor submersion as OT1, and the upstream sensor determines that the water level has reached a predetermined threshold (action limit water depth) as OT2. Then, as shown in the following formula (1), when the time difference OT1 - OT2 is within a certain range, it is determined that the generation of the stagnant water area is estimated, that is, it is determined that there is a determination of the occurrence of the stagnant water area. Otherwise, it is a false alarm, that is, it is determined as a sensor failure.

[0062] t1 ≦ OT1 - OT2 ≦ t2 ··· Formula (1)

[0063] Here, t1 and t2 are the times when the tunnel 10 between the upstream sensor and the downstream sensor is full of water when the inflow rate is the maximum inflow rate and the minimum inflow rate, that is, the maximum time and the minimum time. Therefore, assuming the tunnel internal cavity volume between the two sensors, that is, between the upstream sensor and the downstream sensor is V, then t1 = V / Q1, t2 = V / Q2.

[0064] Then, after starting the stagnant water area generation determination process, the tunnel pit stagnant water area estimation system 50 first performs the water inflow meter single processing in step S1-1. And when the water level reaches the threshold of the 80 [%] alarm or 90 [%] alarm and an alarm is output at the upstream sensor or the downstream sensor, that is, when there is an alarm output, since there is a high possibility that the stagnant water area has occurred, it proceeds to step S1-2. When the water level does not reach the threshold of the 80 [%] alarm or 90 [%] alarm and no alarm is output, that is, when there is no alarm output, since there is a low possibility that the stagnant water area has occurred, the stagnant water area generation determination process is terminated.

[0065] Subsequently, in step S1-2, the tunnel pit water stagnation area estimation system 50 determines the upstream action limit water depth, and at the upstream sensor, determines whether the water level has reached the threshold corresponding to the action limit water depth. If it is determined that the water level has reached the threshold corresponding to the action limit water depth, that is, if there is a determination, the process proceeds to step S1-3. If it is determined that the water level has not reached the threshold corresponding to the action limit water depth, that is, if there is no determination, the water stagnation area generation determination process ends.

[0066] Subsequently, in step S1-3, the tunnel pit water stagnation area estimation system 50 determines whether the downstream sensor is submerged, and at the downstream sensor, determines whether the water level has reached the threshold corresponding to sensor submersion. If it is determined that the water level has reached the threshold corresponding to sensor submersion, that is, if there is a determination, the process proceeds to step S1-4. If it is determined that the water level has not reached the threshold corresponding to sensor submersion, that is, if there is no determination, the water stagnation area generation determination process ends.

[0067] Subsequently, in step S1-4, the tunnel pit water stagnation area estimation system 50 determines the generation of a water stagnation area based on the time difference. When the time difference between the time when the water level is detected to have reached a predetermined threshold (the first threshold) at the upstream sensor and the time when the water level is detected to have reached a predetermined threshold (the second threshold) at the downstream sensor is within the range of not more than the maximum time and not less than the minimum time, it is determined that the generation of a water stagnation area is estimated, and the process proceeds to step S1-5. If the time difference is not within the range of not more than the maximum time and not less than the minimum time, it is determined that a sensor failure is estimated, and the process proceeds to step S1-6.

[0068] Then, in step S1-5, the tunnel pit water stagnation area estimation system 50 determines the generation of a water stagnation area and ends the water stagnation area generation determination process. Also, in step S1-6, the tunnel pit water stagnation area estimation system 50 determines a sensor failure and ends the water stagnation area generation determination process.

[0069] Next, the flowchart will be described. Step S1-1: The tunnel pit water accumulation area estimation system 50 performs single treatment of the water gushing meter. If there is an alarm output, it proceeds to step S1-2; if there is no alarm output, the process ends. Step S1-2: The tunnel pit water accumulation area estimation system 50 determines the upstream action limit water depth. If there is a determination, it proceeds to step S1-3; if there is no determination, the process ends. Step S1-3: The tunnel pit water accumulation area estimation system 50 determines the downstream sensor submersion. If there is a determination, it proceeds to step S1-4; if there is no determination, the process ends. Step S1-4: The tunnel pit water accumulation area estimation system 50 determines the occurrence of the water accumulation area based on the time difference. If the time difference is within the range, it is determined that the occurrence of the water accumulation area is estimated and proceeds to step S1-5; if the time difference is not within the range, it is determined that a sensor failure is estimated and proceeds to step S1-6. Step S1-5: The tunnel pit water accumulation area estimation system 50 determines the occurrence of the water accumulation area and ends the process. Step S1-6: The tunnel pit water accumulation area estimation system 50 determines the sensor failure and ends the process.

[0070] Next, the operation of estimating the water accumulation area in step S2 will be described.

[0071] FIG. 12 is a schematic longitudinal sectional view of the inside of the tunnel pit in a state where only the downstream sensor is submerged in the present embodiment, FIG. 13 is a schematic longitudinal sectional view of the inside of the tunnel pit in a state where the downstream sensor is submerged and the upstream sensor outputs an alarm in the present embodiment, and FIG. 14 is a schematic longitudinal sectional view of the inside of the gently sloping tunnel pit in the present embodiment. In FIGS. 12 to 14, (a) shows the case where the waterway is an open waterway, and (b) shows the case where the waterway is a closed waterway.

[0072] Here, as shown in FIGS. 12 to 14, the operation of estimating the stagnant water area based on the outputs of two adjacent water gush meters 51 installed at two locations spaced apart from each other with respect to the flow direction of the water 14 in the tunnel 10 will be described. Note that the water gush meter 51 installed on the upstream side (the right side in FIGS. 12 to 14) in the tunnel is referred to as the upstream sensor, and the water gush meter 51 installed on the downstream side (the left side in FIGS. 12 to 14) in the tunnel is referred to as the downstream sensor. Then, when the water level at the downstream sensor is equal to or higher than the threshold of sensor submersion, the operation of estimating that a stagnant water area has occurred based on the alarm level (threshold) of the upstream sensor will be specifically described.

[0073] Note that, as shown in FIGS. 12(b), 13(b), and 14(b), when the water channel is a closed water channel, it is considered that there is an inspection opening at the upper part between the upstream sensor and the downstream sensor. When the downstream sensor is submerged, the water gush will be discharged to the outside of the closed water channel through the opening. Here, the amount of water discharged to the outside of the closed water channel is not considered.

[0074] FIG. 12 shows a state where only the downstream sensor is submerged and the water level at the upstream sensor has not reached the alarm level (threshold), that is, the upstream sensor has not reached any threshold for outputting an alarm. Thus, even when the downstream sensor is submerged, if the water level at the upstream sensor has not reached the alarm level (threshold), the tunnel in-pit stagnant water area estimation system 50 does not perform the stagnant water area estimation.

[0075] FIG. 13 shows a state where the downstream sensor is submerged and the water level at the upstream sensor has reached the alarm level (threshold), that is, the upstream sensor has reached any of the thresholds for outputting an alarm. Thus, when the downstream sensor is submerged and the water level at the upstream sensor has reached some alarm level (threshold), the tunnel in-pit stagnant water area estimation system 50 estimates that a stagnant water area has occurred.

[0076] FIG. 14 shows a state where the slope of the water channel is gentle, that is, the bottom surface of the water channel is a gentle slope. In this way, in a water channel with a gentle slope, when the downstream sensor is submerged and the water level at the upstream sensor reaches a certain alarm level (threshold value), the tunnel pit waterlogging area estimation system 50 estimates that a waterlogging area has occurred.

[0077] Next, the operation of estimating the water volume and inflow volume in the waterlogging occurrence section in step S3 will be described.

[0078] FIG. 15 is a diagram for explaining how to obtain the water volume in an open water channel in this embodiment, FIG. 16 is a diagram for explaining how to obtain the bottom area of the open water channel in this embodiment, and FIG. 17 is a diagram for explaining how to obtain the water volume in a closed water channel in this embodiment. In FIG. 16, (a) is a longitudinal sectional view of the water channel, (b) is a sectional view showing section B of (a), and (c) is a sectional view showing section A of (a).

[0079] In this embodiment, the estimation of the water volume in the waterlogging occurrence section is performed based on the observation data output by two water gages 51, an upstream water gage and a downstream water gage, which are respectively installed at two locations spaced apart from each other with respect to the flow direction of the water 14 in the pit of the tunnel 10. Note that the amount of water flowing in from the upstream in the pit of the tunnel 10, that is, the estimated value of the inflow volume in the waterlogging occurrence section, is assumed to be the flow rate of the water 14 measured by the water gage 51 as the upstream sensor.

[0080] Next, a method for obtaining the estimated value of the water volume in the waterlogging occurrence section in an open water channel will be described. Specifically, the water volume in the section between section TS1 and section TS2 shown in FIG. 15 is obtained.

[0081] Let the area of the figure obtained by projecting the cross section of section TS2 onto a horizontal plane be A TS2 Then, the water volume Q TS2TS1 is obtained by multiplying the bottom area on the downstream side by the height between the two points where the two water gages 51 are installed. In the example shown in FIG. 15, the water volume Q TS2TS1 is the bottom area A TS2 on the downstream side and the height difference h TS1TS2and the depth d observed by the spring water meter 51 as the upstream sensor TS1 is obtained from the following formula (2).

[0082] Q TS2TS1 = A TS2 · (h TS1TS2 + d TS1 ) ··· Formula (2)

[0083] Note that in Q TS2TS1 , TS2 refers to the downstream side and TS1 refers to the upstream side.

[0084] Also, the lengths H1 and H2 shown in FIG. 16 are obtained from the following formulas (3) and (4).

[0085] H1 = h1 / sin α ··· Formula (3)

[0086] H2 = h2 / sin α ··· Formula (4)

[0087] And, assuming the area of cross-section B is A TS2 , then A TS2 is obtained from the following formula (5).

[0088] A TS2 = {2rH1π / 2} + {(2r + t d )H2 / 2} ··· Formula (5)

[0089] Also, d TS2 is the depth observed at cross-section TS2.

[0090] Next, the method for obtaining the estimated value of the water storage volume in the water storage generation section in the closed waterway will be described. Specifically, the water storage volume in the section between cross-section M1 and cross-section M2 shown in FIG. 17 is obtained. Note that the amount of water flowing into the closed waterway from upstream, that is, the estimated value of the inflow volume in the water storage generation section, is assumed to be the water flow rate obtained by the spring water meter 51 as the upstream sensor. Specifically, the cross-sectional area is obtained, and the estimated value of the inflow volume is obtained based on the time when the water level exceeds a predetermined threshold value of the upstream sensor.

[0091] Let the graphic area obtained by projecting the cross - section of cross - section M2 onto a horizontal plane be A M2 Then, the water - storage volume Q M2M1 is obtained by multiplying the bottom - area on the downstream side by the height between two points where the two piezometers 51 are installed. In the example shown in Fig. 17, the water - storage volume Q M2M1 is based on the bottom - area A M2 on the downstream side, the height difference h M1M2 between the two points where the two piezometers 51 are installed, and the depth d M1 observed by the piezometer 51 as the upstream - side sensor, and is obtained by the following formula (6).

[0092] Q M2M1 =A M2 ·(h M1M2 +d M1 ) ··· Formula (6)

[0093] Note that d M1 is the depth observed at cross - section M1.

[0094] Next, the case where the water - storage regions occur continuously will be described.

[0095] Fig. 18 is a schematic longitudinal cross - sectional view of the inside of the tunnel pit when there is an obstacle between two adjacent sensors on the downstream side in the present embodiment, and Fig. 19 is a schematic longitudinal cross - sectional view of the inside of the tunnel pit when there is no obstacle between two adjacent sensors on the downstream side in the present embodiment. In Fig. 18, (a) shows the case where the most downstream - side sensor is not submerged, and (b) shows the case where the most downstream - side sensor is submerged.

[0096] Here, as shown in Figs. 18 and 19, in the range where piezometers 51 as sensors are installed at three positions A, B, and C spaced apart from each other in the longitudinal direction inside the pit of the tunnel 10, when a water - storage region occurs in the section between two adjacent sensors, it is assumed that the water - storage regions occur continuously.

[0097] Figure 18 shows a case where there is an obstacle 15 that has occurred for some reason at each of the most downstream sensor, that is, the downstream side of the spring water meter 51 at location A, and two adjacent sensors on the downstream side, that is, between the spring water meters 51 at locations A and B.

[0098] Here, as shown in Fig. 18(a), when the spring water meter 51 at location A is not submerged and the spring water meter 51 at location B is submerged, it is determined that a stagnant water area has occurred only in the section between the spring water meters 51 at locations B and C, and it is not determined that the stagnant water areas have occurred continuously.

[0099] On the other hand, as shown in Fig. 18(b), when both the spring water meter 51 at location A and the spring water meter 51 at location B are submerged, it is determined that a stagnant water area has occurred in the section between the spring water meters 51 at locations A and C, and it is determined that the stagnant water areas have occurred continuously.

[0100] Figure 19 shows a case where there is an obstacle 15 that has occurred for some reason only on the downstream side of the most downstream sensor, that is, the spring water meter 51 at location A, and there is no obstacle 15 between the two adjacent sensors on the downstream side, that is, between the spring water meters 51 at locations A and B.

[0101] In this case, since both the spring water meter 51 at location A and the spring water meter 51 at location B are submerged, it is determined that a stagnant water area has occurred in the section between the spring water meters 51 at locations A and C, and it is determined that a combined stagnant water area has occurred.

[0102] Thus, in this embodiment, the method for estimating the stagnant water area in the tunnel shaft includes a step of selecting an upstream sensor and a downstream sensor, which are respectively installed at two locations on the upstream side and the downstream side that are spaced apart from each other with respect to the flow direction of the water 14, from among the sensors installed in the inclined shaft of the tunnel 10; a step of measuring the water level by the upstream sensor and the downstream sensor; a step of estimating that a stagnant water area has occurred between the two locations where the upstream sensor and the downstream sensor are installed when the time difference between when it is measured by the upstream sensor that the water level has reached the first threshold value and when it is measured by the downstream sensor that the water level has reached the second threshold value is equal to or greater than a predetermined minimum value and equal to or less than a predetermined maximum value. Thereby, it is possible to accurately estimate the stagnant water area in the shaft of the tunnel 10 while having a low cost and a simple configuration.

[0103] Further, the method for estimating the stagnant water area in the tunnel shaft may further include a step of estimating the amount of stagnant water between the two locations where the upstream sensor and the downstream sensor are installed by multiplying the sum of the height difference between the two locations where the upstream sensor and the downstream sensor are installed and the depth of the water 14 measured by the upstream sensor by the area of the cross-section of the shaft at the location where the downstream sensor is installed projected onto a horizontal plane. Thereby, it is possible to accurately estimate the amount of stagnant water in the shaft of the tunnel 10.

[0104] Furthermore, the method for estimating the stagnant water area in the tunnel shaft may further include a step of estimating the inflow amount of the water 14 flowing into the area between the two locations where the upstream sensor and the downstream sensor are installed based on the flow rate of the water 14 measured by the upstream sensor. Thereby, it is possible to accurately estimate the inflow amount of the water 14 flowing into the stagnant water area in the shaft of the tunnel 10.

[0105] Furthermore, the predetermined minimum value and the predetermined maximum value of the time difference are set in advance for each location where the upstream sensor and the downstream sensor are installed. Further, the sensor is a spring water gauge 51 that can directly measure the water level and the flow velocity at the water surface 14a to obtain the flow rate. Further, the sensor can directly measure the water level and the flow velocity at the water surface 14a in the open water channel and the closed water channel to obtain the flow rate, and can set the water level in the state where the sensor is submerged as a threshold value.

[0106] Also, the tunnel pit water stagnation area estimation system 50 is a sensor installed in the inclined pit of the tunnel 10, and includes at least an upstream sensor and a downstream sensor installed at two locations spaced apart from each other with respect to the flow direction of the water 14, a measurement unit that measures the water level by the upstream sensor and the downstream sensor, and when it is measured that the water level has reached the first threshold value by the upstream sensor and when it is measured that the water level has reached the second threshold value by the downstream sensor, a first estimation unit that estimates that a water stagnation area has occurred between the two locations where the upstream sensor and the downstream sensor are installed when the time difference is equal to or greater than the predetermined minimum value and equal to or less than the predetermined maximum value. Thereby, it is possible to accurately estimate the water stagnation area in the pit of the tunnel 10 while having a low-cost and simple configuration.

[0107] Furthermore, the tunnel pit water stagnation area estimation system 50 may further include a second estimation unit that estimates the amount of water stagnation between the two locations where the upstream sensor and the downstream sensor are installed by multiplying the sum of the height difference between the two locations where the upstream sensor and the downstream sensor are installed and the depth of the water 14 measured by the upstream sensor by the area obtained by projecting the cross-section of the pit at the location where the downstream sensor is installed onto a horizontal plane. Thereby, it is possible to accurately estimate the amount of water stagnation in the pit of the tunnel 10.

[0108] Furthermore, the tunnel in-pit stagnant water area estimation system 50 may further include a third estimation unit that estimates the inflow rate of water 14 flowing into the area between the two locations where the upstream sensor and the downstream sensor are installed, based on the flow rate of water 14 measured by the upstream sensor. Thereby, the inflow rate of water 14 flowing into the stagnant water area in the tunnel 10 can be accurately estimated.

[0109] Note that the disclosure of this specification describes the features of a preferred and exemplary embodiment. Various other embodiments, modifications, and variations within the scope and spirit of the appended claims will be naturally conceivable by those skilled in the art upon reviewing the disclosure of this specification.

Industrial Applicability

[0110] This disclosure can be applied to a method and system for estimating a stagnant water area in a tunnel pit.

Explanation of Reference Numerals

[0111] 10 Tunnel 14 Water 14a Water surface 50 Tunnel in-pit stagnant water area estimation system 51 Water gusher

Claims

1. A step of selecting an upstream sensor and a downstream sensor, which are respectively installed at two locations on the upstream side and the downstream side that are spaced apart from each other with respect to the direction of water flow, from among the sensors installed in the inclined tunnel; A step of measuring the water level by the upstream sensor and the downstream sensor; When it is measured by the upstream sensor that the water level has reached a first threshold value and when it is measured by the downstream sensor that the water level has reached a second threshold value, if the time difference between them is equal to or greater than a predetermined minimum value and equal to or less than a predetermined maximum value, a step of estimating that a water stagnation region has occurred between the two locations where the upstream sensor and the downstream sensor are installed; A method for estimating a water stagnation region in a tunnel shaft, including the above steps.

2. A step of multiplying the sum of the height difference between the two locations where the upstream sensor and the downstream sensor are installed and the water depth measured by the upstream sensor by the area obtained by projecting the cross-section of the tunnel shaft at the location where the downstream sensor is installed onto a horizontal plane, to estimate the amount of stagnant water between the two locations where the upstream sensor and the downstream sensor are installed, the method for estimating a water stagnation region in a tunnel shaft according to claim 1, further including this step.

3. A step of estimating the inflow amount of water flowing into the area between the two locations where the upstream sensor and the downstream sensor are installed, based on the water flow rate measured by the upstream sensor, the method for estimating a water stagnation region in a tunnel shaft according to claim 2, further including this step.

4. The method for estimating a water stagnation region in a tunnel shaft according to claim 1, wherein the predetermined minimum value and the predetermined maximum value of the time difference are set in advance for each location where the upstream sensor and the downstream sensor are installed.

5. The method for estimating a water stagnation region in a tunnel shaft according to any one of claims 1 to 4, wherein the sensor is a spring water meter capable of directly measuring the water level and the flow velocity on the water surface to obtain the flow rate.

6. The method for estimating a water stagnation region in a tunnel shaft according to claim 5, wherein the sensor can directly measure the water level and the flow velocity on the water surface in an open water channel and a closed water channel to obtain the flow rate, and can set the water level in the state where the sensor is submerged as a threshold value.

7. A sensor installed in an inclined tunnel shaft, including at least an upstream sensor and a downstream sensor respectively installed at two locations on the upstream side and the downstream side that are spaced apart from each other with respect to the direction of water flow; A measurement unit that measures the water level by the upstream sensor and the downstream sensor; When it is measured that the water level has reached the first threshold by the upstream sensor and the time difference between when it is measured that the water level has reached the second threshold by the downstream sensor is equal to or greater than a predetermined minimum value and equal to or less than a predetermined maximum value, a first estimation unit that estimates that a water stagnation area has occurred between the two locations where the upstream sensor and the downstream sensor are installed; A tunnel pit water stagnation area estimation system comprising:

8. The cross-sectional area of the tunnel at the location where the downstream sensor is installed projected onto a horizontal plane is multiplied by the sum of the height difference between the two locations where the upstream sensor and the downstream sensor are installed and the water depth measured by the upstream sensor, and the second estimation unit that estimates the amount of stagnant water between the two locations where the upstream sensor and the downstream sensor are installed. The tunnel pit water stagnation area estimation system according to claim 7, further comprising:

9. Based on the water flow rate measured by the upstream sensor, a third estimation unit that estimates the inflow amount of water flowing into the two locations where the upstream sensor and the downstream sensor are installed. The tunnel pit water stagnation area estimation system according to claim 8, further comprising:

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