JP2602818B2 - Inspection method for abnormalities such as cavities and cracks in tunnel structures - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for inspecting a tunnel structure for abnormalities such as cavities and cracks.

[Prior art] In civil engineering structures such as roads and railways, tunnels are excavated in basement rocks avoiding the surface of the earth to avoid destruction due to these disasters in disaster prone areas such as landslides and collapses and in dangerous areas. And tend to build.

However, such a tunnel structure also deteriorated due to secular deformation, and it was inevitable that the tunnel structure would eventually break if left as it is.

The secular change of the tunnel structure is classified into mechanical deformation, physical change, and chemical change in terms of phenomena.

Mechanical deformation causes deformation in the tunnel cross-sectional shape due to the change in the stress field, which causes cracks on the lining surface,
It appears as peeling, crushing, board swelling, joint breakage, discrepancy, etc.

Physical changes include runoff of soil behind the lining, swelling of clay minerals, freezing expansion, and the like, and the progress of these causes mechanical deformation.

Chemical changes include rock changes due to weathering, mineral springs,
Corrosion due to groundwater including hot springs, etc., also causes mechanical deformation.

Therefore, before the destruction due to the deformation that has a decisive effect on the safety of the tunnel structure, cracks in the lining surface, water leaks, or the geological structure around the lining back surface are inspected, and It is necessary to decipher the relationship and to perform appropriate repairs and reinforcements.

Japanese Patent Application Laid-Open No. 61-72169 discloses a method for performing fixed point observation.
JP, JP-B-60-213854, and JP-A-52-125401 have proposed the inventions, but all of these techniques perform observation and detection by defining an observation point. Due to this, if the vehicle travels over long distances such as roads and tunnels with frequent traffic, the observation point must be changed and moved each time, and equipment must be deployed for each observation point setting. However, there are problems such as obstructing traffic and congestion, and there is a significant disadvantage in actual observation and inspection.

As a method of performing observation and inspection while reducing traffic congestion without relatively obstructing traffic, necessary equipment is mounted on the traveling vehicle to achieve the inspection purpose continuously while the vehicle is running, and Technology for continuous observation and inspection is disclosed in
Although proposed as disclosed in Japanese Patent No. 2306, in this disclosed invention, since the object of the invention is limited to detection of cracks on the road surface, the projection direction using laser light Comparison of the relative level of the output of the receiver that receives the laser reflected light from the road surface in a different direction from that of the road, and the position detector that receives the reflected light from the road surface in the same direction as the projection direction Is recorded in correspondence with the change in distance.

Because these methods are intended for road surfaces, they will have the intended effect, but they will be able to understand the depth of the tunnel lining and the depth behind it, as in a tunnel. Not suitable for testing.

In other words, although it can be adapted to measuring the condition of the lining surface, it is not suitable for observing the thickness of the lining and the state behind it as intended by the present invention. Reflection on the tunnel light-covered surface falls down to the worker with almost no attenuation, and the worker is exposed to the laser reflected light, which is extremely dangerous and detects a road crack on a road surface in an open environment. However, this method could not be used at all to detect differences such as cavities and cracks in tunnel structures.

[Problems to be solved by the invention] With the conventional detection method, continuous inspection cannot be performed.
It took too long to detect long structures such as tunnels. For this reason, it has been particularly difficult to detect an automobile tunnel where traffic is continuous.

Accordingly, the present invention provides a direct observation and detection of the mechanical deformation of a tunnel structure, as well as a wide range of physical and chemical changes that cause a mechanical deformation. It is an object of the present invention to provide an inspection method that allows continuous inspection in consideration of safety.

[Means for Solving the Problems] In the inspection method of the present invention, infrared rays, gamma rays, laser light, etc. are emitted from a measuring instrument, and the reflected light is not measured, but the tunnel structure is covered. From itself,
In addition, the infrared and radiation emitted through the lining are observed and recorded while moving by the detection device mounted on the vehicle, and the abnormality of cavities, cracks, etc. is determined based on the observation result or the distribution of the observed values. did.

[Operation] According to such an inspection method of the present invention, a wide range of inspected portions can be inspected continuously while moving in the tunnel, and thus has a decisive effect on the safety of the tunnel structure. Prior to such change / deformation, it is possible to regularly and easily inspect the occurrence of abnormalities such as cracks, water leakage, and cavities.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 and FIG. 2 are diagrams schematically showing a main part of an observation vehicle equipped with a detecting device used in the inspection method of the present invention. FIG. 1 shows a side view, and FIG. Indicates a plane.

A parallel rail extending in the front-rear direction is attached to the floor of the observation vehicle 10, and a guide portion with wheels of the gantry 12 is inserted into the rail, and the gantry 12 is mounted to be able to move back and forth. This stand 12
Can open the back door of the observation vehicle 10 and protrude out of the vehicle.

The gantry 12 is also equipped with a thermal infrared video camera 22 of the infrared device 20 and a gamma ray detecting device 32 of the gamma ray device 30. Therefore, the thermal infrared video camera 22 and the gamma ray detecting device 32 can be accommodated in the observation vehicle 10 or exposed outside the vehicle as required. The gantry 12 has a hollowed portion where the gamma ray detection device 32 rides, and a net is formed in the hollowed portion so as to protect the sensor so as not to be affected by the soil that jumps up from the road. ing.

Here, the infrared device 20 means that a heat ray emitted from the surface of an object is captured as an image by a video camera, displayed on a monitor television as a black-and-white gradation image or a color thermograph, and the image is recorded. Refers to any device that can

Further, the gamma ray device 30 captures natural environmental gamma rays, and the captured
214, thallium 208, which can be separated into three components, recorded by a pen recorder, and recorded on other recording devices.

At the center of the bottom of the chassis of the observation vehicle 10, wheels 42 for operating a distance meter 40 are mounted.
Mileage can be measured accurately. When the distance accuracy may be poor, a distance meter (trip meter) that calculates the distance by measuring the rotation speed of the axle of the observation vehicle 10 may be used.

The observation vehicle 10 also includes an infrared device 20 and a gamma ray device.
Various devices related to 30 are installed. That is, in addition to the thermal infrared video camera 22, the infrared
24, Video recorder 26 for driving and recording video tape
The gamma ray device 30 includes a gamma ray detector 32, a spectrum analyzer 34, a pen recorder 36, a digital data recorder 38 as another recording device, and a controller 28b for controlling the same. It has.

The thermal infrared video camera 22 has a viewing angle of 28 ° × 15 ° (wide) to 7 ° × 3.25 ° (narrow), and the instantaneous viewing angles are 1.87 mrad (wide) and 0.47 mrad (narrow), respectively. The resolution is from the minimum detection temperature difference of 0.1 ° C (wide) to
0.15 ° C (narrow), 5m away subject temperature 2m wide
It can be observed in 0.1 ° C units per meter. The viewing angle is not naturally limited to this range, but may be wider or narrower.

The camera angle of the thermal infrared video camera 22 is arbitrarily set within a range of 105 ° left and right with respect to the vertical axis, 90 ° above the horizontal axis, and 30 ° below, so that the entire lining surface can be covered. It is configured so that it can be changed.

In this embodiment, only one thermal infrared video camera 22 is shown, but two or more thermal infrared video cameras 22 may be provided.

The monitor television 24 displays the temperature distribution captured by the thermal infrared video camera 22 on a CRT as a black-and-white grayscale image or a color thermograph, so that the temperature distribution and changes can be visually observed as an image and can be tracked in time series.

The video of the monitor TV 24 is divided into 1 /
Recorded on a video cassette with a 2-inch tape. Therefore, the video of the video cassette can be analyzed later in a laboratory or the like.

The control unit 28a has a function of switching the viewing angle of the thermal infrared video camera 22 and the resolution of the image (instantaneous viewing angle), adjusting the focal length of the image, and switching functions of the entire apparatus.

The gamma ray device 30 captures natural environmental gamma rays with the gamma ray detection device 32, separates and detects this into potassium 40, bismuth 214, and thallium 208 by the spectrum analyzer 34, weighs it, and weighs it on continuous paper by the pen recorder 36. While the data is recorded in the form of a line graph, the digital data recorder 38 records the actual state by a digital signal.

The gamma ray detecting device 32 detects natural gamma rays at an energy level, and uses four or more NaI scintillators having a diameter of 5 inches and a height of 5 inches. In order to improve the reproducibility of data, it is preferable to make the capacity of the scintillator as large as possible. In this case, the energy resolution is 10%.

The spectrum analyzer 34 selects only gamma rays having a predetermined energy level and counts the dose.
A single channel analyzer will be used to measure gamma rays of potassium 40, bismuth 214, and thallium 208.

The pen recorder 36 is a 5-pen type, and the spectrum analyzer 34
Potassium 40, Bismuth 214, Thallium 20 output from
8, bismuth 214 vs potassium 40, thallium 208 vs bismuth 2
It continuously outputs the dose and dose ratio of 14 gamma rays.

The control unit 28b has a function of issuing a command to detect, analyze, output, and record gamma rays.

The digital-data recorder 38 is a spectrum analyzer.
The data output from 34 is recorded on a cassette tape or the like. The data capture interval is 0.5 seconds,
It has the ability to record 16 channels of digital input and 64 channels of analog input along with the recording of hours, minutes and seconds.

The distance meter 40 converts the number of revolutions of the wheel 42 into an electric signal which is distance data.
The data is sent to the pen recorder 36 and the digital-data recorder 38 and recorded therein. The control unit 28c has a function of transmitting a synchronization signal to the distance meter 40, the infrared device 20, and the gamma ray device 30, and taking a sequence between various data.

The observation vehicle 10 has an infrared device 20, a gamma ray device 30,
Also, a power supply device 44 composed of an assembly of batteries having a function of supplying power to the measurement system of the observation vehicle 10 is mounted.

The mounting structure of the thermal infrared video camera 22 and the gamma ray detecting device 32 is optional, but the above-described structure is preferable in that it is separated from the ceiling of the tunnel as much as possible and the shaking is small.

Next, an inspection method using the observation vehicle 10 will be described below.

In the present embodiment, both the observation of infrared rays and gamma rays are performed while the observation vehicle 10 is traveling at a constant speed, for example, 5 km / h. While the observation vehicle 10 is running, the surface of the tunnel lining is photographed by the thermal infrared video camera 22 and its temperature distribution is displayed on the monitor television 24, and at the same time, the image is recorded on a video cassette by the video recorder 26.
The photographing angle is preferably in a range in which the photographing angle is inclined backward by 60 ° from the vertical upper side. In this case, the instantaneous viewing angle of the video camera is 1.87
At mrad, the resolution of a subject 5m away is 0.935cm.

Similarly, while running the observation vehicle 10, the gamma rays coming out of the tunnel lining by the gamma ray device 30 at 0.5 second intervals,
Observe. The gamma ray captured by the gamma ray detector 32 is
The gamma rays of potassium 40, bismuth 214, and thallium 208 are separated by the spectrum analyzer 34 and recorded by the pen recorder 36 and the digital-data recorder 38. If the vehicle is running at 5 km / h, gamma ray spectrum data is recorded at 0.7 m intervals.

The speed of the observation vehicle 10 is an example, and can be changed according to the distance to the subject and necessary local restrictions.

The data thus obtained is analyzed as follows while confirming the position with the distance data.

(1) Cavities The cavities behind the tunnel lining are mainly due to the outflow of sediment by groundwater. Since groundwater temperature fluctuates little throughout the four seasons, it is generally lower than the temperature in summer and higher than the temperature in winter. Therefore, the same temperature pattern phenomenon as groundwater can be seen in the cavity that serves as the groundwater passage. Therefore, while maintaining the underground air and heat balance on the tunnel lining surface, where cavitation occurs,
Since the exchange of heat with groundwater also occurs, measuring the temperature distribution on the tunnel lining surface reveals a temperature pattern in the low or high temperature region where there is a cavity. When this is captured by the thermal infrared video camera 22, an image having a temperature pattern different from that of the other portions appears, and it is understood that the portion has a cavity. The temperature of underground air, which is the basis for interpretation, is on site, and the temperature of groundwater is based on the temperature of spring water from cracks in the lining.

(2) Cracks When a space (tunnel) is created in the ground, the stress field around the space changes. The change in the stress field serves as a source of energy for deformation, and the force for suppressing the deformation acts as a reaction, resulting in the formation of fine voids in the rock or soil tissue structure.

Even if the gap is narrow, which initially allows only gas to pass through, it expands over time to allow water to pass. At the same time, the deformation also progresses, becomes large, and leads to crack formation. However, groundwater does not always seep from the crack. This is because it may be dry or wet depending on the factors and the timing of crack formation, or depending on the presence or absence of groundwater veins.

Here, when the cracks are morphologically viewed in detail, there are those that are shifted so as to overlap and those that are shifted so as to open. The former is formed by compressive force, and the latter is formed by tensile force. When this is captured by the thermal infrared video camera 22, as long as there is a difference between the underground temperature and the ground temperature, a temperature distribution reflecting the form of the crack appears, and this can be determined as a crack.

(3) Water leakage Water leakage is observed when there is a “water path” and “groundwater tank” on the back of the tunnel lining, and there is a “passageway” leading into the tunnel. The amount of leakage can be represented by the product of the width, thickness, and flow velocity of the leakage. The amount of water leakage is related to the size of the waterways, groundwater tanks, passages, etc., and provides important information when detecting cavities and evaluating the factors that cause cracks.

Here, the width of the water leakage can be easily measured by examining the temperature distribution with the infrared device 20, since the temperature of that portion is different from the surrounding temperature. Also, the larger the product of the thickness of the leak and the flow velocity, the closer to the water temperature of the groundwater tank. Therefore, by examining this relationship in advance, if the temperature distribution at the water leaking portion is known, the product of the thickness of the water leak and the flow velocity, that is, the amount of water leak can be known.

(4) Relationship with geology, rock quality, structure, and seismic motion The causes of cavitation in the back of the tunnel lining, cracks in the lining surface, and water leakage include earthquake motion due to weathering, seismic activity, and volcanic activity. To determine this, it is necessary to obtain information such as lithology, faults, radon, behavior of thoron, geothermal and hydrothermal water, and the like. The information includes potassium 40, bismuth 214,
A natural gamma ray spectral distribution such as thallium 208 is suitable. Therefore, by observing and analyzing these spectral distributions with the gamma ray device 30, those problems can be evaluated and analyzed. For example, swelling serpentine has extremely few gamma rays, and time series observations are based on phenomena such as gamma ray component changes in active faults and gamma ray component amounts and component ratios in high-temperature hot water. It can be used for evaluation judgment in.

In this way, by analyzing the data obtained by the observation vehicle 10, abnormalities such as cracks and cavities in the tunnel structure can be found, so that if necessary, the problem areas can be inspected again, repaired, and reinforced. it can.

The above determination can be made even in the traveling observation vehicle 10,
All data is stored in video recorder 26, pen recorder 36,
Since it is described in the digital data recorder 38, it can be carried out after taking it back to the laboratory.

Although one embodiment of the inspection method according to the present invention has been described above, the gamma rays to be observed and recorded are not limited to the above embodiment, and the present invention is not limited to this embodiment, and the present invention is not limited thereto. It goes without saying that the present invention can be practiced with appropriate modifications within the scope of the described invention.

[Effects of the Invention] As is clear from the above description, according to the inspection method of the present invention, it is possible to continuously inspect a wide range of inspected parts while moving in the tunnel, so that the safety of the tunnel structure is improved. Prior to a change or deformation that has a decisive influence on the condition, the occurrence of water leaks, cavities, cracks, and the like can be regularly and easily inspected. Therefore, safety management such as maintenance and repair of the tunnel structure can be reliably performed to prevent a disaster.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing an essential part of an embodiment of an observation vehicle used for carrying out the inspection method of the present invention. FIG. 2 is a schematic plan view of the observation vehicle according to the embodiment. FIG. 3 is a side view showing the actual condition of the inspection inside the tunnel by the observation vehicle according to the embodiment, FIG. 4 is a rear view of the same, and FIG. 5 is a block diagram schematically showing the inspection method of the present invention. is there. 10 ... observation vehicle, 20 ... infrared device 22 ... thermal infrared video camera, 24 ... monitor television 26 ... video tape recorder, 30 ... gamma ray device 32 ... gamma ray detector, 34 ... spectrum analyzer 36 …… Pen recorder, 38 …… Digital data recorder 40 …… Distance meter

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-72169 (JP, A) JP-A-60-213854 (JP, A) JP-A-52-125401 (JP, A) JP-A 60-213 122306 (JP, A) JP-A-53-149058 (JP, A) JP-A-61-38099 (JP, A)

Claims (1)

(57) [Claims] 1. Infrared rays emitted from the lining of a tunnel structure and potassium 40 and bismuth emitted through the lining.
Gamma rays such as 214, thallium 208, etc. are detected by means of infrared detectors mounted on the vehicle and gamma ray detectors and other radiation detectors. A method for inspecting for abnormalities such as cavities and cracks in tunnel structures, characterized by grasping and judging the crack state of the lining from the results and the state of the cavity behind the lining from the observation results by gamma ray detection.