CN104236827B - A kind of Tunnel Water Leakage detection method based on thermograde and device - Google Patents

Abstract

The invention discloses a kind of Tunnel Water Leakage detection method based on thermograde and device, by laying array of temperature sensor on tunnel inner wall, utilize the temperature difference between water and wall and evaporation of water thermolysis, temperature according to each platinum resistance measuring point judges whether tested region exists seepage, it is possible to estimate the shape in seepage region according to detection information.The present invention can position in time when percolating water phenomenon occurs and report to the police, so that management personnel find in the very first time and administer Tunnel Water Leakage disease, further, it is also possible to the development of the existing water leakage defect of long term monitoring, help to observe the structural behaviour evolving trend in tunnel.

Description

A method and device for detecting water leakage in tunnels based on temperature gradient

technical field

The invention relates to the technical field of tunnel water leakage detection, in particular to a temperature gradient-based tunnel water leakage detection method and device.

Background technique

With the improvement of the modernization level of our country's cities and the acceleration of people's life rhythm, the subway is gradually becoming an important part of the public transportation system in big cities due to its convenient and fast advantages. A large number of provincial capital cities and some second-tier cities are investing huge sums of money to build new subways . At the same time, the problems facing the healthy service of subway tunnels have become increasingly prominent. Leakage is the most common and typical structural disease of subway tunnels. Many urban subways in my country are plagued by serious water leakage.

Under the long-term erosion of groundwater, the concrete and steel bars in the tunnel lining are corroded, and the original micro-cracks expand and penetrate, which affects the durability of the tunnel structure. A large amount of water leakage will also reduce the use of various ancillary facilities in the tunnel. function and life, endangering driving safety. For shield tunnels, after local water seepage occurs, when the groundwater supply is insufficient, the loss of groundwater will reduce the pore water pressure, increase the effective stress in the soil, cause uneven settlement due to compaction of the soil, and deformation of the tunnel, resulting in A series of diseases such as staggered platform, disengagement of segment and ballast bed, circumferential convergence, etc. The bending of the tunnel also leads to the opening of the tunnel joint, which further aggravates the leakage. It can be seen that water leakage is not only the most common structural disease in shield tunnels, but also induces a series of other diseases. Therefore, the detection of water leakage diseases in tunnels is particularly important in the current situation.

Existing routine detection of tunnel water leakage usually requires inspectors to carry detection tools or equipment, and use walking methods for visual inspection or measurement. This method has disadvantages such as low efficiency, strong subjectivity, time-consuming, and laborious. In recent years, people have developed rapid and non-destructive detection methods for water leakage such as infrared thermal imaging, laser scanning, ground radar, fiber Bragg grating, and distributed optical fibers, among which the most commonly used is infrared thermal imaging. When the temperature of an object is above absolute zero, the movement of atoms and molecules on the surface of the object emits infrared energy. Infrared thermal imager is a two-dimensional plane imaging infrared system, which can gather infrared radiation energy on an infrared detector to form an infrared thermal image of the measured target. Many studies have shown that there is a temperature gradient inside and outside the leaking water area, and the infrared energy radiated outward is also different, so infrared thermal imaging cameras can be used for effective detection. Infrared thermography has the advantages of high precision, but the cost of equipment is high. If a large-scale detection is required, it needs to rely on the movement of vehicles. Usually, it will be detected along the entire length of the tunnel every once in a while, and each detection period is long. less efficient. Leakage is a random process. If manual or instrumental regular detection is adopted, serious water leakage that occurs during the interval of detection cannot be discovered and disposed of in the first place, which may lead to disasters. Therefore, for the current water leakage problem, a low-cost, long-term and automatic method for detecting water leakage in tunnels is needed.

Contents of the invention

The purpose of the present invention is to provide a method and device for detecting water leakage in tunnels based on temperature gradients in order to overcome the defects of the above-mentioned prior art. Water leakage to solve the problems existing in the existing detection methods.

The purpose of the present invention can be achieved through the following technical solutions:

A method for detecting water leakage in tunnels based on temperature gradients, comprising the following steps:

1) Mark the location where the tunnel seepage water often occurs as the detection area;

2) Arranging a temperature sensor array on the inner wall of the tunnel in each detection area;

3) regularly collect the temperature detected by the temperature sensor;

4) According to the temperature difference between the two temperature sensors, it is judged whether the area between the two temperature sensors sees water. When the tunnel concrete walls are dry, there is almost no temperature difference between the two temperature sensors. When there is water seepage in the wall, due to the temperature difference between the water and the wall and the evaporation and heat dissipation of water, there will be a significant temperature difference between the water seepage area and the non-water seepage area, and the temperature inside the water seepage area shows different variation characteristics. The test found that when the water seeps slowly, there is an obvious temperature gradient change inside the seepage area, and the closer to the water outlet, the greater the temperature gradient change inside and outside the seepage area. In the case of rapid water seepage and wet marks, the temperature inside the seepage area does not have much difference, but the temperature at the edge of the seepage area changes drastically. This feature can be used to simply judge the water seepage intensity. If the temperature difference is less than or equal to the threshold, it is considered that the area is not seepage, and if the temperature difference is greater than the threshold, it is considered that the area is seepage.

The temperature sensor array is arranged in a grid or strip, and the temperature sensor is a patch-type platinum resistance sensor.

During the detection, the temperature difference between two adjacent temperature sensors in the horizontal or vertical direction in the temperature sensor array is used to judge whether there is water seepage in the area between adjacent temperature sensors, and the areas between all adjacent temperature sensors are detected sequentially. Get the location and shape of the leaking water.

According to the collected temperature values of all the temperature sensor measuring points, the shape of the leakage water can be approximately determined by using the following principles: the measurement points with similar temperatures can be considered to have the same leakage water situation, and they are both leakage areas or non-leakage areas. If there is a certain temperature difference between two adjacent measuring points, it is considered that the seepage water situation changes between these two points, and the midpoint of the line connecting the two points is used as the positioning point for approximately determining the edge of the seepage water. Connect all such anchor points with splines or straight lines to obtain an approximate shape of the seepage water.

During the detection, the multi-channel acquisition module can be used to obtain the temperature values of multiple platinum resistance sensors at the same time, and the single-channel acquisition module can be used to sequentially obtain the temperature of each platinum resistance sensor in the way of inspection. In practical applications, the combination of the two should be the best. The interval of each round of collection is 1 hour to 1 day, which is determined according to the severity of water leakage and the importance of the tunnel.

For the location where water leakage often occurs in the tunnel, for the shield tunnel, it is the annular joints, longitudinal joints, grouting holes, etc. near the two ends of the tunnel and the side passage; The size is preferably between 0.5m×0.5m～1m×1m. Since the arrangement of the temperature sensor array is determined by the detection location, for the seam of the shield tunnel, the temperature sensors should be arranged in strips vertically to the seam; for the grouting hole of the shield tunnel and most of the leakage of the mountain tunnel For the water part, the temperature sensors should be arranged in a grid. The number of temperature sensor arrays is determined according to the size of the area to be detected. In order to reduce the cost and control the number of missed detections, the distance between adjacent temperature sensors should be 10cm-20cm.

A tunnel water leakage detection device for implementing the above method, including a detection unit, a data transmission unit and a management control unit, the detection unit is arranged at each detection area, and the detection unit includes a temperature sensor array and a temperature acquisition unit module, the temperature acquisition module acquires the data of each temperature sensor in the temperature sensor array, and sends the data to the management control unit through the transmission unit.

The detection unit also includes a base, a spacer and an analog switch. The base is made of insulating and heat-insulating material as a carrier of the temperature sensor array, and the spacer is arranged on the base to connect the base and the temperature sensor array. Fixed on the inner wall of the tunnel, the temperature sensor array is arranged in a grid or strip shape. The temperature sensor is a patch-type platinum resistance sensor, and is connected to the temperature acquisition module through an analog switch. A heat conduction sensor is set between the temperature sensor and the inner wall of the tunnel. glue.

The data transmission unit includes a wireless transmitting module, a relay station, and a wireless receiving module, the wireless transmitting module is connected to the temperature acquisition module, the wireless receiving module is connected to the management control unit, and the wireless transmitting module and the wireless receiving module are connected according to the distance Choose to transfer data via a relay station or directly.

The management control unit includes a monitoring computer and a database, which are used for saving and reading detection data, alarming and locating water leakage events, and issuing control instructions.

It is characterized in that the temperature acquisition module judges whether to send data according to the detection result. If the detected temperature difference is less than or equal to the threshold, that is, the area does not seep, the temperature acquisition module does not send data; if the detected temperature difference is greater than the threshold, that is, the area If there is water seepage, the temperature acquisition module sends the detection data to the management control unit through the transmission unit.

Compared with the prior art, the present invention utilizes the temperature difference between concrete and groundwater and the evaporation and heat dissipation of water to realize long-term automatic detection of the location where water seepage often occurs in the tunnel. The device can locate and alarm in time when water leakage occurs, so that tunnel management personnel can discover and treat tunnel water leakage diseases in the first time, minimize the loss caused by water leakage, and can also monitor existing tunnels for a long time. The development of water leakage diseases and the estimated area of water leakage can help tunnel managers observe the evolution trend of tunnel structural performance. Moreover, the present invention adopts the wireless sensor network as the data transmission mode, which does not affect the tunnel limit on the cross section, and can be detected as usual when the train is running. In the vertical direction, a large number of transmission cables can be saved, and the cost can be effectively controlled.

Its advantages are:

1) The data transmission unit does not transmit signals when there is no water leakage in normal times, and only automatically transmits signals when water leakage occurs, saving energy and realizing the active leakage reporting function.

2) Long-term automatic monitoring of tunnel water leakage can be realized without manual assistance, and information such as the location and area of water leakage can be provided to improve the efficiency of tunnel operation and management.

3) The temperature is used to indirectly detect water seepage without any damage to the tunnel, the principle is clear, and the structure is simple.

Description of drawings

Fig. 1 is the structure schematic diagram of an embodiment of the tunnel water leakage detection device based on the temperature gradient of the present invention;

Fig. 2 is the detection flowchart of an embodiment of the tunnel water leakage detection device based on the temperature gradient of the present invention;

Fig. 3 is the estimated figure of the shape of seepage water obtained by applying the detection method of the present invention, wherein (a) is the actual shape of seepage water and the temperature of each measurement point, (b) is the measurement point with temperature difference, and (c) is the detection and acquisition water seepage shape.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

Figure 1 and Figure 2 show an embodiment of the temperature gradient-based tunnel water leakage detection device of the present invention, wherein Figure 1 is a schematic structural diagram of the embodiment, and Figure 2 is a flow chart for detection.

As shown in FIG. 1 , a temperature gradient-based tunnel water leakage detection device includes detection units 101 and 102 , a data transmission unit 108 and a management control unit 112 .

The detection units 101 and 102 are used to detect water leakage information, including a temperature sensor array composed of a patch-type platinum resistance sensor 103 , a base 104 , a spacer 105 , an analog switch 106 , and a temperature acquisition module 107 . The temperature sensor array is composed of a plurality of patch-type platinum resistance sensors 103 arranged in strips or grids, and the arrangement and number are determined according to the location and the size of the detection area. Due to the large number of measuring points, in order to facilitate the installation and fixation of the platinum resistance sensor array 103 in the later stage, the platinum resistance sensor array 103 should be pasted on the substrate 104 according to the preset arrangement and spacing. Good insulating materials, so that the temperature fields of two adjacent platinum resistance sensors will not affect each other. Heat-conducting glue is used as the heat transfer material between the patch platinum resistance sensor 103 and the tunnel wall of the area to be detected, so that the platinum resistance sensor array 103 can quickly and accurately sense the temperature of the wall. Due to the poor bonding performance of ordinary heat-conducting adhesives, in order to allow the patch-type platinum resistance sensor 103 and the base 104 to be firmly fixed on the wall, several raised pads 105 should be set on the base 104, and its thickness should be the same as that of platinum. The thickness of the resistance sensor is the same as or slightly smaller than that of the platinum resistance sensor, so as to ensure that the spacer 105 does not cause a gap between the patch type platinum resistance sensor 103 and the wall contact surface. Use super glue to stick the spacer 105 on the tunnel wall, or drill holes on the base 104 and the spacer 105, and fix them on the wall with bolts on site.

The temperature acquisition module 107 is used to read the temperature value of each platinum resistance sensor measuring point and convert it into a digital signal through digital-to-analog conversion for later data transmission. The analog switch 106 is used to control the temperature acquisition module 107 to switch the measured platinum resistance sensor in a polling manner. When detecting, a multi-channel acquisition module can be used to simultaneously obtain the temperature values of a plurality of platinum resistance sensors, and a single-channel acquisition module can be used. The temperature of each platinum resistance sensor is sequentially obtained in the manner of patrolling. The polling time interval is determined according to the stability of the circuit. Since the temperature field does not change rapidly, the polling frequency does not need to be very fast. The interval between the measurement time of the two platinum resistance sensors before and after is 5s to 10s. The test found that the temperature difference between the inside and outside of the seepage area is usually about 0.2 to 0.6 degrees, so a grade A or 1/3 platinum resistance sensor should be selected, and the accuracy of the data acquisition module should also reach about 0.1 degrees.

Each area to be detected is provided with a detection unit. In this embodiment, two detection units 101 and 102 are provided. Each detection unit has unique address information and can be identified by the data transmission unit 108 .

The data transmission unit 108 is used for receiving the detection information from the detection units 101 and 102 and sending it to the management control unit 112 . The data transmission unit 108 is a wireless sensor network, including a wireless transmitting module 109 , a relay station 110 , and a wireless receiving module 111 .

Each detection unit 101 and 102 is equipped with a wireless transmitting module 109, which can periodically transmit the detection information and corresponding address information of the detection unit to the relay station 110.

According to the distance from the detection unit 101 and 102 to the management control unit 112, and the optimal transmission distance of the wireless signal, several relay stations (relay station 110 in this embodiment) are set in the tunnel for receiving the data of the wireless transmission module 109, And pass it to the next relay station, and finally transmit it to the wireless receiving module 111.

The transmission between the wireless transmitting module 109 and the relay station 110 should be a star or tree network, and the transmission between the relay stations should be a strip or combined network.

The wireless receiving module 111 is connected to the management control unit 112 , and the data received by the wireless receiving module 111 first reaches the monitoring computer 114 and then is stored in the database 113 . The monitoring software system 115 realizes the alarm of water leakage and the judgment of the location and shape of water leakage according to the detection information and address information in the database 113 .

The working process of the tunnel water leakage detection device based on the temperature gradient of the present invention is as follows:

Before testing starts, design the layout of measuring points, testing frequency and testing sequence. Select the first detection unit 101 for detection.

Select the first platinum resistance sensor in the area to be measured as the detection object according to the preset detection sequence, and connect the circuit of the first platinum resistance sensor by the analog switch 106, and keep it for a period of time, and the temperature acquisition module 107 acquires the first platinum resistance sensor at this time. The temperature value of a platinum resistance sensor is transmitted to the wireless transmitting module 109, and then the analog switch 106 switches the next platinum resistance sensor. Similarly, the analog switch 106 controls each platinum resistance sensor to be turned on in turn, and the temperature acquisition module collects data until the last platinum resistance sensor is detected, at which point a cycle is completed.

After all the platinum resistance sensors are detected, all the analog switches 106 are turned off, the detection unit 101 starts to sleep, and then the next detection unit 102 is detected. The detection unit 101 resumes work at the next detection time according to the preset detection frequency, and starts a new cycle.

After the wireless transmission module 109 receives the detection information of all platinum resistance sensors, it makes a preliminary judgment on the measured temperature values. If there is no significant difference in all temperature values, it means that there is no water seepage at this time, and these data will not be processed. If there are two temperature values with a certain temperature difference, it means that water seepage is likely to occur at this time. The wireless transmitter module 109 transmits the address of the detection unit and the detection information of all platinum resistance sensors to the relay station.

The relay station transmits the data of the wireless transmitting module 109 to the receiving end 111 immediately, and then the data reaches the management control unit 112 .

After the management control unit 112 receives the data, the monitoring computer 114 alarms and displays the detection area number, and the monitoring software system 115 draws the shape of the leaking water according to the detection information. As shown in Figure 3, if there is a certain temperature difference between two adjacent measuring points, it is considered that the seepage water situation changes between these two points, and the midpoint of the line connecting these two points is used as the positioning point for approximately determining the edge of the seepage water. Connect all such anchor points with spline curves or straight lines to obtain the approximate shape of the seepage water and estimate the area of the seepage water.

For the leaked water that needs to be monitored for a long time without treatment, the management control unit 112 stores the data in the database 113 in time after receiving the data, and draws a long-term monitoring curve by the detection software for the reference of the tunnel management personnel.

Claims (8)

1. A tunnel water leakage detection method based on temperature gradient, is characterized in that, comprises the following steps: 1) Mark the location where the tunnel seepage water often occurs as the detection area; 2) Arrange a temperature sensor array on the inner wall of the tunnel in each detection area. The temperature sensor array is arranged in a grid or strip shape. The temperature sensor is a patch-type platinum resistance sensor. The temperature difference between two adjacent temperature sensors in the horizontal or vertical direction in the array is used to determine whether there is water seepage in the area between adjacent temperature sensors, and to detect the areas between all adjacent temperature sensors in sequence to obtain the leakage water. position and shape; 3) regularly collect the temperature detected by the temperature sensor; 4) According to the temperature difference between the two temperature sensors, it is judged whether there is water seepage in the area between the two temperature sensors; if the temperature difference is less than or equal to the threshold value, it is considered that the area is not water seepage, and if the temperature difference is greater than the threshold value, it is considered that the area is water seepage . 2. A method for detecting water leakage in tunnels based on temperature gradients according to claim 1, characterized in that multi-channel acquisition or single-channel inspection is used to realize the sequential detection of the regions between all adjacent temperature sensors detection. 3. A method for detecting water leakage in tunnels based on temperature gradients according to claim 1, wherein the size of each detection area is between 0.5m×0.5m～1m×1m, and the distance between adjacent temperature sensors is The distance between them is 10cm～20cm. 4. A tunnel water leakage detection device for implementing the method according to any one of claims 1 to 3, characterized in that it comprises a detection unit, a data transmission unit and a management control unit, and the detection unit is arranged in At each detection area, the detection unit includes a temperature sensor array and a temperature acquisition module, and the temperature acquisition module acquires the data of each temperature sensor in the temperature sensor array, and sends the data to the management control unit through the transmission unit. 5. The tunnel water leakage detection device according to claim 4, characterized in that, the detection unit also includes a base, a spacer and an analog switch, and the base is made of an insulating and heat insulating material as a temperature sensor The carrier of the array, the pads are arranged on the base, and the base and the temperature sensor array are fixed on the inner wall of the tunnel. The temperature sensor array is arranged in a grid or strip shape, and the temperature sensor is a patch-type platinum resistance The sensor is connected to the temperature acquisition module through an analog switch, and thermal conductive glue is set between the temperature sensor and the inner wall of the tunnel. 6. The tunnel water leakage detection device according to claim 4, wherein said data transmission unit comprises a wireless transmitting module, a relay station, and a wireless receiving module, said wireless transmitting module is connected to a temperature acquisition module, said The wireless receiving module is connected to the management control unit, and the wireless transmitting module and the wireless receiving module can choose to transmit data through the relay station or directly according to the distance. 7. The tunnel water leakage detection device according to claim 4, characterized in that, the management control unit includes a monitoring computer and a database for saving and reading detection data, alarming and positioning of water leakage events , and the issuance of control instructions. 8. The tunnel water leakage detection device according to any one of claims 4-7, wherein the temperature acquisition module judges whether to send data according to the detection result, if the detected temperature difference is less than or equal to the threshold, that is, the area If there is no water seepage, the temperature acquisition module does not send data; if the detected temperature difference is greater than the threshold, that is, the area seeps water, the temperature acquisition module sends the detection data to the management control unit through the transmission unit.