Joint test method and device for temperature field and stress field of tunnel in severe cold area

Abstract

The invention discloses a combined test method and device for a temperature field and a stress field of a tunnel in a severe cold region, and belongs to the field of tunnel engineering. The tunnel comprises a primary support and a secondary lining, the system comprises a data acquisition instrument, and a surface strain gauge, a thermometer, a temperature measurement beam, a heat conductivity probe, a wind speed sensor and a meteorological sensor which are respectively in communication connection with the data acquisition instrument, and the data acquisition instrument is arranged at the haunch of the tunnel; the surface strain gauge is arranged on the lining surface of the second lining; the thermometer is arranged on the inner side surface of the second lining; the temperature measuring beam is arranged in the primary support and the surrounding rock; the thermal conductivity probe is inserted into surrounding rock; the wind speed sensors and the meteorological sensors are arranged on second linings on the left side and the right side in the tunnel. According to the invention, the temperature field and the stress field of the surrounding rock lining can be monitored, the temperature measuring beam and the surface strain gauge are adopted to monitor the range of the freeze-thaw ring and the change of the frost heaving force, and data support is provided for researching the influence of the thermal-mechanical coupling effect on the cold region tunnel and the dynamic evolution of the tunnel engineering vulnerability.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel engineering, and in particular relates to a method and a device for jointly testing temperature field and stress field of a tunnel in a severely cold region. Background Art

[0002] As more and more tunnels are built in cold regions, tunnel frost damage is becoming more and more serious. These frost damages bring major safety hazards to the normal operation of tunnels, greatly shorten the normal service life of tunnels, are time-consuming and labor-intensive to deal with, and bring huge economic losses to society. Existing monitoring methods for cold region tunnels are mostly focused on monitoring the temperature field, and there are still the following problems:

[0003] 1. When vehicles run at a high speed in a limited tunnel space, a "piston" effect will occur, bringing in external cold air, which has a significant impact on the temperature field of the air and surrounding rock in the tunnel. The conventional method only sets up a meteorological station at the entrance of the tunnel, which cannot accurately monitor the wind speed in the tunnel under the "piston" effect.

[0004] 2. Most scientific research institutions only monitor the temperature field of the tunnel and ignore the importance of the stress field. The damage caused by temperature changes to the tunnel needs to be supported by measured stress and strain data.

[0005] 3. The thermal conductivity of surrounding rock and concrete is of great significance to the simulation of tunnel temperature field. At present, most of the methods used are to measure the thermal conductivity of surrounding rock samples at different temperatures indoors and then take the equivalent strength. The influence of other factors such as water content is not considered, and accurate material parameters cannot be obtained.

[0006] 4. Due to the lack of signals in the tunnel, most of the monitoring of the temperature field and stress field in the tunnel is done manually or automatically, which cannot guarantee the accuracy and sustainability of the data, and the data collection cost is high.

[0007] Therefore, it is necessary to innovate the existing monitoring system to address the above issues. Summary of the invention

[0008] The purpose of an embodiment of the present invention is to provide a joint testing device for temperature field and stress field of tunnels in severe cold regions. It combines the current research status of tunnels in cold regions, comprehensively considers factors such as wind speed, wind direction, and humidity, and carries out tests on temperature field and stress field. The installation of a thermal conductivity probe facilitates the acquisition of the thermal conductivity of the surrounding rock, which facilitates scientific researchers to study the impact of thermal-mechanical coupling on tunnels in cold regions. It is of great significance to further explore the driving mechanism and key factors of the dynamic evolution of tunnel engineering vulnerability, thereby solving at least one technical problem involved in the background technology.

[0009] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0010] The embodiment of the present invention provides a combined testing device for temperature field and stress field of a tunnel in a severe cold region. The tunnel includes an initial support abutting against the surrounding rock and a secondary lining arranged on the inner surface of the initial support. The system includes a data acquisition instrument and a surface strain gauge, a thermometer, a temperature measuring beam, a thermal conductivity probe, a wind speed sensor and a meteorological sensor respectively connected to the data acquisition instrument for communication, wherein:

[0011] The data acquisition device is arranged at the tunnel waist;

[0012] The surface strain gauge is arranged on the surface of the secondary lining;

[0013] The thermometer is arranged on the inner surface of the secondary lining;

[0014] The temperature measuring beam is arranged inside the initial support and the surrounding rock;

[0015] The thermal conductivity probe is inserted into the surrounding rock;

[0016] The wind speed sensor and the meteorological sensor are both arranged on the secondary lining on the left and right sides of the tunnel.

[0017] Preferably, it also includes a data transmission module arranged at the waist of the tunnel entrance. The number of the data acquisition devices is multiple and they are arranged along the extension direction of the tunnel. The multiple data acquisition devices are connected in series through data connection lines and then connected to the data transmission module.

[0018] Preferably, it further comprises a closed chassis, wherein the data acquisition instrument and the data transmission module are both arranged in the closed chassis.

[0019] Preferably, the temperature measuring beam, the temperature meter and the surface strain gauge are arranged symmetrically on the vertical center line of the tunnel monitoring section.

[0020] Preferably, a thermal conductivity measurement hole with a depth of 70 mm is drilled in the surrounding rock, and the thermal conductivity probe is inserted into the thermal conductivity measurement hole.

[0021] Preferably, a temperature measurement hole is drilled on the surrounding rock, the temperature measuring beam is inserted into the temperature measurement hole, and the depth of the temperature measurement hole is the maximum freezing depth of the tunnel site + 0.5 meters.

[0022] Preferably, the thermometer is arranged on the inner surface of the secondary lining through a test rod, and the test rod is a PVC pipe with low thermal conductivity.

[0023] Preferably, the measuring cables respectively connected to the temperature measuring beam and the thermal conductivity probe are arranged downward along the surface of the initial support.

[0024] Preferably, the tunnel monitoring sections are densely arranged in the tunnel entrance section, with adjacent distances of 10 to 50 meters; and sparsely arranged in the middle part of the tunnel, with the distance between adjacent monitoring sections being 100 to 500 meters.

[0025] Preferably, the model of the data acquisition instrument is JTM-MC30, and the model of the data transmission module is JTM-MCM30.

[0026] The present invention also provides a severe cold region tunnel temperature field and stress field joint testing method based on the severe cold region tunnel temperature field and stress field joint testing device, the method comprising the following steps:

[0027] Step 1: Collect data;

[0028] The data acquisition instrument is connected to the surface strain gauge, thermometer, temperature measuring beam, thermal conductivity probe, wind speed sensor and meteorological sensor through cables to collect and store the monitoring data of each sensor. The data acquisition instrument is connected to the data transmission module through optical fiber to upload the collected data to the cloud in real time.

[0029] Step 2: data processing;

[0030] The monitoring platform automatically draws the curve of the sensor detection content changing over time; draws the curve of the freezing depth of the surrounding rock based on the temperature measurement data of the temperature measurement beam; and calculates the freezing and thawing conditions of the tunnel surrounding rock based on the temperature measurement beam;

[0031] Step 3: Analyze the data;

[0032] Through the data of temperature field and stress field, the influence of temperature fluctuation on the freezing and thawing range of surrounding rock and the change of additional stress of frost heave is studied, and the unfavorable position of additional stress of frost heave of lining structure under freezing and thawing cycle is studied;

[0033] Using wind speed monitoring data, the influence of the “piston” effect on the mechanical response of the tunnel is studied;

[0034] Through long-term monitoring, the dynamic evolution of tunnel engineering vulnerability under freeze-thaw cycles is studied;

[0035] With the help of thermal conductivity data, numerical simulation of cold-region tunnels is carried out, and the deformation and mechanical response of tunnel structures caused by freeze-thaw cycles are analyzed in detail. The correctness of the model is verified with the help of existing temperature field and stress field monitoring data.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. For the freezing and thawing conditions of tunnels in cold regions, thermometers are installed in the surrounding rock and lining to monitor the temperature at different depths of the tunnel surrounding rock and lining, and determine the range of the freezing and thawing circle;

[0038] 2. In view of the changes in temperature and humidity in the cold-region tunnel and the influence of "piston wind" after the tunnel is opened to traffic, a micro 4-element meteorological sensor and a wind speed sensor are used for monitoring, and then connected with a data acquisition instrument and a data transmission module to realize automatic collection and real-time data upload;

[0039] 3. The system can monitor the temperature field and stress field of the surrounding rock lining, and use temperature measuring beams and surface strain gauges to monitor the range of the freeze-thaw zone and the changes in frost heave force, providing data support for studying the impact of thermal-mechanical coupling on tunnels in cold regions and the dynamic evolution of tunnel engineering vulnerability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0041] Figure 1 One of the overall structural schematic diagrams of the combined testing device for temperature field and stress field in tunnels in severe cold regions provided by an embodiment of the present invention;

[0042] Figure 2 The second overall structural schematic diagram of the combined testing device for temperature field and stress field in tunnels in severe cold regions provided by an embodiment of the present invention;

[0043] Figure 3 A schematic diagram of the connection structure between the data acquisition device and the data transmission module provided in an embodiment of the present invention;

[0044] Figure 4 This is an assembly position diagram of the temperature measurement beam, thermometer, and surface strain gauge provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0047] See also Figures 1 to 4 As shown, an embodiment of the present invention provides a combined test device for temperature field and stress field of a tunnel in a severe cold region, wherein the tunnel comprises an initial support 1 abutting against the surrounding rock and a secondary lining 2 arranged on the inner surface of the initial support. The system comprises a data acquisition instrument 3 and a surface strain gauge 4, a thermometer 5, a temperature measuring beam 6, a thermal conductivity probe 7, a wind speed sensor 8 and a meteorological sensor 9 respectively connected to the data acquisition instrument 3 for communication.

[0048] The data collector 3 is arranged at the tunnel waist. Specifically, the model of the data collector 3 is JTM-MC30.

[0049] The surface strain gauge 4 is arranged on the surface of the secondary lining 2 .

[0050] The thermometer 5 is arranged on the inner surface of the secondary lining 2 .

[0051] The temperature measuring beam 6 is arranged inside the initial support 1 and the surrounding rock.

[0052] The thermal conductivity probe 7 is inserted into the surrounding rock.

[0053] The wind speed sensor 8 and the meteorological sensor 9 are both arranged on the secondary lining 2 on the left and right sides of the tunnel, that is, on the side walls in the tunnel.

[0054] Specifically, the wind speed sensor 8 is arranged on the right wall of the tunnel at 100, 200 and 300 meters away from the tunnel entrance. The meteorological sensor 9 is arranged on the right wall of the tunnel entrance.

[0055] The system further comprises a data transmission module 10 arranged at the haunch of the tunnel entrance. Specifically, the model of the data transmission module 10 is JTM-MCM30.

[0056] There are multiple data collectors 3 , which are arranged along the extension direction of the tunnel. The multiple data collectors 3 are connected in series through data connection lines 11 , and then connected to the data transmission module 10 through optical fibers 14 .

[0057] The data transmission module 10 is wirelessly connected to the outside via the antenna 16 .

[0058] It should be further explained that the data acquisition device 3 and the data transmission module 10 are both connected to an external power source via an electric wire 17 .

[0059] Specifically, the data collector 3 and the data transmission module 10 are transmitted via a 4G mobile network, thereby enabling automatic collection and real-time data upload.

[0060] The system further comprises a closed chassis 12 , in which the data acquisition device 3 and the data transmission module 10 are both arranged.

[0061] The temperature measuring beam 6, the temperature meter 5 and the surface strain gauge 4 are arranged symmetrically on the vertical center line of the tunnel monitoring section.

[0062] A 70 mm deep thermal conductivity measurement hole is drilled on the surrounding rock, and the thermal conductivity probe 7 is inserted into the thermal conductivity measurement hole. Specifically, the thermal conductivity measurement hole has a depth of 70 mm.

[0063] A temperature measuring hole is drilled on the surrounding rock, and the temperature measuring beam 6 is inserted into the temperature measuring hole. The depth of the temperature measuring hole is the maximum freezing depth of the tunnel site + 0.5 meters.

[0064] The thermometer 5 is arranged on the inner surface of the secondary lining 2 through a test rod (not shown), and the test rod is a PVC pipe with low thermal conductivity.

[0065] The measuring cables 15 respectively connected to the temperature measuring beam 6 and the thermal conductivity probe 7 are arranged downward along the surface of the initial support 1, so that they extend out at the end of the waterproof layer of the tunnel to avoid damage to the waterproof layer.

[0066] The tunnel monitoring sections are densely arranged at the tunnel entrance section, with adjacent distances of 10 to 50 meters; they are sparsely arranged in the middle part of the tunnel, with adjacent monitoring sections at a distance of 100 to 500 meters.

[0067] It should be noted that the surface strain gauge 4, the thermometer 5 and the temperature measuring beam 6 are all arranged along the circumference of the tunnel monitoring section and are not arranged on the ground.

[0068] The present invention also provides a severe cold region tunnel temperature field and stress field joint testing method based on the severe cold region tunnel temperature field and stress field joint testing device, the method comprising the following steps:

[0069] Step 1: Collect data;

[0070] The data acquisition instrument 3 is connected to the surface strain gauge 4, the thermometer 5, the temperature measuring beam 6, the thermal conductivity probe 7, the wind speed sensor 8 and the meteorological sensor 9 through cables to collect and store the monitoring data of each sensor. The data acquisition instrument 3 is connected to the data transmission module 10 through the optical fiber 14 to upload the collected data to the cloud in real time.

[0071] Step 2: data processing;

[0072] The monitoring platform automatically draws the curve of the sensor detection content changing over time; draws the curve of the freezing depth of the surrounding rock based on the temperature measurement data of the temperature measurement beam; and calculates the freezing and thawing conditions of the tunnel surrounding rock based on the temperature measurement beam;

[0073] Step 3: Analyze the data;

[0074] Through the data of temperature field and stress field, the influence of temperature fluctuation on the freezing and thawing range of surrounding rock and the change of additional stress of frost heave is studied, and the unfavorable position of additional stress of frost heave of lining structure under freezing and thawing cycle is studied;

[0075] Using wind speed monitoring data, the influence of the “piston” effect on the mechanical response of the tunnel is studied;

[0076] Through long-term monitoring, the dynamic evolution of tunnel engineering vulnerability under freeze-thaw cycles is studied;

[0077] With the help of thermal conductivity data, numerical simulation of cold-region tunnels is carried out, and the deformation and mechanical response of tunnel structures caused by freeze-thaw cycles are analyzed in detail. The correctness of the model is verified with the help of existing temperature field and stress field monitoring data.

[0078] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0079] In addition, it should be noted that the scope of the methods and systems in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0080] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A combined testing device for temperature and stress fields of tunnels in severe cold regions, wherein the tunnel comprises an initial support abutting against the surrounding rock and a secondary lining arranged on the inner surface of the initial support, characterized in that: The system includes a data acquisition instrument and a surface strain gauge, a thermometer, a temperature measuring beam, a thermal conductivity probe, a wind speed sensor and a meteorological sensor respectively connected to the data acquisition instrument for communication, wherein: The data acquisition device is arranged at the tunnel waist; The surface strain gauge is arranged on the surface of the secondary lining; The thermometer is arranged on the inner surface of the secondary lining; The temperature measuring beam is arranged inside the initial support and the surrounding rock; The thermal conductivity probe is inserted into the surrounding rock; The wind speed sensor and the meteorological sensor are both arranged on the secondary lining on the left and right sides of the tunnel.

2. The combined testing device for temperature field and stress field in tunnels in severe cold regions according to claim 1 is characterized in that: It also includes a data transmission module arranged at the arch waist of the tunnel entrance. There are multiple data collectors, which are arranged along the extension direction of the tunnel. The multiple data collectors are connected in series through data connection lines and then connected to the data transmission module.

3. The combined testing device for temperature field and stress field of tunnels in severe cold regions according to claim 2 is characterized in that: It also includes a closed case, in which the data acquisition instrument and the data transmission module are both arranged.

4. The combined testing device for temperature field and stress field in tunnels in severe cold regions according to claim 1 is characterized in that: The temperature measuring beam, the temperature meter and the surface strain meter are arranged symmetrically on the vertical center line of the tunnel monitoring section.

5. The combined testing device for temperature field and stress field of tunnels in severe cold regions according to claim 1 is characterized in that: A thermal conductivity measurement hole with a depth of 70 mm is drilled on the surrounding rock, and the thermal conductivity probe is inserted into the thermal conductivity measurement hole.

6. The combined testing device for temperature field and stress field in tunnels in severe cold regions according to claim 1 is characterized in that: A temperature measuring hole is drilled on the surrounding rock, and the temperature measuring beam is inserted into the temperature measuring hole. The depth of the temperature measuring hole is the maximum freezing depth of the tunnel site + 0.5 meters.

7. The combined testing device for temperature field and stress field in tunnels in severe cold regions according to claim 1 is characterized in that: The thermometer is arranged on the inner surface of the secondary lining through a test rod, and the test rod adopts a PVC pipe with low thermal conductivity.

8. The combined testing device for temperature field and stress field in tunnels in severe cold regions according to claim 1 is characterized in that: The measuring cables respectively connected to the temperature measuring beam and the thermal conductivity probe are arranged downward along the surface of the initial support.

9. The combined testing device for temperature field and stress field in tunnels in severe cold regions according to claim 1 or 4, characterized in that: The tunnel monitoring sections are densely arranged at the tunnel entrance section, with adjacent distances of 10 to 50 meters; they are sparsely arranged in the middle part of the tunnel, with adjacent monitoring sections at a distance of 100 to 500 meters.

10. A method for jointly testing temperature field and stress field in tunnels in cold regions based on the device for jointly testing temperature field and stress field in tunnels in cold regions according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: Step 1: Collect data; The data acquisition instrument is connected to the surface strain gauge, thermometer, temperature measuring beam, thermal conductivity probe, wind speed sensor and meteorological sensor through cables to collect and store the monitoring data of each sensor. The data acquisition instrument is connected to the data transmission module through optical fiber to upload the collected data to the cloud in real time. Step 2: data processing; The monitoring platform automatically draws the curve of the sensor detection content changing over time; draws the curve of the freezing depth of the surrounding rock based on the temperature measurement data of the temperature measurement beam; and calculates the freezing and thawing conditions of the tunnel surrounding rock based on the temperature measurement beam; Step 3: Analyze the data; Through the data of temperature field and stress field, the influence of temperature fluctuation on the freezing and thawing range of surrounding rock and the change of additional stress of frost heave is studied, and the unfavorable position of additional stress of frost heave of lining structure under freezing and thawing cycle is studied; Using wind speed monitoring data, the influence of the "piston" effect on the mechanical response of the tunnel is studied; Through long-term monitoring, the dynamic evolution of tunnel engineering vulnerability under freeze-thaw cycles is studied; With the help of thermal conductivity data, numerical simulation of cold-region tunnels is carried out, and the deformation and mechanical response of tunnel structures caused by freeze-thaw cycles are analyzed in detail. The correctness of the model is verified with the help of existing temperature field and stress field monitoring data.

Images