Method and system for determining the thermal conductivity of the surrounding rock in the excavation area during the disposal pit excavation process
Patent Information
- Application Number
- CN202611244449.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-17
- Publication Date
- 2026-09-25
AI Technical Summary
[0007]本申请的实施例提供的处置坑开挖过程中确定掘进区域围岩导热系数的方法，通过在处置坑外的预定位置布置第一温度传感器和第二温度传感器，利用传感器在开挖前获得围岩的初始温度数据，以及在开挖过程获得围岩的温度数据，以实时采集开挖过程中围岩受到刀盘的摩擦、切削、挤压和破碎作用所产生的热量影响的温度响应数据，从而获得热量在围岩中的热传导过程；再通过给定一个初始的围岩导热系数，结合实时采集的围岩的温度响应数据确定处置坑的热标定区的围岩导热系数，以便于实现对于刀盘的热转换系数的标定，为后续确定掘进区域的围岩导热系数提供准确的数据基础；进一步地，根据刀盘的热转换系数，确定围岩的当前的掘进区域的热源功率，从而，利用热源功率逆向推断围岩的当前的掘进区域的导热系数，相较传统的围岩导热系数测定方式，无需获取当前掘进区域的岩心样品，就能够实现对于围岩的当前掘进区域的导热系数的实时、准确确定。
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Abstract
Description
Technical Field
[0001] Embodiments of this application relate to the technical field of testing or analyzing materials by measuring changes in heat, and specifically to a method and system for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a disposal pit. Background Technology
[0002] The statements herein are provided merely as background information in connection with this application and do not necessarily constitute prior art.
[0003] High-level radioactive waste geological repositories are typically located in deep surrounding rock. The repositories are constructed by excavating a pit in the deep surrounding rock. During the long-term decay process, high-level radioactive waste continuously releases heat, which is conducted from the repositories to the surrounding rock through heat conduction. The surrounding rock serves as the final medium for conducting the decay heat of high-level radioactive waste, and its thermal conductivity and in-situ storage environment directly affect the spacing between repositories, the spacing between repositories tunnels, and the capacity of the repositories.
[0004] Therefore, in order to assess the thermal conductivity of the surrounding rock for the heat released from the treatment reservoir and ensure the long-term safety of the treatment reservoir, it is necessary to determine the thermal conductivity of the surrounding rock in the current excavation area during the excavation of the treatment pit in order to know the thermal conductivity of the surrounding rock in this area. However, the existing methods for determining the thermal conductivity of the surrounding rock still have many shortcomings. Summary of the Invention
[0005] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.
[0006] In a first aspect, embodiments of this application provide a method for determining the thermal conductivity of surrounding rock in the excavation area during the excavation of a treatment pit, comprising the following steps: S10: determining a thermal calibration zone at a predetermined location within the treatment pit; S20: arranging a first temperature sensor and a second temperature sensor at predetermined locations outside the treatment pit; S30: obtaining initial temperature data of the surrounding rock before excavation using the first and second temperature sensors; S40: obtaining temperature data of the surrounding rock during excavation using the first and second temperature sensors; S50: given an initial thermal conductivity of the surrounding rock, determining the theoretical temperature of the second temperature sensor based on the measured temperature of the first temperature sensor and the given initial thermal conductivity of the surrounding rock; S60: determining the theoretical temperature based on the measured temperature of the second temperature sensor and the theoretical temperature. S70: Determine the thermal conductivity of the surrounding rock in the thermal calibration zone based on the optimal thermal diffusivity; S80: Determine the heat source power of the surrounding rock in the thermal calibration zone based on the measured temperature of the first temperature sensor, the optimal thermal diffusivity determined in step S60, and the thermal conductivity determined in step S70; S90: Determine the heat conversion coefficient of the cutterhead based on the heat source power of the surrounding rock in the thermal calibration zone; S100: Determine the heat source power of the current tunneling area of the surrounding rock based on the heat conversion coefficient of the cutterhead; S110: Determine the theoretical temperature of the sensor arranged in the current tunneling area based on the heat source power determined in step S100; S120: Determine the thermal conductivity of the current tunneling area based on the measured temperature of the sensor in the current tunneling area and the theoretical temperature of the sensor in the current tunneling area.
[0007] The method for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit, as provided in the embodiments of this application, involves arranging a first temperature sensor and a second temperature sensor at predetermined positions outside the treatment pit. These sensors obtain initial temperature data of the surrounding rock before excavation and temperature data during the excavation process. This allows for real-time acquisition of temperature response data influenced by the heat generated by the friction, cutting, compression, and crushing actions of the cutterhead on the surrounding rock during excavation, thereby obtaining the heat conduction process within the surrounding rock. Then, by providing an initial thermal conductivity of the surrounding rock and combining it with the real-time acquired temperature response data, the thermal conductivity of the surrounding rock in the thermal calibration zone of the treatment pit is determined. This facilitates the calibration of the heat conversion coefficient of the cutterhead, providing an accurate data basis for subsequently determining the thermal conductivity of the surrounding rock in the excavation area. Furthermore, based on the heat conversion coefficient of the cutterhead, the heat source power of the current excavation area of the surrounding rock is determined. Thus, the thermal conductivity of the current excavation area of the surrounding rock is inferred from the heat source power. Compared to traditional methods for determining the thermal conductivity of surrounding rock, this method eliminates the need to obtain core samples from the current excavation area, enabling real-time and accurate determination of the thermal conductivity of the current excavation area of the surrounding rock.
[0008] Secondly, embodiments of this application provide a system for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit. The system includes a calibration module, a first temperature sensor, a second temperature sensor, and a processor. The calibration module is configured to determine a thermal calibration zone at a predetermined location within the treatment pit. The first and second temperature sensors are arranged at predetermined locations outside the treatment pit. The system is configured to use the first and second temperature sensors to obtain initial temperature data of the surrounding rock before excavation and to obtain temperature data of the surrounding rock during the excavation process. The processor is set to a given initial surrounding rock thermal conductivity. Based on the measured temperature of the first temperature sensor, the theoretical temperature of the second temperature sensor is determined. Based on the measured temperature of the second temperature sensor and the theoretical temperature, the optimal thermal diffusivity is determined. Based on the optimal thermal diffusivity, the surrounding rock thermal conductivity of the thermal calibration zone is determined. Based on the measured temperature of the first temperature sensor, the optimal thermal diffusivity, and the surrounding rock thermal conductivity of the thermal calibration zone, the heat source power of the surrounding rock thermal calibration zone is determined. Based on the heat source power of the surrounding rock thermal calibration zone, the heat conversion coefficient of the cutterhead is determined. Based on the heat conversion coefficient of the cutterhead, the heat source power of the current tunneling area of the surrounding rock is determined. Based on the heat source power of the current tunneling area of the surrounding rock, the theoretical temperature of the sensors arranged in the current tunneling area is determined. Based on the measured temperature of the sensors in the current tunneling area and the theoretical temperature of the sensors in the current tunneling area, the thermal conductivity of the current tunneling area is determined. Attached Figure Description
[0009] Other objects and advantages of this application will become apparent from the following description of embodiments of this application with reference to the accompanying drawings, and will help to provide a comprehensive understanding of this application.
[0010] Figure 1 This is a schematic diagram illustrating the principle of a method for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a disposal pit, according to an embodiment of this application. Figure 2 This is a schematic diagram of the actual treatment pit and surrounding rock at the excavation site. Figure 3 This is a schematic diagram showing the placement of the first and second temperature sensors outside the actual treatment pit at the excavation site.
[0011] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding. Detailed Implementation
[0012] Exemplary embodiments of this application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.
[0013] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the equipment structure and / or processing steps closely related to the solution according to this application are shown in the accompanying drawings, while other details that are not closely related to this application are omitted.
[0014] The inventors of this application have discovered that, in related technologies, to determine the thermal conductivity of surrounding rock, core samples are typically drilled from the current excavation area of the surrounding rock treatment pit, and the core samples are tested indoors using methods such as steady-state method, transient hot wire method, and transient planar heat source method to determine their thermal conductivity. However, since indoor testing is detached from the in-situ stress, temperature, humidity, and groundwater environment of the surrounding rock treatment pit, the measurement results are difficult to reflect the true thermal conductivity of the surrounding rock in the excavation area. Furthermore, the size of the core samples used for testing is limited, making it difficult to reflect the influence of joints, fissures, and heterogeneity at the rock mass scale on its thermal conductivity. During the acquisition, transportation, packaging, and sample preparation of the core samples, the water content and micro-fissure state of the samples may also be altered, leading to inaccurate thermal conductivity measurement results.
[0015] Furthermore, during the excavation of the surrounding rock treatment pit, the excavation equipment such as the cutterhead will experience friction, cutting, compression and crushing with the surrounding rock, generating heat. In the relevant technologies for determining the thermal conductivity of the surrounding rock, this heat is usually regarded as construction disturbance or test noise, and it is not used as an effective heat source for measuring the thermal conductivity of the surrounding rock.
[0016] Based on this, embodiments of this application provide a method for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a disposal pit, which includes the following steps: S10: Determine the thermal calibration zone at the predetermined location of the treatment pit.
[0017] S20: Arrange a first temperature sensor and a second temperature sensor at a predetermined location outside the treatment pit.
[0018] S30: Using the first and second temperature sensors, the initial temperature data of the surrounding rock is obtained before excavation.
[0019] S40: During the excavation process, temperature data of the surrounding rock is obtained using the first and second temperature sensors.
[0020] S50: Given the initial thermal conductivity of the surrounding rock, determine the theoretical temperature of the second temperature sensor based on the measured temperature of the first temperature sensor and the given initial thermal conductivity of the surrounding rock.
[0021] S60: Determine the optimal thermal diffusivity based on the measured temperature from the second temperature sensor and the theoretical temperature.
[0022] S70: Determine the thermal conductivity of the surrounding rock in the thermal calibration zone based on the optimal thermal diffusivity.
[0023] S80: Determine the heat source power of the thermal calibration zone of the surrounding rock based on the measured temperature of the first temperature sensor, the optimal thermal diffusivity determined in step S60, and the thermal conductivity determined in step S70.
[0024] S90: Determine the heat conversion coefficient of the cutterhead based on the heat source power of the surrounding rock's thermal calibration zone.
[0025] S100: Determine the heat source power of the current tunneling area of the surrounding rock based on the heat conversion coefficient of the cutterhead.
[0026] S110: Based on the heat source power determined in step S100, determine the theoretical temperature of the sensors deployed in the current tunneling area.
[0027] S120: Determine the thermal conductivity of the current tunneling area based on the measured temperature of the sensor in the current tunneling area and the theoretical temperature of the sensor in the current tunneling area.
[0028] The method for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit, as provided in the embodiments of this application, involves arranging a first temperature sensor and a second temperature sensor at predetermined positions outside the treatment pit. These sensors obtain initial temperature data of the surrounding rock before excavation and temperature data during the excavation process. This allows for real-time acquisition of temperature response data influenced by the heat generated by the friction, cutting, compression, and crushing actions of the cutterhead on the surrounding rock during excavation, thereby obtaining the heat conduction process within the surrounding rock. Then, by providing an initial thermal conductivity of the surrounding rock and combining it with the real-time acquired temperature response data, the thermal conductivity of the surrounding rock in the thermal calibration zone of the treatment pit is determined. This facilitates the calibration of the heat conversion coefficient of the cutterhead, providing an accurate data basis for subsequently determining the thermal conductivity of the surrounding rock in the excavation area. Furthermore, based on the heat conversion coefficient of the cutterhead, the heat source power of the current excavation area of the surrounding rock is determined. Thus, the thermal conductivity of the current excavation area of the surrounding rock is inferred from the heat source power. Compared to traditional methods for determining the thermal conductivity of surrounding rock, this method eliminates the need to obtain core samples from the current excavation area, enabling real-time and accurate determination of the thermal conductivity of the current excavation area of the surrounding rock.
[0029] In some embodiments, in step S10, a treatment pit area with uniform lithology and good integrity is selected as a thermal calibration zone. By selecting such a zone as a thermal calibration zone, the proportion of mechanical energy of the cutterhead converted into thermal energy of the surrounding rock during the excavation of the treatment pit can be accurately obtained. This facilitates the calibration of the thermal conversion coefficient of the cutterhead, ensuring the accuracy and reliability of the determined thermal conversion coefficient of the cutterhead, and thereby improving the accuracy of the thermal conductivity of the current excavation area of the surrounding rock determined subsequently.
[0030] In some embodiments, in step S20, the two sensors are arranged on the same straight line as the center of the treatment pit. In this embodiment, by arranging the first and second temperature sensors in this way, the fixed distance between the two sensors is the temperature gradient, which simplifies the subsequent calculation process. Furthermore, since the heat generated by the friction, cutting, compression, and crushing of the surrounding rock during excavation is mainly conducted from the sidewall of the treatment pit along its radial direction towards the interior of the surrounding rock, the heat conduction process between the first and second temperature sensors can be approximated as a one-dimensional unsteady-state heat conduction process. Using this one-dimensional unsteady-state heat conduction process facilitates the accurate determination of the theoretical temperature of the second temperature sensor.
[0031] In some embodiments, step S20, when arranging the first temperature sensor and the second temperature sensor, may further include the following steps: S21: outside the treatment pit, two boreholes are arranged along the radial direction of the treatment pit, with the borehole depth exceeding the center of the treatment pit; S22: the first temperature sensor and the second temperature sensor are respectively arranged in the two boreholes, so that the two sensors are on the same straight line as the center of the treatment pit; S23: the two boreholes are backfilled, so that the two sensors form thermal contact with the surrounding rock.
[0032] In this embodiment, two boreholes are laid out to allow two sensors to be placed outside the treatment pit on the same straight line as the center of the treatment pit. After the sensors are placed in the boreholes, the boreholes are backfilled so that the two sensors can make thermal contact with the surrounding rock. This allows the two sensors to collect temperature response data in real time from the heat generated by the friction, cutting, squeezing and crushing of the surrounding rock by the cutterhead during the excavation process.
[0033] In some embodiments, in step S21, the two drill holes are positioned at different distances from the sidewall of the treatment pit. A first temperature sensor is placed in the drill hole relatively close to the sidewall, and a second temperature sensor is placed in the drill hole relatively far from the sidewall. The first temperature sensor is used to obtain the near-field temperature, and the second temperature sensor is used to obtain the far-field temperature. The far-field theoretical temperature is determined by measuring the near-field temperature, and thus, the optimal thermal diffusivity is accurately determined using the far-field measured temperature and the theoretical temperature. For example, the two drill holes are positioned at distances of 0.15 m and 0.3 m from the sidewall of the treatment pit, respectively.
[0034] In some embodiments, in step S23, thermally conductive sealing material can be used to backfill the two boreholes so that the two sensors installed in the boreholes can form a stable thermal contact with the surrounding rock.
[0035] In some embodiments, in step S30, before the treatment pit is excavated, the temperature of the surrounding rock is continuously monitored for a predetermined time, such as 12 hours, using a first temperature sensor and a second temperature sensor to obtain initial temperature data of the surrounding rock.
[0036] In some embodiments, in step S40, during the excavation of the treatment pit, the current surrounding rock temperature is continuously recorded using a first temperature sensor and a second temperature sensor at a predetermined sampling interval to obtain temperature data of the surrounding rock at multiple sampling times. The sampling interval can be selected as 1 minute.
[0037] In some embodiments, step S50 specifically includes the following steps: S51: Determine the initial measurement temperature of the second temperature sensor.
[0038] S52: Determine the distance between the first temperature sensor and the center of the treatment pit, and the distance between the second temperature sensor and the center of the treatment pit.
[0039] S53: Determine the initial thermal diffusivity of the surrounding rock based on the given initial thermal conductivity of the surrounding rock.
[0040] S54: Determine the theoretical temperature of the second temperature sensor based on the measured temperature of the first temperature sensor, the initial measured temperature of the second temperature sensor, the distance between the first temperature sensor and the center of the treatment pit, the distance between the second temperature sensor and the center of the treatment pit, and the initial thermal diffusivity of the surrounding rock.
[0041] In this embodiment, the rate of change of the measured temperature of the first temperature sensor over time, the initial measured temperature of the second temperature sensor, the distances of the two sensors from the center of the treatment pit, and the initial thermal diffusivity of the surrounding rock determined based on the given initial thermal conductivity of the surrounding rock are considered. This helps to reduce the numerical error of the theoretical temperature of the second temperature sensor, making the optimal thermal diffusivity determined based on the measured temperature of the second temperature sensor and the theoretical temperature closer to the true value. Thus, it is beneficial to determine the thermal conductivity of the surrounding rock in the thermal calibration zone that is more consistent with the actual situation.
[0042] In some embodiments, in step S53, the given initial thermal conductivity of the surrounding rock and the initial thermal diffusivity of the surrounding rock conform to the following relationship: .
[0043] in, The initial thermal diffusivity of the surrounding rock is given by . Given the initial thermal conductivity of the surrounding rock, Let ρ be the density of the surrounding rock, and c be the specific heat capacity of the surrounding rock.
[0044] In some embodiments, in step S54, the measured temperature of the first temperature sensor, the initial measured temperature of the second temperature sensor, the distance between the first temperature sensor and the center of the treatment pit, the distance between the second temperature sensor and the center of the treatment pit, the initial thermal diffusivity of the surrounding rock, and the theoretical temperature of the second temperature sensor conform to the following relationship: .
[0045] in, for The theoretical temperature of the second temperature sensor at time i, where i is the index of the i-th data point and j is the index of the j-th data point. The initial measurement temperature of the second temperature sensor. The distance between the first temperature sensor and the center of the treatment pit. The distance between the second temperature sensor and the center of the treatment pit. For the first temperature sensor Temperature measurement at any given time For the first temperature sensor Temperature measurement at any given time The initial thermal diffusivity of the surrounding rock is given by . Let i be the time corresponding to point i. Let j be the time corresponding to point j. This is the time corresponding to point j-1.
[0046] In this embodiment, by establishing the relationship between the measured temperature of the first temperature sensor, the initial measured temperature of the second temperature sensor, the distance between the first temperature sensor and the center of the treatment pit, the distance between the second temperature sensor and the center of the treatment pit, the initial thermal diffusivity of the surrounding rock, and the theoretical temperature of the second temperature sensor, it is beneficial to accurately determine the theoretical temperature of the second temperature sensor, providing a reliable data basis for subsequently determining the thermal conductivity of the surrounding rock in the thermal calibration zone.
[0047] Furthermore, in the above relationship, erfc(x) represents the residual error function, which is the spatial distribution function of heat after diffusion into an infinite medium. Specifically, it represents the proportion of the remaining temperature influence after the boundary temperature disturbance propagates to a distance x within time t. ) / 2 represents the distance between the midpoint of the first temperature sensor and the second temperature sensor and the center of the treatment pit.
[0048] In some embodiments, in step S60, the optimal thermal diffusivity is determined using the least squares method based on the measured temperature of the second temperature sensor and the theoretical temperature. In this embodiment, the least squares method is used to accurately determine the optimal diffusivity by minimizing the sum of squared errors between the measured temperature of the second temperature sensor and the theoretical temperature. Therefore, based on the optimal value of the surrounding rock thermal diffusivity, the thermal conductivity of the surrounding rock in the thermal calibration zone that better matches the actual situation is determined.
[0049] Specifically, step S60 may include the steps of: determining the least squares objective function, and adjusting the thermal diffusivity to minimize the objective function in order to obtain the optimal thermal diffusivity.
[0050] Furthermore, the objective function takes the following form: .
[0051] Where J represents the objective function, N represents the total number of sampling times, and k represents the k-th sampling time. This represents the temperature data of the surrounding rock at the k-th sampling time. This indicates the theoretical temperature of the second temperature sensor. This indicates the temperature measured by the second temperature sensor.
[0052] In some embodiments, in step S70, the optimal thermal diffusivity and the thermal conductivity of the surrounding rock in the thermal calibration zone conform to the following relationship: .
[0053] in, The thermal conductivity of the surrounding rock in the thermal calibration zone. For optimal thermal diffusivity, Let ρ be the density of the surrounding rock, and c be the specific heat capacity of the surrounding rock.
[0054] In some embodiments, step S80 specifically includes the following steps: S81: Determine the temperature of the surrounding rock when the cutterhead is in its current position based on the temperature measured by the first temperature sensor; S82: Determine the diameter of the treatment pit, the length of the temperature sensor's measurement area, the cutting head's feed speed, and the distance between the first temperature sensor and the excavated sidewall of the treatment pit. S83: Determine the heat source power of the surrounding rock's thermal calibration zone based on the temperature of the surrounding rock at the current position of the cutterhead, the diameter of the treatment pit, the length of the temperature sensor's measurement area, the cutterhead's advance speed, the distance between the first temperature sensor and the excavated sidewall of the treatment pit, the optimal thermal diffusivity, and the thermal conductivity of the surrounding rock in the thermal calibration zone.
[0055] In this embodiment, the temperature of the surrounding rock at the current position of the cutterhead is determined by measuring the temperature of the first temperature sensor. That is, the correspondence between the temperature of the surrounding rock collected by the first temperature sensor and time is converted into the correspondence between the temperature of the surrounding rock and the current position of the cutterhead. Then, combined with the diameter of the treatment pit, the length of the measurement area of the temperature sensor, the advance speed of the cutterhead, and the distance between the first temperature sensor and the side wall of the treatment pit, the influence factors of the heat source power in the thermal calibration zone are comprehensively considered. The heat generated by the heat source in the thermal calibration zone of the surrounding rock per unit time is accurately determined, which helps to reduce the error between the subsequently determined heat conversion coefficient of the cutterhead and the actual situation.
[0056] In some embodiments, in step S83, the temperature of the surrounding rock when the cutterhead is in its current position, the diameter of the treatment pit, the length of the measurement area of the temperature sensor, the cutting speed of the cutterhead, the distance between the first temperature sensor and the excavated sidewall of the treatment pit, the optimal thermal diffusivity, the thermal conductivity of the surrounding rock in the thermal calibration zone, and the heat source power of the surrounding rock in the thermal calibration zone conform to the following relationship: .
[0057] in, For the cutter head in The theoretical temperature of the surrounding rock at the given location, where k is the index of the k-th data point. The position of the cutter head corresponding to the time at point k. The initial temperature of the first temperature sensor. Let be the thermal conductivity of the surrounding rock in the thermal calibration zone, and D be the diameter of the treatment pit. Where is the length of the temperature sensor's measurement area, and v is the feed speed of the cutter head. In order to be in The heat source power of the thermal calibration zone of the surrounding rock at the location. In order to be in The heat source power of the thermal calibration zone of the surrounding rock at the location. For optimal thermal diffusivity, Let be the distance between the first temperature sensor and the excavated sidewall of the treatment pit, and j be the index of the j-th data point. The position of the tool turret corresponding to the time at point j. The position of the tool turret corresponding to the time at point j-1.
[0058] In some embodiments, in step S90, the heat source power of the thermal calibration zone of the surrounding rock and the heat conversion coefficient of the cutterhead conform to the following relationship: .
[0059] in, The heat transfer coefficient of the cutter head. The heat source power of the thermal calibration zone of the surrounding rock. This refers to the idle power of the cutter head. denoted as η, where n is the total number of valid data points used in the thermal conversion coefficient calibration, and k is the index of the k-th data point.
[0060] In some embodiments, in step S100, the thermal conversion coefficient of the cutterhead and the heat source power of the current excavation area of the surrounding rock conform to the following relationship: .
[0061] in, The heat source power of the current excavation area in the surrounding rock. The heat transfer coefficient of the cutter head. This refers to the idle power of the cutter head. This refers to the mechanical work done by the cutter head.
[0062] In some embodiments, step S110 specifically includes the following steps: given the thermal diffusivity of the surrounding rock; determining the theoretical temperature of the sensor arranged in the current tunneling area based on the given thermal diffusivity of the surrounding rock and the heat source power of the current tunneling area of the surrounding rock.
[0063] Furthermore, in step S110, the given thermal diffusivity of the surrounding rock, the heat source power of the current excavation area of the surrounding rock, and the theoretical temperature of the sensors deployed in the current excavation area conform to the following relationship: .
[0064] in, To be arranged in The theoretical temperature of the sensor in the tunneling area at the location, where k is the index of the k-th data point. This represents the location of the tunneling area corresponding to the time at point k. The initial temperature of the first temperature sensor. Let be the thermal conductivity of the surrounding rock in the thermal calibration zone, and D be the diameter of the treatment pit. Where is the length of the temperature sensor's measurement area, and v is the feed speed of the cutter head. For the surrounding rock The heat source power of the tunneling area at the location, For the surrounding rock The heat source power of the tunneling area at the location, Given the thermal diffusivity of the surrounding rock, Let be the distance between the first temperature sensor and the excavated sidewall of the treatment pit, and j be the index of the j-th data point. Let j be the location of the tunneling area corresponding to the time corresponding to point j. This represents the location of the tunneling area corresponding to the time of point j-1.
[0065] In some embodiments, in step S120, when determining the sensor's measured temperature in the current tunneling area, temperature measuring boreholes can be laid in the surrounding rock outside the treatment pit in the tunneling area, and the sensor can be placed in the temperature measuring boreholes to obtain the sensor's measured temperature in the current tunneling area.
[0066] In some embodiments, in step S120, the thermal conductivity of the current tunneling area is determined using the least squares method based on the measured temperature of the sensor in the current tunneling area and the theoretical temperature of the sensor in the current tunneling area. In this embodiment, the least squares method is used to minimize the sum of squared errors between the measured temperature and the theoretical temperature of the sensor in the current tunneling area, thereby facilitating the determination of a thermal conductivity that more closely matches the actual situation.
[0067] Specifically, step S120 may include the following steps: determining the least squares objective function, adjusting the thermal diffusivity to minimize the objective function to obtain the optimal thermal diffusivity; and determining the thermal conductivity of the current tunneling area based on the optimal thermal diffusivity.
[0068] Furthermore, the objective function takes the following form: .
[0069] Where J represents the objective function, N represents the total number of sampling times, and k represents the k-th sampling time. The theoretical temperature of the sensor in the current tunneling area. The sensor measures the temperature in the current tunneling area.
[0070] When determining the thermal conductivity of the current tunneling area based on the optimal thermal diffusivity, the optimal thermal diffusivity and the thermal conductivity of the current tunneling area conform to the following relationship: .
[0071] in, The thermal conductivity of the current tunneling area. For optimal thermal diffusivity, Let ρ be the density of the surrounding rock, and c be the specific heat capacity of the surrounding rock.
[0072] Please see Figure 1 , Figure 1 This illustration shows a schematic diagram of the principle of a method for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a disposal pit, according to an embodiment of this application. Figure 1 In the diagram, region 1 represents the determined thermal calibration zone, and region 2 represents the excavation zone. The treatment pit excavation system 100 for excavating the treatment pit includes a cutterhead 200. In thermal calibration zone 1, two boreholes 30 are arranged in the surrounding rock 20 outside the treatment pit 10. A first temperature sensor 40 and a second temperature sensor 50 are respectively installed in the two boreholes 30. In excavation zone 2, temperature measurement boreholes 60 are arranged in the surrounding rock 20 outside the treatment pit 10, and a sensor 70 is installed in the temperature measurement boreholes 60.
[0073] Further, please refer to Figure 2 and Figure 3 , Figure 2 This diagram shows the actual treatment pit and surrounding rock at the excavation site. Figure 3 This diagram illustrates the placement of a first temperature sensor and a second temperature sensor outside the actual treatment pit at the excavation site. Figure 3 It can be seen that two boreholes 30 are arranged in the radial direction of the surrounding rock 20 outside the treatment pit 10, and the first temperature sensor 40 and the second temperature sensor 50 are respectively installed in the two boreholes 30.
[0074] Embodiments of this application also provide a system for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit. The system includes a calibration module, a first temperature sensor, a second temperature sensor, and a processor. The calibration module is configured to determine a thermal calibration zone at a predetermined location within the treatment pit. The first and second temperature sensors are arranged at predetermined locations outside the treatment pit. The system is configured to use the first and second temperature sensors to obtain initial temperature data of the surrounding rock before excavation and to obtain temperature data of the surrounding rock during the excavation process. The processor is set to a given initial thermal conductivity of the surrounding rock. Based on the measured temperature of the first temperature sensor, the theoretical temperature of the second temperature sensor is determined. Based on the measured temperature of the second temperature sensor and the theoretical temperature, the optimal thermal diffusivity is determined. Based on the optimal thermal diffusivity, the thermal conductivity of the surrounding rock in the thermal calibration zone is determined. Based on the measured temperature of the first temperature sensor, the optimal thermal diffusivity, and the thermal conductivity of the surrounding rock in the thermal calibration zone, the heat source power of the thermal calibration zone of the surrounding rock is determined. Based on the heat source power of the thermal calibration zone of the surrounding rock, the heat conversion coefficient of the cutterhead is determined. Based on the heat conversion coefficient of the cutterhead, the heat source power of the current tunneling area of the surrounding rock is determined. Based on the heat source power of the current tunneling area of the surrounding rock, the theoretical temperature of the sensors arranged in the current tunneling area is determined. Based on the measured temperature of the sensors in the current tunneling area and the theoretical temperature of the sensors in the current tunneling area, the thermal conductivity of the current tunneling area is determined.
[0075] The system for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit, as provided in the embodiments of this application, utilizes a first temperature sensor and a second temperature sensor arranged at predetermined positions outside the treatment pit. These sensors acquire initial temperature data of the surrounding rock before excavation and temperature data during the excavation process. This allows for real-time acquisition of temperature response data influenced by the heat generated by the friction, cutting, compression, and crushing of the surrounding rock by the cutterhead during excavation, thereby obtaining the heat conduction process within the surrounding rock. Then, by providing an initial thermal conductivity of the surrounding rock and combining it with the real-time acquired temperature response data, the thermal conductivity of the surrounding rock in the thermal calibration zone of the treatment pit is determined. This facilitates the calibration of the heat conversion coefficient of the cutterhead, providing an accurate data basis for subsequently determining the thermal conductivity of the surrounding rock in the excavation area. Furthermore, based on the heat conversion coefficient of the cutterhead, the heat source power of the current excavation area of the surrounding rock is determined. Thus, the thermal conductivity of the current excavation area of the surrounding rock is inferred from the heat source power. Compared to traditional methods for determining the thermal conductivity of surrounding rock, this system eliminates the need to obtain core samples from the current excavation area, enabling real-time and accurate determination of the thermal conductivity of the current excavation area of the surrounding rock.
[0076] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.
[0077] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.
Claims
1. A method for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit, characterized in that, It includes the following steps: S10: Determine the thermal calibration zone at the predetermined location of the treatment pit; S20: Arrange a first temperature sensor and a second temperature sensor at a predetermined location outside the treatment pit; S30: Using the first temperature sensor and the second temperature sensor, obtain the initial temperature data of the surrounding rock before excavation; S40: During the excavation process, the temperature data of the surrounding rock is obtained using the first temperature sensor and the second temperature sensor; S50: Given an initial thermal conductivity of the surrounding rock, determine the theoretical temperature of the second temperature sensor based on the measured temperature of the first temperature sensor and the given initial thermal conductivity of the surrounding rock. S60: Determine the optimal thermal diffusivity based on the measured temperature from the second temperature sensor and the theoretical temperature; S70: Determine the thermal conductivity of the surrounding rock in the thermal calibration zone based on the optimal thermal diffusivity. S80: Determine the heat source power of the thermal calibration zone of the surrounding rock based on the measured temperature of the first temperature sensor, the optimal thermal diffusivity determined in step S60, and the thermal conductivity determined in step S70. S90: Determine the heat conversion coefficient of the cutterhead based on the heat source power of the thermal calibration zone of the surrounding rock; S100: Determine the heat source power of the current tunneling area of the surrounding rock based on the heat conversion coefficient of the cutterhead; S110: Based on the heat source power determined in step S100, determine the theoretical temperature of the sensors deployed in the current tunneling area; S120: Determine the thermal conductivity of the current tunneling area based on the measured temperature of the sensor in the current tunneling area and the theoretical temperature of the sensor in the current tunneling area.
2. The method according to claim 1, characterized in that, In step S20, the two sensors are positioned on the same straight line as the center of the treatment pit.
3. The method according to claim 1, characterized in that, The S50 procedure specifically includes the following steps: S51: Determine the initial measurement temperature of the second temperature sensor; S52: Determine the distance between the first temperature sensor and the center of the treatment pit, and the distance between the second temperature sensor and the center of the treatment pit; S53: Determine the initial thermal diffusivity of the surrounding rock based on the given initial thermal conductivity of the surrounding rock; S54: Determine the theoretical temperature of the second temperature sensor based on the measured temperature of the first temperature sensor, the initial measured temperature of the second temperature sensor, the distance between the first temperature sensor and the center of the treatment pit, the distance between the second temperature sensor and the center of the treatment pit, and the initial thermal diffusivity of the surrounding rock.
4. The method according to claim 3, characterized in that, In step S54, the measured temperature of the first temperature sensor, the initial measured temperature of the second temperature sensor, the distance between the first temperature sensor and the center of the treatment pit, the distance between the second temperature sensor and the center of the treatment pit, the initial thermal diffusivity of the surrounding rock, and the theoretical temperature of the second temperature sensor conform to the following relationship: ， in, for The theoretical temperature of the second temperature sensor at time i, where i is the index of the i-th data point and j is the index of the j-th data point. The initial measurement temperature of the second temperature sensor. The distance between the first temperature sensor and the center of the treatment pit. The distance between the second temperature sensor and the center of the treatment pit. For the first temperature sensor Temperature measurement at any given time For the first temperature sensor Temperature measurement at any given time The initial thermal diffusivity of the surrounding rock is given. Let i be the time corresponding to point i. Let j be the time corresponding to point j. This is the time corresponding to point j-1.
5. The method according to claim 1, characterized in that, In step S60, the optimal thermal diffusivity is determined using the least squares method based on the measured temperature from the second temperature sensor and the theoretical temperature.
6. The method according to claim 1, characterized in that, The S80 step specifically includes the following steps: S81: Determine the temperature of the surrounding rock when the cutterhead is in its current position based on the temperature measured by the first temperature sensor; S82: Determine the diameter of the treatment pit, the length of the measurement area of the temperature sensor, the feed speed of the cutterhead, and the distance between the first temperature sensor and the excavated sidewall of the treatment pit. S83: Determine the heat source power of the surrounding rock's thermal calibration zone based on the temperature of the surrounding rock at the current position of the cutterhead, the diameter of the treatment pit, the length of the measurement area of the temperature sensor, the advance speed of the cutterhead, the distance between the first temperature sensor and the excavated sidewall of the treatment pit, the optimal thermal diffusivity, and the thermal conductivity of the surrounding rock in the thermal calibration zone.
7. The method according to claim 6, characterized in that, In step S83, the temperature of the surrounding rock at the current position of the cutterhead, the diameter of the treatment pit, the length of the measurement area of the temperature sensor, the advance speed of the cutterhead, the distance between the first temperature sensor and the excavated sidewall of the treatment pit, the optimal thermal diffusivity, the thermal conductivity of the surrounding rock in the thermal calibration zone, and the heat source power of the surrounding rock in the thermal calibration zone conform to the following relationship: ， in, For the cutter head in The theoretical temperature of the surrounding rock at the given location, where k is the index of the k-th data point. The position of the cutter head corresponding to the time at point k. The initial temperature of the first temperature sensor. Let D be the thermal conductivity of the surrounding rock in the thermal calibration zone, and D be the diameter of the treatment pit. Let v be the length of the measurement area of the temperature sensor, and v be the feed speed of the cutter head. In order to be in The heat source power of the thermal calibration zone of the surrounding rock at the location. In order to be in The heat source power of the thermal calibration zone of the surrounding rock at the location. The optimal thermal diffusivity is... denoted as , where is the distance between the first temperature sensor and the excavated sidewall of the treatment pit, and j is the index of the j-th data point. The position of the tool turret corresponding to the time at point j. The position of the tool head corresponding to the time at point j-1.
8. The method according to claim 1, characterized in that, In step S120, the thermal conductivity of the current tunneling area is determined using the least squares method, based on the measured temperature of the sensor in the current tunneling area and the theoretical temperature of the sensor in the current tunneling area.
9. A system for determining the thermal conductivity of the surrounding rock in the excavation area during the excavation of a treatment pit, characterized in that, It includes: A calibration module, configured to determine a thermal calibration zone at a predetermined location in the treatment pit; A first temperature sensor and a second temperature sensor are arranged at predetermined positions outside the treatment pit. It is configured to use the first temperature sensor and the second temperature sensor to obtain the initial temperature data of the surrounding rock before excavation and to obtain the temperature data of the surrounding rock during the excavation process. The processor is configured to determine the theoretical temperature of the second temperature sensor based on the measured temperature of the first temperature sensor, given an initial thermal conductivity of the surrounding rock. The optimal thermal diffusivity is determined based on the measured temperature from the second temperature sensor and the theoretical temperature. The thermal conductivity of the surrounding rock in the thermal calibration zone is determined based on the optimal thermal diffusivity. The heat source power of the thermal calibration zone of the surrounding rock is determined based on the measured temperature of the first temperature sensor, the optimal thermal diffusivity, and the thermal conductivity of the surrounding rock in the thermal calibration zone. The heat conversion coefficient of the cutterhead is determined based on the heat source power of the thermal calibration zone of the surrounding rock. The heat source power of the current tunneling area of the surrounding rock is determined based on the heat conversion coefficient of the cutterhead. The theoretical temperature of the sensors deployed in the current excavation area is determined based on the heat source power of the current excavation area of the surrounding rock. The thermal conductivity of the current tunneling area is determined based on the measured temperature of the sensors in the current tunneling area and the theoretical temperature of the sensors in the current tunneling area.