Method and system for improving heat dissipation efficiency of filling paste and reducing cracking probability of the paste

Abstract

The present application belongs to the technical field of mining engineering, and specifically discloses a method and system for improving the heat dissipation efficiency of filling paste and reducing the cracking probability of the filling paste. The method is as follows: a cooling pipe network is arranged in a goaf, a water supply control pipeline and a flow regulating valve are connected to the water inlet end of the cooling pipe network, and a three-way valve is used to connect a circulating backwater passage and a discharge pipeline at the water outlet end; a temperature sensor I is fixed in the middle of the mine chamber, a temperature sensor II is arranged at the water outlet end, and each valve and sensor is connected to a control device; during the initial filling and final setting process, the water flow in the cooling pipe network is regulated to make the outlet water temperature close to the initial temperature of the filling paste; after the final setting of the filling paste, the flow regulating valve is regulated to gradually reduce the circulating water temperature in multiple stages until the temperature of the filling paste in the middle part is reduced to the first threshold range; when the real-time monitoring of the outlet water temperature exceeds the second threshold, the three-way valve is controlled to guide the high-temperature waste water into the discharge pipeline; when it is monitored that the temperature of the filling paste in the middle part is stably below the first threshold, all the equipment is stopped, each pipeline is emptied, each valve and temperature sensor is removed, and each pipe opening is closed.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering technology, particularly the field of deep-well backfilling mining method. Specifically, it relates to a method and system for improving the heat dissipation efficiency of backfill paste and reducing the probability of paste cracking, which has high accuracy and foresight, stable and reliable signal, and good heat hazard control effect. Background Technology

[0002] With the continuous increase in the mining depth of deep mines, the downward-facing backfill mining method has become the mainstream technology for ensuring the stability of the surrounding rock and controlling ground pressure and surface subsidence. To meet the requirements of high load-bearing capacity and long-term support, this method generally uses high-cement-content, high-strength cementitious paste for backfilling. However, its hydration reaction is intense, and the heat release is concentrated and large, which easily leads to a significant hydration heat accumulation effect in the closed and narrow stope space, causing two major engineering problems: First, the temperature and humidity inside the stope rise rapidly, creating a harsh working environment of high temperature and high humidity, which seriously endangers the occupational health of underground personnel and the stable operation of equipment; Second, the poor thermal conductivity of the paste makes it difficult for internal heat to be conducted and dissipated, resulting in a large temperature difference between the inside and outside of the paste and a severely uneven cooling rate, thereby generating significant temperature stress and shrinkage stress, which can easily induce cracking and spalling of the backfill, greatly reducing the integrity, long-term stability and support safety of the backfill, and directly threatening the safety of underground mining operations.

[0003] Currently, the technical means for controlling the heat of hydration in deep well paste filling have obvious shortcomings and are difficult to adapt to the process characteristics and safety requirements of down-entry filling. Traditional enhanced ventilation and cooling methods can only improve the air environment on the surface of the roadway and surrounding rock, but cannot penetrate the interior of the paste to achieve effective heat dissipation, thus having little effect on suppressing the temperature rise and temperature difference cracking of the filling body. Similarly, the literature "Research on Hydration Heat Control Technology of Paste Filling in Deep Well Downward Approach" and "Pre-embedded Water Cooling Test of Deep Well Paste Filling Body" both propose a passive cooling method using pre-embedded water pipes. While this can remove heat to some extent, it has three major shortcomings: First, due to the lack of gradient and timing control in the cooling process, direct introduction of cold water in the early stages can easily cause sudden cooling of the paste, exacerbating the temperature difference between the inside and outside, and inducing early cracks. Second, the lack of an intelligent temperature monitoring and linkage control mechanism results in the cooling intensity, water flow rate, and water temperature not matching the characteristics of the paste's solidification and hardening stage, leading to low heat dissipation efficiency and poor temperature control accuracy. Third, the direct return or nearby discharge of the cooled water after heat absorption easily forms a secondary heat source that accumulates in the mining area, not only failing to fundamentally address the heat hazard but also failing to achieve the reuse of system equipment, resulting in poor engineering economics.

[0004] It is evident that existing technologies generally lack integrated and collaborative solutions for improving heat dissipation efficiency, preventing cracking of filling materials, off-site treatment of thermal hazards, and system recycling. Furthermore, their control logic is rudimentary, and signal stability and reliability are low, failing to meet the development requirements of safe, efficient, and green mining in deep wells. Therefore, developing a method and system for heat dissipation and crack prevention of deep well filling paste that combines precise temperature control and crack prevention, efficient internal heat dissipation, intelligent regulation, directional off-site waste heat discharge, and the reusability of key equipment has become a critical technical problem urgently needing to be solved in the field of deep well down-cutting filling mining. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention provides a method for solving the problem that in down-pass backfilling mining, high-grade, high-strength cemented backfill paste releases a large amount of heat during hydration, which easily leads to high-temperature heat damage in the stope and cracking of the backfill itself due to internal and external temperature stress. This method improves the heat dissipation efficiency of the paste and improves the working environment at the working face. Furthermore, this invention provides a system for improving the heat dissipation efficiency of the backfill paste and reducing the probability of cracking.

[0006] A. Pipeline layout: Cooling water pipes are laid back and forth along the stope direction in the goaf to be filled to form a closed cooling pipeline network. The inlet of the cooling pipeline network is connected to the water supply control pipeline and a flow regulating valve is installed at the connection. At the same time, the outlet of the cooling pipeline network is connected to the circulating return water passage and the discharge pipeline in the intake air preparation slope through a three-way valve. The end of the discharge pipeline is equipped with a heat release component. B. Control connection: Temperature sensor I is detachably fixed to the cooling pipe network in the middle of the mine, and temperature sensor II is installed at the outlet of the cooling pipe network. The three-way valve, flow regulating valve, temperature sensor I and temperature sensor II are electrically connected to the control device respectively. C. Filling and heat dissipation: During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to introduce circulating water into the cooling pipe network, so that the outlet water temperature after the water flow in the cooling pipe network is heated is close to the initial temperature of the paste. D. Gradient temperature control: After the filling paste in the goaf has set, the control device adjusts the flow regulating valve to gradually reduce the circulating water temperature in multiple stages according to the hardening cycle of the filling paste, until the temperature in the middle of the filling paste drops to the first threshold range. E. Waste heat discharge: The control device monitors the outlet water temperature of the cooling pipe network in real time through temperature sensor II. When the outlet water temperature exceeds the set second threshold, the control three-way valve directs the high-temperature wastewater into the discharge pipe of the air intake ramp. Otherwise, the control three-way valve directs the outlet water into the circulating return water passage. F. System reuse: After temperature sensor I detects that the temperature in the middle of the filling paste has stabilized below the first threshold, stop all equipment and drain all pipelines. Then remove the three-way valve, flow regulating valve and temperature sensor II and close all pipe ports.

[0007] Furthermore, in step A, the cooling water pipes are laid back and forth along the direction of the mine, above the powdered ore laid on the bottom plate of the access road, and are fixed with steel bars and a false bottom. The vertical and horizontal spacing of the cooling pipe network is 0.8 to 1.5 m.

[0008] Furthermore, in step B, a pressure sensor connected to the control device is installed in the cooling pipe network; in steps C and D, the pressure sensor collects the extrusion stress signal on the cooling water pipe during the solidification process of the paste in real time and uploads it to the control device. The control device automatically adjusts the water supply pressure and water supply flow based on the extrusion stress value and a preset third threshold.

[0009] Furthermore, in step C, the initial temperature of the paste is 35-40°C; the control device regulates the flow regulating valve to control the flow rate of the circulating water in the cooling pipe network, so that the outlet water temperature of the cooling pipe network after being heated is maintained at 35-40°C.

[0010] Furthermore, in step D, the circulating water temperature is gradually reduced in three stages according to the solidification and hardening cycle of the filling paste: First stage: After final coagulation for 24 hours, the control device adjusts the flow regulating valve to maintain the outlet water temperature at 35±1℃. Second stage: 24 hours after final setting ~ 7 days, when the temperature sensor I detects that the peak temperature in the middle of the filling paste has passed and has begun to decrease, or when the sampling intensity of the filling paste exceeds 50%, the flow regulating valve is adjusted to reduce the influent flow, so that the outlet water temperature gradually drops to 22℃. Third stage: 7 days after final solidification, the control device adjusts the flow regulating valve to reduce the temperature monitored by temperature sensor I to the first threshold range.

[0011] Furthermore, in the second stage, when temperature sensor I detects that the temperature in the middle of the filling paste is below 35°C for 1 to 5 consecutive days, it is determined that the temperature peak has passed and has begun to decrease; in the third stage, the control device adjusts the flow regulating valve to reduce the outlet water temperature to below 18°C ​​until the temperature of the filling paste detected by temperature sensor I drops to the first threshold range.

[0012] Furthermore, in step E, the second threshold is 23-27°C; the heat release component is an atomizing nozzle, a heat dissipation finned tube, or a dripping device.

[0013] Furthermore, the first threshold is 23-27°C, and the three-way valve, flow regulating valve and temperature sensor II removed in step F are transferred to the next filling line for reuse.

[0014] The system of the present invention for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking is implemented as follows: it includes a cooling pipe network, a temperature monitoring module, a flow regulating valve, a water supply control pipeline, a circulating water return path, a control device, and a three-way valve. The cooling pipe network is laid back and forth along the stope inside the goaf to be filled. The water inlet of the cooling pipe network is connected to the water supply control pipeline and the water outlet of the circulating return water passage, and a flow regulating valve is installed at the connection. At the same time, the water outlet of the cooling pipe network is connected to the circulating return water passage and the existing discharge pipeline in the air intake slope through a three-way valve. The end of the discharge pipeline is equipped with a heat release component. The temperature monitoring module includes temperature sensor I and temperature sensor II. Temperature sensor I is detachably fixed to the cooling pipe network in the middle of the mine chamber and is used to monitor the temperature of the filling paste in the middle and transmit it to the control device. Temperature sensor II is set at the water outlet of the cooling pipe network and is used to monitor the water outlet temperature and transmit it to the control device. The control device, based on the monitored temperature, coordinates and regulates the flow regulating valve, the water supply pressure of the water supply regulating pipeline, and the three-way valve to achieve temperature control of the filling paste and directional off-site discharge of waste heat; wherein, the temperature monitoring module, the flow regulating valve, the three-way valve, and the control device are detachable and connectable.

[0015] Furthermore, the cooling water pipes are laid back and forth along the direction of the mine stope, above the powdered ore laid on the bottom plate of the access road, and are fixed with steel bars and a false bottom. The vertical and horizontal spacing of the cooling pipe network is 0.8 to 1.5 m. During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to introduce circulating water into the cooling pipe network, so that the outlet temperature of the water in the cooling pipe network after being heated is close to the initial temperature of the paste. After the paste filling in the goaf has finally solidified, the control device regulates the flow regulating valve to gradually reduce the circulating water temperature in multiple stages according to the solidification and hardening cycle of the paste filling, until the temperature of the middle part of the paste filling drops to the first threshold range. The control device monitors the outlet water temperature of the cooling pipe network in real time through temperature sensor II. When the outlet water temperature exceeds the set second threshold, the control device controls the three-way valve to direct the high-temperature wastewater into the discharge pipeline of the intake air preparation ramp; otherwise, the control device controls the three-way valve to direct the outlet water into the circulating return water passage. After the temperature sensor I detects that the temperature of the middle part of the paste filling has stabilized below the first threshold, the control device stops all equipment and empties all pipelines.

[0016] The present invention has the following beneficial effects: 1. This invention addresses the characteristics of deep-well mining environments, such as the enclosed environment, heat release from hydration of pastes, and high mobility of the working face. It abandons the traditional passive cooling approach of single water temperature and constant flow rate commonly used in the field and pioneers a staged gradient active temperature control process that precisely matches the setting and hardening cycle of the paste: warm water circulation with the same initial temperature as the paste is used from filling to final setting to avoid rapid cooling damage; after final setting, the temperature is gradually reduced in stages according to the temperature peak and strength growth law, thereby precisely controlling the temperature difference between the inside and outside of the paste within a safe threshold. This fundamentally solves the problem of shrinkage and cracking of the paste caused by temperature stress, and significantly improves the integrity, stability, and support safety of the filling body.

[0017] 2. This invention breaks through the limitations of existing technologies that rely on "local heat dissipation." It innovatively utilizes a novel heat dissipation model that displaces the heat of hydration of the filling paste in the mining area through cooling water and directionally transfers it to the intake air ramp. This model leverages existing low-temperature intake airways underground as natural radiators, introducing high-temperature cooling water through pre-designed pipelines for heat release. The active and rapid heat dissipation is achieved with the help of the mine's main airflow, thus completely avoiding the accumulation of secondary heat sources in the mining area. Because this new model requires no additional refrigeration equipment, it has low energy consumption and a significantly higher heat dissipation efficiency than traditional ventilation and localized water cooling. Furthermore, the directionally transferred heat can alleviate the problem of fogging in the localized low-temperature areas of the intake air ramp, thereby achieving comprehensive management of heat hazards.

[0018] 3. This invention organically integrates a closed cooling pipe network, dual temperature monitoring, intelligent threshold control, three-way valve diversion, and reusable key equipment to construct a complete process system of "precise temperature control - efficient heat dissipation - intelligent switching - cyclic reuse": Through real-time sensing by temperature / pressure sensors and linkage adjustment by control devices, the two processes of cooling and crack prevention and waste heat discharge are efficiently coordinated, and the temperature control is precise, the response is efficient, and the signal is stable and reliable; moreover, core components such as valves and some sensors can be reused across the route, and the discharge trunk line in the intake air intake ramp can be permanently reused, thereby significantly reducing the engineering cost.

[0019] 4. This invention employs an internal water cooling system with pre-embedded pipe networks within the filling paste, resulting in a heat dissipation efficiency far exceeding that of traditional air cooling. Furthermore, the entire control process does not involve the addition of chemical additives, thus not affecting the early strength of the paste. Additionally, the high-temperature wastewater, after releasing heat, can be recycled for underground dust removal and water spraying, achieving cascade utilization of thermal energy and recycling of water resources. The system of this invention can effectively adapt to the characteristics of deep underground multi-faceted and highly mobile mining with forward filling, fully meeting the requirements for safe, efficient, and green mine construction.

[0020] In summary, this invention breaks through the inherent biases of constant cooling and local heat dissipation in the industry, and pioneers a gradient temperature control anti-crack technology + waste heat spatial transfer process. It also integrates intelligent regulation and reusability architecture to solve the problems of paste cracking and heat accumulation from the source. It is particularly suitable for heat dissipation and crack prevention of paste filling in deep well down-entry routes. Attached Figure Description

[0021] Figure 1 Flowchart of the method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking in this invention; Figure 2 A schematic diagram of the condensate inlet and waste heat discharge path in a single-mine roadway filling system for improving the heat dissipation efficiency and reducing the probability of cracking of filling paste according to the present invention. Figure 3 A schematic diagram illustrating the arrangement principle of the goaf cooling pipe network and temperature sensor I of the present invention; Figure 4 A schematic diagram of the cooling pipe network layout structure in the goaf area according to the present invention; In the diagram, 1-mine stope, 2-intake ventilation ramp, 3-cooling water pipe, 4-inlet of cooling pipe network, 5-outlet of cooling pipe network, 6-temperature sensor I, 7-reinforcing bar, 8-anchor bolt. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments and accompanying drawings, but this is not intended to limit the present invention in any way. Any changes or improvements made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0023] like Figures 1 to 4 As shown, the method of the present invention for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking is characterized by including the following steps: pipeline layout, control connection, filling heat dissipation, gradient temperature control, waste heat discharge, and system reuse. The specific steps are as follows: A. Pipeline layout: Cooling water pipes 3 are laid back and forth along the direction of the stope 1 in the goaf to be filled to form a closed cooling pipeline network. The inlet end 4 of the cooling pipeline network is connected to the water supply control pipeline and a flow regulating valve is installed at the connection. At the same time, the outlet end 5 of the cooling pipeline network is connected to the circulating return water passage and the discharge pipeline in the intake air preparation slope 2 through a three-way valve. The end of the discharge pipeline is equipped with a heat release component. B. Control connection: The temperature sensor I6 is detachably fixed to the cooling pipe network in the middle of the mine 1, and the temperature sensor II is installed at the water outlet 5 of the cooling pipe network. The three-way valve, flow regulating valve, temperature sensor I6 and temperature sensor II are electrically connected to the control device respectively. C. Filling and heat dissipation: During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to introduce circulating water into the cooling pipe network, so that the outlet water temperature after the water flow in the cooling pipe network is heated is close to the initial temperature of the paste. D. Gradient temperature control: After the filling paste in the goaf has set, the control device adjusts the flow regulating valve to gradually reduce the circulating water temperature in multiple stages according to the hardening cycle of the filling paste, until the temperature in the middle of the filling paste drops to the first threshold range. E. Waste heat discharge: The control device monitors the outlet water temperature of the cooling pipe network in real time through temperature sensor II. When the outlet water temperature exceeds the set second threshold, the control three-way valve directs the high-temperature wastewater into the discharge pipe of the air intake ramp 2. Otherwise, the control three-way valve directs the outlet water into the circulating return water passage. F. System reuse: After temperature sensor I6 detects that the temperature in the middle of the filling paste has stabilized below the first threshold, stop all equipment and drain all pipelines. Then remove the three-way valve, flow regulating valve and temperature sensor II and close all pipe ports.

[0024] In step A, cooling water pipes 3 are laid back and forth along the direction of the stope 1 above the fine ore laid on the bottom plate of the access road and are reinforced with steel bars 7 and fixed to the false bottom. The vertical and horizontal spacing of the cooling pipe network is 0.8 to 1.5 m. The inlet and outlet of the cooling pipe network are securely connected to quick couplings.

[0025] In step B, a pressure sensor connected to the control device is installed in the cooling pipe network; in steps C and D, the pressure sensor collects the extrusion stress signal on the cooling water pipe 3 during the solidification process of the paste in real time and uploads it to the control device. The control device automatically adjusts the water supply pressure and water supply flow according to the extrusion stress value and a preset third threshold.

[0026] In step C, the initial temperature of the paste is 35-40°C; the control device regulates the flow regulating valve to control the flow rate of the circulating water in the cooling pipe network, so that the outlet water temperature after the cooling pipe network water is heated is maintained at 35-40°C.

[0027] In step D, the circulating water temperature is gradually reduced in three stages according to the solidification and hardening cycle of the filling paste: First stage: After final coagulation for 24 hours, the control device adjusts the flow regulating valve to maintain the outlet water temperature at 35±1℃. Second stage: 24 hours after final setting ~ 7 days, when the temperature sensor I6 detects that the peak temperature in the middle of the filling paste has passed and has begun to decrease, or when the sampling intensity of the filling paste exceeds 50%, adjust the flow regulating valve to reduce the influent (e.g., reduce by 50%), so that the outlet water temperature gradually drops to 22℃. Third stage: 7 days after final solidification, the control device adjusts the flow regulating valve to reduce the temperature monitored by temperature sensor I6 to the first threshold range.

[0028] In the second stage, when the temperature sensor I6 detects that the temperature in the middle of the filling paste is below 35°C for 1 to 5 consecutive days, it is determined that the temperature peak has passed and has begun to decrease. In the third stage, the control device adjusts the flow regulating valve to reduce the outlet water temperature to below 18°C ​​until the temperature of the filling paste detected by the temperature sensor I6 drops to the first threshold range.

[0029] In step E, the second threshold is 23-27°C; the heat release component is an atomizing nozzle, a heat dissipation finned tube, or a dripping device.

[0030] The first threshold is 23-27°C. The three-way valve, flow regulating valve, and temperature sensor II removed in step F are transferred to the next filling line for reuse. This invention relates to a system for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking, comprising a cooling pipe network, a temperature monitoring module, a flow regulating valve, a water supply control pipeline, a circulating water return path, a control device, and a three-way valve. The cooling pipe network is laid back and forth along the direction of the stope 1 inside the goaf to be filled. The water inlet 4 of the cooling pipe network is connected to the water supply control pipeline and the water outlet of the circulating return water passage, and a flow regulating valve is installed at the connection. At the same time, the water outlet 5 of the cooling pipe network is connected to the circulating return water passage and the existing discharge pipeline in the air intake and mining ramp 2 through a three-way valve. The end of the discharge pipeline is equipped with a heat release component. The temperature monitoring module includes temperature sensor I6 and temperature sensor II. Temperature sensor I6 is detachably fixed to the cooling pipe network in the middle of the mine chamber 1 and is used to monitor the temperature of the filling paste in the middle and transmit it to the control device. Temperature sensor II is set at the water outlet 5 of the cooling pipe network and is used to monitor the water outlet temperature and transmit it to the control device. The control device, based on the monitored temperature, coordinates and regulates the flow regulating valve, the water supply pressure of the water supply regulating pipeline, and the three-way valve to achieve temperature control of the filling paste and directional off-site discharge of waste heat; wherein, the temperature monitoring module, the flow regulating valve, the three-way valve, and the control device are detachable and connectable.

[0031] The cooling water pipes 3 are laid back and forth along the direction of the mine 1 above the powdered ore laid on the bottom plate of the access road and are fixed to the false bottom with steel bars 7. The vertical and horizontal spacing of the cooling pipe network is 0.8 to 1.5m. During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to introduce circulating water into the cooling pipe network, so that the outlet temperature of the water in the cooling pipe network after being heated is close to the initial temperature of the paste. After the paste filling in the goaf has finally solidified, the control device regulates the flow regulating valve to gradually reduce the circulating water temperature in multiple stages according to the solidification and hardening cycle of the paste filling, until the temperature of the middle part of the paste filling drops to the first threshold range. The control device monitors the outlet water temperature of the cooling pipe network in real time through temperature sensor II. When the outlet water temperature exceeds the set second threshold, the control device controls the three-way valve to direct the high-temperature wastewater into the discharge pipeline of the intake air ramp 2. Otherwise, the control device controls the three-way valve to direct the outlet water into the circulating return water passage. After the temperature sensor I6 detects that the temperature of the middle part of the paste filling has stabilized below the first threshold, the control device stops all equipment and empties all pipelines.

[0032] The initial temperature of the paste is 35-40℃. During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to control the flow rate of the circulating water in the cooling pipe network, so that the outlet water temperature of the cooling pipe network after being heated is maintained at 35-40℃.

[0033] The multi-stage gradient reduction of circulating water temperature refers to reducing the circulating water temperature in three stages according to the solidification and hardening cycle of the filling paste: First stage: After final coagulation for 24 hours, the control device adjusts the flow regulating valve to maintain the outlet water temperature at 35±1℃. Second stage: 24 hours after final setting ~ 7 days, when the temperature sensor I6 detects that the peak temperature in the middle of the filling paste has passed and has begun to decrease, or when the sampling intensity of the filling paste exceeds 50%, adjust the flow regulating valve to reduce the influent (e.g., reduce by 50%), so that the outlet water temperature gradually drops to 22℃. Third stage: 7 days after final solidification, the control device adjusts the flow regulating valve to reduce the temperature monitored by temperature sensor I6 to the first threshold range.

[0034] In the second stage, when the temperature sensor I6 detects that the temperature in the middle of the filling paste is below 35°C for 1 to 5 consecutive days, it is determined that the temperature peak has passed and has begun to decrease. In the third stage, the control device adjusts the flow regulating valve to reduce the outlet water temperature to below 18°C ​​until the temperature of the filling paste detected by the temperature sensor I6 drops to the first threshold range.

[0035] The first and second threshold values ​​in the control device are 23 to 27°C, respectively.

[0036] The heat release component is an atomizing nozzle, a heat dissipation finned tube, or a dripping device.

[0037] The dismantled three-way valve, flow regulating valve, and temperature sensor II are transferred to the next filling line for reuse.

[0038] The control device is a PLC, industrial computer, or other existing intelligent controller that can be applied downhole.

[0039] The three-way valve and flow regulating valve are electrically controlled valves, and the temperature sensor I6 and temperature sensor II are both existing temperature sensors that can be applied downhole.

[0040] Example

[0041] like Figures 1 to 4 As shown, taking a section of a metal mine in Yunnan Province mined using the downward-facing backfilling method as an example, high-grade, high-strength cemented paste is used to fill the goaf. To control the heat release during the hydration process of the backfill paste, the following methods are adopted: S100: A layer of fine ore is laid on the bottom plate of the access road in the goaf to be filled. Then, cooling water pipes 3 (using φ32×2.3mm PE cooling pipes) are laid back and forth along the direction of the stope 1 (the pipe spacing in all directions is 1.0m) to form a closed cooling pipe network. The cooling water pipes 3 are fixed to the false bottom by the laid steel bars 7. Then, the water inlet end 4 of the cooling pipe network is firmly connected to the quick connector and extended to the entrance of the stope 1. Then, the water supply control pipeline is connected through the quick connector and the flow regulating valve is installed at the connection. At the same time, a three-way valve is installed at the water outlet end 5 of the cooling pipe network. The three-way valve is used to connect the circulating return water passage and the discharge pipeline in the intake air preparation slope 2. At the end of the discharge pipeline, heat release components such as atomizing nozzles, heat dissipation finned tubes or drip devices are installed.

[0042] S200: Temperature sensor I6 is detachably fixed to the cooling water pipe 3 in the middle of the mine chamber 1 and electrically connected to the control device outside the filling retaining wall of the mine chamber 1 via a data cable; at the same time, temperature sensor II is installed at the outlet end 5 of the cooling pipe network, and the three-way valve, flow regulating valve, temperature sensor I6 and temperature sensor II are electrically connected to the control device respectively.

[0043] S300: During the process from the start of paste filling in the goaf to the final setting of the paste, the control device starts the water pump in the water supply regulation pipeline to circulate water into the pre-embedded cooling pipe network. The control device regulates the flow regulating valve to control the water flow rate, ensuring that the outlet temperature of the water in the cooling pipe network after heating is between 35 and 40°C (i.e., close to the initial temperature of the paste), so as to support the smooth flow of cooling water pipe 3 and equalize the initial temperature, avoiding sudden cooling of the contact surface. At the same time, this water pressure can support the pipe wall of cooling water pipe 3 to resist the compression of the paste.

[0044] S400: After the filling paste in the goaf is completed and has set (8-12 hours after filling), the control device adjusts the flow regulating valve to enter a multi-stage gradient temperature control and crack prevention mode. First stage (after final setting ~ 24h): The control device adjusts the flow regulating valve to maintain the outlet water temperature at 35℃, allowing the filling paste to initially solidify in a mild environment.

[0045] The second stage (24 hours after final setting to 7 days): When temperature sensor I6 detects that the peak temperature in the middle of the filling paste has passed and begins to decline (i.e., the middle temperature remains below 35℃ for 1-5 days), or when the sampling intensity of the filling paste exceeds 50%, the flow regulating valve is adjusted to reduce the influent flow (e.g., reducing the influent flow by 50%), so that the outlet water temperature gradually drops to 22℃. This stage is the main period of intensity growth, and gentle cooling ensures that the internal and external temperature differences are controllable.

[0046] The third stage (7 days after final setting): The control device adjusts the flow regulating valve to reduce the outlet water temperature to below 18°C ​​for subsequent cooling, until the temperature of the filling paste monitored by temperature sensor I6 drops to the first threshold range (i.e., close to the surrounding rock temperature, which is 25°C in this case).

[0047] S500: During the peak period of heat release from the hydration of the filling paste (usually 1-7 days after filling), the waste heat directional discharge mode is simultaneously activated. The control device monitors the outlet water temperature of the cooling pipe network in real time through temperature sensor II. When the outlet water temperature is higher than 25℃ (i.e., the second threshold), the three-way valve is switched to allow the high-temperature wastewater to flow directly into the discharge pipe in the relatively cool inlet air intake ramp 2 without cooling, and is discharged through the atomizing nozzle, heat dissipation finned tube, or drip device at the end of the discharge pipe. The low-temperature, high-speed inlet airflow rapidly vaporizes and cools the discharged high-temperature wastewater, and the heat is discharged with the main airflow, while reducing the probability of fogging in the inlet air intake ramp 2; otherwise, the three-way valve is not switched, and the outlet water is directed into the circulating return water passage.

[0048] S600: After temperature sensor I6 detects that the temperature in the middle of the filling paste in stope 1 stabilizes below 25℃ (i.e., the first threshold) (usually 10-14 days after filling), stop the operation of all equipment and drain the pipeline. Then, remove all valves and temperature sensors and seal all pipe openings to complete the filling of stope 1. The entire set of removed valves and temperature sensors can then be transferred to the next filling route for continued use, and the above steps can be repeated. The discharge pipeline fixed to the intake ventilation ramp 2 can be reused for the entire area.

[0049] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking, characterized in that: The process includes pipeline layout, control connection, filling and heat dissipation, gradient temperature control, waste heat discharge, and system reuse. The specific steps are as follows: A. Pipeline layout: Cooling water pipes (3) are laid back and forth along the direction of the mine (1) in the goaf to be filled to form a closed cooling pipeline network. The inlet end (4) of the cooling pipeline network is connected to the water supply control pipeline and a flow regulating valve is installed at the connection. At the same time, the outlet end (5) of the cooling pipeline network is connected to the circulation return water passage and the discharge pipeline in the intake air preparation slope (2) through a three-way valve. The end of the discharge pipeline is equipped with a heat release component. B. Control connection: The temperature sensor I (6) is detachably fixed on the cooling pipe network in the middle of the mine (1), and the temperature sensor II is installed at the water outlet (5) of the cooling pipe network. The three-way valve, flow regulating valve, temperature sensor I (6) and temperature sensor II are electrically connected to the control device respectively. C. Filling and heat dissipation: During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to introduce circulating water into the cooling pipe network, so that the outlet water temperature after the water flow in the cooling pipe network is heated is close to the initial temperature of the paste. D. Gradient temperature control: After the filling paste in the goaf has set, the control device adjusts the flow regulating valve to gradually reduce the circulating water temperature in multiple stages according to the hardening cycle of the filling paste, until the temperature in the middle of the filling paste drops to the first threshold range. E. Waste heat discharge: The control device monitors the outlet water temperature of the cooling pipe network in real time through temperature sensor II. When the outlet water temperature exceeds the set second threshold, the control three-way valve directs the high-temperature wastewater into the discharge pipeline of the air intake ramp (2). Otherwise, the control three-way valve directs the outlet water into the circulating return water passage. F. System reuse: After the temperature sensor I (6) detects that the temperature in the middle of the filling paste is stable below the first threshold, stop all equipment and drain all pipelines. Then remove the three-way valve, flow regulating valve and temperature sensor II and close all pipe ports.

2. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 1, characterized in that: In step A, the cooling water pipe (3) is laid back and forth along the direction of the mine (1) on the top of the powder ore laid on the bottom plate of the access road and is fixed with steel bars (7) and the false bottom. The vertical and horizontal spacing of the cooling pipe network is 0.8 to 1.5m.

3. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 1, characterized in that: In step B, a pressure sensor connected to the control device is installed in the cooling pipe network; in steps C and D, the pressure sensor collects the extrusion stress signal on the cooling water pipe (3) during the solidification process of the paste in real time and uploads it to the control device. The control device automatically adjusts the water supply pressure and water supply flow according to the extrusion stress value and the preset third threshold.

4. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 1, characterized in that: In step C, the initial temperature of the paste is 35-40°C; the control device regulates the flow regulating valve to control the flow rate of the circulating water in the cooling pipe network, so that the outlet water temperature after the cooling pipe network water is heated is maintained at 35-40°C.

5. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 1, characterized in that: In step D, the circulating water temperature is gradually reduced in three stages according to the solidification and hardening cycle of the filling paste: First stage: After final coagulation for 24 hours, the control device adjusts the flow regulating valve to maintain the outlet water temperature at 35±1℃. Second stage: 24 hours after final coagulation ~ 7 days, when the temperature sensor I (6) detects that the peak temperature in the middle of the filling paste has passed and has begun to decrease, or when the sampling intensity of the filling paste exceeds 50%, the flow regulating valve is adjusted to reduce the influent flow and gradually reduce the outlet water temperature to 22℃. Third stage: 7 days after final solidification, the control device adjusts the flow regulating valve to reduce the temperature monitored by temperature sensor I (6) to the first threshold range.

6. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 5, characterized in that: In the second stage, when the temperature sensor I (6) detects that the temperature in the middle of the filling paste is below 35°C for 1 to 5 consecutive days, it is determined that the temperature peak has passed and has begun to decrease; in the third stage, the control device adjusts the flow regulating valve to reduce the outlet water temperature to below 18°C ​​until the temperature of the filling paste detected by the temperature sensor I (6) drops to the first threshold range.

7. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 1, characterized in that: In step E, the second threshold is 23-27°C; the heat release component is an atomizing nozzle, a heat dissipation finned tube, or a dripping device.

8. The method for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to any one of claims 1 to 7, characterized in that: The first threshold is 23-27°C. The three-way valve, flow regulating valve and temperature sensor II removed in step F are transferred to the next filling line for reuse.

9. A system for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking, characterized in that: This includes cooling pipe network, temperature monitoring module, flow regulating valve, water supply control pipeline, circulating water return path, control device, and three-way valve. The cooling pipe network is laid back and forth along the direction of the mine (1) inside the goaf to be filled. The water inlet (4) of the cooling pipe network is connected to the water supply control pipeline and the water outlet of the circulating return water passage, and a flow regulating valve is installed at the connection. At the same time, the water outlet (5) of the cooling pipe network is connected to the circulating return water passage and the existing discharge pipeline in the air intake and mining ramp (2) through a three-way valve. The end of the discharge pipeline is equipped with a heat release component. The temperature monitoring module includes temperature sensor I (6) and temperature sensor II. Temperature sensor I (6) is detachably fixed on the cooling pipe network in the middle of the mine (1) to monitor the temperature of the filling paste in the middle and transmit it to the control device. Temperature sensor II is set at the outlet (5) of the cooling pipe network to monitor the outlet water temperature and transmit it to the control device. The control device, based on the monitored temperature, coordinates and regulates the flow regulating valve, the water supply pressure of the water supply regulating pipeline, and the three-way valve to achieve temperature control of the filling paste and directional off-site discharge of waste heat; wherein, the temperature monitoring module, the flow regulating valve, the three-way valve, and the control device are detachable and connectable.

10. The system for improving the heat dissipation efficiency of filling paste and reducing the probability of paste cracking according to claim 9, characterized in that: The cooling water pipe (3) is laid back and forth along the direction of the mine (1) above the powder ore laid on the bottom plate of the access road and is fixed with steel bars (7) to the false bottom. The vertical and horizontal spacing of the cooling pipe network is 0.8 to 1.5 m. During the process from the start of the paste filling operation in the goaf to the final solidification of the paste, the control device regulates the flow regulating valve to introduce circulating water into the cooling pipe network, so that the outlet temperature of the water in the cooling pipe network after being heated is close to the initial temperature of the paste. After the paste filling in the goaf has finally solidified, the control device regulates the flow regulating valve to reduce the circulating water temperature in multiple stages according to the solidification and hardening cycle of the paste filling, until the temperature of the middle part of the paste filling drops to the first threshold range. The control device monitors the outlet temperature of the cooling pipe network in real time through temperature sensor II. When the outlet temperature exceeds the set second threshold, the control device controls the three-way valve to direct the high-temperature wastewater into the discharge pipeline of the intake air preparation ramp (2). Otherwise, the control device controls the three-way valve to direct the outlet water into the circulating return water passage. After the temperature sensor I (6) monitors that the temperature of the middle part of the paste filling is stable below the first threshold, the control device stops all equipment and drains all pipelines.

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