A method for preventing and treating water disaster and heat disaster of deep vertical shaft working face and utilizing geothermal energy

Abstract

This invention discloses an integrated method for preventing water and heat hazards and utilizing geothermal energy in deep vertical shaft working faces, relating to the field of mining construction engineering. It can reduce the temperature of the surrounding rock within a range of 100m to 200m below the working face using negative energy consumption, while also effectively sealing off high-pressure water hazards in the deep surrounding rock. The method is carried out in the following steps: Step 1: Drilling and pipe layout at the working face; Step 2: Extraction of high-temperature water below the working face; Step 3: Surface heat extraction; Step 4: Groundwater reinjection and flushing; Step 5: Grout preparation; Step 6: Grouting stage. The final effect is to reduce the temperature of the surrounding rock within a range of 100m to 200m below the working face using negative energy consumption, while also effectively sealing off high-pressure water hazards in the deep surrounding rock.

Description

Technical Field

[0001] This invention relates to the field of mining construction engineering. Background Technology

[0002] The development of the national economy cannot be separated from the support of energy and resources such as coal and metals. As various mineral resources in shallow strata are gradually depleted, the mining of mineral resources at depths of over 1,000 meters has gradually become the norm, and the construction of deep vertical shafts is a key prerequisite for realizing these deep mining operations.

[0003] During the construction of deep vertical shafts, water and heat hazards have become critical factors seriously threatening construction safety. Deep groundwater resources are abundant and under high pressure, making them highly susceptible to flooding into the shafts under construction, leading to mine flooding accidents. Simultaneously, as the shaft depth increases, the ground temperature gradually rises, with the surrounding rock temperature at some deep working faces exceeding 60°C. This not only poses a significant threat to the lives of miners but also severely restricts normal mine production.

[0004] However, at present, the management of water hazards and heat hazards in deep vertical shaft construction are two independent systems, and the integration of disaster management technologies is insufficient.

[0005] Pre-grouting is a common and effective method for addressing water inrush at the working face of shaft construction. When construction reaches a certain depth and severe water inrush is detected, downward-facing boreholes can be drilled at the working face. Grouting pipes are inserted into these boreholes to inject grout into the area below the working face, pre-sealing potential water sources. After excavation reaches the appropriate location, the amount of water flowing into the shaft around the perimeter will be significantly reduced.

[0006] To address the heat hazard problem at the shaft working face, a common approach is to install a cooling system on the ground. This system generates cool air through air conditioning units and then uses ventilation ducts to deliver the cool air to the shaft working face, thereby reducing the working face temperature and meeting construction requirements.

[0007] Furthermore, heat hazard control consumes a large amount of energy, including the cooling capacity directly used for cooling the working face and the cooling capacity lost during the cold air transport process. The latter is particularly significant when the well is deep. This heat hazard control method is clearly contrary to my country's energy conservation and emission reduction policy. Therefore, those skilled in the art urgently need to develop a highly integrated and more energy-efficient method for controlling water and heat hazards in deep vertical wells. Summary of the Invention

[0008] To address the above problems, this invention proposes an integrated method for preventing and controlling water and heat hazards in deep vertical shaft working faces and utilizing geothermal energy. This method can reduce the temperature of the surrounding rock within a range of 100m to 200m below the working face of the vertical shaft through negative energy consumption, and at the same time effectively seal off high-pressure water hazards in the deep surrounding rock. The technical solution of this invention is as follows: It is carried out according to the following steps: Step 1: Drilling holes and laying out pipes at the working face; The working face is cleaned and prepared, and then a drilling machine is used to drill holes in the working face. The holes in the working face include water injection holes 1, water extraction holes 2 and grouting holes 3. Water injection holes 1 and water extraction holes 2 are arranged opposite each other on the edge of the working face, while grouting holes 3 are arranged in the same way as the pre-grouting of the working face. A lower pumping pipe 16 is arranged in the pumping hole 2, and a lower return pipe 15 is arranged in the injection hole 1. The lower pumping pipe 16 is connected to the pumping water transfer tank 10 in the transfer station 12, and the lower return pipe 15 is connected to the return water transfer tank 8 in the transfer station 12. The pumping water transfer tank 10 is also connected to the inlet of the heat exchanger 17 through the upper pumping pipe 13 and the groundwater inlet pipe 18. The return water transfer tank 8 is connected to the outlet of the heat exchanger 17 through the upper return pipe 14 and the groundwater outlet pipe 19. The lower pumping pipe 16 and the upper pumping pipe 13 are respectively equipped with a first water pump 11 and a second water pump 9; Step 2: Extracting high-temperature water below the working face; The first water pump 11 is used to extract high-temperature groundwater below the working face 4 and transport it to the pumping transfer tank 10 at the transfer station 12. Then, it is lifted to the ground by the second water pump 9 and sent to the heat exchanger 17 on the ground through the groundwater inlet pipe 18. During the pumping process, the flow rate, pressure, and temperature of the water are monitored in real time. When the temperature of the pumped water is below 30℃, it indicates that the surrounding rock has been scourted and cooled. Step 3: Ground heat extraction; The extracted groundwater enters the heat exchanger 17 on the ground directly through the groundwater inlet pipe 18, where it exchanges heat with the fluid working medium on the other side. After the high-temperature groundwater releases heat and cools down, it enters the reinjection process through the groundwater outlet pipe 19. Step 4: Groundwater reinjection and flushing; The water that releases heat in the heat exchanger 17 on the ground is transferred to the return water transfer tank 8, and the water is injected back into the surrounding rock below the working face 4 by the pressurized water pump 22. Step 5: Slurry preparation; When the pumping temperature is below 30℃, the surrounding rock has been scourted and cooled, and the preparation of slurry begins. Step Six: Grouting Stage; Connect the grouting hole 3 to the grouting pipe and the grouting pump, and inject the grout into the surrounding rock through the grouting hole 3. The basic process of grouting is the same as that of pre-grouting at the working face of the vertical shaft.

[0009] In step one, the boreholes are arranged around the central axis of the well shaft, and the boreholes are drilled from the working face in the direction of well shaft excavation. All the boreholes are inclined to the outer perimeter of the well shaft.

[0010] The water injection hole 1 and the water extraction hole 2 are located on both sides of the working face; The reinjection process in step four and the pumping process in step three are run continuously to achieve a better effect of inducing water flow in deep formations. If the water volume in the pumping pipeline is insufficient, surface water is injected into the groundwater outflow pipe to enhance the water flow.

[0011] The slurry prepared in step five is a temperature-controlled slurry formed by adding 30% to 40% by volume of phase change microcapsules to ultrafine cement slurry. The phase change temperature of the core material in the phase change microcapsule is above 30°C. During the stirring process of slurry preparation, the slurry temperature is controlled below 30°C, that is, the material in the phase change microcapsule is in a solid state. After the grout enters the surrounding rock, the phase change microcapsules absorb heat, further reducing the temperature of the surrounding rock. As the grout solidifies, the purpose of grouting and water plugging is achieved.

[0012] This invention addresses the issue that existing methods for controlling water and heat hazards in deep vertical shaft working faces are independent, energy-intensive, and fail to effectively utilize geothermal energy in deep, high-temperature strata. Therefore, this invention proposes a comprehensive technology integrating water and heat hazard control with geothermal utilization in deep vertical shaft working faces. By pre-drilling holes in the working face and burying pumping and injection pipes as well as grouting pipes, high-temperature water is drawn from one side of the pumping pipe. After being transferred at a drainage transfer station, the water is lifted to a surface heat exchange system for heat exchange. The cooled water is then reinjected into the strata through an injection pipe on the other side of the working face. This pumping and reinjection process induces water flow that scours and cools the surrounding rock, thus achieving the dual effects of heat hazard control and geothermal utilization. When the temperature of the pumped water drops to approximately 30°C, the cooling process of the surrounding rock ends, and the grouting and water plugging process begins. The grout containing phase change microcapsules is injected into the surrounding rock through the grouting pipe. The phase change microcapsules absorb heat, which causes the surrounding rock to cool down further. At the same time, the solidified grout can block water, thus achieving the dual goals of water and heat hazard control. Ultimately, this forms an integrated technology for water and heat hazard prevention and geothermal utilization in deep vertical shaft working faces.

[0013] This invention can treat heat and water hazards in deep vertical shaft working faces in an integrated manner, and also effectively utilize the heat energy contained in high geothermal heat hazards. The final effect of the application is to reduce the temperature of the surrounding rock within a range of 100m to 200m below the working face of the vertical shaft with negative energy consumption, and at the same time effectively seal the high water pressure hazards in the deep surrounding rock.

[0014] This invention treats the high geothermal heat hazard of the surrounding rock in deep vertical shafts as a form of energy, fully extracting and utilizing it. Compared with previous methods for cooling and treating working faces, this method is more energy-efficient and turns waste into treasure. In addition, this invention uses phase change microcapsule slurry to uniformly treat water and heat hazards in deep vertical shaft working faces. The method is simple, easy to implement, and convenient to operate. Attached Figure Description

[0015] Figure 1 Schematic diagram of the layout of water extraction holes, water injection holes and grouting holes at the working face; Figure 2 Elevation view of the working face dewatering and reinjection process; Figure 3 Schematic diagram of a water injection transfer station; Figure 4 Schematic diagram of a ground heat exchange device; In the diagram: 1-Injection hole; 2-Pumping hole; 3-Grouting hole; 4-Working face; 5-Deep surrounding rock; 6-Well wall; 7-Induced water flow; 8-Return water transfer tank; 9-Second water pump; 10-Pumping water transfer tank; 11-First water pump; 12-Transfer station; 13-Upper pumping pipe; 14-Upper return water pipe; 15-Lower return water pipe; 16-Lower pumping pipe; 17-Heat exchanger; 18-Groundwater inlet pipe; 19-Groundwater outlet pipe; 20-Heat recovery pipe; 21-Heat extraction pipe; 22-Pressure pump. Detailed Implementation

[0016] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0017] The integrated technology for water and heat hazard prevention and geothermal utilization in deep vertical shaft working faces includes: drilling rigs, advanced drilling, water injection and extraction pipelines, water pumps, grouting pipelines, grouting pumps, grout preparation, transfer stations, heat exchangers, process monitoring systems, etc.

[0018] The drilling machine is a device used to drill holes on the working face. The drilling machine has certain requirements for controlling the deviation of the drilled holes. Water injection hole 1, water extraction hole 2, and grouting hole 3 are all drilled using the drilling machine.

[0019] The aforementioned pre-drilling is a process of drilling holes downwards from the working face of a vertical shaft using a drilling rig. The holes are arranged around the shaft's axis and are all inclined at a certain angle outwards towards the shaft axis to expand the effective area. The inclination angle is set to approximately 0.05, and the drilling depth can be determined based on the shaft construction speed. The pre-drilling includes water injection holes 1, water extraction holes 2, and grouting holes 3. Water injection holes 1 and water extraction holes 2 are both located at the edge of the working face, respectively on opposite sides. The arrangement of grouting holes 3 is similar to the traditional pre-grouting method for the working face.

[0020] The aforementioned water extraction and injection pipeline is installed in the pumping hole 2 and the injection hole 1 to extract and inject groundwater. The pipeline is made of steel, with pre-fabricated or perforated holes on its sides. During operation, one side of the injection pipeline injects water under high pressure, while the other side of the pumping pipeline draws water under negative pressure, inducing a flow of water from one side to the other to scour and cool the surrounding rock. The water extraction and injection process can be carried out in batches, such as... Figure 1 The process is carried out from top to bottom and from left to right. After completing the water pumping and injection task, the pumping hole 2 and the injection hole 1 can be directly sealed, or these pipes can be used for subsequent grouting.

[0021] The water pumps are used to power the water pumping and injection process. For the pumping process, a first water pump 11 is required to draw high-temperature water from the working face to the pumping transfer tank 10. A second water pump 9 is also required to lift the high-temperature water from the transfer station 12 to the ground. For the injection process, a water pump is installed at the transfer station 12. Return water flows back to the return transfer tank 8 in the transfer station 12 by gravity, and then is pressurized and reinjected into the surrounding rock using a water pump 22. To prevent water leakage during reinjection, a stop plug should be installed in the reinjection hole.

[0022] The grouting pipe is a pipe embedded in the grouting hole 3 for injecting grout. The pipe is made of steel, and its side is perforated or pre-fabricated for grouting. The grouting process is carried out after the first stage of water pumping is completed. Special functional grout is injected into the fissures of the surrounding rock, mainly to seal groundwater and also to partially mitigate heat damage.

[0023] The grouting pump is a device that provides power for the grouting process. The selection of the grouting pump is determined based on the grout flow rate and the required head. The required head of the grouting pump is mainly determined based on the grouting pressure to ensure the injection of grout. During the grouting process, in order to avoid grout leakage in the grouting hole 3, it is necessary to set the grout stop plug appropriately.

[0024] The slurry preparation refers to the apparatus and its supporting equipment used for slurry mixing and stirring. For deep vertical shaft construction, long-distance slurry transportation is difficult, so it is advisable to install some or all of the equipment on a suspended platform. In this invention, a certain proportion of phase change microcapsules is added to the traditional cement slurry. The phase change microcapsules account for 30% to 40% of the solid material. The phase change material in the phase change microcapsules is preferably a phase change paraffin or similar material with a phase change temperature around 30°C. The temperature is controlled below 30°C during slurry stirring to ensure that the material in the phase change microcapsules remains in a solid state. After the slurry is injected into the surrounding rock through the injection hole 3, the solid in the phase change microcapsules melts and absorbs heat, further reducing the temperature of the surrounding rock. Subsequently, the slurry gradually solidifies, sealing the cracks in the surrounding rock and acting as a water-blocking agent.

[0025] The transfer station 12 is located at a certain depth for the transfer of water for both pumping and reinjection. When the construction shaft is deep, such as over 1,000 meters, the pump's lift may be insufficient, necessitating the installation of a transfer station 12. The transfer station 12 is typically located at a depth of 700 meters underground. The transfer station 12 includes a pumping transfer tank 10 and a return transfer tank 9. When drawing water from deep underground, hot water is first pumped to the pumping transfer tank 10, then to the surface for heat exchange. After releasing heat at the surface, the cooled water enters the return transfer tank 8 of the transfer station 12, and is subsequently reinjected into the surrounding rock of the working face 4 to cool the surrounding rock.

[0026] The ground heat exchange device 17 is a heat exchange device installed on the ground to obtain deep geothermal energy, such as a plate heat exchanger or a shell-and-tube heat exchanger. One side of the ground heat exchange device 17 is connected to the groundwater inlet pipe 18 and the groundwater outlet pipe 19, while the other side is connected to the heat extraction pipe 21 and the heat recovery pipe 20. The working fluid after heat extraction can supply domestic hot water to the vicinity of the deep vertical shaft plant area.

[0027] The process monitoring system monitors the fluid pressure, flow rate, and temperature during the pumping and reinjection process, as well as the grout pressure and flow rate during the grouting process. Temperature testing during the pumping and reinjection process is used to determine the timing for starting grouting. When the temperature of the pumped water drops below 30°C, it can be considered that the surrounding rock below the working face has cooled down completely, and subsequent grouting construction can begin.

[0028] Step 1: Drilling holes in the working face; The working face is cleaned and prepared, followed by drilling using a drilling rig. The boreholes are arranged around the central axis of the shaft, starting from the working face in the direction of shaft excavation. All boreholes are inclined at a certain angle to the outer perimeter of the shaft so that the pumping and reinjection processes can affect a wider area of ​​the surrounding rock. This also facilitates grouting and water plugging of the surrounding rock around the shaft excavation area. The working face boreholes include water injection holes 1, water extraction holes 2, and grouting holes 3. Water injection holes 1 and water extraction holes 2 are arranged opposite each other at the edges of the working face, while grouting holes 3 are arranged in the same manner as the pre-grouting of the working face.

[0029] Step 2: Extracting high-temperature water below the working face; A pumping pipe is installed in the pumping hole 2. The first water pump 11 is used to pump high-temperature groundwater below the working face 4 and transport it to the pumping transfer tank 10 at the transfer station 12. Then, it is lifted to the ground by the second water pump 9 and sent to the heat exchanger 17 on the ground through the groundwater inlet pipe 18. During the pumping process, the flow rate, pressure, and temperature of the water are monitored in real time. When the temperature of the pumped water is lower than 30°C, it indicates that the surrounding rock has been basically scourted and cooled.

[0030] Step 3: Ground heat extraction; The extracted groundwater enters the surface heat exchanger 17, such as a plate heat exchanger or a shell-and-tube heat exchanger, directly through the groundwater inlet pipe 18. The high-temperature groundwater undergoes comprehensive heat exchange with the fluid working medium on the other side. The fluid working medium on the other side enters through the heat extraction pipe 21 and then flows out through the heat recovery pipe 20. After the high-temperature groundwater releases heat and cools down, it enters the reinjection process through the groundwater outlet pipe 19. The heat exchange area of ​​the heat exchanger 17 is determined according to the heat exchange volume of the fluids on both sides, and should be designed to maximize the heat release and cooling of the high-temperature groundwater.

[0031] Step 4: Groundwater reinjection and flushing; Water that releases heat in the heat exchanger 17 on the ground will be transferred to the reinjection water pipeline at the working face via the transfer station 12. The water will then be reinjected into the surrounding rock below the working face 4 by the pressurized water pump 22, effectively cooling the deep surrounding rock. The reinjection and pumping processes should ideally operate continuously to achieve better deep stratum induced water flow 7. If the water volume in the pumping pipeline is insufficient, surface water can be used to enhance the flow. The reinjection and scouring of the surrounding rock can be carried out in stages, such as... Figure 1 The scouring process is carried out in stages, from top to bottom and from left to right, to effectively cool the surrounding rock.

[0032] Step 5: Slurry preparation; When the pumping temperature drops to around 30℃, the initial cooling of the surrounding rock is complete, and the grouting stage begins. Grout preparation can be completed on a suspended platform. The grout is mainly a temperature-controlled grout formed by adding 30%~40% by volume of phase change microcapsules to traditional ultrafine cement grout. The phase change temperature of the core material in the phase change microcapsules is above 30℃, while the grout temperature needs to be controlled below 30℃ during the mixing process, meaning the material in the phase change microcapsules remains in a solid state.

[0033] Step Six: Grouting Stage; Connect the grouting pipe to the grouting pump, and inject the phase change microcapsule grout into the surrounding rock through grouting hole 3. The basic process of grouting is consistent with the pre-grouting of traditional vertical shaft working faces. After the grout enters the surrounding rock, the phase change microcapsules absorb heat, further reducing the temperature of the surrounding rock. As the grout solidifies, the purpose of grouting and water plugging is achieved. During the grouting process, the grouting pressure and grouting volume need to be monitored in real time. After grouting is completed, core drilling and water inflow detection can be performed to evaluate the grouting and water plugging effect.

[0034] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. An integrated method for preventing water and heat hazards and utilizing geothermal energy in deep vertical shaft working faces, characterized in that, Follow these steps: Step 1: Drilling holes and laying out pipes at the working face; The working face is cleaned and prepared, and then a drilling machine is used to drill holes in the working face. The holes in the working face include water injection holes (1), water extraction holes (2) and grouting holes (3). The water injection holes (1) and water extraction holes (2) are arranged opposite each other on the edge of the working face, while the grouting holes (3) are arranged in the same way as the pre-grouting of the working face. A lower pumping pipe (16) is arranged in the pumping hole (2), and a lower return pipe (15) is arranged in the injection hole (1). The lower pumping pipe (16) is connected to the pumping transfer tank (10) in the transfer station (12), and the lower return pipe (15) is connected to the return transfer tank (8) in the transfer station (12). The pumping transfer tank (10) is also connected to the inlet of the heat exchanger (17) through the upper pumping pipe (13) and the groundwater inlet pipe (18). The return transfer tank (8) is connected to the outlet of the heat exchanger (17) through the upper return pipe (14) and the groundwater outlet pipe (19). The lower pumping pipe (16) and the upper pumping pipe (13) are respectively equipped with a first water pump (11) and a second water pump (9); Step 2: Extracting high-temperature water below the working face; The first water pump (11) extracts high-temperature groundwater below the working face (4) and transports it to the pumping transfer tank (10) at the transfer station (12). Then, it is lifted to the ground by the second water pump (9) and sent to the heat exchanger (17) on the ground through the groundwater inlet pipe (18). During the pumping process, the flow rate, pressure, and temperature of the water are monitored in real time. When the temperature of the pumped water is below 30℃, it indicates that the surrounding rock has been scourted and cooled. Step 3: Ground heat extraction; The extracted groundwater enters the heat exchanger (17) on the ground directly through the groundwater inlet pipe (18), where it exchanges heat with the fluid working medium on the other side. After the high-temperature groundwater releases heat and cools down, it enters the reinjection process through the groundwater outlet pipe (19). Step 4: Groundwater reinjection and flushing; The water that releases heat from the heat exchanger (17) on the ground is transferred to the return water transfer tank (8), and the water is injected back into the surrounding rock below the working face (4) by the pressurized water pump (22); Step 5: Slurry preparation; When the pumping temperature is below 30℃, the surrounding rock has been scourted and cooled, and the preparation of slurry begins. Step Six: Grouting Stage; Connect the grouting hole (3) to the grouting pipe and the grouting pump, and inject the grout into the surrounding rock through the grouting hole (3). The basic process of grouting is the same as that of pre-grouting at the working face of the vertical shaft.

2. The integrated method for preventing water and heat hazards and utilizing geothermal energy in a deep vertical shaft working face according to claim 1, characterized in that, In step one, the boreholes are arranged around the central axis of the well shaft, and the boreholes are drilled from the working face in the direction of well shaft excavation. All the boreholes are inclined to the outer perimeter of the well shaft.

3. The integrated method for preventing water and heat hazards and utilizing geothermal energy in a deep vertical shaft working face according to claim 1, characterized in that, The water injection hole (1) and the water extraction hole (2) are located on both sides of the working face; The reinjection process in step four and the pumping process in step three are run continuously to achieve a better effect of inducing water flow in deep strata (7); if the water volume in the pumping pipe is insufficient, surface water is injected into the groundwater outflow pipe to enhance the water flow.

4. The integrated method for preventing water and heat hazards and utilizing geothermal energy in a deep vertical shaft working face according to claim 1, characterized in that, The slurry prepared in step five is a temperature-controlled slurry formed by adding 30% to 40% by volume of phase change microcapsules to ultrafine cement slurry. The phase change temperature of the core material in the phase change microcapsule is above 30°C. During the stirring process of slurry preparation, the slurry temperature is controlled below 30°C, that is, the material in the phase change microcapsule is in a solid state. After the grout enters the surrounding rock, the phase change microcapsules absorb heat, further reducing the temperature of the surrounding rock. As the grout solidifies, the purpose of grouting and water plugging is achieved.

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