Method for inhibiting development of water guide fracture zone of pre-mining grouting construction structure key layer

Abstract

The invention discloses a method for inhibiting development of a water guide fracture zone of a pre-mining grouting construction structure key layer. The method comprises the following steps that 1, an occurrence position of an overlying strata primary structure key layer is determined; 2, the development range of the water guide fracture zone is determined; 3, a construction horizon of an artificial structure key layer is analyzed and determined, and the thickness and the position of the structure key layer with the highest water guide fracture zone sweeping position are determined accordingto the overlying strata structure key layer analyzed in the step 1 and the water guide fracture zone development height calculated in the step 2; 4, the vertical thickness and the horizontal width inthe artificial structure key layer are determined; and 5, construction grouting parameters of the artificial structure key layer is determined. Therefore, an original structure key layer is thickenedand reinforced by utilizing ground horizontal directional drilling grouting construction structure key layer before coal seam stoping, the thickness and hardness characteristics of the structure key layer are improved, and vertical development of mining fractures is inhibited, so that the purpose of water-preserved coal mining is achieved.

Description

technical field [0001] The invention relates to the technical field of water disaster prevention and control in underground engineering such as underground mines, and in particular to a method for inhibiting the development of water-conducting fracture zones by pre-mining grouting to construct key layers of structures. Background technique [0002] As the coal resources in the eastern part of my country are dwindling and approaching depletion, the western region has become a key area for coal mining. Most of the coal-rich western regions are in arid and semi-arid ecologically fragile areas. The available water resources are very limited, and the contradiction between supply and demand of water resources is becoming increasingly acute. However, in the process of high-intensity coal resource development in western coal mining areas, it will inevitably cause damage to the regional groundwater environment. Therefore, coal development induces water environmental pollution and ecolo...

AI Technical Summary

Problems solved by technology

The transfer and storage of groundwater resources after coal mining is a passive treatment method after the destruction of the overlying rock aquifer and the loss of groundwater, which cannot achieve in-situ protection of the overlying rock aquifer; adjusting the mining method before mining is to sacrifice a large amount of coal The resource method does not meet the needs of high-efficiency development of coal resources in my country; during the mining process, the plugging and grouting of the water-conducting fracture zone will easily cause a large amount of slurry to flow into the goaf, resulting in a large amount of grouting and poor plugging effect. It belongs to the passive treatment method that causes the destruction and disturbance of the overburden aquifer

For example: the patent with the publication number CN102865081A discloses a water conservation mining method that determines the mining sequence of each working face in each block according to the water conservation mining condition parameters and groundwater distribution trend data. This method adopts different mining methods for different geological conditions. However, this method achieves water resource protection by adjusting the coal mining process and transferring and storing groundwater. This method destroys the structure of the overburden aquifer, and the groundwater is bound to be affected by pollutants such as oil pollution from stope equipment during the transfer and storage process. pollution; the patent publication No. CN107100625A discloses a water-retaining mining method for filling and reducing mining cracks by water injection in the overlying rock. Pressurized water injection actively compacts the lower rock mass in the overlying rock separation space to reduce the development height of the water-conducting fracture zone. During the process, it is very easy to cause a large amount of water gushing in the goaf, and there is a safety risk; the patent with the publication number of CN110242301A discloses a two-step grouting modified water-retaining coal mining method in the roof aquifer. Slurries of different materials are injected into the aquifer and the vertical fracture channel respectively. On the one hand, the thickness of the aquifer is increased before mining, and on the other hand, the vertical fracture is prevented from connecting the aquifer and the goaf after mining. Grouting was performed on the roof water-resisting layer, but the layer of the grouting water-resisting layer was not given, which did not fundamentally inhibit the development height of mining vertical water-conducting fractures, and the grout easily flowed in during the post-mining grouting process. In the gob area, the plugging effect of the fracture zone is not good, and if a large amount of chemical slurry is used, it is easy to cause groundwater pollution; the patent with the publication number CN1963148 discloses a water-retaining coal mining method using the structural key layer as the water-resisting layer. This method is to protect the structural key layer by selecting the appropriate coal mining method and process parameters, rather than fundamentally solving the problem of structural key layer rupture and water conduction, and for production mines, adjusting the coal mining method and process will cause coal resources. It is seriously wasteful and difficult to realize in reality, so it is difficult to protect the key layer of the structure; the patent with the publication number of CN106050234A discloses a construction technology for protecting groundwater during coal mining. Fractures are performed in between to form fracturing fractures penetrating the water-conducting fracture development zone, and grouting forms an isolation layer, so as to realize the protection of surface water and upper pore water, and actively release the lower fissure water

However, the fracturing of the bedrock in this method is a secondary damage to the original bedrock, which can easily cause the vertical cracks in the water-conducting fracture zone to extend upward; For grouting, since the grout has a certain solidification time, it is very easy to cause the grout to enter the caving zone along the water-conducting fissure zone and fill it to the goaf, resulting in a large amount of grout loss and waste, and causing safety risks to stope production

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