Method for protecting high-stress ore pillars by aid of pressure relief precrack

Abstract

The invention discloses a method for protecting high-stress ore pillars by the aid of a pressure relief precrack. After back production by an open stope method, the pressure relief precrack is formed on contact portions of the ore pillars and a top plate, and dimension parameters of the pressure relief precrack include that the height h of open seams is smaller than or equal to 0.2m, and the depth b of the open seams is larger than or equal to 0.2m and smaller than or equal to 1m. Stress transfer of the pressure relief precrack is sufficiently utilized, ores on sides of the ore pillars in a pressure relief precrack affected region is prevented from becoming a tensile-stress peeling damage region, and tensile stress peeling type damage of the ore pillars is relieved; by the aid of action of the side ore pillars after stress transfer of the pressure relief precrack, a three-way stress action body is formed in a core region of each ore pillar, core portions of the ore pillars are assuredly in a three-way compression stress state, high-strength self-bearing ability under high confining pressure of the ore pillars is sufficiently realized, and a self active protecting effect of the ore pillars is achieved. By the aid of outward stress transfer of the pressure relief precrack, plastic regions in the ore pillars are reduced, and safety and stability of the ore pillars are guaranteed.

Description

technical field [0001] The invention relates to a method for protecting pillars by applying pressure relief pre-cracks to transfer stress in underground pillars in high-stress areas, and is mainly suitable for the protection of stress-damaged pillars in underground open-field mining mines, especially for high-pressure mines. Protection of pillars damaged by stress crushing and cracking. Background technique [0002] In the production process of open-pit mining in metal mines, due to the stress redistribution under the influence of the in-situ stress of the original rock and the mining stress of production blasting, a large number of stress concentrations and high stresses are formed on the supporting pillars of the underground stope. area, causing large-area stress damage to the ore pillar, which is mainly manifested in high-stress crushing damage, pillar cracking and peeling damage, and shear damage. The occurrence of this damage form will greatly affect the stope The prod...

AI Technical Summary

Problems solved by technology

However, the problem with this protective measure is that the mechanical process of the joint action of mining and original rock stress still exists, and the high-stress environment in which the ore pillar is located and the mechanical behavior of stripping, crushing and shear failure still have an effect on the ore pillar. It is a passive protective technical measure, and under stress failure, it is difficult to use anchor rods to form anchors for reinforcement

At the same time, the construction cost of this protective measure is high, the process is complicated, and the control is difficult

Other methods include using artificial ore pillars to replace the original rock ore pillars, forming the effect of using rigidity to control rigidity. The cost and support process are more complicated, and it is difficult to control and protect the pillar damage in the safe mining of underground mines.

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