Roadway roof fall hazard classification method considering two-way unequal compressive stress field

Abstract

The invention relates to a method for grading roadway roof fall hidden dangers considering two-way unequal pressure stress field. The method obtains the radial depth of the plastic zone according to the buried depth of the roadway, the bulk density of surrounding rock, the ratio of two-way pressure, the cohesion of surrounding rock and the internal friction angle. The height of the hidden danger of roof fall is obtained from the radial depth of the plastic zone, and the level of the hidden danger of roof fall is classified according to the height of the hidden danger of roof fall. Considering the effect of in-situ stress, and overcoming the defect that the conventional surrounding rock classification method is only applicable to bidirectional isobaric stress environment, it has a better scope of application.

Description

technical field [0001] The invention belongs to the field of roadway roof fall classification, and specifically relates to a method for classifying roadway roof fall hidden dangers in consideration of two-way unequal pressure stress field, which has wider application range and higher accuracy. Background technique [0002] Due to the concealment, suddenness and high risk of roof fall in the coal roadway supported by bolts, excessive support has to be used to prevent roof fall accidents. Many coal mines waste hundreds to tens of millions of yuan in support every year. In this way, the occurrence of roof fall accidents cannot be effectively prevented. Therefore, it is necessary to classify the hidden dangers of roof fall in the roadway, and carry out differentiated support for the roadways with different levels of hidden dangers of roof fall, so as to ensure the safety of the roadway and reduce the support cost. At present, there are two main classification methods for roadway...

AI Technical Summary

Problems solved by technology

[0002] Due to the concealment, suddenness and high risk of roof fall in the coal roadway supported by bolts, excessive support has to be used to prevent roof fall accidents. Many coal mines waste hundreds to tens of millions of yuan in support every year. In this way, the occurrence of roof fall accidents cannot be effectively prevented. Therefore, it is necessary to classify the hidden dangers of roof fall in the roadway, and carry out differentiated support for the roadways with different levels of hidden dangers of roof fall, so as to ensure the safety of the roadway and reduce the support cost

At present, there are two main classification methods for roadway roof fall hazards. One is that there is a stable rock formation in the deep part of the roof, and the location of the stable rock layer determines the degree of roof fall hazard. This method plays a very important role in the targeted control of layered composite roofs under low stress conditions. Good results, but because there is no direct introduction of the important index of ground stress, there are certain limitations for the classification of roof fall hazards in high-stress roadways; another classification method is to classify the surrounding rock stability according to the loosening range of the roadway. In-situ stress is understood, but it is only applicable to roadways under the condition of two-way equal pressure strips, while most high-stress roadways are in two-way unequal pressure stress environments

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