Grasping the distribution characteristics of the supporting pressure and the variation with the mining advance, it provides the foundation for the colliery control theory and the decision making of efficient mining. The paper is to simulate the process of the mineral extraction by the technology of numerical simulation. In the process of mineral extraction the variation rule of the supporting pressure in the wall is payed attention to. Analyze the variation disciplinarian of them, then give some useful conclusions. There are certain guidances to the fieldwork.


Researching the motion disciplinarian of the wall rock and the variation of the stress field with mining, they provide the foundation for reducing the accidents in the mineral extraction. The sport injury of rock mass in the mining is a very complex process. Studying the movement disciplinarian of the rock formation above the coal bed and the distribution characteristics of the supporting pressure, they have very great significances in the mineral extraction so that we can advance the working face of excavating coal and dig the laneway in the proper time and spot. Due to the complexity of the motion damage, the diversity of rock substance, the Complexity factor of surrounding and etc., the research for them is limited at certain degree.

This article applies FLAC3D to stimulating the process of excavating coal so that we study the variation disciplinarian of the support pressure. This paper also puts forward some constructive advices for the fieldwork.


Through the long-term engineering practice and theory research, there are systemic researches for the basal motion regulation of the rock formation above the coal bed. The certain abundant fruits are gained.

Motion regulation of rock mass above coal bed

When the area of the goaf is small, the critical breadth is not reached. The rock mass do not break at that time. As extending of the goaf, the critical breath that leaves the rock mass break is reached and the rock mass begins to break. As the cracked rocks fill the free space of excavation and support part of the gravities of the above rock mass, the structural system reaches new balance. As continuously extending of the goaf, the rock mass breaks and the cracked rocks fill the free space of excavation once again. The rock mass reaches balance once again. The motion of the rock mass is the cyclic process that is mentioned above.

Four phases and three medium properties

The motion and the wreck of coal mass is summed up as four phases and three medium properties. Four phases:

  1. The upper plate has not cracked.

  2. The upper plate cracked, but the cracked rocks have not filled up the goaf.

  3. The cracked rocks have filled up the goaf after the upper plate cracked.

  4. The motion of the rock mass has reaches the ground.

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