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Abstract Considering the geotechnical conditions of the Zhaolou coal mine，similitude material centrifugal experiment is done，and the stress variation at different positions in coal seam roof is found. The following results have been drawn. (1) Because of the excavation of coal，the pressure variation of coal pillar is evident，the influencing distance is about 35 m，10–15 m ahead the working face；and the maximum pressure concentration coefficient is produced，which reaches 2.8. (2) The pressure of immediate roof reaches its peak value，which is 1.74，immediately when the working face arrives；and it decreases firstly and then rises after the working face passes. (3) The peak value of the pressure of the basic roof occurs after 5–10 m excavation of coal，and the corresponding maximum pressure concentration coefficient reaches 3.91 on the condition of basic roof. Therefore special measures must be carried out. (4) The step of rupture on the basic roof is about 30 m. The research results are important to the design of coal channel，the excavation，and the prevention of geotechnical disaster.
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Received: 12 August 2008
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