| This thesis objectively describes the pressure characteristics of shallow working face and the process of surface subsidence; analyses the granular media features of soil surface and explains the short dynamic load phenomenon while pressure coming from working face, based on work done principle of granular media. With the help of key strata theory of Academician Qian Minggao,regarding to the condition of shallow weak-cohere bedrock, and using the combinational strata theory, the forced model of pillar was built to specificly analyse the condition between sliding and rotation of the combinational strata. It was estinated that the combinational strata must be sliding under such circumstance; and figured out the maximum angle of rotation under different degree of failure. Besides, the the combinational strata stability upon periodical pressure was discussed.The thesis, taking 3-1-up-201 working face in Changhangou mine as background, systematically observing rock pressure and surface subsidence then analysing the datas, found the characteristics of law of strata behavior and surface subsidence under the conditon of shallow coal seam, the result of which is basically same as the theory. And to know more about the moving status of overlying strata, a combinational strata model upon numerical simulation was set up to explore the abutment pressure and destruction of overlying.According to roof force model, support under shallow coal seam, namely surround rock and given deformation and given load of combinational strata were used to calculate resistance on support. Then based on the reality of Changhangou, which choosing shield, the thesis analses the relationshipship between pillar resistance and r sheild support resistance of sheild, and finds a way to measure yield load of support under shallow coal seam. At the end of the thesis, it is taking support of 201 working face in Changhangou mine as an example to verify the researching conclusion.
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