基于薄板理论的首采工作面基本顶来压步距研究

基本顶破断对工作面来压具有重要影响。为了研究首采工作面的基本顶破断机理,根据顶板发生初次破断和周期性破断时的边界条件,分别建立了四边固支、三边固支一边简支的顶板薄板力学模型。利用伽辽金法对薄板模型进行力学计算,对工作面顶板破断时基本顶岩层的应力分布特征与破断机理进行了分析。通过极限破断准则得出顶板破断位置与来压步距。结果表明:工作面基本顶破断与上覆岩层载荷、工作面长度、推进距离、岩层厚度、泊松比等因素有关,与板的弹性模量无关。现场观测顶板来压步距与理论计算结果较吻合,可为首采工作面来压预报提供依据。

Study on the basic roof weighting step of the first mining face based on thin plate theory

The basic roof breaking has an important effect on the working face weighting. In order to study the breaking mechanism of the basic roof, according to the boundary condition of the initial breaking and periodic breaking of the roof, the mechanical models of three edges fixed-one edge simply supported plate and four edges fixed plate were established. The stress distribution characteristics and breaking mechanism of the basic roof breaking were analyzed by means of the Galerkin method. The theoretical solutions of the maximum bending moment were deduced. Through the breaking criterion the roof breaking position and weighting step were obtained. The results show that the basic roof breaking was related to the overburden load, the length and advancing distance of working face, the roof thickness, the Poisson ratio, not related to the elastic modulus. The roof weighting step of field observations and theoretical results were in good agreement, which can provide the basis for the forecasting of the roof weighting.