1、PDF外文：http:/ Numerical Simulation of Coal Floor Fault Activation Influenced by Mining WANG Lian-guo,MIAO Xie-xing School of Sciences,China University of Mining&Technology,Xuzhou,Jiangsu 221008,China Abstract:By means of the numerical simulation software ANSYS,the activation regularity of c
2、oal floor faults caused by mining is simulated.The results indicate that the variation in horizontal,vertical and shear stresses,as well as the horizontal and vertical displacements in the upper and the lower fault blocks at the workface are almost identical.Influenced by mining of the floor rock,th
3、ere are stress releasing and stress rising areas at the upper part and at the footwall of the fault.The distribution of stress is influenced by the fault so that the stress isolines are staggered by the fault face and the stress is focused on the rock seam around the two ends of the fault.But the in
4、fluence in fault activation on the upper or the lower fault blocks of the workface is markedly different.When the workface is on the footwall of the fault,there is a horizontal tension stress area on the upper part of the fault；when the workface is on the upper part of the fault,it has a horizontal
5、compressive stress area on the lower fault block.When the workface is at the lower fault block,the maximum vertical displacement is 5 times larger then when the workface is on the upper fault block,which greatly increases the chance of a fatal inrush of water from the coal floor. Key words:mining；fa
6、ult activation；simulation 1 Introduction In this paper we attempt to appraise the activation regularity and deformation of coal floor faults caused by mining.Damage mechanisms of rock around coal floor faults are described from different aspects and in different contexts110.Descriptions can,to some
7、extent,intensify our understanding of coal floor fault activation caused by mining.However, looking at the effect of these views,a mechanical analysis cannot achieve the purpose of pictures and clarity.For a more profound understanding of the regularity of fault activation caused by mining at the wo
8、rkface,we use computers to make numerical simulations and obtain a series of valuable conclusions. 2 Numerical Calculation of Model Formation Considering the different fault activations influenced by the workface on the upper and lower fault blocks,we build two calculation models according to
9、the state of the plane strain.Fig.1 is a calculation model(Model )of the workface on the lower fault block,showing the loading on the top of the terrane according to the distributional characteristics11 of mine pressure.Given the conditions of mining technology of the Qinan mine,the terrane 70
10、 m fore- and-aft the workface and 30 m deep under the coal floor is simulated.The lithology of the floor is Berea sandstone and the elastic modulus E=1.09104MPa,the Poissons ratio=0.34,the cohesion C=2.94MPa,the internal friction angle=35 and the density=2.5 kN/m3.The calculation model of the workfa
11、ce on the upper part of the fault(Model )is the same as that of Model except that the abutment pressure ahead of the workface is on the upper part of the fault. 3 Numerical Simulation Results and Analysis For both models,the isoline graphs of horizontal, vertical and shear stresses as well as the ho
12、rizontal and vertical displacements of models and have been calculated and are plotted respectively as Figs.23. 3.1 Distribution characteristics of horizontal stresses Influenced by mining of the coal floor rock, there are horizontal stress releasing areas and rising areas at the upper part an
13、d at the footwall of the fault. The distribution of horizontal stresses is influenced by the fault and it is obvious that the stress isolines are staggered by the fault face and the stress is concentrated on the rock seam around the two ends of the fault. In model I,stress is concentrated at the sha
14、llow part of the orebody at the footwall of the fault.The horizontal stress is 6.410 MPa.The horizontal stress under the fault face is 3.14.9 MPa.The lower part of mined-out areas on the lower fault block releases pressure,and may even turn to tension stress of about 0.5 MPa.But in the deeper part,the horizontal stress turns to compressive stress and the value increases gradually. In model ,the stress is concentrated at the lower part of the orebody on the lower fault block and the
