Experimental study of spatial variation of migmatite and chlorite quartz schist's strength

In order to analysis spatial variability of migmatite and Chlorite quartz schist's strength,and the reliability of slope after considering spatial variability.We carried out the point load test according to line spacing sampling in the mine stope.The experimental variation function is calculating with geostatistics theory.Spherical Model,Gaussian Model and Index Model are introduced to character spatial variation of rock mass strength.The fitting analysis program is written by Using Visual Basic,relevant model parameters are obtained and the local rock mass strength analysis is performed,finally attenuation function of the variance of migmatite and chlorite quartz schist is obtained.In the end,Monte Calo and BISHOP methods are used to compare the effect of spatial variability of rock mass strength in simple model of migmatite and Chlorite quartz schist.The results indicate that regardless of the rock mass strength spatial variability(T=0) and slitting width T take smaller values(T>0) there is a gap which influenced by nugget constant C0.The slope reliability index calculation value increases after considering the spatial variability of rock mass that is in conformity with the objective reality,otherwise should be conservative analysis.But the calculated value of the slope reliability index increased with the increase of slitting width T presents the monotonous growth rule,slitting width high value calculation is more dangerous.Small width is better toslices method after considering the spatial variability of rock mass.