Analysis on fracturing and initiation pressure and initiation location in multi slicing seam

According to multi slicing of the seam,deep depth and high varied inclination in Chongqing Songzao Mining Area,there were a blindness problem existed in t he selection of the seam fracturing parameters and the layout of the coalbed methane boreholes. The broken failure criterion of the maximum tensile stress theory was app lied to establish a model to calculate the initial pressure of the fracturing pressure for the multi slicing seam with the theoretical analysis. An experiment Analysis was cond ucted on the inclination and deep depth affected to the seam fracture initiation pressure and the initiation location. The results showed that when at a same depth,the initiat ion pressure of the seam fracturing would not be changed with the inclination changed. When at a same inclination,the initiation pressure of the seam fracturing would be i n a linear increased relation to the seam depth and would be same to the theoretical calculated initiation pressure with the variation law of the seam inclination and depth. The initiation location of the multi slicing seam fracturing would be in a soft slice.Net type cracks would be formed in the horizontal seam and there were no obvious major_ crack existed. With the inclination increased,there would be obvious major cracks formed in the inclined seam and the net type cracks around the major cracks would be st eadily reduced.