Finite Element Analysis On Problems Of Surrounding Rockmass Stress

In this paper a new rock mass stresses measurement method which is named the Controlled Fracturing Method CFM) is studied systematically. The method to calculate the original rockmass stresses is also discussed, and the rusult compare to ABAQUS. Some useful measured and analyzed results are obtained.Essentially the new technique invoves using some technique to frature the rock mass in two or three pre-determined diretions.Then,in the light of the inherent relationship between each peak pressure (or the breakdown pressure) and the rock mass stresses,the maximum and the minimum principal stresses ,together with their respective directions,are obtained. In the controlled fracturing technique two parallel holes are drilled, into which hydraulic pressure is axes of the two holes. Presented in this paper are the mechanism governing controlled fracturing ,the morphology of rock fractures, theoretical basis for stress measurement bu the CFM, and engineering cases to which this technique is applied . In short ,the CFM is a development of the hydraulic fracturing technique over conventional stress measurement methods,this method has such advantages as being easuier and quicker to operate and requiring simpler and cheaper apparatuses. Moreover the parallel boreholes -sleeve fracturing technique for rockmass measurement is presented. This method if specially suitable for problem of high rock stress measurement . Finally ,the practial theories of calculating on original rockmass stresses form surrounding rock stresses which can be directly measured are proposed.