Hydraulic Fracture Test And Crack Propagation Simulation By Element-Free Method

The hydraulic fracturing of rock mass is one embranchment of the fissured rock mass seepage-stress coupling research. Up to now study on this problem is just in its initial stage, lots of basic theoretical problems should be researched more deeply.Along with the development of society, lots of heavy constructions is developing to the underground, underground engineering can't separate with the force of groundwater, all of these promote the development of hydraulic fracturing research..Hydraulic fracturing is firstly applied to increase the output of oil well as a technique, and then is applied to test the preliminary ground stress. Along with construction of hydropower project, exploitation of ore, deposition of nuclear waste, development of terrestrial heat and so on, more and more geotechnical engineering is in the high hydraulic head, and deep embedded geohydrological condition, the hydraulic fracturing of rock mass is paid more and more attentions by engineering scholars.In this thesis, hydraulic fracture test basic research and calculating method was developed by support of the key project of National Natural Science Fund. Firstly the present situation of hydraulic fracturing of rock mass was talked about, then, the hydraulic fracturing of rock mass test was carried out with cement mortar (analogue material of rock mass) thick tube hollow cylinder through seepage-stress coupling apparatus that was developed by the laboratory of seepage control in Hohai. Through the analysis of data, the thesis discussed the mechanism of the hydraulic fracturing of rock mass. This thesis introduced the basic theory of element-free method, and how to trace the crack propagation of rock mass, then simulated the crack propagation of test sample without outside hydraulic pressure, and compared the calculated result with the fact status.At last, the thesis summed up the unsolved questions, and pointed out the expectations.