In order to study the influence law of crustal stress on the fracture pressure and hydraulic fracture during hydraulic fracturing

the physical simulation experiment which used similar materials and hydraulic fracturing experiment system is conducted; and then the information of hydraulic fracture is extracted with the help of 3D scanning device for coal rock section and displacement meter. The research results show that with the principal stress difference increases

the fracture pressure decreases gradually; the break-up time becomes shorter progressively; the superficial area of fracture surface becomes larger with the principal stress difference increases; the fracture surface also turns into rough increasingly; the fracture is easier to appear steering

bifurcation when confining pressure is close

the dynamic effects of fracturing fluid is more obvious; the fracture opening decreases with the principal stress difference increasing. The research results can provide reference and data support for the further study of hydraulic fracturing experiment and building the fracture network system.