| Rock fracture is closely related to the fields of civil engineering,petroleum engineering and mining engineering.Pore and plastic zone are common in rock mass.The pore pressure and elastic-plastic properties of rock have a significant influence on the fracture properties of rock.It is of great significance to study the fracture properties of rock with pore pressure under elastic-plastic conditions,which can provide theoretical guidance for solving related engineering problems.A three-point bending test device that controls pore pressure and confining pressure respectively is designed in this paper.And a new experimental method for rock fracture toughness measurement under pore pressure condition is proposed.Multiple sets of three-point bending tests are conducted using the similar specimens with different pore pressures by using this device.At the same time,a new characterization method is proposed for rock fracture parameters under confining pressure and pore pressure.A 2D fluid-solid coupling model of finite element is built.The fracture parameters of rock under the conditions of different pore pressure and confining pressure are obtained.The rock fracture parameters obtained by experimental test,theoretical deduction and numerical simulation are compared.A numerical model of elastoplastic hydraulic fracturing is built by XFEM.The influence of elasticity,elastoplastic condition,permeability and initial pore pressure on the propagation of hydraulic fracture is studied,and the three-point bending test and theoretical derivation are verified. |
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