The Research On The Strain-softening Behavior Of The Deep Joints Rock And The Interaction Between The Surrounding Rock And The Supporting Structure

In deep mining engineering, joints is ordinary existence. Due to the deep joint rock mass ina complex and high stress of the engineering geological environment，compared with thesurrounding rock of shallow, deep surrounding rock show the very big difference in themechanical properties. The supporting design of deep engineering have facing new problems instability analysis of supporting structure and the interaction between surrounding rock-support,So, in-depth understanding of deep joint rock mass failure process of nonlinear behavior forengineering design have important guiding significance. However, due to the deep joint rockmass has strong heterogeneity and anisotropy, it is very difficult to put forward a nonlinearconstitutive model which can fully express all kinds of rock mass mechanics behavior,Especially reflect joint rock mass after the peak behavior (such as strain softening and flashbehavior, etc.) more difficult.In view of the above question, in the previous research results foundation, discusses thedeep joint rock mass damage mechanism and strength degradation characteristics.Based onHoek-Brown standards, establish contact in the quantitative GSI rock rating system and macrocontinuum theory. Constructs the equivalent strain softening model for deep joint rock mass.With FLAC3Dfinite software for the tool, comparatived with the deep roadway face spaceconstraint effect in different constitutive model, Study the the deep surrounding rocks ofdifferent GSI indicators strain localization feature, Improved nonlinear dilatancy angle model,put forward a suitable dilatancy angle of the nonlinear model for deep joint rock.According tothe yielding of u-shape set mechanical characteristics, constructs the yielding of u-shape setsupport characteristic curve; as the foundation with joint rock mass strain softening model,establish the three dimensional numerical model for deep roadway, calculation of ground rockcurves and supporting characteristic curve. And draw the following important conclusions:（1）Build a jointed rock mass equivalent strain softening model which consider confiningpressure effect, These model can reasonable expression of the process that strength graduallydegradation in joint rock mass.（2）Based on the interaction between surrounding rock-support, in roadway excavationprocess, whether constant (including the dilatancy angle is zero) dilatancy angle or nonlineardilatancy angle model, when applied supporting structure in the same position, supporting structure which under the pressure of surrounding rock are basically the same, rock dilatancyangle of surrounding rock space constraint effect is very small.（3）The construction of the yielding of U shaped steel bracket support characteristiccurve,which can be more reasonable reaction of u-shape set stress deformation characteristics, itis consistent in surrounding rock stability analysis and the actual situation.（4）Application of Convergence-Constraint Method to analysis the surrounding rockstability in deep buried level roadway and shaft, combined with the application can be seen, theConvergence-Constraint Method can be objectively reflect between the surrounding rock andsupport interaction, which can provide the reference for the similar mine construction andmining design.