Macro-Micro Research Of Shear Creep Characteristics And Constitutive Model In Anchored Jointed Rock Mass

With the accelerated development of the urban construction process,underground engineering is moving deeper.Along with this,many problems will be faced,the deep geological environment is complex.The rock mass anchoring mechanism does not clearly restrict the safe development of deep engineering.Exploring the time-dependent mechanism and anchoring mechanism of deep anchored rock mass is a key scientific issue to ensure the safety and stability of deep anchored surrounding rock.This paper illustrates the studies on the mechanical properties of sheared creep of anchored jointed rock mass under different joint inclination angles through the laboratory uniaxial shear creep macro test and the CT scan test combined with macro and meso composite damage model,and obtains the conclusions as follows:?1?Rock joints with different inclination angles have different degrees of deterioration in mechanical properties.As the inclination angle increases,the shear strength shows a trend of first decrease and then increase.The change law of shear strength of jointed rock masses with different joint inclination angles is as below:?_45°>?_60°??_30°>?_0°;?2?Under the condition of the same joint inclination angle,the shear creep mechanical properties of the anchored jointed rock mass are improved compared with the unanchored jointed rock mass,and the anchor rod increases the creep threshold of unstable rock mass damage.For both instantaneous and creep deformation,the anchored jointed rock mass shows a significant improvement effect compared to the unanchored jointed rock mass,especially the instantaneous deformation suppression effect of the rock mass is extremely significant;?3?An analysis was conducted on the CT scan images of anchored rock masses with different joint inclination angles of the same fault,and studies were performed on the crack growth law of anchored joint rock masses under different joint inclination angles.Furthermore,the relationship between the long-term shear strength of anchored jointed rock mass and the variation of crack increment was analyzed under different joint inclination angle conditions;?4?The processed CT images were reconstructed in three dimensions to obtain reconstructed rock masses with different joint inclination angles.Studies were performed on the correlation between the long-term shear strength of anchored jointed rock mass and the said dimension,density,and value,so as to provides a new direction for the research on the long-term shear strength of anchored jointed rock masses;?5?A composite model of macro and meso damage was established based on the studies on the relation between macro damage and mesopore volume fraction.Introduced the elastoplastic damage mass.An improved Burgers model combining macro and meso was established and related parameters were studied as well to verify the rationality of such model.