Effect of Bedding Orientation and Spatial Variability of Stratification Shear Strength on Stability of Transversely Isotropic Rock Slope

The spatial variability of soil properties is inherent. A series of direct shear tests were carried out on strongly weathered slates samples with weak bedding planes, the result of which indicates the existence of variability of shear strength parameters. Based on the testing results, several numerical simulations of slopes were conducted considering such a variability of shear strength. The results had shown that the weak bedding planes affect the shape of sliding arc as well as the factor of safety of slopes. As the dip angle of bedding planes increases, the shape of the sliding surface changes from circular to a mixed form of circular and planner. When incorporating the spatial variability of weak planes’ shear strength into the stability analysis, the safety factors of slopes would reduce, in which the sliding arc exhibited a sliding band comprising multiple sets of sliding arcs.

Optimization of Measuring Points Layout around a Tunnel in the Transversely Isotropic Rock Mass

The arrangement of measuring points has a great impact on the uniqueness and accuracy of the back analysis of displacement. To explore the arrangement method of measuring points in the anisotropic rock mass, the principle of maximum displacement is applied to study the optimization of measuring points layout around a tunnel in the transversely isotropic rock mass. Firstly, the criterion of maximum displacement is deduced. Secondly, the variations of displacement with angle and radius are analyzed, respectively, and two key lateral pressure coefficients are obtained. Thirdly, some principles of measuring points arrangement are summarized according to the criterion of maximum displacement. Finally, an example is given to prove the correctness of these principles. These principles can be used to guide the arrangement of displacement measuring points in the transversely isotropic rock mass, especially suitable for shaft excavation in horizontal sedimentary rock.