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.

ON PARTIAL CLOSURE OF VARIABLE WIDTH SLIT WITH END ZONES OF PLASTIC DEFORMATIONS IN A ROCK

Рассматривается задача о сжатии изотропной горной среды с щелью переменной ширины с концевыми пластическими зонами. Считается, что взаимодействие поверхностей щели под действием тектонических и гравитационных усилий в массиве горной породы может приводить к возникновению зон контакта. Исследуется случай возникновения нескольких участков контакта берегов щели. При этом считается, что на некоторой части площадки контакта возникает сцепление берегов, на остальной части возможно проскальзывание. Нахождение неизвестных параметров, характеризующих частичное закрытие щели, сводится к решению системы сингулярных интегральных уравнений. Определены контактные напряжения, значения размеров участков контакта и концевых зон пластических деформаций. The problem of compression of an isotropic rock medium with a slit of variable width is considered. The slit has end plastic zones. It is assumed that the interaction of slit surfaces under tectonic and gravitational forces in a rock mass can lead to the formation of contact zones. The case of the occurrence of several contact areas of the slit faces is considered. It is assumed that the cohesion of the faces occurs on some part of the contact area, and slippage is possible on the rest. Finding unknown parameters characterizing the partial closure of the slit is reduced to solving a system of singular integral equations. The contact stresses, sizes of contact areas and end zones of plastic deformations are determined.