Water reservoir loading of long anisotropic valleys with irregular topographies

Abstract

The nature of the stress field induced by water reservoir loading of long anisotropic valleys is considered using an analytical method proposed earlier by the authors. The rock mass is modeled as a linearly elastic, transversely isotropic or nearly isotropic and homogeneous continuum that deforms under a condition of plane strain. The method is used to determine stresses in symmetric and asymmetric valleys induced by water reservoir loading with or without gravity. Numerical examples are presented to analyze the disturbance associated with a water reservoir on the existing gravitational stress field. They show that the presence of a water reservoir does not much affect the horizontal and vertical gravity-induced normal stresses except near the valley bottom. There the effect of the water reservoir is to reduce the magnitude of the gravity-induced horizontal tensile stress and to increase the magnitude of the gravity-induced vertical compressive stress. On the other hand water reservoir loading affects the gravity-induced shear stress in a relatively large region below the valley. Finally a parametric study is presented on the effect of 1. (1) water reservoir height, 2. (2) degree of anisotropy, and 3. (3) orientation of anisotropy on the magnitude and distribution of stresses induced by water reservoir loading only.