ABSTRACT

Strict analysis methods for geotechnical problems include three parts: Firstly, the model describing the geotechnical properties is set up, as a linear elastic body, nonlinear elastic body, or elastoplastic body must be clear. Secondly, the required parameters of the model are confirmed. Thirdly, the calculation method is found for the model to solve the engineering practical problem. Geotechnical stress-strain relationship is complex in practical engineering, having the characteristics of nonlinearity, elastic-plastic and viscoplasticity, dilatancy, anisotropy, etc., at the same time influenced by stress path and strength development degree and geotechnical condition, composition, structure and temperature and so on (Shen Zhujiang 1980, Shen Zhujiang et al. 1982). At present the studies on rock and soil mechanics are mostly for a certain type of rock and soil, and have rarely been used in specific project. To estimate the stress and displacement caused by external load in the soil, the stress-strain relationship should firstly be understood and then analyzed according to the boundary conditions. But for a long time, limited by computational difficulties and inadequate understanding of rock-soil, deformation and strength have been artificially separated during calculation. That is one problem of calculating the deformation and displacement, another is the problem of calculating maximum load or maximum stress that causes soil damage. In fact, the deformation of

soil continuously happens in the initial stress state until destruction. As a result of artificial simplified to only consider deformation without effect of yielding in local, and the only damage and no matter how deformation, making the analysis results inconsistent with the actual situation (Mechanics teaching and research section of water conservancy institute in east China 1984). Because elastic-plastic model is practical in the description of soil properties, domestic and foreign researches of elastic-plastic model have made certain achievements and elastic-plastic model is made a useful try in engineering application. However, because of the complexity of the model itself and the material of soil, whether in theory or in practice, elastic-plastic model remains constantly being improved and perfected. Especially, applied research of the model is worth further exploration in combination with regional characteristics of soil.