STABILITY ANALYSIS OF SLOPES IN TERMS OF EFFECTIVE STRESS

抄録

Of the different types of analysing the stability of earth slopes the most convenient is known as the Swedish method, in which the circular slide surface can be commonly used. The socalled ψ = 0-analysis, based on the result of undrained shear tests, such as in situ vane tests or unconfined compression tests in the laboratory, is not appropriate for estimating the long-term stability, though it might give a correct result under fortunate conditions, when the stability of slopes just after a construction operation is treated.
This paper concerns with some important problems involved in another analysing method, called as c, ψ-analysis, in which the shear strength of soils is expressed in terms of effective stress. The stability analysis is applied to a slide occurred along a small river in the Norwegian quick clay. Combining the results of borings, samplings, in situ tests and pore pressure measurements in the field, together with those of laboratory tests, it is concluded that the composed slide surface should be used, in stead of simple circular surface. As the cause of the slide it is assumed that considerably large amount of excess pore pressure in the clay layer might contribute to the occurrence of the slide.