Determination of earth pressure distributions for Decomposed basalt soil slope

The completed decomposed basalt (CDB) silt is a common type of soil in the southwest area of China. With the rapid development of highway projects, many CDB soil slopes were cut for highway constructions in this area. In order to evaluate the stability of the slope, it is necessary to determine the strength parameters of CDB soil. Given the uncertainties of field conditions, in-situ load-displacement test is an effective and efficient method to estimate the passive earth pressure and strength parameters of in-situ soil. The test configurations and procedures of in-situ passive earth pressure test are described in this study. In addition, 28 in-situ load-displacement tests of two CDB soil slopes have been conducted Based on limit equilibrium theory, the calculation methods of maximum and minimum passive earth pressure are derived Strength parameters include cohesion and friction angle are also calculated The measured results are match well with the predicted results of Coulomb and Log spiral methods. Therefore, this in-situ test method can provide an adequate method for estimating passive earth pressure.