An experimental study of expansion deformation characteristics of weak expansive soil under multi-stage load

In order to study the expansion deformation characteristics of compaction weak expansive soil, the tests of consolidation and expansive deformation characteristics of the weak expansive soil from a slope in Gaochun were conducted. The consolidation and expansive deformation characteristics under pressures of 300, 200, 150, 100, 75, 50, 25 and 12.5 kPa in different water content and different initial water content were analyzed. The test results show that the initial dry density and water content have certain influence on the weak soil's expansive deformation, under the same other conditions, expansion deformation increases with the increasing initial dry density, and decreases with the increasing initial water content. The typical curve characteristics of the process of consolidation and deformation of the expansive soil were also analyzed. The characteristics of the boundary point on the curve of the soil consolidation and expansive between expansive area and compression area under different initial dry density and water content are summarized, and the results are given that the overlying press of a boundary point has the linear relationship between the boundary point void ratio and the initial dry density under the two initial water content. Through the analysis and fitting of the soil tests data and combined with the derivation of the relationship between the void ratio and the initial state in the process of soil deformation, the calculation methods of the expansion deformation amount of the weak expansion soil is proposed. Combined with the load distribution in the engineer wrapper methods of embankment, the layered summation method is used to deduce the calculation methods of the expansive deformation amount in the embankment, to propose the prediction calculation methods in the expansive deformation value of embankment.