ANALYSIS OF TWO-DIMENSIONAL PLANE STRAIN CONSOLIDATION CHARACTERISTICS FOR UNSATURATED SOILS UNDER PIECE-WISE CYCLIC LOADING

On basis of the Dakshanamurthy and Fredlund's 2D plane strain consolidation theory of unsaturated soils,the Fourier sinusoidal series expansion and Laplace transformation are adopted to give the semi-analytical solution of excess pore-air pressure,excess pore-water pressure and settlement considering the piece-wise cyclic loading,and the degenerate method is applied to verify the correctness of the semi-analytical solution obtained in this paper. Then,combined with three specific piece-wise cyclic loads,the influence on the consolidation of unsaturated soils are analyzed with the change of permeability coefficient ratio(k_a/k_w、k_x/k_z) and load characteristic parameters(a). The results investigated in this paper show that the settlement will be accelerated by amplifying the value of k_a/k_w or k_x/k_z. The loading parameter can speed up the consolidation and result in a smaller settlement. The 2D plane strain consolidation of unsaturated soils is obviously affected by the piece-wise cyclic loading,therefore the consolidation process of unsaturated soils can be effectively controlled by changing the construction speed and setting the radial drainage device in the actual construction process,that is,the research results in this paper can provide important theoretical basis for the design and construction of unsaturated soils foundation.