Study On One-dimensional Consolidation Theory Of Double-layered Soil Considering The Effect Of Stress History

Although the stress history of soil has great influence on its compression and consolidation behavior, there is little study so far on the consolidation theory of layered soils taking account of the effect of stress history. In this thesis, one-dimensional consolidation theory of double-layered soil considering the effect of stress history is studied in detail. The main research work is as follows:Based on the available studies on the linear consolidation theory of single layered and over-consolidated soil, one dimensional equations for linear consolidation of double layered soil considering the effect of stress history are proposed according to the different moving role of the interface of over-consolidated soil and normally consolidated soil under the conditions of one-way drainage and two-way drainage in the consolidation process, and the corresponding computer code ODLCADOS is developed by semi-analytical method and by Fortran programming. A verification is then made to show the reasonability of the computer code. Finally, by using the computer code, a great amount of computation is made through typical numerical examples, and the behavior of one-dimensional linear consolidation of double-layered soil taking account of the effect of stress history is illustrated.It has been shown that once the effect of stress history is taken into consideration, the consolidation behavior of saturated soil differs greatly from that described by Terzaghi's theory, and the settlement is smaller and the rate of consolidation is greater than these without considering the effect of stress history. The magnitude of load and the pre-consolidation pressure, as well as the variations of compressibility and permeability of the two soil layers is all of significant influence on the consolidation behavior.