One-dimensional Consolidation Theory For Layered Structured Soils And The Behavior Analyses

Structure is one of the important property of natural soils. As structure has much influence on the mechanical property of soils, structured soils has different consolidation behavior form the soils without considering structure. The study of one-dimensional consolidation of structured soils is thus very important. However, there is few study on the consolidation of structured soils due to its complexity. For the consolidation of layered soils, it seems no study so far.. In this thesis, one-dimensional consolidation of layered structured soils was studied as follows.Firstly, using simplified k-σ' and mv-σ' models and considering two drainage conditions, the approximate solution for one-dimensional consolidation of single layered structured soils under time-dependent loading was obtained. Then considering the influence of various factors, such as structure and load, the consolidation behavior was analyzed. The results indicated the rate of excess pore water pressure dissipation of structured soils was faster than that of soils without considering structure, and the final settlement of structured soils was smaller than that of soils without considering structure. Also, it was shown that lower structural yield stress and higher load maked faster rate of excess pore water pressure dissipation, faster rate of settlement and smaller final settlement. Furthermore, the load had a stronger influence on final settlement than structural yield stress.Secondly, one-dimensional consolidation control equation of double layerd structured soils under time-dependent loading was established. The approximate solution for this equation was then obtained, considering two drainage conditions. Considering the influence of various factors, such as consolidation parameter before and after the collapse of structure, structural yield stress and consolidation parameter of the two layers of soil, the consolidation behavior for double layerd structured soils was analyzed.Finally, one-dimensional consolidation control equation of layerd structured soils under time-dependent loading was established and the approximate solution for this equation was then given, considering two drainage conditions. The consolidation behavior for layerd structured soils was finally analyzed. For layered structured soils with weak layer, different layer of soil had a different degree of influence on rate of excess pore water pressure dissipation and rate of settlement. The weak laver is the most influential one.