Experimental Study On Behaviours Of Rheological Consolidation And Unloading Rebound Of Saturated Remolded Cohesive Soils

The rheology consolidation and unloading rebound properties of saturated clay mean a lot in practice.In this thesis,seepage experiment under varying-head condition,rheology consolidation experiment,axial unloading rebound experiment and a series of experiments are conducted with remolded saturated clay samples which is took from Xinyang City of Henan Province,by using improved seepage-consolidation joint test system.The main results obtained from the experiment researches are summarized as follows:1.This thesis deduced the ‘waterhead-time' expression content of variable head seepage experiment under the condition of Darcy law,exponential seepage model and Hansbo seepage model,and suggests a new method of fitting three parameter seepage model.According to the test results,there is an obvious deviation from the Darcy law to the seepage of different void ratio test samples.At the same time,the exponential seepage model and Hansbo seepage model are more suitable to fit the test data.2.The one-dimensional rheological consolidation test shows that the rheological behavior of the test samples is obvious,the primary consolidation and the second consolidation which can not be ignored in the analysis of soil deformation are coupled obviously.The single drainage rheological consolidation test shows an obvious lagging of the pore pressure which will not immediately increase to the maximum value after loading,and the cut-off time of the primary consolidation and the secondary consolidation determined by the traditional Casagrande method and the pore pressure dissipation method are inconsistent.In addition,the effects of void ratio,over consolidation ratio,drainage condition and sample height on the rheological consolidation behavior of the remolded saturated clay samples are obviou.3.The process of unloading rebound can be regarded as the inverse process of rheology consolidation.So,the process of unloading rebound can be divided in primary rebound and second rebound.The main influence factors in the unloading rebound process are the unloading ratio,the maximum consolidation stress,the rate of unloading and so on.The process of axial unloading rebound of the saturated clay is influenced by both rheology consolidation and unloading rebound properties,andthere exists 'critical unloading ratio'.