Experiments On Creep Behavior Of Dredge Fill

Based on the comprehensive summaries on rheology behavior of dredger fill at home and abroad, the properties of dredger fill silty sands from Caofeidian port and of dredger fill clay from Dayaowan port are systematically studied. Through the routine soil experiment and creep test in laboratory, combined with model analysis and FLAC3D numerical model, the creep behavior and models of dredger fill are further investigated. The research achievements and some conclusions are given as follows:(1) By analyzing routine soil test and field data, a systematic generalization about the basic mechanical properties of the dredger fill and physical indicators had been made. By uniaxial compression test, soil compressive strength, modulus of compression and other indicators are determined, which provides a reference information for the subsequent consolidation creep test and creep model.(2) By doing one-dimensional consolidation creep tests for the dredger fill, a series of consolidation creep curves are drawn, and some conclusions on creep law are achieved. Select a suitable empirical formula to describe the strain-time, stress-strain relationship, and further discuss the consolidation creep characteristics, which are influenced by dry density, normal stress, sample dimensions and other parameters.(3) Through direct shear tests of dredger fill, the paper summarizes the moisture’s impact on shear strength parameters, which also provides reference information for the subsequent direct creep test and creep model. Through direct shear creep tests, the creep law is also summarized. Further select an appropriate experience formula which describes the strain-time, stress-strain relationships. Lots of parameters of the dredger fill consolidation creep properties are also analyzed such as normal stress, shear stress, dry density, moisture content and sample size.(4) The test results are analyzed by using composite element model of generalized Kelvin model and Burgers model. The two kinds of model parameters are obtained. Through comparing the experimental curves with theoretical data, it is found that the Burgers’element combined model shows a better fitting effect.(5) Numerical simulation of creep sample is executed by using FLAC3D combined with Burgers model, the comparison of empirical formula and theoretical model is done, and the rationality of the model obtained is also verified.