| The characteristic of soft soils includes high natural moisture content, high natural void ratio, high compressibility, low shear strength, low coefficient of consolidation, long consolidation process, large disturbance, poor permeability, complex shape distribution in soil layers, physical properties differing from each other in the layers, and these characteristic leads to the problems of base stabilization and deformation in the practice of the geotechnical engineering. In order to solving the problems, knowing the engineering properties of soft soils is very important. With different sedimentary origin and material construction, soft soil engineering differes in different area.A typical example is the soft soils from Ningbo, and there are many research on the soft soils from Ningbo at present that many of them are concentrated on the conventional physical and mechanical properties. In other words, there is few research which concentrated on the nonlinear consolidation properties, rheological property, microstructure, constitutive and so on, and in this situation it’s becoming difficult to solve the two problems. Thus, more researches need to be carrying through. Based on the above, this paper takes soil examples from Ningbo to conduct the nonlinear consolidation properties research from the macroscopic and microscopic level. The main work includes:(l)Carrying out the routine physical tests on Ningbo typical soft clay, using the conventional compression tester, carrying out the one-dimensional consolidation experiment and compression-rebound-recompression experiment for the soft clay, analyzing the one-dimensional nonlinear consolidation characteristics of soft clay and summarizing the property of one-dimensional nonlinear consolidation of soft clay in Ningbo.(2)Carrying out the SEM tests for soft clay from Ningbo which are in different consolidation state to get the micro image, including the origin sample and the consolidated soil samples. In this way, we can view the micro structure, soil particles and distribution characteristics and orientation of porosity in soft clay.(3)Carrying out the mercury injection test for soft clay from Ningbo which are in different consolidation state, including the origin sample and the consolidated soil samples in different consolidated pressures. In this way, these will be known:the change of the porosity’s sizes and the distribution of different porosities in soil... |
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