The Studies On Deformation Of Roadbed With Saturated Silty Soil

With the rapid development of Chinese highway, silty sand becomes a common roadbed and the settlement, forecasting of silty subgrade has aroused wide concerns in engineering gradually. Because the saturated silty soil has characteristics of high compression, bulky water content and low strength, more detailed research is required in the settlement process. Therefore, the settlement characteristic and vertical distribution of additional stress of saturated silty soil are discussed with finite difference software. Tendency law of the settlement deformation in saturated silty soil is acquired, all of these have practical significance in the construction of the expressway.This paper combines various of Mechanical properties of saturated silty soil, the simulation with deformation of saturated silty soil subgrade in different conditions under vehicle load is performed, detailed comparative analysis to simulation results has been done. Main research contents are as follows:1. Collect large amount of literature, mainly including the articles about the deformation mechanism of saturated silty soil and traffic load on the affection of the settlement on embankment , which provides the necessary theoretical basis and reference value for writing the paper ;2. Simulate the traffic load in different conditions, analyze and verify the applicability of the numerical simulation method in the study of subgrade settlement, then make a comparative analysis under the results of different conditions ;3. In terms of the deformation of subgrade settlement, make a comparative analysis in details of static simulation method and dynamic analysis to identify the pros and cons between these two, and some guideline for settlement forecast of saturated silty sand subgrade have been brought forward.The main research results are as follows:1. The traffic load can simplify to equivalent static load, simulate the settlement deformation of saturated silty soil under the static load, and make a comparative analysis between theoretical methods recommended by the specifications for design of highway subgrades, verify the simplicity,the accuracy,the visuality of this method . 2. Stress status of the saturated silt roadbed in simplified static load is simulated; comparison and analysis between stress and settlement of the roadbed are performed in aspects such as soil condition, embankment height, underground water level and axial load. Developing tendency of stress and settlement of the roadbed has been concluded.3. Simplify the traffic load into the triangular wave load. From the simple harmonic motion, study the stress state of saturated silty soil subgrade by instantaneous action and soil deformation condition under cyclic dynamic load.4. Static calculation only response with elastic-plastic settlement under simplified static load. Simple harmonic dynamic computation can reflect deformation along with long cycle load and accumulated residual deformation under cyclic dynamic load.