A Research On The Soft Roadbed’s Settlement Mechanism Of Shaozhu Expressway

The soft soil widely distribute in China’s coastal areas. Stability and deformation are often encountered in expressway construction on the soft clay ground. Expressway demands not only embankment stability but also demanding post-construction settlement, especially difference settlement.Taking the soft road foundation of the expressway which is from Shaoxing to Zhuji as the research object, combining relevant engineering data, the summary and analysis of the monitored settlement results about testing section(from K4+943to K5+140) was made in this article. In order to making dynamic simulation of loading process of the embankment and systematically looking at emitting water consolidation and stress variation’s characteristics in the loading process and after the process is complete, the elastic-plastic finite-element model, based on Mohr-Coulomb rule.was built by making use of large finite element analysis software ABAQUS. Finally, the predictions were made about the cross-section of K5+013by making ues of some settlement forecasting models, then the computational results were compared with the field data.The major achievements of this paper as follow:1) According to625days monitoring data, the research on settlement rule of the soft road foundation was made combining related geological data, the result shows: the settlement is larger in the middle of Embankment than sides; The fill section and construction have influence on the settlement and lateral displacement of roadbed; the preceding loading influence more on settlement of roadbed than the later loading.2) Based on simplifying plastic drainage plates down to sand-wall, the finite element model was constructed. Then the result of FEM displays the numerical results are basically consistent with measurement results. The biggest settlement happened on the surface position of the center of the embankment. The biggest lateral displacement occured at toe of slope. The Vertical deformation and horizontal deformation rate is high in the loading process. The deformation rate decreases after the process is complete, and eventually converges, and the horizontal deformation convergent rate is faster than the vertical deformation. and also improvement could be made in the construction monitoring according to the distributing complexion of distortion and-stress in the model.3) The hyperbolic model, Hushino method and Exponential method were used to forecast the settlement of K5+013respectively. The results showed better results are obtained in short-term prediction with these predictive models,but the hyperbolic model is the best in long-term prediction among these models.