The Study Of Settlement Calculation And Consolidation Characteristic For Vacuum Combined With Surcharge Preloading

This dissertation analyzes separately the consolidation mechanism of vacuum preloading, preloading and vacuum combined with surcharge preloading, then discussing the differences among them. According to the experimental information, the plane strain FEM based on the Biot consolidation theory, which based on the linear-elastic model, has been used to research the consolidation characteristic for the three kinds of strengthening methods. The results which have been calculated by FEM based on Duncan-Chang non-linear-elastic model, are compared with the settlement results of field monitor. Dynamic estimate of ground settlement and research for settlement correction factor have been done by using layer wise summation method combined with the modified GAOMUJUNJIE method. When evaluating the ultimate settlement for vacuum preloading and vacuum combined with surcharge preloading, not only it should be considered that the calculation ultimate settlement which is modified using the settlement correction factor in criterion is larger than the practical settlement, but also should be considered that the main consolidation settlement which is calculated using the compression coefficient gotten from the conventional triaxial compression test, is larger than the calculation value using the vacuum state's. In the end, the numerical values of ultimate settlement for vacuum preloading and preloading have been discussed simply. It is concluded that there are some relationships between the ultimate settlement and pervasion coefficient or poisson ratio.