Sand Wells Ground Plane Strain Equivalent Methods Of Research

Although vertical drains have been widely used to consolidate the soft clay ground, several open questions such as evaluating the effect of consolidation and accurately forecasting the settlement of soft ground remain to be solved both in the field of analytical study and in engineering design. Therefore, to develop more efficient calculation methods to analysis the behavior of sand drained ground plays an important role both in the theoretical and the practical sides of such problems.At first, based on the progress made by former scholars, consolidation theories for sand drained ground and sand wall ground are reestablished respectively in this thesis. An exact solution and an approximate solution are respectively obtained for each case, according to the vertical strain has or has no relationship with the depth of subsoil. After compare with the approximate solution, the accuracy of exact solution was detected; whilst by comparing to the results of numerical solution, the reasonableness of the exact solution was verified. At the same time, the widely used approximate solution is verified unreasonable in theoretical aspect.Furthermore, a general equivalent condition was obtained by matching the horizontal average degree of consolidation for sand drained ground in axisymmetric condition to the counterpart for sand wall ground in plane strain condition. In fact, several existing matching methods developed by the scholars, such as Hird and Indraratna etc., are the particular cases for the one obtained in this thesis. Both well resistance and smear are incorporated into the equivalent equation. The relationship between permeability and size of unit cell in the two cases is also reflected in the equivalent equations, so sand ground in three dimensions can be converted to plain strain problems.Consequently, the FE implement for static consolidation equation is summarized, and the important parameters of the Cam-clay model and also the sand drained ground, which should be used in the plane strain FEM analysis for a sand drained ground, were discussed in detail.