Non-linear settlement calculation method based on soil parameters obtained from pressuremeter tests

In the conventional calculation method for foundation settlement, there is a certain error between the calculation parameters determined by laboratory tests and the actual soil parameters, which leads to a large difference between prediction and reality. To overcome this shortcoming and consider the nonlinearity of foundation settlement, it is feasible to determine the calculation parameters by in-situ tests. The pressuremeter tests are easy to operate and low cost and can be used to measure the soil parameters at different depths. Therefore, on the basis of the previous research results, a non-linear settlement calculation method based on the calculation parameters obtained from the pressuremeter tests is studied. The main contents and achievements are as follows: (1) the shortcomings of the current commonly used settlement calculation methods and the reasons for the low accuracy of the calculated results are analyzed and summarized. (2) According to the stress characteristics and principles of the pressure meter tests, and the distribution laws of soil stress of the pressure meter hole wall as well as the M-C yield criterion, the parameters E_t0, c and φ needed in the settlement calculation are derived theoretically. (3) According to the non-linear tangent modulus method proposed by Yang Guang-hua, the principle and procedure of calculating the nonlinear settlement of foundation based on the results of pressuremeter tests are derived and given. (4) The proposed method is verified through projects, and the results are compared with those predicted by the codes (layer-wise summation method). The comparison shows that the prediction based on the parameters derived from in-situ tests is closer to the real settlement. Because the nonlinear soil and the settlement caused by shear deformation of soil can be considered in the pressuremeter tests at different depths, this exploratory study lays a foundation for the calculation of foundation deformation by the results of in-situ test in the future. It can also be regarded as a reference for other projects.