Settlement Calculation Method of Lakeside Soft Soil Foundations Based on the Statistical Analysis of Physical and Mechanical Indexes

The understanding of the settlement deformation law of lakeside soft soil foundations and the definition of a reasonable settlement calculation formula are essential when setting the basis for road design and construction. The present study focuses on the application of a statistical analysis of physical and mechanical indexes to study the settlement law of the lakeside soft soil foundations, with the Jinan-Weishan expressway in China as the study case. With this aim, a correlation among the natural void ratio, compressive modulus, natural water content, density, and liquid index of the lakeside soft soil layer was performed. An improved method for settlement calculation was proposed by combining the calculation formula for predicting settlement for soft soil foundations in the lakeside area with the layer-wise summation method. Laboratory tests were performed to verify its validity. The results evidence a positive correlation of the natural void ratio with the water content and the liquid index, as well as the compressive modulus with the density. The natural void ratio reveals a negative correlation with the density, as well as the compressive modulus with the natural water content and the liquid index. Both the theoretical calculations and the experimental results illustrate that the settlement initially increases rapidly with time, then increases slowly until eventually reaching a stable state after about the 190th day. The settlement deviation between experimental findings and theoretical calculations after 190 days was less than 10%. This supports the suitability of the improved method of determining e–p curves based on density.