Equations for Calculating the Foundation Settlement of Zhanjiang Formation Gray Clay Considering the Influence of Multiple Factors

The Zhanjiang Formation gray clay has physical properties similar to the muddy clay of other areas, such as a large void ratio and high-water content. At the same time, it also has mechanical properties that differ from muddy clay in other areas, such as high strength and low compressibility. When calculating the foundation settlement, the equation that calculates the foundation settlement as suggested by the code tends to produce values of compression modulus that are too small, which leads to larger calculated values. This study investigated the relationship between the pressure and deformation of Zhanjiang Formation gray clay foundations with different densities, water content, and stress histories by means of a plate loading model test. It revealed the influence of these factors on the deformation modulus, and the quantitative relationship between this modulus and the density of soils, water content, and the over consolidation ratio was established. In doing so, the aforementioned quantitative relationship was applied to the equation which calculated the foundation settlement as suggested by the current code, thereby proposing a pertinent formula relevant to Zhanjiang Formation gray clay foundations. The formula was subsequently applied to two engineering examples, and the settlement amounts output were in agreement with actual measured values, indicating it is reasonable and feasible for practical application. Therefore, it can provide a reference for the calculation of foundation settlements across the coastal area of Beibu Gulf.