Deterioration of Soil-Cement Piles in a Saltwater Region and Its Influence on the Settlement of Composite Foundations

Abstract

Soil-cement mixed piles are widely used to improve soft subsoil. But in regions with high-salinity groundwater, the soil-cement is susceptible to deterioration. At present, however, the design code for soil-cement pile composite foundations does not consider the deterioration effect of soil-cement. The saltwater region in the Yellow River Delta of China is used as a case study. Based on early strength tests of soil-cement, a practical prediction method for the lifecycle bearing capacity of soil-cement piles is put forward, and the influence of deterioration on the settlement of composite foundations is studied using model tests and numerical simulation. The prediction method of pile bearing capacity considers the progressive deterioration of soil-cement, and it shows that the deterioration of soil-cement has a great influence on bearing capacity of mixed piles with an increase in age, and the loss ratio of bearing capacity quickly reduces with a decrease in pile diameter. The deterioration also increases the settlement of composite foundations. Furthermore, pile defects aggravate the deterioration effects of soil-cement piles on the settlement of composite foundations.