The influence of organic matter on the strength development of cement-stabilized marine soft clay

Abstract

The organic matter within clay soil is one of the important factors affecting its engineering characteristics. In this study, the influence of organic matter on the strength evolution of cement-stabilized marine soft clay is evaluated by scanning electron microscopy (SEM) and unconfined compressive strength (UCS) testing. The experimental results show that the after-curing clay water content of the specimens increased with the organic matter content. However, the after-curing unit weight decreased with the organic matter content. The strength decreased with the increase in the amount of organic matter. The strength loss (SL) increased with the organic matter content. A new mathematical model was determined and then used to quantitatively analyze the strength of the investigated samples. A relationship between the strength and organic matter content was established. The evaluation of the accuracy of this new strength model was carried out by comparing the predicted values and measured values, and the results indicated that the deviation was mostly within 10%. Finally, the microscopic changes of the sample surface and influencing mechanism of the organic matter were revealed through SEM. A high soil strength is mainly due to a relatively low porosity, a dense microstructure and the formation of hydration products.