Search

This paper presents an experimental investigation on the ultra-soft marine soil recovered from the seabed in deep-water areas in South China Sea (SCS). An improved T-bar penetrometer is made and em...

Thixotropy of soil is, after softening by remoulding, a process of time-dependent return to a harder state under constant water content and constant volume conditions. This paper presents a critical review of previous investigations on the thixotropy of soft clay. Thixotropic behavior is primarily a structural effect accompanied by the spontaneous dissipation of excess internal energy, and some microstructural observations provide a deeper insight into its mechanism. Mathematical theories and models to simulate thixotropic strength recovery of soil are introduced. Different test methods to evaluate the thixotropic behavior of soil are summarized. Correlations between the thixotropic behavior of soil and some basic indexes, such as water content, Atterberg limits, mineralogy, activity and salt concentration, are described. Some remarks on future improvement for thixotropy of soil are also provided based on the results of up-to-date research.

Soft clay forms a big proportion of the seabed ground. In a marine environment, waves, wind, and earthquakes, often known as cyclic loads, are a main contributor to the loading of the seabed. The safety of offshore structures relies on the response of soft marine clay to these cyclic loadings. Its very fine-grained composition, and hence low permeability, is the defining factor for soft marine clay showing a very different response to cyclic loading than sand. The responses of soft marine clay subjected to cyclic loading range from degradation in soil strength and stiffness to principal stress rotation, excess pore pressure generation, and deformation accumulation. These dynamic characteristics of soft marine clay are strongly influenced by several factors, including loading level (amplitude, frequency, and number of cycles), loading history, and path. The purpose of the present paper is to present an overview of the research results on the characteristics of soft marine clay under cyclic loading in the past decades. Some remarks on future research for improving the understanding of dynamic characteristics of soft marine clay are also provided based on the results of up-to-date research.

Characterization of the hydraulic property of a specific geomaterial is of fundamental importance in engineering design and application. This paper reports an experimental investigation to the hydr...