Influential Factors of the Static Shear Properties of Coral Mud in the South China Sea

Yang Shen,Xue Shen,Long Yang,Shaoyu Li,Xiaoxi Rui

doi:10.1155/2020/8856987

Abstract

Coral mud, a kind of special material used for constructing islets in reclamation projects, is widely spread in the South China Sea. Combined with microstructure research, a series of triaxial tests were performed in this paper to study the static shear strength characteristics and potential factors that can influence them. The effective stress path was similar to the total stress path because of the unique microstructure resulting in a high strength and a high dissipation rate of the pore pressure in the coral mud. The initial void ratio and the initial confining pressure affected the strength and deformation characteristics of the coral mud. When the soil came to failure, the pore pressure coefficient Af varied linearly with the initial void ratio. The critical friction angle was greatly influenced by the confining pressure, and its magnitude first developed to a peak value and then decreased as the void ratio increased. This change showed that there was a linear relationship between the initial elastic modulus E0i and lgp0 as well as between the secant modulus E50 and p0. The estimation ability of Cam-Clay was verified in this research. The value of parameter λ was determined incrementally by a larger initial void ratio, while the value of parameter M decreased smoothly first and then rose slightly; the selection of parameter κ was approximately 0.0035. The results supported that the Cam-Clay model is able to simulate the stress-strain relationship of coral mud, and a referenced estimation can be reliably and efficiently obtained for the reclamation projects of constructing islets.

Highlights

Introduction e South ChinaSea covers a vast area and enjoys a superior geographical location and strategic position [1]
Calcareous soil with large particles is first deposited at the bottom under gravity, while small particles, referred to as coral mud, are suspended in the water to form silty sand after drifting [2]
According to the standard [20], coral mud is silty clay, with a uniformity coefficient of Cu 37.5 and coefficient of curvature Cc 0.4; it is classified as poorly graded soil

Summary

Introduction

Introduction e South ChinaSea covers a vast area and enjoys a superior geographical location and strategic position [1]. China has accelerated the development and utilization of coral reefs in the South China Sea. During the filling process, calcareous soil with large particles is first deposited at the bottom under gravity, while small particles, referred to as coral mud, are suspended in the water to form silty sand after drifting [2]. Because of the intermittent construction of the filling operation, the coral soil layer presents a discontinuous distribution in the foundation. As a weak interlayer whose settlement and bearing capacity will inevitably affect the whole foundation, it is necessary to conduct in-depth and systematic research on the shear characteristics of coral mud to provide scientific and reasonable design parameters for the engineering construction of coral reefs

Methods

Results

Conclusion