Undrained deformation behavior of marine clay under two-way cyclic loading

Abstract

In offshore engineering, marine clays, which are widespread in the southeastern coastal areas of China, may be subjected to two-way cyclic stresses. To experimentally investigate the effects of the two-way cyclic stress with low-stress amplitude on the cyclic behavior of soft marine clay, a series of triaxial tests is performed on intact marine clay from Zhoushan covering various values of the cyclic stress ratio (CSR) and confining pressure (p′₀). Several useful conclusions are inferred: First, the double-amplitude axial strain (ε_DA), dynamic axial modulus (E), and energy dissipation (W) increase with the CSR. Second, under the same CSR, the value of ε_DA is independent of p′₀. The values of E and W increase with increasing p′₀ during cyclic loadings_, whereas the normalized modulus and normalized energy are independent of p′₀. Third, an allowable CSR is proposed based on the strain behavior and energy concept. Based on the experimental results, two equations are established to predict the dynamic axial modulus and double-amplitude axial strain.

Keywords:

• Marine clay
• two-way cyclic loading
• energy dissipation
• shakedown behavior
• stiffness degradation

Disclosure statement

We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, and there is no professional or other personal interest of any nature or kind in any product, service, and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grant No. 42102313) and Science and Technology project of POWERCHINA Huadong Engineering Corporation (Grant No. KY2021-KC-02-03).