Deformation Behavior of Saturated Soft Clay under Cyclic Loading with Principal Stress Rotation

Zunan Fu,Tingyu Wu,Yanming Yu,Wenbo Song,Pengfei Wei,Guoshuai Wang

doi:10.3390/app11198987

Abstract

Under long-term traffic loading, the soil elements in subgrade are subjected to continuous principal stress rotation. In order to study the deformation properties of soft clays under traffic loading with principal stress rotation, a series of cyclic torsional shear tests were conducted on Wenzhou soft clays under different torsional cyclic stress ratios and degrees of principal stress rotation. The test results showed the stiffness softening of soil under long-term traffic loading. In addition, the principal stress rotation induced by traffic loading aggravated the deformation of clay samples and pore pressure accumulation. A modified dynamic pore pressure model was applied to consider the effect of principal stress rotation on undrained cumulative pore pressure, predicting the growth of cumulative pore pressure at different cycles. Considering loading cycles and the principal stress rotation, a modified Hardin–Drnevich (H-D) backbone curve model under traffic loading with principal stress rotation was proposed, and the predictive values of this model agreed well with the experimental values. Compared with the traditional H–D model, this model better reflects the cyclic deformation of soft clays under long-term traffic loading with principal stress rotation.

Highlights

Wenzhou soft clay is a typical soft clay
To improve the service performance of traffic facilities in coastal areas and to control the maintenance costs, it is necessary to study the cyclic behavior of saturated soft clay under traffic loading
Η =η =zθ cyczθ σz cyc rotation can lead to an increase in the accumulated pore pressure

Summary

Introduction

Wenzhou soft clay is a typical soft clay. It has a high water content, low shearing strength, low permeability, and high compressibility. Quaternary period and is widely distributed in the coastal areas of China [1]. In this region, rapid economic development has led to a significant increase in transportation construction, most of which is built on the soft ground. The traffic loading exerted by the transportation is a typical cyclic loading. To improve the service performance of traffic facilities in coastal areas and to control the maintenance costs, it is necessary to study the cyclic behavior of saturated soft clay under traffic loading

Methods

Results

Conclusion