Long-Term Cyclic Loading Impact on the Creep Deformation Mechanism in Cohesive Materials

Andrzej Głuchowski,Wojciech Sas

doi:10.3390/ma13173907

Abstract

Long-term cyclic loading is observed in a wide range of human activities, as well as in nature, such as in the case of ocean waves. Cyclic loading can lead to ratcheting which is defined as progressive accumulation of plastic deformation in a material. Long-term cyclic loading causes a time effect (creep), which is a secondary compression effect. In this article, we conducted 15 triaxial tests on four types of cohesive materials in undrained conditions to evaluate the damage and failure mechanism. To characterize the strain and pore pressure development, we modified the Yanbu resistance concept. On the basis of the static creep tests, we concluded that the stress paths for undrained creep behavior have to take into account the pore pressure developed during long-term cyclic loading. Pore pressure build-up and plastic strain accumulation during long-term cyclic loading are dependent on the number of loading cycles. Finally, we proposed the failure criterion, which was based on the Modified Cam-Clay constitutive model.

Highlights

Over the past years, the effect of cyclic loading on the performance of soil structures has been a focus of numerous papers, mainly because of the development of road networks and an increase of human activities in zones where soft soils are subgrade soils
We present the results of undrained one-way stress-controlled cyclic loading
We present the results of undrained one-way stress-controlled cyclic loading triaxial tests on three types of cohesive material

Summary

Introduction

The effect of cyclic loading on the performance of soil structures has been a focus of numerous papers, mainly because of the development of road networks and an increase of human activities in zones where soft soils are subgrade soils. The focus for testing has shifted from a dynamic to a quasi-static perspective, where permanent deformation is the main adverse effect [1,2,3,4]. The impact of cyclic loading on soil response has the most destructive effect in undrained conditions. Failure develops after numerous load repetitions, due to the accumulation of irrecoverable deformations; as a result of plastic deformation accumulation, the soil reaches the serviceability limit Excess pore water pressure decreases the effective stress in the soil skeleton, and failure can occur [3,9,10,11,12].

Methods

Results

Conclusion