The Effect of Temperature on Dynamic Characteristics of Frozen Clay under Principal Stress Rotation

Bin-Long Zhang,Le-Le Lei,Wei Ma,Hossein Moayedi,Da-Yan Wang,Zhi-Wei Zhou

doi:10.1155/2021/3127253

Abstract

The foundation soil is always subjected to complex stress, including continuous rotation of the principal stress caused by traffic and earthquake loads. To comprehend the dynamic characteristics of frozen clay under complex stress sate, including continuous rotation of the principal stress, this study investigates the effect of temperature on the dynamic characteristics of frozen clay under principal stress rotation using a frozen hollow cylinder apparatus (FHCA-300). The test results reveal that the cumulative plastic strain of frozen clay samples exponentially increases with the rising of temperature under principal stress rotation. The influence of temperature is more profound with a high cyclic stress ratio (CSR). A decrease in temperature can improve the stiffness of the frozen clay, reduces its energy dissipation, and enhances its ability to resist dynamic loading. However, the principal stress rotation phenomenon may aggravate the damage of frozen clay and increase the energy dissipation and reduces its ability to resist dynamic loading. Based on the experimental data, an empirical expression was proposed to describe the coupling influence of CSRs and temperature on the axial resilient modulus of frozen clay, which can predict the development of axial resilient modulus under different thermal-mechanical conditions.

Highlights

Frozen soils are compound materials composed of solid mineral particles, polycrystalline ice, unfrozen water, and gaseous inclusions. ey are widely distributed in cold regions or artificial ground freezing projects [1, 2]
A series of FHCA tests were performed to investigate the effect of temperature on dynamic characteristics of frozen clay under complex stress path involving principal stress rotation. e evolutions of cumulative plastic strain, hysteresis loop, resilient modulus, and damping ratio were analyzed
The following main conclusions can be obtained from this study: (1) e temperature has a significant influence on the generalized cumulative plastic. e cumulative plastic strain rate is greater with the temperature increase, resulting in greater final cumulative plastic strain. e effect of temperature seems to be more profound with a high cyclic stress ratio (CSR)

Summary

Introduction

Frozen soils are compound materials composed of solid mineral particles, polycrystalline ice, unfrozen water, and gaseous inclusions. ey are widely distributed in cold regions or artificial ground freezing projects [1, 2]. The artificial ground freezing (AGF) method, which is widely used in large-scale cross-sea and river-crossing projects in coastal areas, is an effective underground engineering support technology [3] In these projects, frozen soils as a foundation or supporting wall are subjected to dynamic loads such as those from waves, traffic, and earthquakes. The effects of temperature, confining pressure, freeze-thaw cycles, initial compaction degree, and initial water content on the dynamic shear modulus and damping ratio of various frozen soils were investigated under multistage cyclic loading by using a triaxial apparatus [5,6,7,8]. E results obtained from tests showed that the residual deformation increases significantly with the increase of cycles, cyclic stress ratio, temperature, freeze-thaw cycles, and cyclic amplitude but decreases with that of frequency, water content, and confining pressure. A series of dynamic loading tests were conducted using FHCA-300 to assess the evolution of the dynamic strain, stress-strain hysteresis curve, resilient modulus, and damping ratio with number of cycles under principal stress rotation. e results provide a significant guidance for the design and operation of frozen soil engineering

Test Material and Methods

Test Result and Discussion

Conclusions