Strength Change Mechanism of Undisturbed Red Clay and Remolded Red Clay

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Strength Change Mechanism of Undisturbed Red Clay and Remolded Red Clay

Journal Title: 河南科技大学学报（自然科学版） - Year 2019, Vol 40, Issue 3

Abstract

In order to study the strength characteristics and influencing mechanism of red clay, direct shear tests were carried out on undisturbed soil samples and remolded soil samples under different normal stresses σ.Scanning electron microscopy ( SEM) was used to compare and analyze the differences of microstructure between the undisturbed soil and remolded soil, such as particle unit contact, joint state, pore morphology and distribution. The influence mechanism of soil microstructure on macroscopic mechanical properties was revealed. The results show that when σ is less than the critical stress, the τof the undisturbed soil is higher than that of the remolded soil, otherwise, the undisturbed soil τis lower than the remolded soil.τThe critical value depends on the void ratio of the soil. The larger the void ratio is, the larger the critical value is. The cohesive force of the undisturbed soil is higher than that of the remolded soil, and the internal friction angle is lower than that of the remolded soil. There are significant differences in the mechanical properties between the remodeling soil and the undisturbed soil. The magnitude of the difference depends on the microstructure of the undisturbed soil. The concept of “closed pores and open pores”of red clay is proposed and applied to the mechanism analysis of shear strength of red clay, which has certain engineering guiding significance.

Authors and Affiliations

Jiayu CHEN, Zhikui LIU

Keywords

undisturbed soil; remolded soil; shear strength; microstructure;

EP ID EP469106
DOI 10.15926/j.cnki.issn1672-6871.2019.03.010
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