Experimental study on dynamic strength properties of compacted loess under wetting-drying cycles

被引：0

作者：

Wang T. ^{[1
]}

Hao Y. ^{[1
]}

Wang Z. ^{[1
]}

Cheng L. ^{[2
]}

Li J. ^{[1
]}

机构：

[1] College of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi

[2] College of Engineering Management and Real Estate, Henan University of Economics and Law, Zhengzhou, 450046, Henan

来源：

Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | 2020年 / 39卷 / 06期

基金：

中国国家自然科学基金;

关键词：

Compacted loess; Critical wetting-drying cycles number; Dynamic strength; Microstructure; Soil mechanics; Wetting-drying cycles;

D O I：

10.13722/j.cnki.jrme.2019.0945

中图分类号：

学科分类号：

摘要：

In order to understand the dynamic strength change law of compacted loess caused by wetting-drying cycles, a series of wetting-drying cycles tests, soil dynamic triaxial tests and scanning electron microscope tests were carried out under different wetting-drying cycle paths, and the dynamic strength and microstructure images of compacted loess were obtained. The results indicate that the dynamic strength and dynamic strength index of compacted loess decrease first and then increase with increasing the number of wetting-drying cycles, and that the turning points of the σd-n, cd-n and φd-n curves are obviously different due to the influence of the wetting-drying amplitude. The degradation degree of the dynamic strength increases first and then decreases with increasing the number of wetting-drying cycles, and even has a negative value. The critical wetting-drying cycles number nc is the limit of the whole structure damage and the whole structure strengthening of compacted loess, and changes with the wetting-drying amplitude. The macro and micro structure characteristics of samples in the process of wetting-drying cycles indicate that the increasing number of pores in the humidifying process and the cracks on the surface and in the inside of samples during dehumidification lead to the structural damage and strength reduction of compacted loess. The main reasons for structure strengthening and strength increasing are that soil particle structure develops to mosaic structure, pore structure develops to uniform small pore and matrix suction makes soil sample tend to be dense. © 2020, Science Press. All right reserved.

引用

页码：1242 / 1251

页数：9

共 29 条

[1] GUAN G S, RAHARDJO H, CHOON L E., Shear strength equations for unsaturated soil under drying and wetting, Journal of Geotechnical and Geoenvironmental Engineering, 136, 4, pp. 594-606, (2010)
[2] PIRES L F, BACCHI O O S, REICHARDT K., Gamma ray computed tomography to evaluate wetting/drying soil structure changes, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 229, 3, pp. 443-456, (2005)
[3] TANG C S, CUI Y J, SHI B, Et al., Desiccation and cracking behaviour of clay layer from slurry state under wetting-drying cycles, Geoderma, 166, 1, pp. 111-118, (2011)
[4] WANG D Y, TANG C S, CUI Y J, Et al., Effects of wetting-drying cycles on soil strength profile of a silty clay in micro-penetrometer tests, Engineering Geology, 206, pp. 60-70, (2016)
[5] YUAN Zhihui, NI Wankui, TANG Chun, Et al., Experimental study of structure strength and strength attenuation of loess under wetting- drying cycle, Rock and Soil Mechanics, 38, 7, pp. 1894-1902, (2017)
[6] WANG Fei, LI Guoyu, MU Yanhu, Et al., Experimental study of deformation characteristics of compacted loess subjected to drying-wetting cycle, Rock and Soil Mechanics, 37, 8, pp. 2306-2312, (2016)
[7] LIU Hongtai, ZHANG Aijun, DUAN Tao, Et al., The influence of alternate dry-wet on the strength and permeability of remolded loess, Hydro-Science and Engineering, 4, pp. 38-41, (2010)
[8] HU Changming, YUAN Yili, WANG Xueyan, Et al., Experimental study on strength deterioration model of compacted loess under wetting-drying cycles, Chinese Journal of Rock Mechanics and Engineering, 37, 12, pp. 2804-2817, (2018)
[9] ZHANG Fangzhi, CHEN Xiaoping, Influence of repeated drying and wetting cycles on mechanical behaviors of unsaturated soil, Chinese Journal of Geotechnical Engineering, 32, 1, pp. 41-46, (2010)
[10] NOWAMOOZ H, MASROURI F., Influence of suction cycles on the soil fabric of compacted swelling soil, Comptes Rendus Geoscience, 342, 12, pp. 901-910, (2010)

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