Experimental Study on Influence of Confining Pressure and Water Content on Dynamic Strength of Slate Residual Soil

doi:10.19657/j.geoscience.1000-8527.2021.019

Abstract

Abstract:

Under the influence of special geotectonic conditions, the slate and phyllite in western Sichuan-eastern Tibet are strongly weathered, and the residual soil is widely distributed. It is of great practical significance to study the dynamic characteristics of metamorphic rock-derived, highly-weathered soil in this area. In this study, dynamic triaxial experiment was carried out on the slate residual soil from the region. The results show that the moisture content and confining pressure have obvious influence on dynamic strength of the samples. Under the same consolidation stress and consolidation ratio, the strength decreases with increasing water content. Under the same moisture content and consolidation ratio, the strength increases with increasing consolidation stress, but the correlation is not proportional. The dynamic cohesion of slate residual soil decreases with increasing water content, and the former is highly sensitive to the latter. However, the dynamic friction angle has little changes with increasing water content and is less sensitive to the latter.

Key words: western Sichuan-eastern Tibet, slate residual soil, water content, confining pressure, dynamic strength, dynamic triaxial experiment

CLC Number:

P642

WANG Lei, GUO Changbao, LI Bin, HUANG Xin, ZHENG Zhihua, WANG Jiaqi. Experimental Study on Influence of Confining Pressure and Water Content on Dynamic Strength of Slate Residual Soil[J]. Geoscience, 2021, 35(01): 161-166.

Figures/Tables 8

Fig.1 Particle grading curve of residual soil

Table 1 Physical parameters of the residual soil

干密度ρ_d/ (g·cm^-3)	天然含水率 w/%	相对密度 G_s	塑限 w_P/%	液限 w_L/%	塑性指数 I_p
1.77	11	2.65	6.5	14.5	8.0

Fig.2 Photo of the sample used in the experiment

Fig.3 Damaged samples after the experiment

Table 2 Experiment scheme of the dynamic triaxial test

材料	状态	试验条件
材料	状态	固结比K_c	围压σ₃/kPa			荷载频率/Hz
重塑样	含水率(11%)	1	100	200	300	1
	含水率(13%)	1	100	200	300	1
	含水率(15%)	1	100	200	300	1
	含水率(17%)	1	100	200	300	1
	含水率(19%)	1	100	200	300	1

Fig.4 Typical time-history curves of dynamic stress (a) and axial strain (b) obtained from the experiment

Fig.5 Correlation of dynamic failure stress with water content and confining pressure

Fig.6 Variation of dynamic cohesion force (a) and dynamic friction angle (b) with water contents

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