Rainfall Infiltration: Effects on Slope Stability of Loess Terraces in Mountainous Area of Southern Ningxia

doi:10.11924/j.issn.1000-6850.casb20190800551

Abstract

Abstract:

The paper aims to study the effects of rainfall infiltration on the slope stability of loess terraces in mountainous area of southern Ningxia. We established a finite element model for the stability analysis by using the software ABAQUS, and studied the variation of failure time and safety factors of 3 different types of terraced slopes: the level terrace, alternate terrace and original slope (control) under different rainfall infiltration intensities (28-38 mm/h) and the slope gradient (15°-30°). The results showed that: the failure time of the terraced slope decreased with the increase of rainfall infiltration intensity and satisfied the power function relation; the failure time of the level terrace was significantly higher than that of the alternate terrace and original slope; the safety factors of the terraced slope decreased with the increase of the rainfall infiltration intensity too, but satisfied the linear function relation; the safety factors of the level terrace had no significant difference between the alternate terrace and original slope. Under the condition of rainfall, the construction of loess terraces can increase the stability of shallow terrace slope, but has little effect on the stability of deep terrace slope.

Key words: rainfall infiltration, loess terrace, slope stability, finite element, mountainous area of southern Ningxia

CLC Number:

S859.84

Liu Jiali, Tian Jia, Liang Zhiqi, Zhang Zhimin, Yang Zekang, Ma Jianwen, Zhao Yan. Rainfall Infiltration: Effects on Slope Stability of Loess Terraces in Mountainous Area of Southern Ningxia[J]. Chinese Agricultural Science Bulletin, 2020, 36(27): 88-98.

Figures/Tables 11

References 30

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土壤类型	小于该粒径的土质量百分数/%							d₁₀/mm	d₆₀/mm
黄土	<5 mm	<2 mm	<1 mm	<0.5 mm	<0.25 mm	<0.1 mm	<0.075 mm	d₁₀/mm	d₆₀/mm
黄土	100	91.71	78.22	44.72	31.33	22.15	18.03	0.02	0.74

土壤类型	小于该粒径的土质量百分数/%							d₁₀/mm	d₆₀/mm
黄土	<5 mm	<2 mm	<1 mm	<0.5 mm	<0.25 mm	<0.1 mm	<0.075 mm	d₁₀/mm	d₆₀/mm
黄土	100	91.71	78.22	44.72	31.33	22.15	18.03	0.02	0.74

变异来源（因素）	Ⅲ类平方和	自由度	均方	F 值	P 值	分布值X/%
边坡坡度	11.732	3	3.911	552.119	0.001^**	75.442
梯田边坡类型	0.446	2	0.223	31.448	0.001^**	2.867
降雨入渗强度	2.942	5	0.588	83.065	0.001^**	18.918
修正后总计	15.551	71

变异来源（因素）	Ⅲ类平方和	自由度	均方	F 值	P 值	分布值X/%
边坡坡度	11.732	3	3.911	552.119	0.001^**	75.442
梯田边坡类型	0.446	2	0.223	31.448	0.001^**	2.867
降雨入渗强度	2.942	5	0.588	83.065	0.001^**	18.918
修正后总计	15.551	71

梯田边坡类型	梯田边坡类型	平均值差值	标准误差	显著性	95%置信区间
梯田边坡类型	梯田边坡类型	平均值差值	标准误差	显著性	下限	上限
水平梯田	隔坡梯田	0.1421	0.0243	0.001^**	0.0935	0.1907
水平梯田	原始边坡	0.1838	0.0243	0.001^**	0.1352	0.2323
隔坡梯田	原始边坡	0.0417	0.0243	0.091	-0.0069	0.0902
隔坡梯田	水平梯田	-0.1421	0.0243	0.001^**	-0.1907	-0.0935
原始边坡	隔坡梯田	-0.0417	0.0243	0.091	-0.0902	0.0069
原始边坡	水平梯田	-0.1838	0.0243	0.001^**	-0.2323	-0.1352