Study on safety and stability of high altitude dumps under intense drying-wetting alternation

doi:10.16265/j.cnki.issn1003-3033.2022.03.010

Abstract

Abstract:

In order to reveal impacts of intense drying-wetting alternation on safety and stability of high altitude dumps, numerical calculation was carried out for open mining No. 1 and No. 2 dump of limestone mine for cement in high altitude mining area. The distribution law equation of matric suction and shear strength equation were introduced for unsaturated soil based on unsaturated-saturated seepage theory. Therefore, the evolution characteristics of the unsaturated-saturated seepage field and stability of dumps were studied under intense drying-wetting alternation. The results show that as drying-wetting alternation intensity increases, the soil changes from unsaturated state to saturated one on dumps' slopes, and its shear strength decreases. There is no slippage on slope of No. 1 dump. However, the No. 2 dump is affected by intense alternation, and slip area is located between slope foot and the second step, which develops into deep layer as the alternation intensity grows. The slope displacement of dumps increases continuously while safety factor decreases along with the increase of the intensity.

Key words: intence drying-wetting alternation, high altitude, dump, safety and stability, slope

DONG Jianjun, YANG Di, YAN Bin, MEI Yuan. Study on safety and stability of high altitude dumps under intense drying-wetting alternation[J]. China Safety Science Journal, 2022, 32(3): 75-83.

Figures/Tables 14

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Tab.3

Basic parameters of SWCC model for dump slopes

$β /$ kPa^-1	$k s /$ (m·s^-1)	$γ w /$ (kN·m^-3)	$θ s /$ %	$θ r /$ %	$α$	m	n
0.005	2.5×10^-6	9.8	50.29	11.90	0.06	0.15	4

Tab.3

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工程材料	天然容重/ (kN·m^-3)	饱和容重/ (kN·m^-3)	摩擦角/ (°)	水下摩擦角/ (°)	黏聚力/ kPa	水下黏聚力/ kPa
碾压堆石坝	20.5	—	35	—	5	—
人工填土	21.5	22.5	25.3	23.7	4	3
松散碎石土	20.5	21.0	20	18	8	4
稍密碎石土	21.0	22.0	22	20	10	5
强风化花岗闪长岩	22.5	22.8	30	25	40	30
中风化花岗闪长岩	25.2	25.5	38	35	500	400
碾压废石	20.4	—	35	33	—	—