Evaluation of safety state for dump in-service under severe drying-wetting cycles at high altitude

doi:10.16265/j.cnki.issn1003-3033.2023.10.2246

Abstract

Abstract:

In order to reveal the effects of severe drying-wetting cycles on the limestone dump slopes safety status at high altitudes. The slopes of No.1 and No.2 in-service dump in limestone mining areas for cement in high-altitude mining areas was taken as the research object. The unsaturated soil shear strength equation and the matrix suction distribution equation were imported based on the unsaturated-saturated seepage theory. Therefore, the evolution characteristics of the unsaturated-saturated seepage field in the dump slopes under severe drying-wetting cycles were analyzed by numerical calculation, and the safety state of the limestone dump slope was evaluated. The results show that under the action of drying-wetting cycles, the soil changed from the unsaturated to the saturated state on the limestone dump slope. With the increasing number of drying-wetting cycles, the maximum vertical displacement of the limestone dump slope continues to increase. The numerical calculations of the maximum vertical displacement of the slope are in good agreement with the actual monitored values. What is more, as the number of drying-wetting cycles increases, the factor of safety of the limestone dump slope continues to decrease. In addition, it was found that the limestone dump slope in-service is stable under the action of severe drying-wetting cycles.

Key words: high altitude, severe drying-wetting cycle, dump, safety state, slope

DONG Jianjun, JIANG Hao, YAN Bin, YANG Di. Evaluation of safety state for dump in-service under severe drying-wetting cycles at high altitude[J]. China Safety Science Journal, 2023, 33(10): 94-103.

Figures/Tables 22

Fig.1

Fig.2

Fig.3

Tab.1

Basic parameters of SWCC model

β/(kPa^-1)	k/(m·s^-1)	$γ w$ /(kN·m^-3)	m
0.005	2.5×10^-6	9.8	0.15

Tab.1

Tab.2

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8

Fig.9

Fig.10

Fig.11

Fig.12

Fig.13

Tab.3

Fig.14

Fig.15

Fig.16

Tab.4

Tab.5

Tab.6

References 10

[1]	杨果林, 陈子昂, 张红日, 等. 干湿循环作用下平缓型膨胀土边坡失稳破坏机制研究[J]. 中南大学学报:自然科学版, 2022, 53(1):95-103.
	YANG Guolin, CHEN Ziang, ZHANG Hongri, et al. Collapse mechanism of gentle expansive soil slope in drying and wetting cycles[J]. Journal of Central South University:Science and Technology, 2022, 53(1):95-103.
[2]	董建军, 梅媛, 李昕, 等. 高海拔排土场边坡安全稳定性SBAS-InSAR监测[J]. 中国安全科学学报, 2022, 32(1):92-101. doi: 10.16265/j.cnki.issn1003-3033.2022.01.013
	DONG Jianjun, MEI Yuan, LI Xin, et al. SBAS-InSAR monitoring of slope safety and stability of high altitude dumps[J]. China Safety Science Journal, 2022, 32(1): 92-101. doi: 10.16265/j.cnki.issn1003-3033.2022.01.013
[3]	廖进星. 浩吉铁路膨胀岩高边坡降雨入渗稳定性分析[J]. 铁道科学与工程学报, 2021, 18(4): 908-917.
	LIAO Jinxing. Stability analysis of high slope of swelling rock under rainfall infiltration of Haolebaoji-Ji'an railway[J]. Journal of Railway Science and Engineering, 2021, 18(4): 908-917.
[4]	蔡文倩, 王建德, 姜立春. 分层排土场边坡降雨入渗过程及稳定性分析[J]. 有色金属:矿山部分, 2021, 73(5): 35-42.
	CAI Wenqian, WANG Jiande, JIANG Lichun. Analysis on rainfall infiltration process and stability of layered dump slope[J]. Nonferrous Metals:Mining Section, 2021, 73(5): 35-42.
[5]	CHRISTOFER K, HARIANTO R, ALFRENDO S. Effect of variations in rainfall intensity on slope stability in Singapore[J]. International Soil and Water Conservation Research, 2017, 5(4): 258-264. doi: 10.1016/j.iswcr.2017.07.001
[6]	湛文涛, 肖杰, 陈冠一, 等. 膨胀土边坡渗流数值模拟及稳定性分析[J]. 工业建筑, 2018, 48(9): 133-139.
	ZHAN Wentao, XIAO Jie, CHEN Guanyi, et al. Numerical simulation of seepage and stability analysis of expansive soil slope[J]. Industrial Construction, 2018, 48(9): 133-139.
[7]	杨和平, 唐咸远, 王兴正, 等. 有荷干湿循环条件下不同膨胀土抗剪强度基本特性[J]. 岩土力学, 2018, 39(7):2311-2317.
	YANG Heping, TANG Xianyuan, WANG Xingzheng, et al. Shear strength of expansive soils under wet-dry cycles with loading[J]. Rock and Soil Mechanics, 2018, 39(7): 2311-2317.
[8]	杨济铭, 张红日, 陈林, 等. 基于数字图像相关技术的膨胀土边坡裂隙形态演化规律分析[J]. 中南大学学报:自然科学版, 2022, 53(1):225-238.
	YANG Jiming, ZHANG Hongri, CHEN Lin, et al. Analysis of crack morphology evolution law of expansive soil slope based on digital image correlation technology[J]. Journal of Central South University:Science and Technology, 2022, 53(1):225-238.
[9]	董建军, 杨嫡, 闫斌, 等. 剧烈干湿交替下高海拔排土场安全稳定性研究[J]. 中国安全科学学报, 2022, 32(3):75-83. doi: 10.16265/j.cnki.issn1003-3033.2022.03.010
	DONG Jianjun, YANG Di, YAN Bin, et al. Study on safety and stability of high altitude dumps under intense drying-wetting alternation[J]. China Safety Science Journal, 2022, 32(3): 75-83. doi: 10.16265/j.cnki.issn1003-3033.2022.03.010
[10]	GB 50421—2018, 有色金属矿山排土场设计标准[S].
	GB 50421-2018, Standard for waste dump design of nonferrous metal mines[S].

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

干湿循环次数	主影像	从影像	时间基线/ d	空间基线/ m	入射角/ (°)
1	2021-05-28	2021-06-09	12	-13.656	42.110
2	2021-07-03	2021-07-15	12	-6.516	42.123
3	2021-08-20	2021-09-01	12	-42.573	42.120
4	2021-09-01	2021-09-13	12	-44.365	42.113

干湿循环次数	1号排土场边坡			2号排土场边坡
干湿循环次数	模拟值/ mm	监测值/ mm	相对误差/%	模拟值/ mm	监测值/ mm	相对误差/ %
1	5.3	4.7	12.8	6.2	5.3	17.0
2	10.8	10.1	6.9	12.7	11.4	11.4
3	17	15.9	6.9	19.5	17.8	9.6
4	23.4	22	6.4	26.6	24.3	9.5

工况	二等排土场边坡安全稳定性标准	南排土场边坡安全稳定性标准
自然	1.20~1.25	1.25
降雨	≥1.10	1.15

干湿循环次数	安全系数			稳定性
干湿循环次数	1号排土场	2号排土场	安全稳定性标准	1号排土场	2号排土场
1	1.453	1.352	>1.15	稳定	稳定
2	1.385	1.305	>1.15	稳定	稳定
3	1.329	1.242	>1.15	稳定	稳定
4	1.288	1.195	>1.15	稳定	稳定