| 高寒矿区软弱基底排土场边坡稳定性数值模拟 |
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| 引用本文： | 杨幼清.高寒矿区软弱基底排土场边坡稳定性数值模拟[J].地质与勘探,2020,56(1):198-208. |
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| 作者姓名： | 杨幼清 |
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| 作者单位： | 中国科学院青海盐湖研究所盐湖资源综合高效利用重点实验室，青海西宁； 青海省盐湖地质与环境重点实验室，青海西宁； 中国科学院大学，北京； 青海大学地质工程系，青海西宁； 青海大学农牧学院，青海西宁 |
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| 基金项目： | 国家自然科学基金资助项目(编号：41572306，41867073)，中国科学院“百人计划”资助项目(编号：Y110091025)，青海省自然科学基金资助项目(编号：2014-ZJ-906)，教育部长江学者和创新团队发展计划项目(编号：IRT-17R62)，高等学校学科创新引智计划资助项目（编号：D18013）联合资助 |
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| 摘 要： | 为研究青藏高原东北部高寒地区冻融条件下,软弱基底露天煤矿排土场边坡变形破坏模式和边坡极限堆载高度,本文以青海天峻祁连山北缘江仓露天煤矿排土场作为试验区,采用二维有限元法模拟分析了5种不同堆载高度工况下排土场边坡变形破坏模式,基于折减系数法确定排土场边坡安全系数和稳定性评价。分析结果表明:在容许堆载高度范围内,随着排土场边坡堆载高度的增加,排土场边坡位移量表现出显著增长的变化趋势,其水平方向与垂直方向最大位移量分别为1. 631 m和6. 320 m,当超过容许堆载高度范围,排土场边坡位移量发生突变,呈显著性降低的变化趋势,其位移量降低幅度为64. 27%～102. 32%;塑性变形区表现出沿排土场边坡承载基底位置处的草甸型软弱界面,向排土场边坡坡底位置扩展;剪应力在坡底位置处出现应力集中现象,且剪应力集中范围由边坡承载基底向上、向坡体内部扩展且呈连通趋势,其结果形成后缘拉裂、前缘剪切滑移的整体边坡变形破坏模式;排土场边坡安全系数随着堆载高度的增加表现出二次函数降低(R~2=0. 9896)的变化规律,当排土场边坡高度为65 m时,则达到边坡设计容许高度,且其安全系数为1. 25。本次研究所得到的排土场承载由草甸构成的软弱基底在坡底位置处的变形结果,与野外试验区边坡堆载作用下所形成的实际情况基本吻合。研究结果可为高寒矿区排土场边坡变形破坏科学防治,提高边坡稳定性研究,提供理论支撑依据和实际指导意义。
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| 关 键 词： | 高寒地区排土场软弱基底数值模拟安全系数边坡稳定性 青海省 |
| 收稿时间： | 2019/3/1 0:00:00 |
| 修稿时间： | 2019/8/29 0:00:00 |
Numerical simulation of slope stability of the mine dump with a soft basement in alpine regions |
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| Yang Youqing.Numerical simulation of slope stability of the mine dump with a soft basement in alpine regions[J].Geology and Prospecting,2020,56(1):198-208. |
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| Authors: | Yang Youqing |
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| Abstract: | The purpose of this work is to study the deformation failure mode and limit heap-load height of dump slopes with soft basements in open-pit coal mine dumps in alpine regions under freeze-thaw conditions. The dump of the Jiangcang opencast coalmine located in the northern edge of the Qilian Mountains, Qinghai Province was taken as the test area. Two-dimensional finite element method was used to simulate the slope deformation and failure processes of the dump under five different heaped heights. The reduction coefficient method was used to determine the safety factor and stability evaluation of the dump slope. The results show that in the range of allowable surcharge heights, with the increase of the surcharge height of the dump slope, the displacement of the dump slope exhibits a significant increasing trend. The maximum displacements in horizontal and vertical directions are 1.631 m and 6.320 m, respectively. When the height range of the allowable stack load is exceeded, the change trend of the displacement of the soil slope reduces, and the displacement of the slope is 64.27%~102.32%. The plastic deformation zone of the dump slope extends from the meadow weak interface of the bearing basement to the bottom of the slope. At the bottom of the slope, concentration of shear stress appears, which extends to the slope body along the upper part of the bearing basement and tends to be connected. A model of deformation and failure of the whole slope is constructed, in which the trailing edge is cracked and the leading edge is sheared and slides. With the increase of surcharge height, the safety factor (Fs) of the dump slope decreases by a quadratic function (R2=0.9896).When the slope height of the dump is 65 m, reaching the designed allowable height of the dump slope (Fs=1.25). The deformation results of the soft basement at the bottom of the slope from numerical simulation arelargely consistent with the actual situation in the field test area. The results of this study can provide theoretical support and practical guidance for prevention and control of slope deformation and failure and the improvement of slope stability in alpine mining areas. |
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