Experimental study on instability mechanism and critical intensity of rainfall of high-steep rock slopes under unsaturated conditions

Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and intensity of precipitation.A large-scale model experiment was conducted on a self-designed physical simulation experiment platform to investigate the failure and instability of high-steep rock slopes under unsaturated conditions.The real-time reproduction of the progressive failure process in high-steep rock slopes enabled the determination of the critical rainfall intensity and revealed the mechanism underlying slope instability.Experiment results indicated that rainfall may be the primary factor contributing to rock mass instability,while continuous pillar mining exacerbates the extent of rock mass failure.The critical failure stage of high-steep rock slopes occurs at a rainfall intensity of 40 mm/h,whereas a rainfall exceeding 50 mm can induce critical instability and precipitation reaching up to 60 mm will result in slope failure.The improved region growing segmentation method(IRGSM)was subsequently employed for image recognition of rock mass deformation in underground mines.Herein an error comparison with the simple linear iterative cluster(SLIC)superpixel method and the original region growing segmentation method(ORGSM)showed that the average identification error in the X and Y directions by the method was reduced significantly(1.82%and 1.80%in IRGSM;4.70%and 6.26%in SLIC;9.45%and 12.40%in ORGSM).Ultimately,the relationship between rainfall intensity and failure probability was analyzed using the Monte Carlo method.Moreover,the stability assessment criteria of rock slope under unsaturated condition were quantitatively and accurately evaluated.

Deformation and failure of a high-steep slope induced by multi-layer coal mining

During underground mining,accurate revelation on the deformation and failure mechanisms of a high-steep slope under multi-layer mining conditions facilitates the prevention and control of geological disasters in mines.Numerical simulation based on discrete element theory can be used to explore the characteristics and mechanism of action of deformation and failure of a slope under complex geological and multi-layer mining conditions.By utilising PFC2 D(particle flow code) software,the deformation and failure characteristics of a high-steep slope in Faer Coal Mine in Guizhou Province,China were investigated.Additionally,the mechanism of influence of different numbers of mining layers on the deformation and failure of the high and steep slope was elucidated.The result showed that after the goaf passed by the slope toe,multi-layer mining aggravated the subsidence and deformation of the slope toe:the slope toppled forward as it sank.The toppling of the slope changed the slope structures:the strata in the front of the slope were transformed from anti-dip to down-dip features.Extruded by collapsedtoppled rock mass,the slope toe and the rock mass located in the lower part of the slope toe generally exhibited a locking effect on the slope.Multi-layer mining degraded the overall stability of the slope,in that the total displacement of the slope was much greater than the total mining thickness of the coal seams.Based on the aforementioned research,ideas for preventing and controlling geological disasters during mining operations under a high-steep slope were proposed.

GIS-based 3D limit equilibrium analysis for design optimization of a 600 m high slope in an open pit mine

Combining the GIS （geographic information systems） grid-based data with four proposed column-based 3D slope stability analysis models, a comprehensive solution of a high-steep open-pit slope has been obtained. For six searching ranges, 19 critical slip surfaces of different sizes have been studied, in which the minimum 3D safety factor is 1.33. Comparison of 3D safety factors of designed and proposed slope plans shows for all the critical slip surfaces for the proposed plan, the smallest 3D safety factor is 1.33 under the most unfavorable condition. This means that the proposed plan of the high slopes, about 600 m, of an open pit （2-5° steeper than designed plan） is feasible.

Cut slope reinforcement technique in open-pit mines

The design and practice in supporting the cut slope of an open-pit mine wereintroduced, in which the high pressure grouting method was used in reinforcing the weak formation inthe slopes. Based on a detailed geological survey of the slope, a theoretical analysis was carriedout, and the design parameters were proposed, where the Tresca or Mohr-Coulomb yield criteria wasemployed. A patent technology, named 'Technology of high pressure and multiple grouting in differentlevels within a single hole', was employed in the construction. Anchor bars were also installed asgrouting proceeds. This method combines anchoring and grouting comprehensively and was foundsuccessful in practice.

Numerical simulation study of the influence on stability of slope by underground mining under opencast coal mine slope

In view of the study on mining transferred from open-pit to underground, the research on the problem of the stabil- ity of slope is less. This article combined the actual situation of the Gaohai Coal Mine in Fuxin City and set up a three-dimensional model of the part of Huizhou open-pit slope by the finite difference software. Through the three-dimensional numerical simulation study of the influence on the stability of slope by underground mining, the basic characteristics of the open-pit slope deformation and the situation of basic stability were discussed. The simulation results of the mining slope of the displacement and deformation analysis of the state for mining provide a reference to the slope stability research.

Comprehensive analysis of multiple machine learning techniques for rock slope failure prediction

In this study,twelve machine learning(ML)techniques are used to accurately estimate the safety factor of rock slopes(SFRS).The dataset used for developing these models consists of 344 rock slopes from various open-pit mines around Iran,evenly distributed between the training(80%)and testing(20%)datasets.The models are evaluated for accuracy using Janbu's limit equilibrium method(LEM)and commercial tool GeoStudio methods.Statistical assessment metrics show that the random forest model is the most accurate in estimating the SFRS(MSE=0.0182,R2=0.8319)and shows high agreement with the results from the LEM method.The results from the long-short-term memory(LSTM)model are the least accurate(MSE=0.037,R2=0.6618)of all the models tested.However,only the null space support vector regression(NuSVR)model performs accurately compared to the practice mode by altering the value of one parameter while maintaining the other parameters constant.It is suggested that this model would be the best one to use to calculate the SFRS.A graphical user interface for the proposed models is developed to further assist in the calculation of the SFRS for engineering difficulties.In this study,we attempt to bridge the gap between modern slope stability evaluation techniques and more conventional analysis methods.

露天矿高陡复杂边坡软弱岩层组“坐落-滑移式”破坏模式研究

边坡稳定性问题随露天矿开采的进行不断突出,而边坡软弱岩层严重影响边坡稳定性。大量工程实例显示,露天矿含软弱岩层组的高陡复杂边坡失稳模式通常为“坐落-滑移式”破坏。为明晰露天矿高陡复杂边坡软弱岩层组“坐落-滑移式”破坏模式的破坏机理,以某露天矿为例,提出一种针对露天矿含软弱岩层组高陡复杂边坡的综合分析方法。研究结果表明:采用工程地质分析、传统极限平衡方法和数值模拟分析相结合的综合分析方法,针对该类型复杂边坡可发挥不同分析方法的优势,较全面地从地质自然环境条件、定性定量方面、应力应变角度分析边坡破坏机理及模式,总结归纳出含软弱层组露天矿高陡复杂边坡“坐落-滑移式”破坏的“坐落-滑移-剪出”三段式破坏特征,为其他类似复杂边坡稳定性的分析和防治提供思路和手段。

点荷载试验在典型露天采场超高边坡工程地质勘察中的应用

夏日哈木镍钴矿山拟建大型超高边坡露天采场,需进行边坡工程地质勘察工作。岩石抗压强度是重要的工程地质参数,如何在青藏高原山区快速获得各类岩石的单轴抗压强度等参数非常关键,尤其是各类难以进行室内压缩试验的风化或蚀变岩石。本次在野外现场采用济南矿岩HDH-1型岩石点荷载仪对矿区内各类岩石进行点荷载试验,并通过前人总结的点荷载强度与单轴抗压强度转换公式计算出了各类岩石的单轴抗压强度及层状(条带状)岩石的各向异性指数。本次点荷载试验克服了昆仑山区岩石测试加工工序复杂、周期较长、成本高等因素,且适用于风化层、蚀变带内不易进行室内压缩试验的岩石,是一种间接测量估算岩石相关强度参数的快捷方法,对以后西部山区的工程地质勘察工作具有较为广泛的借鉴作用。

金属露天矿山高陡顺倾边坡稳定性分析研究

金属露天矿山高陡顺倾边坡易形成大规模变形体或大型滑坡,防治难度大,是矿山安全高效生产的重大隐患。本文通过系统开展滇西北衙金多金属矿区万硐山矿段露天采场顺层边坡稳定性分析实例,研究了不同计算方法和不同工况下该类边坡滑坡失稳条件,采用数值模拟计算分析相结合的方法得出其滑坡类型及失稳模式,并提出了这类结构的露天矿山边坡风险管控措施建议,为矿山后续开采提供依据,指导矿山实际生产。

基于S-SAR边坡雷达的超高海拔露天矿山边坡监测技术研究

为研究超高海拔露天矿山边坡雷达监测技术,本文以西藏巨龙铜矿露天采场西山高陡边坡划定的重点监测区域为研究对象,分析合成孔径边坡雷达(S-SAR)监测数据。结果表明:超高海拔露天矿边坡雷达监测数据特征主要受天气气候因素的影响。其中,高海拔露天矿边坡冻融循环是影响边坡稳定性及雷达监测的重要因素,冻结导致土体膨胀,增加内部压力,而融化使土体强度减弱,融水渗透加剧。因此,通过研究超高海拔边坡雷达监测数据特征,提早发现边坡的变形情况,了解边坡的变形规律,能有效提升矿山边坡的整体安全性。

露天矿台阶对高密度电法勘探影响的实验研究

露天矿边坡稳定性评估是预防边坡事故发生的基本手段之一,物探结论一直作为重要依据被广泛采纳。在露天矿台阶上进行高密度电法勘探时,为研究台阶对勘探结果的影响,本文进行了水槽相似材料模拟实验,研究了待测剖面内的电流场分布。实验结果显示:待测剖面中靠近上下坡面线及清扫平台宽度线的浅部位置电流密度大,且分布均匀;中部位置电流密度变化急剧,且电流密度等高线的形状与台阶形状相似;深部位置电流密度小,变化迟缓;待测剖面上靠近坡底线的位置出现明显的电流聚集效应,台阶地形下的电流密度比在平面地形下的电流密度大,且分布不均匀。这表明应用高密度电法实测时,露天矿台阶会导致中部位置和靠近坡底线位置处的反演成果异常。

砖瓦用黏土矿历史遗留废弃矿山边坡治理浅析

内蒙古呼和浩特市和林格尔县是构建我国北方生态安全屏障的重要组成部分。为系统解决该地区历史遗留废弃矿山以往矿山开采过程中所引发的崩塌、滑坡等一系列地质灾害问题,提升区域生态系统质量,选用削坡垫坡工程对和林格尔县某区域21处砖瓦用黏土矿历史遗留废弃矿山图斑的高陡边坡进行治理。在对项目区内各边坡实际情况进行具体分析后,通过公式计算出是否需要削垫坡及削垫坡范围,采用南方CASS11软件DTM三角网两期土方法精确计算土(石)方量。此治理工程可最大程度上消除地质灾害隐患且使治理后边坡与周边原始地形相协调,为内蒙古地区其他历史遗留废弃矿山边坡治理工程提供方法和经验。

综合监测手段对露天高陡边坡局部垮塌的分析研究

本文通过对福建省上杭县紫金山金铜矿露天采场东帮进行综合监测,结合边坡雷达预警数据、GNSS监测数据、内部位移计监测数据,分析因降雨引起的采场东北帮820~868边坡在重力及雨水冲刷的双重作用下突破临界约束而出现的突然性垮塌。边坡雷达有监测到位移加速变形的趋势,但未及时发出预警。利用综合监测手段,更进一步准确分析高陡边坡。为解决边坡雷达预警问题更进一步监测边坡局部垮塌变形,本文设置预警分区,对采场东北帮820~868边坡进行区域圈定,设置更为敏感的预警阈值。减小圈定区域边坡雷达监测黄色预警和红色预警的短期预警值、长期预警值和预警面积,对曾经出现垮塌区域设置预警分区,从而做出更加准确的预警,显示监测数据波动变化的趋势,为类似高陡露天边坡监测提供参考。

基于DEM的露天煤矿坡顶线与坡底线的提取研究

以黑岱沟露天煤矿0.5 m分辨率DEM为例,运用ArcGIS软件,提出一种基于高分辨率DEM的露天煤矿坡顶线与坡底线提取方法。通过计算DEM中坡顶和坡底的平面曲率,利用矿山DEM在坡顶、坡底的平面曲率与坡面、平盘的平面曲率存在差别,从而分离坡顶线和坡底线。该方法操作简便,精度较高,为我国露天煤矿地理信息生产提供了技术支持。

影响矿山边坡稳定性的软弱夹层蠕变参数分析

针对软弱夹层蠕变特性对矿山边坡整体稳定性的影响,使用FLAC^(3D)有限差分软件,分别采用Mohr-Coulomb模型和Burgers模型,对四川黄山石灰石矿山边坡稳定性进行分析。以坡脚处为特征点,考虑计算得出的软弱夹层蠕变特性的水平位移是不计蠕变的6.36倍,说明软弱夹层的蠕变特性对边坡的变形影响很大。分别对Burgers蠕变模型中η_(K)和η_(M)进行分析,经历相同的蠕变时间(150 d),η_(K)越小,边坡滑带剪应变速率增量越大,表明η_(K)影响岩体变形的减速蠕变周期和进入等速蠕变的时间;η_(K)和η_(M)分别增大一个数量级,特征点的水平位移增量分别为6.5%和1.93%,说明黏性系数影响蠕变变形的过程,但对蠕变变形值影响极小。

高精度测量技术在矿山边坡监测中的应用研究

为了提高矿山边坡监测精度与检测结果的可靠性,通过高精度测量技术对某矿山开展边坡监测技术研究。根据矿山的实际情况、占地面积、覆盖范围以及所选高精度测量技术有效测距等,进行不同等级监测网的布置;采用高精度测量技术,由信号发射装置发出信号,信号经过岩体、边坡表面后会发生反弹,反弹的信号在其他路径返回,再被信号发射装置所接收,实现对矿山边坡监测数据的反馈。在观测站布置控制点、监测点,确保监测点之间保持良好通信联系后,设计矿山边坡警戒观测线,通过警戒观测与矿山边坡失稳预警,完成监测方法的设计。实验结果表明:按照规范对矿山边坡监测,可以确保监测结果与人工现场测量结果保持高度一致,提高了测量结果的可靠性与准确性。

基于无人机倾斜摄影的露天矿高边坡形变监测方法

矿产资源开采虽然创造了巨大的经济效益,但也对矿山环境造成了一定的破坏。露天开采作为相对较为常见的矿产资源开采形式,随着开采深度的不断增加,其矿区边坡高度以及面积也在随之不断增加,使得矿区高边坡的稳定性受到严重影响。为保证安全生产,降低经济损失,切实做好露天矿高边坡形变监测就显得尤为重要。基于此,本文对无人机倾斜摄影的露天矿高边坡形变监测方法进行分析,以供参考。

露天石灰岩矿山高陡岩质边坡治理

因不规范开采形成的高陡边坡,易引发滑坡、坍塌等地质灾害,给矿山安全稳定带来极大影响。文章以溧阳某采石灰岩矿山为例,分析了该矿山地质环境条件,探讨了高陡岩质边坡整治及生态修复策略,希望可以为类似边坡治理提供借鉴。

综合物探技术在露天矿山边坡地质勘测中的应用

露天矿山边坡矿体内部存在裂隙、节理等岩体结构,对边坡稳定性产生直接或间接的影响。而单一的物探技术只能获取地质结构某一方面的信息,在地质勘探方面存在局限性。为确保边坡稳定,设计一种综合物探技术下露天矿山边坡地质勘测方法。以地下介质电阻率、密度等地球物理特征为依据,融合瞬变电磁法、高密度电法、地震映像法作为综合物探手段,在Geogiga Front End Free软件工具上,形成地震映像图和视电阻率截面图。根据所得勘测结果显示,通过地震映像法能准确描述出地质形态、地层结构和厚度,高密度电法能够清晰展示出边坡区域下浅层塌陷部分的空间范围及低阻特性明显的填充物,瞬变电磁法能够准确地对超过百米深的地层中的异常体做出响应,证明综合物探技术具有良好的勘探能力。

废弃矿山高陡边坡生态修复治理技术研究与实践

随着矿山开采进程的深入,因矿山地质生态环境破坏引发的地质灾害和安全隐患已成为制约部分地区发展的瓶颈。为修复矿山地质地貌、消除矿山地质安全隐患、提高废弃矿山绿植覆盖率,以某典型废弃露天矿山为例,针对该矿山存在的高陡边坡、废渣堆积、地貌破坏等地质环境问题,基于“防治结合”的原则,提出了“坡面削(清)方+挡土墙+排水沟+封边墙+场地平整+客土喷播绿化+覆土绿化”的生态环境保护与修复治理技术,介绍了该技术施工工艺和质量控制措施。项目实施后,不仅有效消除了地质灾害隐患,改善了矿区地貌景观及周边生产生活环境,更为矿山生态环境修复治理探索了一条新路径。