UAV-mounted Ground Penetrating Radar: an example for the stability analysis of a mountain rock debris slope

This paper describes scientific research conducted to highlight the potential of an integrated GPR-UAV system in engineering-geological applications.The analysis focused on the stability of a natural scree slope in the Germanasca Valley,in the western Italian Alps.As a consequence of its steep shape and the related geological hazard,the study used different remote sensed methodologies such as UAV photogrammetry and geophysics survey by a GPR-drone integrated system.Furthermore,conventional in-situ surveys led to the collection of geological and geomorphological data.The use of the UAV-mounted GPR allowed us to investigate the bedrock depth under the detrital slope deposit,using a non-invasive technique able to conduct surveys on inaccessible areas prone to hazardous conditions for operators.The collected evidence and the results of the analysis highlighted the stability of the slope with Factors of Safety,verified in static conditions(i.e.,natural static condition and static condition with snow cover),slightly above the stability limit value of 1.On the contrary,the dynamic loading conditions(i.e.,seismic action applied)showed a Factor of Safety below the stability limit value.The UAV-mounted GPR represented an essential contribution to the surveys allowing the definition of the interface debris deposit-bedrock,which are useful to design the slope model and to evaluate the scree slope stability in different conditions.

Distributed Fiber Optic Monitoring and Stability Analysis of a Model Slope under Surcharge Loading

In the discipline of geotechnical engineering, fiber optic sensor based distributed monitoring has played an increasingly important role over the past few decades. Compared with conventional sensors, fiber optic sensors have a variety of exclusive advantages, such as smaller size, higher precision, and better corrosion resistance. These innovative monitoring technologies have been successfully applied for performance monitoring of geo-structures and early warning of potential geo- hazards around the world. In order to investigate their ability to monitor slope stability problems, a medium-sized model of soil nailed slope has been constructed in laboratory. The fully distributed Brillouin optical time-domain analysis （BOTDA） sensing technology was employed to measure the horizontal strain distributions inside the model slope. During model construction, a specially designed strain sensing fiber was buried in the soil mass. Afterward, the surcharge loading was applied on the slope crest in stages using hydraulic jacks and a reaction frame. During testing, an NBX-6o5o BOTDA sensing interrogator was used to collect the fiber optic sensing data. The test results have been analyzed in detail, which shows that the fiber optic sensors can capture the progressive deformation and failure pattern of the model slope. The limit equilibrium analyses were also conducted to obtain the factors ofsafety of the slope under different surface loadings. It is found that the characteristic maximum strains can reflect the stability of the model slope and an empirical relationship was obtained, This study verified the effectiveness of the distributed BOTDA sensing technology in performance monitoring of slope.

Safety monitoring and stability analysis of left abutment slope of Jinping Ⅰ hydropower station

Safety monitoring and stability analysis of high slopes are important for high dam construction in high mountainous regions or precipitous gorges. In this paper, deformation characteristics of toppling block at upper abutment, deforming tensile rip wedge in the middle part and deep fractures are comprehensively analyzed based on the geological conditions, construction methods and monitoring results of left abutment slope in Jinping Ⅰ hydropower station. Safety analyses of surface and shallow-buried rock masses and the corresponding anchorage system are presented. The monitoring results indicate that the global stability of the large wedge block in the left abutment is effectively under control, and the abutment slope is stable in a global sense. After the completion of excavation, the deformations of toppling block at the top of the slope and deep fracture zone continue at a very low rate, which can be explained as 'rock mass creep'. Further monitoring and analysis are needed.

Microseismic monitoring and numerical simulation on the stability of high-steep rock slopes in hydropower engineering

For high-steep slopes in hydropower engineering, damage can be induced or accumulated due to a seriesof human or natural activities, including excavation, dam construction, earthquake, rainstorm, rapid riseor drop of water level in the service lifetime of slopes. According to the concept that the progressivedamage （microseismicity） of rock slope is the essence of the precursor of slope instability, a microseismicmonitoring system for high-steep rock slopes is established. Positioning accuracy of the monitoringsystem is tested by fixed-position blasting method. Based on waveform and cluster analyses of microseismicevents recorded during test, the tempo-spatial distribution of microseismic events is analyzed.The deformation zone in the deep rock masses induced by the microseismic events is preliminarilydelimited. Based on the physical information measured by in situ microseismic monitoring, an evaluationmethod for the dynamic stability of rock slopes is proposed and preliminarily implemented bycombining microseismic monitoring and numerical modeling. Based on the rock mass damage modelobtained by back analysis of microseismic information, the rock mass elements within the microseismicdamage zone are automatically searched by finite element program. Then the stiffness and strengthreductions are performed on these damaged elements accordingly. Attempts are made to establish thecorrelation between microseismic event, strength deterioration and slope dynamic instability, so as toquantitatively evaluate the dynamic stability of slope. The case studies about two practical slopes indicatethat the proposed method can reflect the factor of safety of rock slope more objectively. Numericalanalysis can help to understand the characteristics and modes of the monitored microseismic events inrock slopes. Microseismic monitoring data and simulation results can be used to mutually modify thesensitive rock parameters and calibrate the model. Combination of microseismic monitoring and numericalsimulation provides a more objective basis for the numerical model and parameters and a solidmechanical foundation for the microseismic monitoring.

Primary Investigations on Yangtze River Bank Slope Stability in Wanzhou for the Three Gorges Reservoir Project

This paper investigates the main factors contributing to bank slope failures, such as the structure of rock and soil, water level change, bank slope gradient, vegetation, weathering and human activities. Based on these investigations, the bank slope failure models are analyzed. The stability of bank slopes in Wanzhou is investigated using geological surveying, 2D resistivity imaging surveying, excavated trenches and other methods. Finally, the disasters of bank slope failures in Wanzhou were investigated in detail. The results show that instability problems might occur in 60.38 km of bank slopes when the water level rises to 175 m. It is suggested that 37.8 km of unstable bank slopes should be stabilized, and 14.2 km of unstable banks should be moved or avoided after further geological surveying and reconnaissance. These results provide scientific basis and reliable data for the government to develop the third geodisaster prevention plan for the Three Gorges reservoir.

Quantitative human risk analysis of 2015 Shenzhen dump failure considering influence of urbanization

With the rapid development of urbanization, a large amount of construction spoil was stockpiled around cities and formed extensive dumps. Construction spoil is one of the main construction and demolition(C&D) waste and municipal solid waste(MSW). Once the construction spoil dump becomes unstable, it will bring great risks to the surrounding residents. A catastrophic dump failure occurred on 20 December 2015 in Guangming New Strict, Shenzhen, China. Approximately 2.51×10^(6) m^(3) of construction waste slid out from the dumpsite, destroying 33 houses and causing total 77 casualties. This paper attempts to analyze the failure probability of the construction spoil dump using Monte Carlo simulation considering the spatial variability of soil properties, and to quantify the dynamic human risk considering the increasing urbanization. Influence of urbanization on the human element at risk is analyzed by referring to multi-temporal remote sensing images. A quantitative human risk assessment model is employed to determine the landslide human risk referring an assessment criteria curve between frequency of number fatalities and number of fatalities(F-N curve). It is found that the societal risk at daytime was 0.078, 0.088, and 1.432 in 2002, 2014, and 2015, respectively. Meanwhile, the societal risk at night was 0.034, 0.037, and 0.611 in 2002, 2014, and 2015, respectively. The quantitative method was benchmarked by the other landfill failure. It implies that the human risk increased with the development of urbanization and its value at daytime was approximately twice as much as at night. The new approach for the human risk assessment provides guidance for modern MSW landfills and highlights the obvious influence of urbanization on the human risk in other areas.

考虑降雨入渗的高边坡开挖支护稳定性分析

【目的】为研究降雨入渗对多级开挖支护后高边坡的稳定性,针对四川达州市某高边坡工程,基于ABAQUS软件并结合现场工程地质和水文地质条件,建立高边坡开挖降雨渗流模型。【方法】考虑不同降雨条件的影响,引入多层非饱和土计算方法,结合现场监测情况,对降雨工况进行研究,进而研究非饱和土边坡的稳定性。【结果】研究结果表明,孔隙水压、边坡位移与降雨强度和降雨持续时间呈正相关,长时间高强度降雨易使多级开挖的高边坡产生较大滑移。【结论】建议采取边开挖边支护的施工措施。研究成果可为高边坡多级开挖支护的稳定性研究提供一定的参考。

新疆阜康抽水蓄能电站含泥夹层变形体稳定性分析

新疆阜康抽水蓄能电站上水库0号变形体底部含泥夹层较为发育,严重威胁工程稳定运行。为了评价含泥夹层变形体稳定性,基于变形体有限元分析以及表面位移、测斜孔位移监测数据,研究变形体失稳破坏特征及位移时空变化规律。结果表明:变形体在天然情况下处于稳定状态,在压坡体的作用下,边坡整体安全系数由1.33提高至1.51,安全系数较天然状态下增加13.5%。压坡处理后变形体稳定性明显提高,但是含泥夹层的强度参数对变形体稳定性影响较大,含泥夹层强度参数降低40%,变形体整体安全系数低于1.0。变形体各表面变形测点累计水平位移最大8.56 mm,累计垂直位移最大10.03 mm;测斜孔上下游与左右岸最大平均位移不超过0.6 mm。变形体的变形主要表现为沿含泥夹层蠕滑变形,应在工程施工、水库蓄水及运行期间对变形体不同部位进行系统的变形监测工作。

冻融环境下露天矿边坡稳定性和变形特性研究

为分析冻融环境下露天矿山边坡稳定性影响机理,选取内蒙古某露天矿山为研究区,采用合成孔径边坡雷达监测技术,对该矿采场边坡进行连续不间断监测,研究冻土融化以及渗流作用影响下露天矿山边坡变形规律。研究结果表明:冰冻期加之渗流作用导致边坡表面土体出现冷冻膨胀现象,变形量增加;长期冰冻状态使得边坡内部应力分布逐渐趋于稳定,从而减缓变形速度;解冻过程中,边坡土体产生收缩变形,加剧了边坡软弱层的破坏,从而降低边坡整体稳定性。因此研究冻融及渗流条件下边坡变形机理可为露天矿边坡长期稳定性评价提供基础依据及工程指导,并为露天矿山边坡安全监测提供一定参考。

基于S-SAR边坡雷达的滑坡形变监测分析研究

露天矿山边坡安全是矿山安全的保障,边坡表面变形监测数据分析有助于获得准确的滑坡时间预测,因此,滑坡形变监测分析研究是研究的重点。本文对比分析了两个矿山滑坡时的合成孔径边坡雷达变形监测数据,获得了在滑坡时边坡表面变形监测特征曲线,进而建立了变形特征曲线与滑坡之间的关系。通过分析发现了边坡在发生破坏性变形之前会有多次异常的加速变形现象,这一点与斋藤法的三阶段变形相符。边坡在滑坡前并不会呈加速—匀速—再加速的变形规律,而是会重复多次加速—匀速—加速循环的变形现象。

某露天钼矿采场边坡稳定性分析及监测技术

露天矿山边坡普遍存在稳定性安全隐患,为分析某露天钼矿采场边坡稳定性,采用现场勘察及数值模拟的方法,对该采场不良地质条件及边坡稳定性进行研究。结果表明:采场部分区域存在渗水点、裂缝、坍塌等不良地质条件,采场东帮边坡水位线较高,地下水是影响边坡稳定的主要因素;采场边坡整体较为稳定,局部区域存在隐患,采用边坡雷达及GNSS监测设备形成双重动态实时监测系统,对边坡进行全天候实时监测,预报滑坡灾害,为矿山安全生产保驾护航。

高寒高海拔地区某排土场边坡滑坡模式分析与雷达监测效果研究

为解决高海拔露天矿排土场边坡安全稳定性监测中存在的常规监测仪器布置以及人员值守的高投入和高风险等问题,本文以西藏某露天铜矿排土场边坡为研究对象,选取典型剖面,通过岩石室内物理力学试验获得坡体岩石物理力学参数,采用简化Bishop和Morgenstern-Price极限平衡法方法分别计算排土场不同滑坡模式下现状边坡各分区稳定性系数,针对高海拔地区的独特气候,利用InSAR监测高海拔排土场边坡形变信息,综合评价高海拔排土场边坡安全稳定性,为高海拔排土场边坡滑坡灾害风险预警与防控提供理论和技术支持。

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。

边坡雷达在临湖露天矿山边坡监测中的应用

为分析某临湖露天矿山边坡稳定性,借助边坡雷达对临湖露天边坡实时监测,基于合成孔径雷达差分干涉测量技术获取边坡变形信息,采用无人机对边坡进行航测,获取临湖边坡表面影像数据和数字高程模型,将SAR图像与地形数据进行几何映射三维匹配。监测结果显示,目前主要形变区域位于西部边坡-10 m到58 m,分析该区域边坡位移变化趋势,表明边坡整体处于相对稳定状态,近期大规模滑坡风险不大。实践表明边坡雷达监测系统具有高适用性和可靠性,能够有效判别边坡稳定性状态,识别潜在滑坡区域等,对临湖边坡的安全高效开采具有重要的现实意义。

基于数字化监测的土质边坡监测分级及稳定性分区方法研究

为实现土质边坡的监测分级、提升监测设备的非冗余布设水平,先结合土质边坡稳定性影响指标的归一化取值和采用层次分析法确定的指标影响权重,构建了分区危险性评价模型;再基于边坡分区危险性系数进行了边坡危险性分级,并结合规范标准建立了与其相匹配的监测分级及设备布设数量建议;最后结合实际工程验证了该方法的可行性和可靠性。研究结果表明:1)基于土质边坡监测分级的影响指标选取相对合理;2)分区危险性评价模型可行;3)相较常规边坡监测方法,根据边坡危险性进行分级监测更符合边坡工程实际,设备的非冗余布设水平更高。研究结果可供不同类型边坡的监测作业参考。

GNSS边坡监测与事故风险分析平台融合应用

在露天煤矿开采过程中,边坡的稳定性关乎矿山正常的生产运营。在矿山建设投产开始直至采完闭矿,滑坡、裂缝等影响始终贯穿矿山的整个开采周期。传统的人工光学设备边坡稳定性监测方式,无法满足全天候、全时段监测,从而延误了预警的最佳时机。随着卫星导航技术和差分解算技术的发展,GNSS边坡监测方式以其低成本、全天候实时监测的优点逐步成为矿山监测的主要方式。本文以山煤进出口集团河曲旧县露天矿为例,通过两期GNSS边坡、排土场监测案例,介绍了全球卫星导航系统原理、边坡监测系统组织架构、多源数据融合等。

高速公路边坡路堑施工风险与稳定性评估

文章综合分析了某公路工程施工风险,研究制定了相应的边坡防护措施,并对边坡稳定性进行了进一步评估。同时,通过实际加固方式对边坡变形量进行监测。研究结果表明,大部分边坡处于非稳定状态,但经过加固后,边坡变形量明显小于未加固边坡,并且随着时间的推移,变形量趋于稳定。因此,可以得出结论,施工后边坡逐渐进入稳定状态,采用锚杆支护、喷锚混凝土和挡土墙等加固方式效果显著。

雷达技术在露天矿边坡监测预警中的应用

露天矿边坡的稳定性是矿山安全和生产效率的关键因素,传统的监测方法在实时性和准确性上存在局限性。因此,文章探讨了雷达技术在露天矿边坡监测预警中的应用,分析了雷达系统的构成、工作原理及其在边坡稳定性分析中的高级算法。通过实时监测边坡位移和倾斜度,以及应用神经网络和线性回归模型进行数据分析和趋势预测,旨在展示雷达技术如何提高监测数据质量、处理速度和预警的准确性。这些分析和应用对提升矿山安全管理、预防环境破坏及推动地质监测技术发展具有重要意义。

基于Chebyshev-Galerkin-KL展开的土质边坡稳定可靠度分析

提出了一种基于Chebyshev-Galerkin-KL(Karhunen-Loève)展开的新型随机场离散方法,推导了该方法的理论公式,并研发了基于Python语言的边坡滑体体积计算及其失效模式自动识别的高效程序。采用一个水位上涨时的非饱和土坡算例验证了方法的有效性。结果表明:所提随机场生成方法为求解第二类Fredholm积分方程提供了一种新思路,可准确表征岩土体参数的空间变异性。基于Python提出的边坡风险评估程序,与随机有限元计算过程不耦合,极大地提升了开展边坡风险评估的效率,从而增强预测滑坡致灾风险的时效性。此外,研究中非饱和土坡算例可靠度分析结果表明:水位上涨速度越慢,最大水位高度越高,该边坡的安全程度将越低。岩土体参数的竖向空间变异性对该算例边坡安全系数的影响甚微,但对滑体体积的影响较为显著。在对水位上升条件下的边坡开展可靠度分析时,应关注抗剪强度参数间的负相关性,否则将会低估边坡的安全程度。

基于FLAC^(2D )、GPS监测和人工巡视相结合的某矿山排土场边坡稳定性分析

受矿山的不合理排放堆积、自然降雨冲刷以及地形等因素的影响,使得大面积的堆积型斜坡极易发生滑坡地质灾害,严重威胁矿山人员的生命财产安全。为了解决矿山排土场边坡失稳带来的潜在隐患,定期合理地开展矿山排土场边坡稳定性分析具有重要的作用。前人使用FLAC^(2D)解决一些边坡稳定性的研究较少,本文以某矿山拟建排土场边坡为研究对象,在现场调查的基础上,创新性地运用FLAC^(2D)软件进行数值模拟分析,定性和定量对排土场边坡三种不同工况(天然状态、7°地震、浸水)下的稳定性进行验算。同时,将GPS监测和人工巡视相结合,根据相关的GPS监测标准和人工巡视要求,给出了针对排土场边坡变形监测措施。结果表明:经定性、定量计算后,三种工况下的边坡稳定系数高于安全系数,达到了安全等级一级的要求,证明了拟建排土场的安全性和稳定性。该分析方法能为该矿其他排土场边坡稳定性分析提供借鉴。