双排微型桩加固碎石土滑坡物理模型试验研究

通过3组不同桩间距下双排微型桩加固碎石土滑坡室内模型试验,研究微型桩受力变形特性和滑坡推力传递规律。试验结果表明:双排微型桩承受的滑坡推力主要集中在滑面以上1/3桩身范围内,桩身最大弯矩位于滑面附近,且桩群均以第一排桩达到其弹性受力极限而失效;桩间距为5d时,微型桩群对桩间土的遮蔽阻挡效果最好,桩群能承受的滑坡推力最大,且桩顶位移最小,滑坡推力在排桩间分布最合理,其传递系数α在（0.5,0.7）间取值。     

碎石土滑坡的因素敏感性计算分析

通过资料搜集整理和分析、现场工程地质调查与勘探和室内外的物理力学试验,采用弹塑性接触有限元强度折减法、不平衡推力法和数理统计分析法,结合工程实例,分析了影响碎石土滑坡各因素的敏感性,结果表明,按因素敏感度从大到小排列,主要影响碎石土滑坡稳定性的因素依次为滑面岩土体内摩擦角、地形坡度、滑体饱水面积比和滑面岩土体的内聚力。地形坡度大、具有低内摩擦角滑面的碎石土滑坡的整体稳定性较差,而连续降雨、强降雨会抬高地下水位增大滑体饱水面积比,降低滑面带岩土体抗剪强度,增加下滑力,对碎石土滑坡的稳定性将产生最不利的影响。同时,在对碎石土滑坡进行加固处理时,必须优先考虑采取提高滑面等效内摩擦角、降低地形坡度结合降低地下水位措施,其次考虑采取提高滑面岩土体内聚力的措施。     

Numerical modelling of rheological properties of landslide debris

Debris flow has caused severe human casualties and economic losses in landslide-prone areas around the globe. A comprehensive understanding of the morphology and deposition mechanisms of debris flows is crucial to delineate the extent of a debris flow hazard. However, due to inherent complex field topography and varying compositions of the flowing debris, coupled with a lack of fundamental understanding about the factors controlling the geomaterial flow, interparticle interactions and its final settlement resulted in a limited understanding of the flow behaviour of the landslide debris. In this study, a physical model was set up in the laboratory to simulate and calibrate the debris flow using PFC, a distinct element modelling-based software. After calibration, a case study of the Varunavat landslide was taken to validate the developed numerical model. Following validation with an acceptable level of confidence, several models were generated to evaluate the effect of slope height, slope angle, slope profile, and grain size distribution of the dislodged geomaterial in the rheological properties of debris flow. Both qualitative and quantitative analysis of the landslide debris flow was performed. Finally, the utility of retaining wall and their effect on debris flow is also studied with different retaining wall positions along the slope surface.

     

滑坡转化泥石流启动的人工降雨试验研究

滑坡直接转化而成的泥石流通常比滑坡本身运移距离更远,波及范围更广,危害也更严重,但目前相关转化机制及其影响因素的研究较少。2020年10月20日位于白龙江左岸、甘肃省舟曲县的虎家崖暴发小型泥石流,侵入省道313,威胁毗邻村庄。通过现场调查、室内岩土试验、遥感解译和降雨资料分析,本文对虎家崖泥石流形成的地质环境条件、运移及堆积特征等进行了调查,研究了浅层滑坡失稳并直接转化为泥石流的主要特征、过程、影响因素及其形成机理,探讨其未来发展趋势。研究表明：(1)虎家崖上游狭长沟道堆积体受到长达19 d、累计98.5 mm的持续性降雨的激发而发生慢速滑坡,区域强震造成的坡体结构损伤对滑坡发育也有贡献。(2)滑坡后段与滑坡前缘的剪出部分在运动过程中直接转化为泥石流,但中段滑坡体则维持剪切滑动。(3)转化过程受滑坡前缘剪出土体饱水程度、沟道坡度与落差以及地表径流等因素的影响。(4)虎家崖狭长沟道后缘可能因毗邻泄流坡滑坡活动牵引而破坏,同时上游沟道残余滑坡体与灰岩崩塌体、出口右侧残余滑坡体可能受降雨、地震等激发而失稳,再次转化为泥石流,威胁沟道下方虎家崖村和省道S313。

     

基于GIS的滑坡、泥石流灾害危险性区划关键问题研究

随着GIS技术的引入,滑坡、泥石流灾害危险性区划的效率和准确性得以大大提高。依据工程地质类比原则,在灾害学理论指导下,结合专家打分、层次分析、人工神经网络、信息量、Logistic回归、统计量等模型方法,以MAPGIS软件为平台,利用C++语言开发了滑坡、泥石流灾害危险性区划评价分析系统;并重点探讨了GIS支持下的滑坡、泥石流灾害危险性区划过程中的因子分析、模型选取、模型复合、单元划分、系统集成、结果评价等关键问题,建立了一整套基于GIS的滑坡、泥石流灾害评价方法体系。应用该系统对长江三峡库区和辽宁省鞍山市分别开展了滑坡、泥石流灾害危险性区划研究,取得了较好的效果。     

基于数字滑坡技术的暴雨滑坡、泥石流预警、监测模型研究

中国学者在暴雨滑坡、泥石流预测预报研究领域取得的成果为采用数字滑坡技术进行暴雨滑坡、泥石流预警、监测模型研究提供了宝贵的基础,应用数字滑坡技术建立暴雨滑坡、泥石流预测模型的原则是：（1）必须在滑坡、泥石流形成条件理论指导下;（2）应了解研究区地质环境及滑坡、泥石流特征;（3）就基于数字滑坡技术而言,只能选取遥感方法可能...     

Dynamic modeling of Meiping landslide process

Natural Hazards - Landslide disaster monitoring has always been an important research topic. In this study, we used the finite element numerical method to simulate the Meiping landslide dynamic...     

滑坡碎屑流冲击拦挡结构的离散元模拟

拦挡结构可以有效减小滑坡致灾范围、减弱致灾强度。文章以滑坡碎屑流为研究对象,通过对比模型试验和数值模拟结果,校正三维离散元模拟参数,进而研究不同坡脚角度和挡板高度对冲击力、最大水平运动距离的影响。研究结果表明:三个坡脚角度碎屑流冲击力的变化过程存在明显区别,坡脚角度为35°和45°时,冲击力时程曲线经历了两个显著的变化阶段:线性增大、线性减小。而坡脚角度为55°时,碎屑流冲击力时程曲线出现三个变化阶段:线性增加、恒力阶段、线性减小。挡板高度越高,恒力阶段的持续时间越短,冲击力线性减小阶段时间越长。小颗粒（2.5~10 mm）对挡板的冲击效应显著;中等颗粒（10~25 mm）随着挡板高度的增加,对挡板的冲击效应逐渐增大;而大颗粒（25~60 mm）作用在挡板上的冲击效应出现突变,与其他两种颗粒对比,整个运动过程冲击效应不显著。碎屑流的运程随着挡板高度的增加逐渐减小。对比三个坡脚角度下挡板的拦挡效果,坡脚角度α≤45°时,拦挡效果显著。     

降雨作用下碎石土滑坡解体变形破坏机制研究

为了揭示碎石土滑坡的变形解体破坏机制,结合工程实例,通过资料搜集整理和分析、现场工程地质调查与勘探和室内外的物理力学试验,采用不平衡推力法、数理统计分析方法和三维弹塑性接触有限元算法,以及运用碎石土边坡地下水管网状排泄系统理论,分析降雨作用下碎石土滑坡的变形解体破坏过程,揭示了降雨作用下中深层碎石土滑坡变形解体破坏的主要机制和一般的力学机制。结果表明,一定强度的长时间连续降雨或强降雨是中深层碎石土滑坡发生失稳的主要触发因素;采用考虑降雨作用的弹塑性接触有限元算法,可以更好地反映该类型滑坡在降雨作用下所处的实际状态及滑坡的滑动过程,可以为该类型滑坡稳定性的准确评价和预测预报提供可资借鉴的方法。     

碎石土古滑坡弹塑性接触有限元稳定性分析

为了准确评价碎石土古滑坡的稳定性,通过资料搜集整理和分析、现场工程地质调查与勘探和室内外的物理力学试验,采用三维大变形弹塑性接触有限元算法,结合复活碎石土古滑坡工程实例,提出利用三维计算结果计算二维剖面稳定性系数的方法,分析了滑坡的稳定性。结果表明,采用三维大变形弹塑性接触有限元算法分析滑坡稳定性可以考虑滑坡体的空间效应,使计算结果更加符合实际。新方法可以更准确分析碎石土滑坡的稳定性和获得该类型滑坡所处的实际状态,为滑坡治理提供准确的科学信患。     

The influence of rainstorm pattern on shallow landslide

In this study, the influence of the rainstorm pattern on shallow landslide is examined. The physically-based shallow landslide model is used to conduct this examination with considering four representative rainstorm patterns including uniform, advanced, central, and delayed rainstorms. The results show that in spite of the rainfall duration and the rainfall pattern, the rainstorm with less than the minimum landslide-triggering rainfall amount will not trigger landslide. However, for the rainstorm with greater than the minimum landslide-triggering rainfall amount, the occurrence of landslide significantly depends not only on the rainfall duration but also on the rainfall pattern. Among the four representative rainstorm patterns, the delayed rainstorm has the greatest rainfall duration threshold for landslide occurrence, followed by the central rainstorm, and then the uniform rainstorm. In addition, for each rainstorm pattern, the corresponding rainfall duration threshold for landslide occurrence decreases with the increase of rainfall amount, and seems to be constant for large rainfall amount.     

颗粒粒径对滑坡碎屑流动力特征及能量转化的影响——以四川省三溪村滑坡为例

滑坡碎屑流的能量演化机制涉及复杂的碰撞、摩擦和能量转化,对滑坡灾害的防治具有重要意义。以四川省三溪村滑坡为例,采用离散元法建模,研究了不同土颗粒粒径下滑坡的运动堆积特征、能量演化过程及其对建筑物的影响。结果表明,在不同粒径条件下,滑坡的堆积特征变化不大,但它们对能量转换和建筑物的冲击力有显著的影响。粒径越大,滑坡启动速度越快,峰值动能速度越高,碰撞耗散能量越大,摩擦耗散能量越少。粗粒土中颗粒间距越大,颗粒间的碰撞效应越明显,有利于能量传递,因此,对房屋的冲击力越大。因此,在模拟过程中不能忽视颗粒粒径对滑坡碎屑流动力学特征的影响。这些研究结果揭示了不同粒径土粒在滑坡运动过程中的能量演化机制,为能量演化对建筑冲击的影响提供了初步的认识,可为滑坡碎屑流的防治提供指导依据。     

影响云南省滑坡泥石流活动的几个自然因素

根据1989～2002年云南省滑坡、泥石流调查资料，在单因素分析的基础上，确定地形、岩土体类型、降雨、地震、活动断裂、气候带和植被覆盖率共7个因素是云南省影响滑坡泥石流的主要自然因素。通过R-型因子分析、逐步回归分析和灰色关联度分析，得出对滑坡影响程度由大到小的因子排序是：海拔和高差、地形坡度、地震、活动断裂、岩组、降雨量；对泥石流影响程度由大到小的因子排序是：活动断裂、海拔和高差、岩组、降雨量、地震。     

基于ArcGIS可视化建模方式的区域滑坡危险性评价

滑坡危险性评价是滑坡灾害防治的重要前提和基础,简单高效的评价方式是其中的一个研究重点。本文以四川安县作为研究区域,基于ArcGIS中的分析功能,引入可视化的建模工具Modelbuilder,以模型的方式演示和运行整个滑坡危险性评价过程,得到了滑坡危险性的分级图,并进行对比分析。实验结果表明,利用可视化建模方式完成复杂地区的滑坡危险性评价,能够简化操作流程,节约时间和精力。     

滑坡影响因素的效果测度分析

滑坡做为一种主要的地质灾害类型，灾域广，灾情重，灾频高，与其它地质灾害相比有显著特点。深重的滑坡灾害，不仅给人民生命财产造成严重损失，也成为阻碍国民经济发展的一大制约因素。研究其产生的影响因素与分类，对此地质灾害的防治具有重要的理论意义与经济价值。效果测度分析方法具有系统因素分析与样本分类双重功能，是一种简便易于操作的信息数据分析评价决策方法，在环境保护、减灾对策和灾害评价等方面应用很广。本文将效果测度分析方法应用于滑坡影响因素与分类的量化分析，力求对地质灾害的防治理论与技术方法做出有意义的贡献。     

Assessing the influence of morpho-structural setting on landslide abundance

Knowing the factors that influence landslide abundance and distribution is important to evaluate landslide susceptibility and hazard. Visual interpretation of aerial photographs (API) can be used to collect spatially distributed information on bedding attitude (BA), in an area. Where a map of the location of bedding traces (BTs), i.e. lines showing the intersection of bedding planes with the local topography, is available, the map can be used to obtain BA point data and to prepare maps showing morpho-structural domains. The possibility of using BA maps to investigate the influence of morpho-structural settings on landslide abundance is hampered by the lack of understanding of the influence of the length of the BTs, and of the parameters used to interpolate the BA data on the structural zonation. To investigate the problem, we used information on 207 BTs obtained through API in the Collazzone area, Central Italy, and we prepared 150 maps showing BA information. This was accomplished using 15 different values for the segmentation length of the BTs (S), and 10 different values for the tension parameter (T) used for the interpolation. We compare the results against previous results obtained for the same area adopting a heuristic approach to the segmentation of the same set of BTs. Next, we compare the geographical distribution of old deep-seated, deep-seated and shallow landslides in five morpho-structural domains in the study area, and we analyse the influence of the structural settings on the abundance of the different types of landslides.     

水库蓄水对库岸滑坡的影响研究

水库蓄水将显著改变库岸的水文地质条件,进而影响滑坡的稳定状态。以鄂西南某水库为例,阐述了库水位对滑坡稳定性影响的一般规律,并采用剩余推力法计算分析了滑带土抗剪参数、库水位变化和地下水疏干系数对库岸滑坡的影响。在此基础上,对蓄水后库岸滑坡的变形模式进行了模拟分析。研究表明,水库蓄水不仅使滑坡稳定性发生变化,滑坡的变形模式也将由推移式转变为牵引式。     

Large volcanic landslide and debris avalanche deposit at Meru,Tanzania

Meru volcano is located within the Northern Tanzanian Divergence Zone where the east branch of the East African Rift splits into several branches. The 4565-m-high Meru volcano is breached on the east flank by a horseshoe-shaped scar following a major collapse associated with the Momella debris avalanche approximately 9000 years ago. Remote sensing combined with detailed field mapping allowed the characterisation of the Momella debris avalanche deposit, structure, and texture. Hummocks, ridges, lineaments, lobes, grabens and shear zones are observed on the surface of the deposit. The most common facies observed are the mixed facies with indurated and shattered outcrops and the matrix facies. The collapse involved a volume of 20 ± 2 km³ with a deposit that spread over an area of 1250 km², up to the base of Kilimanjaro. Based on field evidence, we suggest that water played a key role in the deformation, facies formation, avalanche emplacement and mobility of the entire deposit but to a lesser extent south of Ngurodoto complex. The deformation and emplacement of the avalanche were accommodated by both extension and shearing on a water-fluidised basal layer.     

大光包滑坡启动机制的物理模拟试验

安县大光包滑坡是汶川地震触发的规模最大的滑坡,为了研究其形成机制,本文结合野外现场调查,利用三维振动台物理模拟试验,研究了大光包滑坡在地震作用下的启动机制与破坏过程,探讨了滑坡发生与坡体结构的密切关系。研究结果表明:大光包滑坡一个楔型槽状滑落体,沿着白云岩沙化层面和坡体中垂直于层面倾坡内早期X构造裂隙构成,是层面与裂隙在地震力作用下扩展并破坏的宏观表现;振动作用下坡体首先在坡顶产生一系列的拉张裂缝,随后在坡体下部产生剪切裂缝;后缘拉裂面、东侧白云岩层面和西侧拉裂边界将坡体切割成楔形体并滑下;滑坡为一后退式滑坡,呈多次后退式破坏。