Landslide risk assessment and management by decision analytical procedure for Dereköy, Konya, Turkey

The Dereköy landslide threatening the town of Dereköy, Konya, Turkey is investigated in order to assess and manage the associated risk. Dereköy town, located 12 km west of Konya city center, which is the second largest city in central Anatolia, has been extending due to the demand for new settlement places in Konya for the last decade. As most of the town is situated on the slopes of Meram river valley, on which the slope movements are observed, the risk of landslide has been increasing due to these new settlements. In this study, the landslide risk in Dereköy is assessed by following the so-called decision analytical procedure. The risk is defined by multiplication of hazard and consequences of the hazard. The hazard, which is the probability of slope failure, is computed by using the first-order second-moment (FOSM) method. The possible consequences of a landslide in Dereköy are analyzed and their costs are assessed relative to each other. A decision tree for choosing among the possible alternatives for reducing the risk is constructed in order to manage the risk.     

Landslide protection of the historical heritage in Odessa (Ukraine)

This study focuses on the specifics of modern geological conditions and deformations of landslide-affected slopes within the historical center of the city of Odessa. Landslide protection was developed in the 19th century and during 1960s on adjacent coastal areas, according to urban planning and landslide protection plans. The historical center was formed around the Odessa port and includes several unique architectural monuments such as the 142-m-long Potemkin Stairs, Primorsky Boulevard, and the Odessa Opera Theater. Architectural and urban planning designs in the city include landslide protection and preventive measures. Results of landslide studies show that landslide development along the Odessa coast is influenced primarily by tectonic movements and the heterogeneity of the geological substrata. All historical and contemporary protective and preventive landslide measures maintain their engineering geological integrity and effectiveness despite the differences in time of their construction and design.     

滑坡临滑预报的态矢量方法研究

态矢量是统计物理学中对连续场进行粗粒化描述的一种方法。将其引入滑坡预报中,通过将滑坡危险区划分为n个子区域,在各个时间窗内对一系列子区域的监测数据进行态矢量分析,将监测数据与降雨量态矢量的模等归一化后叠加,研究一段时间内滑坡位移态矢量的发展变化规律,并提出利用态矢量进行滑坡预报的新方法。以新滩滑坡为例,对累计水平位移进行态矢量分析,发现在滑坡前态矢量的模和态矢量增量的模均发生了明显突变,按态矢量曲线的变化规律,依据滑坡预警分级方法提出3级滑坡预警,最高预警级别预报的滑坡时间比实际滑坡时间提前2天。研究结果表明,态矢量的急剧突变是滑坡发生的前兆,可以用来进行滑坡的短期和临滑预报。     

三峡库区土门子滑坡变形破坏机制分析

在研究土门子滑坡地质环境和变形特征的基础上,对滑坡的成因机制、变形破坏模式及起动机制进行了分析。结果表明,该滑坡为前缘牵引后缘平推式,现处于整体蠕动变形局部滑移阶段,持续强降雨是诱发其失稳破坏的主导因素,针对滑坡体可能沿多个剪出口发生变形破坏等特征、提出了相应工程防治建议,对指导该类工程的设计和施工具有参考意义。     

甘孜州色达县典型牵引式滑坡地质灾害形成机理分析--以甘孜州甲学乡甲热滑坡为例

甲热滑坡位于甘孜州色达县甲学乡境内,属于典型的牵引式滑坡,滑坡体平均坡度约35°,主要由碎石土组成,滑坡长约195 m,宽约280 m,平均厚约15 m,滑坡体总方量约60万m3,属中型滑坡。滑坡坡体中上部变形现象较明显,若发生滑动,将直接威胁当地41户160人居民的生命财产安全。本文在进行野外现场基础地质调查后,对滑坡体的变形破坏机制进行了定性分析,并利用三位有限元数值模拟进行了定量分析,对以后研究同类滑坡的稳定性具有重要意义。     

江苏镇江焦山索道上站滑坡治理中技术方法的应用

镇江市是江苏省滑坡地质灾害较为严重的城市,其地质灾害防治工作开展较早,积累了一定的防治管理经验。而焦山索道上站滑坡治理工程是多种滑坡治理技术方法和措施的综合应用,通过混凝土抗滑桩、锚索、锚杆、排水以及挂网喷播复绿等技术方式和措施的应用,成功地完成了焦山索道上站的滑坡治理工程,为镇江市其他滑坡地质灾害的治理提供了一定的参考借鉴作用。     

Landslide and Tsunami 21 November 2000 in Paatuut,West Greenland

A large landslide occurred November 21, 2000 at Paatuut, facing the Vaigat Strait onthe west coast of Greenland. 90 million m³ (260 million tons) of mainly basalticmaterial slid very rapidly (average velocity 140 km/h) down from 1,000–1,400 maltitude. Approximately 30 million m³ (87 million tons) entered the sea, creatinga tsunami with an run-up height of 50 m close to the landslide and 28 m at Qullissat,an abandoned mining town opposite Paatuut across the 20 km wide Vaigat strait. Theevent was recorded seismically, allowing the duration of the slide to be estimated tocirca 80 s and also allowing an estimate of the surface-wave magnitude of the slideof 2.3. Terrain models based on stereographic photographs before and after the slidemade it possible to determine the amount of material removed, and the manner ofre-deposition. Simple calculations of the tsunami travel times are in good correspondencewith the reports from the closest populated village, Saqqaq, 40 km from Paatuut, whererefracted energy from the tsunami destroyed a number of boats. Landslides are notuncommon in the area, due to the geology with dense basaltic rocks overlying poorlyconsolidated sedimentary rocks, but the size of the Paatuut slide is unusual. Based onthe observations it is likely at least 500 years since an event with a tsunami of similarproportions occurred. The triggering of the Paatuut slide is interpreted to be caused byweather conditions in the days prior to the slide, where re-freezing melt water inpre-existing cracks could have caused failure of the steep mountain side.     

储层特低渗透成因分析与评价——以安塞油田沿25区块为例

应用测井资料和铸体薄片、扫描电镜、X 衍射、粒度分析、压汞等化验分析资料综合研究了安塞油田沿25区块长6储层的特低渗透成因和影响因素,并评价了储层储集性能。分析表明,该区块储层物性总体较差,发育粒间孔、溶蚀孔,孔隙结构类型属小孔隙、微细喉道型。其特低渗透成因主要受沉积作用和成岩作用的共同影响,具体表现为：不同沉积微相储层的物性差异较大,软组织含量大、粒度细和成分成熟度较低是造成储层特低渗透特征的主要原因。同时成岩压实、胶结作用使得储层的孔隙度、渗透性进一步减小、变差,而溶蚀作用和成岩缝的产生又在很大程度上改善了储层的特低渗透特征。根据物性和孔隙结构参数分析,将研究区储集岩分为3类,水下分流河道与河口坝砂体是主要储层分布相带。     

A geotechnical investigation of the retrogressive Yaka Landslide and the debris flow threatening the town of Yaka (Isparta,SW Turkey)

In this study the factors affecting the retrogressive Yaka Landslide, its mechanism and the hazard of debris flow on the town of Yaka are investigated. In the landslide area, the first landslide was small and occurred in March 2006 on the lower part of the Alaard?ç Slope near the Gelendost District town of Yaka (Isparta, SW Turkey). The second, the Yaka Landslide, was large and occurred on 19 February 2007 in the soil-like marl on the central part of Alaard?ç Slope. The geometry of the failure surface was circular and the depth of the failure surface was about 3 m. Following the landslide, a 85,800 m³ of displaced material transformed to a debris flow. Then, the debris flow moved down the Eglence Valley, traveling a total distance of about 750 m. The town of Yaka is located 1,600 m downstream of Eglence Creek and hence poses a considerable risk of debris flow, should the creek be temporarily dammed as a result of further mass movement. Material from the debris accumulation has been deposited on the base of Eglence Valley and has formed a debris-dam lake behind a debris dam. Trees, agricultural areas, and weirs in the Eglence Creek have seen serious damage resulting from the debris flow. The slope angle, slope aspect and elevation of the area in this study were generated using a GIS-based digital elevation model (DEM). The stability of the Alaard?ç Slope was assessed using limit equilibrium analysis with undrained peak and residual shear strength parameters. In the stability analyses, laboratory test results performed on the soil-like marls were used. It was determined that the Alaard?ç Slope is found to be stable under dry conditions and unstable under completely saturated conditions. The Alaard?ç Slope and its vicinity is a paleolandslide area, and there the factor of safety for sliding was found to be about 1.0 under saturated conditions. The Alaard?ç Slope and the deposited earthen materials in Eglence Creek could easily be triggered into movement by any factors or combination of factors, such as prolonged or heavy rainfall, snowmelt or an earthquake. It was established that the depth of the debris flow initiated on the Yaka Landslide reached up to 8 m in Eglence Creek at the point it is 20 m wide. If this deposited material in Eglence Creek is set into motion, the canal that passes through Yaka, with its respective width and depth of 7 and 1.45 m, could not possibly discharge the flow. The destruction or spillover of this canal in Yaka could bring catastrophic loss to residents which are located within 3–5 m of the bank of the canal. Furthermore, if material present in the landslide source area slides and this displaced material puts pressure on the unstable deposited material in Eglence Creek, even more catastrophic loss would occur to the town of Yaka. In this study, it was determined that debris flows are still a major hazard to Yaka and its population of 3,000. The results provided in this study could help citizens, planners, and engineers to reduce losses caused by existing and future landslides and debris flow in rainfall and snowmelt conditions by means of prevention and mitigation.     

Analysis of the 2003 Varunawat Landslide,Uttarkashi, India using Earth Observation data

Mass movements such as landslides in mountainous terrains are natural degradation processes and one of the most important landscape-building factors. Varunawat Parbat overlooking Uttarkashi town witnessed a series of landslides on 23 September 2003 and the debris slides and rock falls continued for 2 weeks. This landslide complex was triggered due to the incessant rainfall prior to the event, and its occurrence led to the blockage of the pilgrim route to Gangotri (source of the Ganges river) and evacuation of thousands of people to safer places. Though there was no loss of lives due to timely evacuation, heavy losses to the property were reported. High-resolution stereoscopic earth observation data were acquired after the incidence to study the landslide in detail with emphasis on the cause of the landslide and mode of failure. Areas along the road and below the Varunawat foothill region are mapped for landslide risk. It was found that the foothill region of the Varunawat Parbat was highly disturbed by man-made activities and houses are dangerously located below steep slopes. The potential zones for landslides along with the existing active and old landslides are mapped. These areas are critical and their treatment with priority is required in order to minimise further landslide occurrences.     

A new rock mass classification for Coal Measures Rocks

This paper examines a new rock mass classification system (RMCR) for Coal Measures Rocks which is based on extensive laboratory testing results. The new system has been developed using 12 parameters which consist of mineral content index, uniaxial compressive strength, uniaxial tensile strength, Young's modulus of elasticity, shear strength, cohesion of rocks, angle of internal friction, point load index, cone indenter index, Cerchar index, Shore schleroscope hardness and specific energy index. The RMCR value was obtained by a number of laboratory and in situ testing results which were obtained from the coal site. The objective of the RMCR is to estimate the rock mass properties for engineering purposes.     

岩质滑坡的时间预报与水力启动模型

摘 要 岩质滑坡发生时间的适时超前预报是一个世界性难题,之所以长期不得其解,主要是缺乏对滑坡成生机理的明晰认识和未建立正确的量化模型。本文根据我国长江三峡工程库岸和西南山区积累的大量滑坡实例调查资料并参考国外的一些研究成果,排除了地形控制论与地层控制论观点,阐明了滑坡形成的必要条件是斜坡具有易滑结构;滑坡发生的充分条件是有一定强度的诱发因素作用。故而诱发因素的动态变化对滑坡发生的时间具决定意义。\r\n鉴于地下水诱发的岩质滑坡分布最广,为建立正确的水力启动模型,本文归纳了近代典型岩质滑坡的主要特征：（1）滑面是导水性差异最大的贯通面;（2）滑体长度大而厚度小,长厚比多在20左右;（3）滑坡前缘段先启动;（4）临滑前在前缘段有渗水、冒水或喷水现象;（5）出水宽度之和远小于前缘段总宽度。根据这些特征和水力学、水文地质学的成熟理论指出jennings（1970）等人提出的岩质斜坡稳定性模型存在下列问题：（1）未表明贯通面上岩体重力分布状况;（2）空隙水压力的分布特征与前述滑坡现象和水力学原理相悖;（3）未考虑通水率问题。然后,本文按顺向坡中的易滑超倾坡和椅状坡两个类型建立了斜坡稳定性模型和滑坡水力启动临界值（基本）计算公式。提出潜滑面的综合内摩擦角和通水率的确定方法：（1）滑坡反算;（2）对无水压滑坡滑面倾角和渗水边坡通水率进行观测统计;（3）剪切试验和简易水文地质试验;（4）物探方法。\r\n本文还讨论了新模型的实用意义和应用范围,并对解决这类复杂地质灾害问题的研究途径发表了作者的认识,强调了积累经验的重要性。     

Landslide Hazard Zonation using Remote Sensing and GIS: a case study of Dikrong river basin, Arunachal Pradesh, India

Landslides are among the most costly and damaging natural hazards in mountainous regions, triggered mainly under the influence of earthquakes and/or rainfall. In the present study, Landslide Hazard Zonation (LHZ) of Dikrong river basin of Arunachal Pradesh was carried out using Remote Sensing and Geographic Information System (GIS). Various thematic layers namely slope, photo-lineament buffer, thrust buffer, relative relief map, geology and land use / land cover map were generated using remote sensing data and GIS. The weighting-rating system based on the relative importance of various causative factors as derived from remotely sensed data and other thematic maps were used for the LHZ. The different classes of thematic layers were assigned the corresponding rating value as attribute information in the GIS and an “attribute map” was generated for each data layer. Each class within a thematic layer was assigned an ordinal rating from 0 to 9. Summation of these attribute maps were then multiplied by the corresponding weights to yield the Landslide Hazard Index (LHI) for each cell. Using trial and error method the weight-rating values have been re-adjusted. The LHI threshold values used were: 142, 165, 189 and 216. A LHZ map was prepared showing the five zones, namely “very low hazard”, “low hazard”, “moderate hazard”, “high hazard” and “very high hazard” by using the “slicing” operation.     

Analytic network process model for landslide hazard zonation

Various controlling factors such as lithology, slope angle, slope aspect, landuse, channel proximity etc. are generally considered for the landslide hazard assessment. Although outer dependence of these parameters to a landslide is inevitably taken into account, inter-dependence among the factors is seldom addressed. Analytic Network Process (ANP) is the multi-criteria decision making (MCDM) tool which takes into account such a complex relationship among parameters. In this research, an ANP model for landslide susceptibility is proposed, priority weights for each parameter controlling the landslide were determined, and a hazard map was prepared of an area in a fragile mountainous terrain in the eastern part of Nepal. The data used in the example were derived from published sources, aerial photographs and a topographic map. However, the procedures developed can readily incorporate additional information from more detailed investigations.     

黄莲树滑坡破坏变形机理浅析

以三峡库区奉节县黄莲树滑坡的破坏变形为例,以地表位移、降雨、地下水、库水位的监测为依据,综合分析研究了监测参数的变动和致灾因子相互作用对滑坡稳定性的影响关系,开展破坏变形机理探讨研究,总结形成了初步的研究成果。该研究成果对滑坡的监测预警预报技术具有重要的理论意义,并且对其它以库水位涨落和降雨为主要致滑因子的滑坡的监测临滑预报具有重要的参考价值和指导意义。     

Evaluation of potential landslide damming: Case study of Urni landslide,Kinnaur, Satluj valley,India

This work aims to understand the process of potential landslide damming using slope failure mechanism,dam dimension and dam stability evaluation. The Urni landslide, situated on the right bank of the Satluj River, Himachal Pradesh(India) is taken as the case study. The Urni landslide has evolved into a complex landslide in the last two decade(2000-2016) and has dammed the Satluj River partially since year 2013,damaging ～200 m stretch of the National Highway(NH-05). The crown of the landslide exists at an altitude of ～2180-2190 m above msl, close to the Urni village that has a human population of about 500.The high resolution imagery shows ～50 m long landslide scarp and ～100 m long transverse cracks in the detached mass that implies potential for further slope failure movement. Further analysis shows that the landslide has attained an areal increase of 103,900 ± 1142 m^2 during year 2004-2016. About 86% of this areal increase occurred since year 2013. Abrupt increase in the annual mean rainfall is also observed since the year 2013. The extreme rainfall in the June, 2013; 11 June(～100 mm) and 16 June(～115 mm),are considered to be responsible for the slope failure in the Urni landslide that has partially dammed the river. The finite element modelling(FEM) based slope stability analysis revealed the shear strain in the order of 0.0-0.16 with 0.0-0.6 m total displacement in the detachment zone. Further, kinematic analysis indicated planar and wedge failure condition in the jointed rockmass. The debris flow runout simulation of the detached mass in the landslide showed a velocity of ～25 m/s with a flow height of ～15 m while it(debris flow) reaches the valley floor. Finally, it is also estimated that further slope failure may detach as much as 0.80 ±0.32 million m^3 mass that will completely dam the river to a height of 76±30 m above the river bed.     

Landslide hazard zonation by deterministic analysis (Veľká Čausa landslide area, Slovakia)

A practical application of a simple and economical solution to landslide hazard zonation based on slope stability analysis was carried out in the Veľká Čausa landslide, Horná Nitra region, central Slovakia. The region is prone to different types of slope deformation controlled by geological structure, physical and mechanical properties of materials, complicated hydrogeological setting, undulating morphology, and man-made influence. Taking into consideration the cause of the landslide, identified as groundwater change, two scenarios of landslide activity have been investigated. Scenario 1 considers the maximum groundwater level recorded from March 1995 to October 1998, corresponding to the period starting from the most recent landslide activity up to the end of remediation work. Scenario 2 considers the maximum groundwater level recorded from November 1998 to December 2004, after the remediation works, and corresponding to the actual situation of the landslide. It has been found from this study that slope angle has the highest influence on landslide instability in the Veľká Čausa landslide. Therefore, high resolution Digital Elevation Model (DEM) is essential for obtaining reasonable results. In addition, an appropriate selection of the model input parameters (e.g., shear strength) is very important. The validation between the calculated landslide hazard zonation map and results of monitoring survey were examined. The results show moderate to good agreement with the inclinometric and geodetic measurements. It was also verified that the most active part of the landslide is the north-western side.     

江西省资溪县西源滑坡成因分析及其治理

以资溪县西源滑坡为研究对象,根据勘察资料采用经典的传递系数法对天然状态和饱水状态滑坡的稳定性进行了计算,表明自然状态滑坡处于基本稳定状态,饱和状态滑坡处于不稳定状态;根据滑坡体勘察成果,采用抗滑支挡和地表排水综合治理措施,取得了良好成效。     

大光包滑坡滑带碎裂岩体原位钻孔剪切试验研究

传统滑坡深度探测方法只能确定坡体部分稀疏单点的深度,无法准确反应整个滑坡体的深度分布情况,且探测成本高昂。针对该问题,本文发展了一种基于升降轨InSAR形变的滑坡深度反演方法,其基本流程是:首先利用时序InSAR技术分别获取升轨和降轨卫星视线向形变速度场,再根据卫星视线向与滑坡的空间几何关系,解算获得滑坡表面沿坡向和法向的二维形变场,进一步在质量守恒准则下构建基于坡面二维形变的滑坡深度反演模型,实现滑坡深度的反演计算。本文以四川省理县桃坪乡古滑坡体为研究对象,InSAR成果显示该滑坡运动面积~2.9 km²,流变参数取0.7时,反演滑坡深度集中分布在9~33 m,滑坡体积约3.49×10⁷ m³,结果与已有研究结论基本一致,证明了本文发展理论与方法的可靠性。且本文提出方法可获得滑坡体连续的深度数据,能更为直观地反映滑坡危险区域,可为滑坡灾害影响分析及灾害防治提供关键的数据支撑。     

Landslide studies along the national highway (NH 39) in Manipur

The present study investigates the factors associated with the occurrence of landslides along with the National Highway (NH 39) connecting Assam-Manipur (India) to Myanmar. Kinematics and slope stability analyses were used to gain an understanding of the causes of slope failure despite the terrain comprising material with a high safety factor. The study area falls within a high seismic zone along the regional Churachandpur-Mao Thrust (CMT) situated west of the Indo-Myanmar subduction zone. Based on these studies of seismicity, slip rates, creeping, among others, it was inferred that CMT is a creeping regional fault running parallel to the subduction zone boundary creeping segment of CMT and that the CMT requires further monitoring to assess the landslide hazard in the region.