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1.
The prediction of rockfall trajectories below a rock cliff is essential in susceptibility, hazard and risk maps, particularity
close to populated areas. The Monte da Lua hill area in Portugal, a tourist destination close to the historic city of Sintra
(UNESCO World Heritage), is a typical granite boulder chaos landscape where from time to time rockfalls occur, the last such
event having occurred on 29 January 2002. This area is therefore suitable to develop a rockfall study in order to provide
hazard and risk maps a basis for mitigation measures. A preliminary investigation of the area leads to the identification
of 188 potentially dangerous boulders. Detailed locations and geotechnical characteristics in terms of geometry, strength
and context were sampled for each boulder. Digital elevations at 1 × 1 m resolution, known rockfall trajectory and building
locations are provided in a GIS project for the study together with the spatial database of boulder characteristics. The modelling
approach was conducted in two steps: (1) discrimination of the boulders in terms of static and dynamic mobility behaviour
with multivariate analysis; (2) stochastic simulation of rockfall trajectories. The rockfall trajectory algorithm proposed
is straightforward and is only dependent on elevation data, initial location of boulders and a friction angle. Due to the
slope of the area, it assumes that rockfall is always of the rolling or sliding type. The friction angle was calibrated on
the basis of the rockfall travel distance recorded on 29 January 2002 and generates simulated “realistic” trajectories. A
smaller friction angle increases all simulated trajectories, leading to more “pessimistic” scenarios. The combined analysis
of trajectories and potential damage to buildings and discrimination in terms of static and dynamic behaviour provides a final
table in which all 188 sampled boulders are classified in one of the five risk grades. 相似文献
2.
Lu Zheng Guangqi Chen Yange Li Yingbin Zhang Kiyonobu Kasama 《Geomechanics and Geoengineering》2014,9(2):142-152
Rockfall is the most frequent major hazard in mountainous areas. For hazard assessment and further countermeasure design, realistic and accurate prediction of rockfall trajectory is an important requirement. Thus, a modeling method to represent both geometrical parameters of slope and falling rock mass is required. This study, suggests taking the advantages of discontinues deformation analysis (DDA) and geographical information system (GIS). In this study, after developing a three dimensional (3D) DDA program, firstly a special element named contact face element (CFE) was introduced into 3D DDA; secondly, effectively modeling tools with GIS support were developed. The implementation of CFE also improves the efficiency of both the contact searching and solution process. Then a simple impact model was devised to compare the 3D DDA implemented directly with a sliding model with theoretical analysis to verify the reliability of the modified 3D DDA program and investigate the parameter settings. Finally, simulations concerning rock shapes and multi-rocks were carried out to show the applicable functions and advantages of the newly developed rockfall analysis code. It has been shown that the newly developed 3D DDA program with GIS support is applicable and effective. 相似文献
3.
我国多山,崩塌灾害频繁发生,相应的风险评价也得到了越来越多的关注。由于崩塌发生和运移过程的高度不确定性以及历史数据的不完备,往往很难进行相应的定量风险评价。四川罗家青杠岭的崩塌现场非常典型,而且现场资料较全、历史数据较多并且明确,是开展崩塌风险定量研究的很好实例。通过现场工程地质调查、测绘和统计分析,确定了历史崩塌的物源区、堆积区、最大运移距离、年发生概率以及坡体上的4块典型危岩体A-D。基于历史崩塌堆积区的块石统计特征以及物源区危岩体失稳启动位置的不确定性,利用二维Rockfall模拟软件对所在坡面的恢复系数及摩擦系数进行了反演。在此基础上,对危岩体A-D失稳后的运动特征进行了随机性数值模拟和统计分析,从而确定了崩塌的到达概率。基于崩塌发生概率、到达概率、承灾体时空分布概率和易损性的乘积,作者对罗家青杠岭崩塌进行了定量风险评价。评价结果表明,危岩体A和D的风险值处于不可接受的风险区间,块石B和C的风险值处于警告的风险区间,严重威胁着坡脚附近居民的生命财产安全,有必要采取相应的防灾减灾措施。 相似文献
4.
滚石灾害是山区常见的地质灾害类型,研究滚石的运动特征对地质灾害调查及危险性评估有着重要意义。通过对尼泊尔某项目滚石灾害后现场进行工程地质调查,分析其灾害成因机制,查明事故原因。调查结果表明:9 ·15灾害非人类活动的影响,属自然地质灾害,造成事故的主要原因为超高位岩体崩塌,而滚石的范围又超过前期预测的危险区。通过现场痕迹分析,推测出滚石的运动路径。根据调查出的撞击点位置、物质组成及几何特征,作者提出运用运动学原理还原滚石运动轨迹,并利用rocfall软件对超高位危岩体崩落后的运动轨迹进行随机模拟分析,推算出超高位危岩体崩落后能量大小的变化,为防护措施方案提供可靠的依据。张口式帘式网韧性强,防护能级高,对高陡边坡滚石灾害能起到很好的效果。本文可为类似高陡边坡的危岩治理防护提供参考。 相似文献
5.
In this paper, a study aimed to assess the rockfall hazard along a portion of the SS18 coastal road, located in the coastal area of Maratea (Basilicata Region, Southern Italy), is presented. The relevance of this study derives from the location of the study area, because the SS18 is a strategic roads in a touristic area, and, since the hazard assessment was performed in 2004 within a project financed by the Viability Regional Department of Autonomous National Company of Roads (ANAS), from the possibility to validate the results by using real rockfall events occurred after 2004. The procedure for assessing the rockfall hazard was composed of four sequential analyses: (i) geomechanical and kinematic characterization of rock mass, (ii) implementation of Romana’s (1985) Slope Mass Rating (SMR) method for identifying the potential boulder release areas (rockfall initiation areas), (iii) determination of rockfall trajectories by using a 3D numerical model (ROTOMAP), (iv) calculation and mapping of the hazard index by combining three factors, i.e., (a) lithological features of outcropping materials on rock faces, (b) kinematic compatibility defined by simulating the rockfall trajectories, and (c) spatial distribution of occurred rockfall events. Finally, the proposed methodology was validated by combining the distribution of the hazard levels along the road with the location on the SS18 of the rockfall events occurred from 2004 to 2014. 相似文献
6.
Rockfall susceptibility zoning at a large scale: From geomorphological inventory to preliminary land use planning 总被引：3，自引：0，他引：3
Rockfall, up to several hundreds of cubic meters, is a frequent and rapid landslide which menaces extensive areas in mountainous territories. Rockfall susceptibility zoning map at a large scale (1:5000–1:25 000) can be the first tool for land use planning in order to manage rockfall risk. A methodology allowing to analyze susceptibility in extensive areas with optimum cost/benefit relationship is needed. This work analyzes rockfall susceptibility in an extensive rocky mountain of the Principality of Andorra (Pyrenees Mountains), first on the rock slope and then on the exposed area located below. The rockfall record, obtained by means of geomorphological analysis, supplies the main data to analyze the susceptibility on the rock slope. An additional historical inventory verifies the accuracy of rockfall sizes recorded by means of the geomorphological analysis. According to the classification recommended by the Guidelines of Joint Technical Committee, the density of rockfall features on the rock slope assesses susceptibility in four levels. Subsequently, susceptibility on exposed areas has been analyzed by means of reach probability of rock blocks analysis using empirical models. Data acquired from thirteen recent events, from 1999 to 2004, have been used to verify the accuracy of the two empirical models mainly used (reach angle and shadow angle). Five reach probability limits (1, 0.5, 0.25, 0.01, and 0) establish boundaries between susceptibility levels. The resulting rockfall susceptibility zoning map allows: (a) to identify land areas and human elements exposed to rockfalls and, (b) to establish several exposition levels. This map can be a useful and cost-effective tool for administrations responsible to manage natural risk in order to guide urban grow in extensive areas or decide upon work programs based on in-depth analysis (hazard and risk). 相似文献
7.
以穿越汶川震区的成兰铁路龙门山关键段为例, 探索提出了强震扰动背景下重大工程场区多尺度滑坡危险性评估方法。利用信息量模型反演评估了汶川地震诱发的同震滑坡空间分布特征, 以此为前提开展了区域和局地两种空间尺度的滑坡危险性预测评估。在区域廊带尺度上, 分别利用可能最大降雨量预测方法和信息量模型, 进行了日超越概率10%的最大降雨量时空分布预测及其诱发滑坡的危险性评估; 同时, 结合地震危险性区划成果, 开展了50年超越概率10%的基本地震动诱发滑坡的危险性评估。在局地场站尺度上, 利用基于崩塌运动过程模拟的Rockfall Analyst软件, 开展了柿子园大桥周边崩塌运动学特征(Runout)模拟和危险性评估。滑坡和崩塌危险性评估的结果分别为铁路规划选线和场站防护设计提供了不同尺度的地质安全依据。 相似文献
8.
针对香丽高速公路边坡地质灾害,在详细的道路工程勘察设计文件的基础上,结合现场踏勘调查,系统地研究了其边坡地质灾害的主要类型、发育特征和分布规律;提出高速公路等线性工程边坡灾害的基本地质条件、自然诱发因素、人类工程活动和灾害历史记录等完整信息评价指标。采用层次分析法、专家评分法与因素累积法相结合的研究方法,建立了线性工程边坡地质灾害易发性评价模型,并基于GIS平台完成了香丽高速公路边坡地质灾害的易发性区划。为指导香丽高速公路地质灾害的危险性评价及科学防治提供了重要依据,对类似山区道路等线性工程边坡地质灾害危险性评价研究与实践具有一定的示范作用和参考价值。 相似文献
9.
Rock fall is a common natural hazard causing significant damage to infrastructure and loss of life and property. This paper describes selection of prevention method, construction processes and the results of a rockfall hazard assessment for the village of Sarica (Gürün region, Turkey) based on an engineering-geological model. The study area is located on the lower parts of an area with very steep cliffs and 40-500 slopes with fractured sedimentary and volcanic rocks. Detailed studies have been conducted in the region to prevent the risk of any rockfalls. Maps and charts are prepared including the rock blocks that are likely to fall and the related housing area under the risk. It was found that block sizes reached 3 m3. Rockfall analyses were performed along the selected profiles using the Rocfall V.5.0 software. Kinetic energy, bounce height, horizontal location of rock end-points and velocity of the rocks along each section were evaluated separately for each profile. This data was used to select design and construction of rockfall preventing system. In this study professional type rock fall barrier (catchment fence) was used. This method was chosen because it was cheaper, more practical and reliable than others. 相似文献
10.
崩塌地质灾害的致灾体具有隐蔽性特征,传统的调查手段难以查明所有的致灾体,而隐蔽性致灾体一旦失稳破坏,往往造成群死群伤的灾难事故.因此,如何提早识别与预防灾难的发生,成为地质灾害防治学者专家关注的焦点.以凯里市龙场镇崩塌灾害为例,运用GIS技术,采用风险评估的方法,对影响崩塌灾害发生的各因素进行叠加综合,从而分析出灾害的易发性、危险性和易损性,得到灾害的风险性,从而为灾害的预防提供参考与指导. 相似文献
11.
ROckfall risk MAnagement assessment: the RO.MA. approach 总被引：1，自引：1，他引：0
The analysis of risk for vehicles and drivers as a result of rockfall on a road is relevant to design management in geotechnical engineering. This process is very complex due to the large number of parameters involved. In this paper, we discuss risk analysis and management procedures for roads subject to rockfall phenomena. To this aims, we are proposing a quantitative method (the RO.MA. approach). We developed an abacus to define the threshold values of acceptable rockfall risk for a given road. Rockfall risk is calculated using an Event Tree approach and compared with the abacus thresholds to evaluate road safety and the need for additional protective measures to reduce the risk to an acceptable level. The approach was successfully applied at a test site located in Bard, Aosta Valley, north-western Italy. 相似文献
12.
Rosa María Mateos Inmaculada García-Moreno Paola Reichenbach Gerardo Herrera Roberto Sarro Joan Rius Raúl Aguiló Federica Fiorucci 《Landslides》2016,13(4):751-763
The Tramuntana range, in the northwestern sector of the island of Mallorca (Balearic Islands, Spain), is frequently affected by rockfalls which have caused significant damage, mainly along the road network. In this work, we present the procedure we have applied to calibrate and validate rockfall modelling in this region, using 103 cases of the available detailed rockfall inventory (630 rockfall events collected since the eighteenth century). We have exploited STONE (Guzzetti et al. 2002), a GIS-based rockfall simulation software which computes 2D and 3D rockfall trajectories starting from a DTM and maps of the dynamic rolling friction coefficient and of the normal and tangential energy restitution coefficients. The appropriate identification of these parameters determines the accuracy of the simulation. To calibrate them, we have selected 40 rockfalls along the range which include a wide variety of outcropping lithologies. Coefficients values have been changed in numerous attempts in order to select those where the extent and shape of the simulation matched the field mapping. Best results were summarized with the average statistical values for each parameter and for each geotechnical unit, determining that mode values represent more precisely the data. Initially, for the validation stage, 10 well-known rockfalls exploited in the calibration phase have been selected. Confidence tests have been applied to their modelling results taking into account not only the success but also the mistakes. The best accuracy is obtained when the rockfall has a preferential trajectory and worse results when the rockfall follows two or more trajectories. Additionally, the greater the rockfall runout length, the less precise the simulation is. We have further validated the calibrated parameters along the Ma-road (111 km), the main transportation corridor in the range, using 63 rockfall events that occurred during the past 18 years along the road. Of the rockfalls where source areas were properly identified, 81.5 % are well represented by STONE modelling, as the travel paths and the depositional areas are successfully ascertained. Results of the analysis have been used by the Road Maintenance Service of Mallorca to assess hazard and risk posed by rockfall at regional scale to design the road management plan. 相似文献
13.
Vishal V. Siddique T. Purohit Rohan Phophliya Mohit K. Pradhan S. P. 《Natural Hazards》2017,85(1):487-503
A massive disaster occurred in June 2013 in Kedarnath, India, due to cloudburst and extremely heavy rain along the Chorabari glacier. The resulting flash floods further aggravated the instability of natural and hill cut slopes at different places on the downstream side. The village Rambara that existed in close proximity of Kedarnath was swept away under flow of debris and water. The immediate surrounding area, which housed over a hundred and fifty shops and hotels, was completely washed away leaving no trace of civilization. This calamity in Uttarakhand is considered as India’s worst natural disasters after the tsunami in December 2004. On the downstream of the affected areas lie other pilgrim destinations that witness innumerable footfalls every year. Investigation of the health of the slopes on the routes to these destinations is therefore very important to ensure minimal damage to humans and machinery. The Himalayan terrain is a tectonically active mountain belt, having a large number of unstable natural and road cut slopes. Such slopes with rugged topography lie in the high seismic vulnerability zone. Further, the instability is aggravated by natural and anthropogenic activities increasing at a rapid and uncontrollable rate. In the light of the Kedarnath tragedy, more advanced research is being conducted along the National Highways to monitor and prevent slope/structure failures. This study was conducted to evaluate the hazard potential along National Highway-58, near Saknidhar village of Devprayag district by analysing rockfall using hazard rating systems and numerical simulation. Rockfall hazard rating systems were applied to evaluate the conditions of the slopes and to identify the associated risks. Based on the field and laboratory analyses, the parameters required for numerical models were determined. The bounce height, roll-out distance, kinetic energy and speed of the detached blocks were determined by using a competent rockfall simulator. The results obtained were used to identify rockfall risk in the region. Optimization strategies were applied during investigation by modifying the slope angle, ditch width and ditch angle to assess the possibility of a hazard to occur in different scenarios. The simulation studies revealed that an increasing slope angle could significantly increase the kinetic energy of the rock blocks. However, an increase in the ditch angle and the ditch width reduces the energy of moving blocks. The maximum bounce height above the slope varied from 0.003 m to 0.8 m for 10-kg blocks, whereas the maximum velocity and the maximum kinetic energy under such circumstances were 7.882 m/s and 379.89 J, respectively. The barrier capacity was found to be 233.18 J for 10-kg falling blocks at a height of 10.02 m. From the optimization studies, it was found that the risk can be reduced by up to 13 % if the slope of 70° has a ditch angle of 15° while on a flat ditch, the maximum risk will be at an angle of 65°. If the ditch angle is increased, the vertical component of the falling blocks is more effective than that in case of a flat ditch. These optimization studies lay foundation for advanced research for mitigation of rockfall hazards in similar potential areas.
相似文献14.
Rockfall susceptibility has been analysed in mountain cliffs of the Cantabrian Range, North Spain. The main aim of this analysis has been to build a predictive model of rockfall activity from a low number of environmental and geological variables. The rockfall activity has been quantified in a GIS. The cartographic information used shows the spatial distribution of all the recent talus screes as well as their associated source areas in the rock-slopes. The area relation At/Ar (recent talus scree polygon/source basins) in the rock slopes has been used as the rockfall activity indicator. This relation has been validated in 50 pilot rock-slopes and compared with the relation number of recent rock fragments/source basin, obtained from field work. The environmental factors causing rockfall depend on the rock slope situation, and these are: altitude and sun radiation on the rock cliff. The geological factors considered are: lithology, relative position of the main discontinuities with respect to the topographic surface and two morphologic parameters: the roughness and slope gradient. A logistic regression analysis has been applied to a population of 442 limestone and quartzite rock cliffs. The dependent variable is the rockfall activity indicator, which allows the definition of two classes of rock cliff units: low and high activity. The independent variables are altitude, sun radiation (equinox radiation, summer solstice radiation, winter solstice radiation), slope roughness, slope gradient,anisotropy and lithology. Results suggest that it is possible tobuild a valid cartographic predictive model for rockfall activity in mountain rock cliffs from a limited number of easily obtainable variables. The method is especially applicable in massive rock slopes or in regions with uniform rock mass characteristics. 相似文献
15.
贵州省大方县小屯乡法启村一组崩塌地质灾害为一高位崩塌地质灾害隐患,崩塌方式以零星崩落为主,威胁下部83户510名居民及法启火车站安全。本文以贵州省大方县小屯乡法启村一组崩塌地质灾害隐患为例,根据勘查及调查测绘,模拟剖面的选取,坡面的参数确定,运用Rockfall软件数值模拟,模拟出崩塌落石运动过程中的特征参数,掌握了崩塌落石的运动特征,为该地质灾害防治提供了重要的参数依据。研究结果表明,Rockfall数值模拟在零星高位崩塌地质灾害勘查中可分析出崩塌落石的主要堆积停留区、最远崩落距离和各点位的落石动能、最大弹跳高度等详细数据,避免了公式计算的单一性,体现了模拟的随机性,与崩塌地质灾害的实际运动特征更接近,可更有效的指导崩地质灾害的防治,具有重要实践意义。 相似文献
16.
M. K. Ansari M. Ahmad Rajesh Singh T. N. Singh 《Journal of the Geological Society of India》2018,91(1):47-56
The Saptashrungi gad temple (SGT) situated on basaltic hills belongs to Deccan volcanic of Upper Cretaceous to Lower Eocene, is one among the 51 Shakti Peeths and most holy place for pilgrims. Rockfall is a major problem in the past and causing danger to the lives of the villagers settled at the toe of the SGT hill as well as the pilgrims who perform parikrama along the tracks. On the evening of 16 April 2011, an old woman died due to rockfall at SGT hill when she was performing parikrama, moreover, two persons got injured during the deliverance process of this old woman from the continuous rockfall activity. The problem of rockfall could be linked to rainfall, jointing, weathering, man-made or the compounding of all. In this research, the rockfall hazard analysis at SGT hill is assessed using both 2D and 3D rockfall programs along the two parikrama paths: Parikrama Path 1 (or the Badi Parikrama Path ‘BPP’), and Parikrama Path 2 (or the Chhoti Parikrama Path ‘CPP’). Also, the study area of the SGT hill has been divided into eight zones (Zone#01 to Zone#08), based on field observations, orientations of joint sets and hill slope faces and eighteen topographic profiles (AA' to RR') have been taken from these eight zones for rockfall analysis. A detailed topographic survey along with field investigation has been carried out along the temple for ascertaining the nature of rock, discontinuity orientations, and slope geometry. DEM has been generated using topographic profile in ArcGIS to facilitate the 3D rockfall analysis. Maximum rock block sizes are taken into the analysis and run-out distance, bounce height, kinetic energy and velocity of the basaltic blocks are evaluated separately. Based on the analyzed data, the rockfall hazard zone map has been prepared and site having potential rockfall risks have been identified. Finally, wire/net meshing has been proposed after removal of unstable blocks as a stabilization and protection measures.It is worth mentioning here that for the first time rockfall hazard assessment was made in such detail for a site. Suggestions made are implemented by the State Government for the protection of the temple as well as the life of pilgrims performing the parikrama from the rockfall. 相似文献
17.
Rockfalls are common in the steep and vertical slopes of the Campania carbonate massifs and ridges, and frequently represent
the main threat to the anthropogenic environment, potentially damaging urban areas, scattered houses, roads, etc. Despite
the generally limited volumes involved, the high velocity of movement (from few to tens of metres per second) poses rockfalls
among the most dangerous natural hazards to man. Evaluating the rockfall hazard is not an easy task, due to the high number
of involved factors, and particularly to the difficulty in determining the properties of the rock mass. In this paper, we
illustrate the assessment of the rockfall hazard along a small area of the Sorrento Peninsula (Campania region, southern Italy).
Choice of the site was determined by the presence of a road heavily frequented by vehicles. In the area, we have carried out
detailed field surveys and software simulations that allow generating simple rockfall hazard maps. Over twenty measurement
stations for geo-mechanical characterization of the rock mass have been distributed along a 400-m-long slope of Mount Vico
Alvano. Following the internationally established standards for the acquisition of rock mass parameters, the main kinematics
have been recognized, and the discontinuity families leading to the different failures identified. After carrying out field
experiments by artificially releasing a number of unstable blocks on the rock cliff, the rockfall trajectories along the slope
were modelled using 2-D and 3-D programs for rockfall analysis. The results were exploited to evaluate the rockfall hazard
along the threatened element at risk. 相似文献
18.
重庆南川市甑子岩W12 #危岩崩塌预警分析 总被引：6，自引：0，他引：6
岩崩是基岩山区一种常遇的地质灾害，具有突发性强，可预见性差，危害性大的特点。文章通过对重庆南川金佛山甑子岩W12^#危岩体现场勘查，分析了该危岩体的成因机制和破坏模式。采用常规监测仪器和人工变形量测手段进行了预警预报研究，成功地预报了金佛山甑子岩W12^#危岩的崩塌，避免了重大的经济损失和人员伤亡。研究成果可为研究岩崩系统发展演化机制、探索突发性地质灾害的空间预警和防灾减灾决策提供可靠依据。 相似文献
19.
Rockfall risk assessment to persons travelling in vehicles along a road: the case study of the Amalfi coastal road (southern Italy) 总被引：2，自引：0，他引：2
The paper deals with the assessment of rockfall risk to persons travelling in vehicles along the SS163 road, an important transportation corridor supporting a high vehicle traffic within the well-known tourist area of the Amalfi Coast (southern Italy). To this aim, the Rockfall Hazard Rating System (RHRS) and quantitative risk assessment (QRA) procedures, in this latter case for three rockfall risk scenarios, are applied. With reference to a large portion (33.820 out of a total of 50.365 km) of the SS163 road, the obtained QRA results highlight that, although the estimated individual risk to life satisfies the adopted tolerable risk criterion, the computed societal risk cannot be tolerated. Starting from this result, site-specific QRA analyses—carried out with reference to some road sections chosen on the basis of the RHRS results—allow the detection of the SS163 portions where the individual risk to life exceeds the tolerable risk threshold and, then, the recourse to mitigation measures could reveal necessary. In this regard, RHRS and QRA methods can be considered complementary tools in prioritizing the road sections where construction funds can be profitably spent in order to mitigate the rockfall risk with reference to both direct consequences (life loss) and indirect ones (traffic delay and diversions). 相似文献