共查询到20条相似文献，搜索用时 62 毫秒
1.
Paolo Budetta 《Landslides》2011,8(3):381-389
On December 15, 2008, a rock slide of approximately 4,000 m3 occurred near San Severino di Centola (Cilento, Province of Salerno). The landslide occurred along very steep bedding planes
intersected by tectonic joints affecting a rocky cliff. The landslide debris, formed by several boulders, came to a halt along
the gentler slope below. Many blocks reached the slope base including the national road n° 562 and injuring a motorist on
the road. Furthermore, the road suffered heavy damages causing a halt in traffic for many weeks. Several signs of the impacts
were detected along the slope and on the road; also, the volumes of some boulders were measured. The area affected by block
trajectories stretch down slope about 4,900 m2. By means of 2D and 3D trajectory codes using the “lumped-mass” method, it was possible to estimate more suitable impact
energy restitution and rolling friction coefficients, to reconstruct rock fall trajectories, and to calculate total kinetic
energies. Extending to the surrounding slope (surface about 2 ha) these data, a hazard scenario was carried out, displaying
the pattern of iso-energy distribution curves calculated along 11 critical profiles, and zones exposed to 70% and 30% of frequencies
of block transits and endpoints. Successively, with reference to the Swiss Federal Guidelines, another scenario was prepared
on the basis of rock fall intensity values and the return period of the 2008 landslide event. In this way, it was possible
to define areas of high, moderate and low hazard. The degrees of hazard are assigned according to their consequences for construction
activity and outline zones where additional protection is required. The construction of a retaining embankment was believed
suitable for local risk mitigation. 相似文献
2.
In this work an overview of the potential rock fall source areas and propagation assessment in the Province of Potenza territory has been presented. The rock fall process is characterized by two steps: the detachment of blocks and subsequently their propagation along the slope. The adopted methodology, used for the first time in the study area, and the software Histofit and FlowR have been very useful tools for the preliminary assessment of rock fall susceptibility at a regional scale, in particular because they have required low data of the study area. Only the DEM may be sufficient together with an appropriate choice of the input parameters and algorithms, that is to say: calculation method, directions algorithm, inertial algorithm and friction loss function. The output of the model is a map of the rock fall source areas, the propagation probabilities and the propagation kinetic energy. The results show that the adopted methodology is successful for the identification of rock fall source areas at a regional scale and the propagation probability obtaining an interesting rock fall susceptibility map. 相似文献
3.
Rockfall Hazard Analysis From Discrete Fracture Network Modelling with Finite Persistence Discontinuities 总被引：2，自引：1，他引：1
Cédric Lambert Klaus Thoeni Anna Giacomini Davide Casagrande Scott Sloan 《Rock Mechanics and Rock Engineering》2012,45(5):871-884
Developing an accurate representation of the rock mass fabric is a key element in rock fall hazard analysis. The orientation, persistence and density of fractures control the volume and shape of unstable blocks or compartments. In this study, the discrete fracture modelling technique and digital photogrammetry were used to accurately depict the fabric. A volume distribution of unstable blocks was derived combining polyhedral modelling and kinematic analyses. For each block size, probabilities of failure and probabilities of propagation were calculated. A complete energy distribution was obtained by considering, for each block size, its occurrence in the rock mass, its probability of falling, its probability to reach a given location, and the resulting distribution of energies at each location. This distribution was then used with an energy–frequency diagram to assess the hazard. 相似文献
4.
5.
This paper presents probabilistic assessment of seismically-induced slope displacements considering uncertainties of seismic ground motions and soil properties.A stochastic ground motion model representing both the temporal and spectral non-stationarity of earthquake shakings and a three-dimensional rotational failure mechanism are integrated to assess Newmark-type slope displacements.A new probabilistic approach that incorporates machine learning in metamodeling technique is proposed,by combining relevance vector machine with polynomial chaos expansions(RVM-PCE).Compared with other PCE methods,the proposed RVM-PCE is shown to be more effective in estimating failure probabilities.The sensitivity and relative influence of each random input parameter to the slope displacements are discussed.Finally,the fragility curves for slope displacements are established for sitespecific soil conditions and earthquake hazard levels.The results indicate that the slope displacement is more sensitive to the intensities and strong shaking durations of seismic ground motions than the frequency contents,and a critical Arias intensity that leads to the maximum annual failure probabilities can be identified by the proposed approach. 相似文献
6.
将场地斜坡稳定随机模拟分析结果与区域斜坡空间不稳定性预测结合起来,基于层次分析建立了区域斜坡空间破坏概率的多层模糊稳定分析方法,实现了场地斜坡稳定非确定性模型评价结果与区域稳定性研究相结合,借助这一关系模型可以实现空间点评价向空间面评价的过渡．以川南经济开发区区域斜坡空间破坏概率预测为例进行了方法验证,结果显示这种方法可以克服区域斜坡不稳定性评价中的定量化困难,物理意义更加明确． 相似文献
7.
Significantly different estimates of seismic hazard may result for the same site as aneffect of different methodological choices underlying the adopted procedures. In orderto explore this aspect, two approaches devoted to probabilistic seismic hazard assessment are considered for the evaluation of hazard in a seismic area in Northern Italy. In particular, results of a standard procedure are compared with those obtained by an innovative approach. Fundamental features of this last methodology are the extensive use of intensity data relative to seismic effects observed at the site of interest during past earthquakes and the basic role attributed to the parameterisation of uncertainty which affects the considered pieces ofinformation. The analysis indicates that the new approach supplies results significantlydifferent from those obtained from standard methodology and that these differences strongly depend on strategies adopted for data processing and for the management of uncertainties which affect input parameters. 相似文献
8.
陕南秦巴山区地质灾害危险性评价研究 总被引：3，自引：3，他引：0
陕西省是中国地质灾害最严重的省份之一,而陕南秦巴山区地质灾害灾情尤为严峻,因此进行地质灾害危险性评价对指导防灾减灾工作意义重大。文章以陕南秦巴山区为研究区,基于GIS技术与2001-2016年研究区地质灾害灾情数据,分析研究了区内地质灾害与各指标因子之间的敏感性关系,并确定了高程、岩土体类型、断裂构造、降雨等7个影响地质灾害发生较大的因子作为区域地质灾害危险性评价指标。其次,以各指标条件下地质灾害数量和累计发生频次曲线斜率的突变为依据,对评价指标因子进行状态分级。最后,运用信息量法建立栅格数据模型展开区域地质灾害危险性评价。研究结果表明:高危险性、较高危险性、中危险性的地区占研究区总面积的百分比分别为10.52%、28.31%、30.19%,区内地质灾害点的空间分布与地质灾害危险性评价结果基本一致,信息量模型的预测精度为90.16%。文章将经验知识与数据驱动的分析方法相结合,应用于较大范围的地质灾害危险性区划,研究结果可为区域地质灾害防治工作提供参考依据。 相似文献
9.
This study provides a procedure for assessing seismic hazardand uncertainties in regions that are characterised by a large non-instrumental earthquakedatabase and a seismic and tectonic behaviour which doesn't allow an evident seismic zonation.This procedure is a synthesis of the non-zoning or non-parametric methodology (using extremevalues distribution functions as proposed by Epstein and Lomnitz, 1966) and the zoning orparametric methodology (using the theorem of total probability as proposed by Cornell, 1968)via a logic tree procedure taking into consideration the advantages offered by each of these.Taking the area which we shall describe as the east coast of Spain and surrounding inland areas,an application was made and a specific logic tree was developed in order to solve the problems anduncertainties related to the evaluation of the seismic hazard using both methodologies. The use of thelogic tree allowed the systematisation of a large number of solutions obtained. A number of relevantresults were obtained which show that in some cases there are great differences in the seismichazard results provided by the non-zoning and the zoning methodologies. In these cases, mean value andstandard deviation of the obtained results provide an intermediate solution to the over-conservativeestimation provided by the non-zoning methodology and the lowest results provided by the zoningmethodology. In other cases results provided by both methodologies are significantly closer.In any case, synthesis among both methodologies gives a wider knowledge of the uncertaintiesassociated with the seismic hazard results. Finally uncertainties increase with the decreaseof the annual probability of exceedence and in sites with a seismic history of large size earthquakes. 相似文献
10.
为了在斜坡危险性区划中考虑岩体结构的控制作用,将粗糙集和模糊模型识别理论用于区域斜坡岩体结构识别,并结合信息量法对斜坡单元进行空间危险性预测。尝试在指标中考虑深部岩体结构特征和岩层变形构造（断层、岩层曲率）,将该方法应用于巴东新城区库岸斜坡危险性区划。结果表明：巴东新城区滑坡的主要影响因素有坡向和岩层倾向关系、坡角和岩层倾角关系、构造条件,可将斜坡分为3种结构类型。不同结构类型斜坡在危险性评价时各指标的影响程度或权重不同,可将巴东新城区划分为4个危险性等级,与现有滑坡比较验证了结果的合理性。 相似文献
11.
Summary A quantitative procedure for hazard and risk assessment of large landslides that can develop as rock avalanches is discussed
in this paper. Reference is made to the IMIRILAND project, where a multidisciplinary methodology has been developed paying
particular attention to the landslide modeling process that leads to the quantification of the hazard, i.e. the prediction
of the occurrence probability, the involved area and the run-out velocity. The risk assessment methodology is exemplified
in the paper with reference to two cases: the Ceppo Morelli and Rosone landslides, both of which are located in the Italian
Western Alps. The results of these applications show that, despite the development of sophisticated 3D numerical methods,
many uncertainties still remain in the process of modeling large and complex landslides, related in particular to the definition
of the probability of failure and the rheological parameters to be used for the prediction of rock mass behavior. However
geo-mechanical models are found to be very valuable tools to verify, from a mechanical point of view, the assumptions introduced
through the geo-structural and geo-morphological analyses concerning the volume and the kinematics of the unstable mass, and
their role is fundamental for the determination of the involved area when mechanical parameters can be assumed with sufficient
reliability.
Author’s address: Marta Castelli, Politecnico di Torino – Dipartimento di Ingegneria Strutturale e Geotecnica, Corso Duca
degli Abruzzi 24, 10129 Torino, Italy 相似文献
12.
Complex system approach to interpretation of monitoring time series: two case histories from NW Bohemia 总被引：1，自引：1，他引：0
Ever wider implementation of information technologies is flooding us by monitoring data. To an efficient risk management,
those data have to be processed and assessed in the same rate as they are recorded and transported. Paper demonstrates some
methods dealing with intrinsic, nonlinear dynamics of slope system for computerized safety assessment of monitoring time series,
their modeling and early warning launching. Analysis and modeling of phase changes – i.e. specific transient states between
different developmental stages of dynamics of unstable slope systems, enabled to fix new types of precursors for rock fall
warning and to enhance time prediction of rock fall occurrence. Mathematically well based, novel numerical and topological
methods from the toolbox of complex system theory were successfully implemented to that challenge. Their pattern-recognition
ability, i.e., diagnostic sensitivity, and more realistic results of modeling of time series relevant patterns have reached
beyond ranges of regularly used—both the idea- and the data-driven—methods. Moreover, results yielded by phase space analyses
are in good agreement with the ones by numerical fractal analyses. Obtained results have strengthened the primary, mainly
theoretically based hypothesis; the dynamics of an unstable rock slope has to be considered as behavior of nonlinear, dissipative,
non-equilibrium, self-organizing complex system. Correspondingly to the theoretical assumptions, two qualitatively different
types of slope system dynamics—near to equilibrium and far from equilibrium states, were identified. All field monitoring
data used originated in practice of highly automated, integrated IT system of monitoring assessment, and management of rock
fall hazard at sandstone rock walls in the NW Bohemia. 相似文献
13.
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
14.
Renato Macciotta C. Derek Martin Tom Edwards David M. Cruden Tim Keegan 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(3):171-186
Relationships between weather conditions and rock fall occurrences have been acknowledged in the past, but seldom have such relationships been quantified and published. Rock falls are frequent hazards along transportation corridors through mountainous terrain, and predicting hazardous rock fall periods based on weather conditions can enhance mitigation approaches. We investigate the relationship between weather conditions and rock fall occurrences along a railway section through the Canadian Cordillera. Monthly weather-rock fall trends suggest that the seasonal variation in rock fall frequency is associated with cycles of freezing and thawing during the winter months. The intensity of precipitation and freeze–thaw cycles for different time-windows was then compared against recorded rock falls on a case-by-case approach. We found that periods when 90% of rock falls occurred could be predicted by the 3-day antecedent precipitation and freeze–thaw cycles. Some rock falls not predicted by this 3-day antecedent approach occurred during the first two weeks of spring thaw. These findings are used to propose a rock fall hazard chart, based on readily available weather data, to aid railway operators in their decision-making regarding safe operations. 相似文献
15.
The rock mass structure determines the possible unstable blocks that can induce rock fall phenomena. The stability analyses
must therefore be based on an accurate geo-structural survey. In this work, the stability conditions of several steep slopes
along a motorway in the Far East have been evaluated through key block analysis based on traditional surveys and on laser
scanner acquisitions. Discontinuity orientations and positions on the rock face are derived from the point cloud in order
to perform the reconstruction of the rock mass and to identify blocks in the slope. Results obtained from both the traditional
and the new method is in good agreement. Stability analyses have been performed for evaluating the kinematic feasibility of
different failure mechanisms. The rock block shapes and volumes are computed by performing 2D and 3D analyses whereas the
failure mechanisms are examined using the key block method. Parametrical analyses have been carried on to evaluate the influence
of slope angle variation. DEM models have also been set up. The relative hazard is determined by statistically evaluating
the kinematical feasibility of different failure mechanisms. Hazard mapping has been utilized to identify the best methodology
for risk mitigation. 相似文献
16.
A review of assessing landslide frequency for hazard zoning purposes 总被引：11，自引：0，他引：11
The probability of occurrence is one of the key components of the risk equation. To assess this probability in landslide risk analysis, two different approaches have been traditionally used. In the first one, the occurrence of landslides is obtained by computing the probability of failure of a slope (or the reactivation of existing landslides). In the second one, which is the objective of this paper, the probability is obtained by means of the statistical analysis of past landslide events, specifically by the assessment of the past landslide frequency. In its turn, the temporal frequency of landslides may be determined based on the occurrence of landslides or from the recurrence of the landslide triggering events over a regional extent. Hazard assessment using frequency of landslides, which may be taken either individually or collectively, requires complete records of landslide events, which is difficult in some areas. Its main advantage is that it may be easily implemented for zoning. Frequency assessed from the recurrence of landslide triggers, does not require landslide series but it is necessary to establish reliable relations between the trigger, its magnitude and the occurrence of the landslides. The frequency of the landslide triggers can be directly used for landslide zoning. However, because it does not provide information on the spatial distribution of the potential landslides, it has to be combined with landslide susceptibility (spatial probability analysis) to perform landslide hazard zoning. Both the scale of work and availability of data affect the results of the landslide frequency and restrict the spatial resolution of frequency zoning as well. Magnitude–frequency relationships are fundamental elements for the quantitative assessment of both hazard and risk. 相似文献
17.
滑坡危险性定量评估是滑坡风险评估中的关键和难点,也是当前国际风险管理研究中的热点问题.以滑坡密集分布的黑方台南塬为研究区,以32处典型滑坡为研究对象,依据多期三维数字高程模型(DEM),提出了一种基于强度的滑坡危险性定量评估技术方法.根据多期三维地形信息的解译及野外调查,编制多期滑坡分布图,计算滑坡活动的频率.利用GIS技术,利用滑坡体积与速度的乘积计算滑坡强度.将滑坡危险性定义为滑坡频率和滑坡强度的乘积,同时调查和分析了黑方台地区各类承灾体的类型、价值及其在相应滑坡强度下的易损性,在此基础上开展了单体滑坡风险评估和黑方台南塬滑坡风险区划. 相似文献
18.
地质灾害危险性评价是防灾减灾工作的重要依据。本文以汶川县城周边64 km2为例,应用遥感信息提取技术与GIS空间分析方法,根据IKONOS遥感图像和地形图及野外调查资料,提取了崩塌和滑坡易发性评价因子,采用信息量法确定了因子分值,计算了崩塌和滑坡易发性,并分别提出崩塌和滑坡的危险性计算方法,形成了汶川地区崩塌和滑坡危险性分区图。研究结果表明:新的崩塌和滑坡危险性评价方法能够反映区内地质灾害危险程度,该方法可行,结果合理,这为中、大比例尺区域范围内地质灾害危险性研究提供了有益的思路。 相似文献
19.
P. Marinos G. Bouckovalas G. Tsiambaos N. Sabatakakis A. Antoniou 《Engineering Geology》2001,62(4):343-356
The 1999, Ms=5.9, Athens earthquake caused serious structural damage to buildings in the western part of Athens, Greece. This paper presents the ground zoning against seismic hazard proposed shortly after the earthquake in order to aid reconstruction of the area. Existing engineering geological and geotechnical data were combined with local observations to provide a unified set of classification criteria, consistent with provisions of the Greek Seismic Code EAK. The accuracy and the possible limitations of this zoning procedure are addressed through comparison with observed damage distribution as well as results from seismic ground response analyses performed at sites with well established soil profiles. There is clear evidence that the proposed zones correspond to geological formations exhibiting grossly different seismic response with regard to the design of common engineering structures. However, the mostly qualitative nature of the guidelines for ground categorisation provided by EAK and the general lack of systematic, site-specific geotechnical data for the whole area induce uncertainties in the definition of the seismic design actions for the different zones. These objective uncertainties certainly demand increased conservatism but do not limit application of the proposed methodology for first aid, preliminary planning in the event of destructive earthquakes. 相似文献
20.
皖南山区是安徽省地质灾害高发区域。本文选取黄山市徽州区为研究区,根据区内地形地貌和地质构造特点,选取了高程、坡度、坡向、断裂构造、水系、土地覆盖类型、工程地质岩组、人类活动强度等8项致灾因子作为地质灾害危险性评价指标。结合地质灾害野外实地调查成果,采用信息量模型法对研究区进行地质灾害危险性评价,探索建立适合皖南山区的地质灾害危险性评价模型。 相似文献