Airblast evolution initiated by Wangjiayan landslides in the M_(s)8.0 Wenchuan earthquake and its destructive capacity analysis

Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific attention.To quantitatively analyze the intensity of airblast initiated by landslides,the Wangjiayan landslide,occurred in the Wenchuan earthquake,is selected here with the landslide propagation and airblast evolution being studied using FLUENT by introducing the Voellmy rheological law.The results reveal that:(1)For the Wangjiayan landslide,its whole travelling duration is only 12 s with its maximum velocity reaching 36 m/s at t=10 s;(2)corresponding to the landslide propagation,the maximum velocity,28 m/s,of the airblast initiated by the landslide also appears at t=10 s with its maximum pressure reaching594.8 Pa,which is equivalent to violent storm;(3)under the attack of airblast,the load suffered by buildings in the airblast zone increases to 1300 Pa at t=9.4 s and sharply decreased to-7000 Pa as the rapid decrease of the velocity of the sliding mass at t=10 s,which is seriously unfavorable for buildings and might be the key reason for the destructive collapse of buildings in the airblast zone of the Wangjiayan landslide.

Evaluation model of landslide hazards induced by the 2008 Wenchuan earthquake using strong motion data

Landslides induced by the 2008 Wenchuan earthquake in the Longmenshan area were relatively well instrumented, which makes it possible to investigate the landslides using ground motion records. Firstly, this paper analyzes the data from Wenchuan earthquake on both regional and local site scale. The analyses show that the Newmark accumulative displacement calculated from the ground motion recorded in a particular geological hazard zone corresponds to the hazard intensity in that zone; the larger the displacement, the more serious the geologic hazard. The calculated result also shows that the displacement is related to the Arias intensity, which represents the total energy released during the earthquake at the observation site. Secondly, this paper constructs an evaluation model of Newmark displacement calculated with Arias intensities to estimate the subsequent slope failure resulting from the earthquake. The calculated results based on the model fit well with the distribution of actual landslides, suggesting that this method is useful for hazard evaluation. Therefore, this type of model can be used for estimating regional-scale distribution of earthquake-induced landslides and their associated hazards immediately after an earthquake.

Relationships between ground motion parameters and landslides induced by Wenchuan earthquake

The MS8.0 Wenchuan earthquake induced severe landslide hazards.For the first time in China,large numbers of strong motion records were obtained during the Wenchuan earthquake,providing the opportunity to study the relationships between ground-motion parameters and the earthquake-induced landslides.Nearly 40 groups of records from the main shock distributed along the Longmenshan fault lines were used to carry out this study.The results appropriate to the Longmenshan area are as follows：1 The threshold of the peak ground acceleration（PGA） is about 0.7 m/s2.When the PGA reaches 2 m/s2,the landslide hazards are very serious; 2 The threshold of the peak ground velocity（PGV） is about 0.5 m/s.When the PGV reaches 1.5 m/s,severe landslide hazards will be induced; 3 The threshold for the Arias intensity（Ia） is about 0.2 m/s.When the Ia in one horizontal direction reaches 2 m/s,landslide hazards will be very serious; 4 As for the relevance order of the parameters to earthquake-induced landslides,Ia is the leading parameter,followed by PGV,and finally PGA.The results presented in this paper are consistent with the results from other studies,indicating that the threshold of the ground motion parameters for strong earthquakes is of the same order of magnitude as that of moderate earthquakes.Landslide density of local sites fluctuated with the increase of ground motion intensity if the thresholds were reached.When the upper limits are exceeded,the landslide density remains at a certain level with relatively little variation.

The Spatial Distribution and Attribute Parameter Statistics of Landslides Triggered by the May 12th,2008,MW7.9 Wenchuan Earthquake

A complete landslide inventory and attribute database is the importantly fundamental for the study of the earthquake-induced landslide.Substantial landslides were triggered by the MW7.9 Wenchuan earthquake on May 12th,2008.Google Earth images of preand post-earthquakes show that 52194 co-seismic landslides were recognized and mapped,with a total landslides area of 1021 km2.Based on the statistics,we assigned all landslide parameters and established the co-seismic landslides database,which includes area,length,and width of landslides,elevation of the scarp top and foot edge,and the top and bottom elevations of each located slope.Finally,the spatial distribution and the above attribute parameters of landslides were analyzed.The results show that the spatial distribution of the co-seismic landslides is extremely uneven.The landslides that mainly occur in a rectangular area(a width of 30 km of the hanging wall of the Yingxiu-Beichuan fault and a length of 120 km between Yingxiu and Beichuan)are obviously controlled by surface rupture,terrain,and peak ground acceleration.Meanwhile,a large number of small landslides(individual landslide area less than 10000 m2)contribute less to the total landslides area.The number of landslides larger than 10000 m2 accounts for 38.7%of the total number of co-seismic landslides,while the area of those landslides account for 88%of the total landslides area.The 52194 co-seismic landslides are caused by bedrock collapse that usually consists of three parts:source area,transport area,and accumulation area.However,based on the area-volume power-law relationship,the resulting regional landslide volume may be much larger than the true landslide volume if the landslide volume is calculated using the influenced area from each landslide.

Analysis of debris flow control effect and hazard assessment in Xinqiao Gully,Wenchuan M_(s)8.0 earthquake area based on numerical simulation

Xinqiao Gully is located in the area of the 2008 Wenchuan M_(s)8.0 earthquake in Sichuan province,China.Based on the investigation of the 2023"6-26"Xinqiao Gully debris flow event,this study assessed the effectiveness of the debris flow control project and evaluated the debris flow hazards.Through field investigation and numerical simulation methods,the indicators of flow intensity reduction rate and storage capacity fullness were proposed to quantify the effectiveness of the engineering measures in the debris flow event.The simulation results show that the debris flow control project reduced the flow intensity by41.05%to 64.61%.The storage capacity of the dam decreases gradually from upstream to the mouth of the gully,thus effectively intercepting and controlling the debris flow.By evaluating the debris flow of different recurrence intervals,further measures are recommended for managing debris flow events.

Slope Debris Flows in the Wenchuan Earthquake Area

Avalanches and landslides,induced by the Wenchuan Earthquake on May 12,2008,resulted in a lot of disaggregated,solid material on slopes that could be readily mobilized as source material for debris flows.Rainstorms triggered numerous slope debris flows with great damage to highways and rivers over the subsequent two years.Slope debris flows(as opposed to channelized debris flows) are defined as phenomena in which high-concentration mixtures of debris and water flow down slopes for short distances to highways and river banks.Based on field investigations and measurements of 19 slope debris flows,their main characteristics and potential mitigation strategies were studied.High rainfall intensity is the main triggering factor.Critical rainfall intensities for simultaneous occurrence of single,several and numerous slope debris flow events were 20 mm/day,30mm/day,and 90 mm/day,respectively.Field investigations also revealed that slope debris flows consist of high concentrations of cobbles,boulders and gravel.They are two-phase debris flows.The liquid phase plays the role of lubrication instead of transporting medium.Solid particles collide with each other and consume a lot of energy.The velocities of slope debris flows are very low,and their transport distances are only several tens of meters.Slope debris flows may be controlled by construction of drainage systems and by reforestation.

Interpretation of the Spatial Distribution Characteristics of the Co-seismic Landslides Induced by the 1920 Haiyuan M81/2 Earthquake Using Remote Sensing Images

Analyzing the spatial distribution characteristics of earthquake-induced secondary disasters based on advanced techniques is significantly important,especially in understanding the process of strong earthquakes in the Loess Pateau.Using ArcGIS,this study interprets multi-temporal high-resolution satellite images,field investigation data,and historical seismic records.Major conclusions are obtained as follows:①Landslides induced by the Haiyuan earthquake are mainly distributed in the intersection area of the end of the Haiyuan fault and Liupanshan fault,as indicated by multiple dense distribution centers;②The landslide distribution of the Haiyuan Earthquake is determined by the distance to the fault,topographic relief,slope,lithology,and other factors.In detail,the closer the distance to the fault,the greater the density of the landslide.The greater the slope and relief of the terrain,the greater the density and the smaller the average area of a landslide.Compared with tertiary strata,Quaternary strata has a larger average area,and the density of the landslides is smaller;③The density curve of the death toll in the Haiyuan earthquake can be used as a reference for the distribution of co-seismic landslides.Several Haiyuan co-seismic landslides are distributed in the Tongwei landslide area;however,the major landslides here are induced by the 1718 Tongwei earthquake rather than the 1920 Haiyuan earthquake;④The co-seismic landslides of the Haiyuan earthquake exhibits the“slope effect”in the south-west plate of Haiyuan fault,presenting the dominant sliding direction towards the fault and epicenter;however,the“slope effect”is not evident in the northeast plate of the fault.

Analysis of Earthquake-Triggered Failure Mechanisms of Slopes and Sliding Surfaces

Earthquake-induced landslides along the Dujiangyan-Yingxiu highway after the Ms 8.0 Wenchuan earthquake in 2008 were investigated. It was found that： （1） slopes were shattered and damaged during the earthquake and open tension cracks formed on the tops of the slopes; （2） the upper parts of slopes collapsed and slid, while the lower parts remained basically intact, indicating that the upper parts of slopes would be damaged more heavily than the lower parts during an earthquake. Large-scale shaking table model tests were conducted to study failure behavior of slopes under the Wenchuan seismic wave, which reproduced the process of deformation and failure of slopes. Tension cracks emerged at the top and upper part of model, while the bottom of the model remained intact, consistent with field investigations. Depth of the tension crack at the top of model is 32 cm, i.e., 3.2 m compared to the prototype natural slope with a height of 14 m when the length scale ratio （proto/model） is lo. Acceleration at the top of the slope was almost twice as large as that at the toe when the measured accelerations on shaking table are 4.85 m/s2 and 6.49 m/s2, which means that seismic force at the top of the slope is twice the magnitude of that at the toe. By use of the dynamic-strength-reduction method, numerical simulation was conducted to explore the process and mechanism of formation of the sliding surface, with other quantified information. The earthquake-induced failure surfaces commonly consist of tension cracks and shear zones. Within 5 mfrom the top of the slope, the dynamic sliding surface will be about 1 m shallower than the pseudo-static sliding surface in a horizontal direction when the peak ground acceleration （PGA） is 1 m/s2; the dynamic sliding surface will be about 2 m deeper than the pseudo-static sliding surface in a horizontal direction when the PGA is lo m/sL and the depths of the dynamic sliding surface and the pseudo-static sliding surface will be almost the same when the PGA is 2 m/s2. Based on these findings, it is suggested that the key point of anti-seismic design, as well as for mitigation of post-earthquake, secondary mountain hazards, is to prevent tension cracks from forming in the upper part of the slope. Therefore, the depth of tension cracks in slope surfaces is the key to reinforcement of slopes. The depth of the sliding surface from the pseudo-static method can be a reference for slope reinforcement mitigation.

Qualitative Analyses of Correlations between Strong Ground Motions of the Three Large Earthquakes and Landslide Distributions

In this work,the correlations between spatial distributions of landslide point density(LPD)and strong ground motions of the three strong earthquakes are qualitatively investigated.Meanwhile the qualitative relationship between the distribution of LPD and the fault rupture process is also characterized.Three strong events are the Lushan,Wenchuan,and Jiuzhaigou earthquakes.In order to reconstruct the near filed strong ground motions and the fault processes of these earthquakes,the broadband ground simulation method of University of California Santa Barbara(UCSB)and the simplified crustal layer structures are applied.To show the rationality of the UCSB method,the fault slip distributions of the three earthquakes reconstructed by the kinematic rupture generator model in the UCSB method are compared with those by inversed.Furthermore,the validation of the UCSB method for the three earthquakes is also carried according to the validation exercise of the Southern California Earthquake Center(SCEC)Broadband Platform(BBP).Lastly,the fields of peak ground acceleration(PGA)and peak ground velocity(PGV)in three mutually perpendicular directions of the three earthquakes are achieved.Generally,the landslide distribution length of large LPD values along the fault strike is less than the fault strike length.Therefore,the slip modes of earthquake faults affect the distributions of landslides.For the strike slip earthquakes,the distributions of large LPD values relate well to PGA and PGV components of the parallel and normal to the fault strike.For the reverse slip earthquakes,distributions of LPD relate to ground motion components in all directions.Moreover,distributions of landslides in near fields of earthquakes are significantly affected by the focus parameters and fault scales.

基于振动台试验的不同含石率土-石混合体边坡地震动响应差异性研究

针对土-石混合体边坡动力响应特性尚不明确的问题,基于相似原理设计开展了3组不同含石率土-石混合体边坡大型振动台试验,系统地对比分析了不同含石率土-石混合体边坡动力响应的差异。研究结果表明:土-石混合体边坡在地震作用下的加速度响应符合自由面效应,即边坡在近坡顶端处的加速度放大效应要明显强于坡体内,而不同含石率土-石混合体边坡在不同频率正弦波激振作用下的动力响应差异明显,这是因为不同含石率土-石混合体边坡结构的动力特性存在差异;地震作用下,模型边坡动土压力由边坡浅表层至坡体内部呈不断增大趋势,但由于坡体变形与损伤程度不同,不同含石率边坡整体的动土压力响应程度不同;且在地震波分级加载过程中,边坡不同部位处动土压力的突变可作为边坡产生动力破坏的依据;随着含石率的上升,地震作用下边坡整体的变形程度逐渐降低:20%含石率边坡表现为由浅层至深层的连续滑动,而40%与60%含石率的边坡变形则相对较小,40%含石率边坡仅表层岩土体发生滑移,60%含石率边坡仅浅表层土体发生剥落,含石率的提升对土-石混合体边坡起到了加固作用。

基于GIS的汶川地震滑坡灾害影响因子确定性系数分析

2008年5月12日14时28分,四川省汶川发生了8.0级大地震,地震诱发了数以万计的滑坡灾害。在大约48678km2的区域内,采用震后航空像片与多源卫星影像解译并结合野外调查验证的方法,共圈定出48007个地震滑坡灾害。在此基础上,选取地层、岩性、断裂、地震烈度、宏观震中、地表破裂调查点、地形坡度、坡向、顺坡向曲率、高程、水系与公路共12个影响因子作为汶川地震诱发滑坡影响因子,利用GIS强大的空间分析能力与确定性系数方法,对这12个影响因子进行敏感性研究。研究结果表明:(1)寒武与震旦系是地震滑坡易发地层,侵入岩组、灰岩为主的岩组是地震滑坡发育的高敏感性岩组;(2)地震滑坡受中央断裂影响最大,同时还受控于前山断裂,受后山断裂的影响较小;(3)地震滑坡易发性分别随着地震烈度、与震中的距离、与地表破裂点距离的增加而减少;(4)坡度大于40°是地震滑坡的易发坡度,E,ES方向为地震滑坡的易发坡向,高程范围为1000～2000m,尤其是高程1000～1500m范围为地震滑坡易发区;(5)400m水系缓冲区和2000m公路缓冲区范围内滑坡易发性较高。确定研究区内各地震滑坡影响因子最利于滑坡发生的数值区间,为进一步地震滑坡区域评价及预测奠定基础。

GIS支持下基于层次分析法的汶川地震区滑坡易发性评价

2008年5月12日14时28分,四川汶川发生了Ms8.0级大地震,地震诱发了数以万计的滑坡灾害。在大约48678km2的区域内,采用震后遥感影像解译并结合野外调查的方法,共解译出48007个滑坡。应用GIS技术,建立了汶川地震诱发滑坡灾害及相关地形、地质空间数据库,分析了断层、岩性、高程、坡度、坡向、河流、公路等7个因素与滑坡分布的关系,应用滑坡面积百分比这一标准来分别衡量每个因素中各个级别对滑坡的影响程度;然后使用层次分析法对这7个参数进行权重分析;在GIS平台下对这些参数进行综合分析,通过分析结果将研究区内滑坡按易发程度分为极高易发区、高易发区、中易发区、低易发区与极低易发区5类,极高易发区与高易发区面积约8211km2,占研究区总面积的16.9%;最后,使用汶川地震滑坡数据库对研究结果进行检验,检验曲线表明分区效果良好,其中极高易发区与高易发区内实际发生滑坡面积为430km2,占滑坡总面积的60.5%。

唐家山滑坡成因机制与堰塞坝整体稳定性研究

根据唐家山滑坡的地质背景,研究滑坡及堰塞体工程地质特征,分析唐家山滑坡类型及发生的地质成因机制;基于唐家山堰塞体的岩体结构稳定性分析、宏观现象监控与地表位移监测,研究堰塞体的整体稳定性。研究得出如下结论与启示:(1)唐家山滑坡属于基岩顺层滑坡,是典型的地震诱发高速滑坡,滑坡滑动带可能发育在层间剪切带,滑坡区发育的构造背景为复式倒转背斜的一翼。(2)唐家山堰塞体整体结构以块状岩体为主,上覆风化松散堆积物,整体地质稳定性较好;堰塞体地表位移监测显示,泄洪对地表位移有影响,最大位移约140mm,随后位移增量较小,目前处于稳定状态。(3)应注重地震诱发滑坡→堰塞湖→溃决→洪水的"多米诺"链式灾变研究;应注重含层间剪切带斜坡的工程地质调查分析和地震滑坡危险性研究。

汶川地震大光包滑坡动力响应特征研究

运用FLAC3D模拟大光包滑坡变形失稳特征,并输入距离滑坡约4.3 km的清平台站强震加速度三向记录,结果表明:其地震动力响应较为复杂,受控于斜坡形态、岩体(地质)结构及地震强度和振动持时等因素,在水平加速度响应方面,前缘滑坡更为明显,地震动频率更高,振幅更大,利于前缘的顺层失稳滑动;在竖向加速度响应方面,后缘滑体的振幅更大,竖向加速度(绝对值)数倍于水平加速度,利于拉裂、振碎解体和抛掷失稳。大光包滑坡与简单均值结构的边坡地震动力响应特征不完全一致,随高程、坡度放大的趋向性和节律性不明显。结合地震动力响应和运动特征,对滑坡堆积和滑源进行概化分区:(1)下部顺层滑坡堆积区,是滑坡的主堆积区,分布于滑坡东侧,堵塞黄洞子沟;(2)上部崩滑堆积区,分布于滑坡西北、北侧,具有明显的带状特征;(3)后缘陡壁及倒石堆区,侧缘拉裂边界,近直立不规则凹凸状断壁,分布多组张拉裂隙,说明受陡倾角张性裂隙控制,表现为张性破坏特征,陡崖下部分布大量倒石堆,呈串珠状分布,以碎块石为主,岩性与后缘及北侧陡壁岩体一致,系地震后的重力调整所致;(4)顺层滑面及擦痕区,在滑面上分布大量与岩层倾向相同的擦痕,说明顺层滑坡在后部具有向北方向偏转滑动的特征。

地震高位滑坡形成条件及抛射运动程式研究

根据典型地震高位滑坡坡体结构特点及地震斜坡响应,对其形成机制进行探讨,认为P波的垂直上抛作用及S波的水平剪切作用,将强卸荷带下限以外裂隙切割的岩体结构面贯通并使其丧失与下部岩体的结合力,后至的面波经地形放大后,巨大的加速度(通常>2 g)将斜坡上部表层高位岩体近水平或斜向上抛出,形成地震高位滑坡。

肖家桥滑坡堵江机制及灾害链效应研究

地震是滑坡灾害的一个重要触发因素,而这类形式的滑坡通常体积较大。以肖家桥滑坡为例,在对滑坡区进行详细的地质调查基础上,结合动力有限元分析技术,再现滑坡三维空间失稳过程。在此基础上,提出肖家桥滑坡形成及堵江的4个阶段:地震触发及岩体的累进破坏→滑体破坏、高速下滑→撞击解体、堵江形成堰塞体→震动密实。通过对堰塞体结构特征及不同工况下堰塞体的稳定性分析的成果表明:堰塞体边坡在天然状态下稳定性较好,当再次发生强地震时可能会发生局部的坍塌;最可能的破坏方式为"漫顶式"逐级冲刷破坏,由于其内部岩体结构相对较为完整,发生管涌及整体破坏的可能性较小。

“5·12”汶川地震崩塌滑坡危险性评价——以都汶公路沿线为例

选择地震极重灾区(都汶公路沿线)作为研究区域,利用遥感影像解译和野外调查数据,采用信息量方法,分析地震崩塌滑坡对影响因子的敏感性,结合GIS技术评价地震崩塌滑坡的危险性。研究表明,都汶公路沿线最利于地震崩塌滑坡的条件为:(1)坡度:大于35°;(2)坡向:E,ES和S坡向;(3)坡面粗糙度:大于1.15;(4)距断层距离:5～20km;(5)土地利用类型:林地、灌木林地和疏林地;(6)地层岩性:元古代闪长岩、元古代斜长花岗岩、元古界玄武岩、安山岩、石炭系灰岩、泥灰岩和志留系灰绿色千枚岩及石灰岩,尤其是元古界玄武岩和安山岩。利用信息量综合因子叠加技术,对研究区域崩塌滑坡体进行危险性评价,并将其分为极高度危险区、高度危险区、中度危险区、轻度危险区以及基本无危险区。危险性评价结果表明:研究区域大部分处于中度危险区、高度危险区、极高度危险区,三者面积占总面积的70.34%,其中极高度危险区占到总面积的19.15%,范围较大,在公路修复和重新规划建设中应加强预防这些区域发生崩塌滑坡;基本无危险区范围较小,仅占总面积的11.81%;在分布特征上,极高度危险区和高度危险区主要分布在映秀至草坡河段上,草坡河至汶川段大部分处于轻度危险区及以下。研究结果可为震后公路恢复、重建及灾区重建提供科学指导与技术支持。

汶川地震极重灾区地质背景及次生斜坡灾害空间发育规律

5·12汶川大地震造成大量的次生斜坡灾害,本次研究区域为汶川大地震的11个重灾区,包括汶川、北川、青川、安县、平武、茂县、江油、彭州、什邡、绵竹、理县等市县。通过对重灾区航片、卫片、雷达图像的解译研究发现,重灾区次生斜坡灾害的主要灾种表现为崩塌、滑坡以及崩塌、滑坡高速运动解体形成的碎屑流(个别地方由于水的参与表现为泥石流)以及它们堵江形成的堰塞湖。研究发现地震次生斜坡灾害的发育具有明显的丛集性规律。从区域上看,次生斜坡灾害明显呈带状,沿龙门山断裂带展布,并主要受北川—映秀断裂控制。各灾种的发育在不同地段发育的规模、频率差别较大。以灾害分布面积来排序,汶川县灾害面积最大,为131.55km2,其次为北川县,为45.57km2,其余9个县(市)灾害面积相差不大,均介于6～17km2,其中理县灾害面积最小,为6.25km2。各灾种的发育在不同地段发育的规模、频率差别较大。青川县、平武县灾种主要为滑坡,汶川县、茂县、安县、理县灾种主要表现崩塌转化的碎屑流,北川的主要灾种则为碎屑流,其次为滑坡,什邡、彭州、绵竹、江油等地主要灾种为崩塌。灾种发育的这种地域性差别主要受控于地层岩性,除此而外,还与构造特征、地形地貌等因素紧密相关。研究表明:岩性对灾害种类的展布有决定性控制作用。统计发现,岩性越坚硬,崩塌、碎屑流发育率越高,滑坡则在软岩地区、较软岩地区和较坚硬区发育率最高,泥石流则在软岩地区最为发育。地形地貌对次生斜坡灾害的发育有重要影响,统计表明,崩塌、碎屑流以及泥石流在1200～2000m坡段范围内发育率最高,其次为800～1200m坡段;而滑坡则在800～1200m坡段范围发育率最高。对坡度而言,除11°～20°坡度范围外,崩塌和碎屑流的发育率总体具有随坡度增高而增大的特点;而滑坡和泥石流的发育率呈现典型的单峰特征,在1°～20°范围内发育率最大。坡向对地震次生斜坡灾害的发育影响不明显。地震次生斜坡灾害的发育规律表明,地震斜坡灾害的发生主要受控于活动构造本身,并沿活动构造呈带状展布,同时受场地条件如岩性、地形地貌等因素的强烈控制。

四川汶川Ms8级地震引发的滑坡与地层岩性、坡度的相关性

震后遥感影像解译与调查结果表明,在大约48678km2的区域内,汶川Ms8.0级地震诱发了不低于48000处滑坡灾害。基于GIS的空间分析方法,使用滑坡面积百分比(LAR)与滑坡密度(LC)2个参数,对地震滑坡的空间分布与地层岩性、坡度之间的关系进行统计分析。在整个研究区范围内,滑坡面积百分比约为1.4622%,滑坡密度约为0.9862个/km2。结果表明,滑坡多发生在坡度25～50°的区域内,滑坡易发性随着坡度的增加而升高。寒武纪地层中滑坡易发性最大,LAR约10%,LC约6.5个/km2,震旦系、奥陶系和侵入岩次之,这些地层和岩石对地震滑坡的发生均是敏感的。综合分析坡度、地层岩性与滑坡空间分布的关系,结果表明,在以较破碎岩石为主的地层中,滑坡多发生在坡度小于30°的部位;在以较坚硬岩石为主的地层中,滑坡多发生在坡度大于40°的部位。

强震区断裂活动与大型滑坡关系研究

活动断裂带与大型滑坡之间的关系一直是人们关注的热点问题。通过汶川Ms8.0级地震活动断裂和大型滑坡调查,阐述龙门山活动断裂带大型滑坡形成的地质背景,总结活动断裂带大型地震滑坡的分布特征、形态特征、启动特征和分段特征及其相关影响因素。基于野外调查资料,以龙门山中央断裂带谢家店子滑坡为例,采用离散元方法模拟分析滑坡的启动和快速运移过程,提出高速远程滑坡的致灾后果决定于启动方式、飞行路径和堆积特征3个方面。本项研究对于认识断裂活动与大型滑坡之间的关系以及滑坡成灾后果预测具有重要的指导作用。