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已有的滑坡统计数据和研究成果显示,滑坡发生的时间具有明显的周期分布规律特征,除了与降雨季节相关的因素外,受日月引力潮的影响也较明显。从固体潮理论出发,推导简化弹性地球模型地表的潮汐应力表达式,阐述固体潮汐作为滑坡日周期因子对滑坡的影响。在安全系数表达式中考虑潮汐应力的作用,并从表达式中阐述潮汐应力触滑的机制,剖析潮汐应力触发滑坡机制。以1985年的湖北省秭归县新滩特大型滑坡作为算例,采用折线滑动为破坏模式,论述潮汐应力与时间的相关性,以及边坡稳定性安全系数与时间的相关关系。计算结果表明,潮汐应力与边坡安全系数随时间均呈明显日周期及半日周期变动,该边坡稳定性系数的极差与不考虑潮汐应力下的稳定性系数的比值达到3.4%;滑坡发生的时间与潮汐应力处于峰值的时间较为吻合,说明潮汐应力很可能是除降雨等主因之外的触发临界状态滑坡发生的另一因素。 相似文献
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边坡失稳是涉及土体大变形的动态演化过程,该过程往往决定了滑坡失事后果。传统的边坡稳定分析方法如极限平衡方法与有限元方法难以模拟边坡失稳演化过程,尤其是失稳后的土体变形破坏过程。边坡失稳受到多重不确定性因素影响,其中一个重要因素是土体参数的空间分布不均匀性。在考虑土体参数的空间不均匀分布情况下,本文采用一种随机极限平衡-物质点法研究边坡不同破坏模式的动态演化过程,同时利用极限平衡方法简单、高效的优点和物质点方法模拟土体大变形破坏的能力。以一个两层不排水土坡算例为例,识别了4种不同的边坡破坏模式（即浅层、中层、深层和渐进）,研究了它们的演化过程与土体参数的空间分布之间的关系。结果表明边坡的破坏模式演化过程与土体参数的空间分布密切相关,强调了岩土工程勘察信息对充分表征土体参数空间变异性的重要作用。 相似文献
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根据工程地质条件可将边坡划分为岩质边坡、土质边坡和岩土质边坡三类和若干亚类。各类边坡的变形破坏形式主要有散落、崩塌、滑坡和错落等。土质边坡一般都以滑坡和崩塌形式产生破坏,岩质边坡的破坏形式主要有滑坡、错落和崩塌三种,沿岩体的各种软弱结结构面发生。崩塌多发生在60°以上的陡坡,滑坡多产生在30°～60°的凸形边坡上,结构面倾角小于坡角的顺向坡易产生沿层滑动,断裂构造处、岩溶发育区、河流凹岸等位置的边坡易发生变形破坏,此外,人类工程活动、暴雨等也可导致边坡的变形破坏。为防治边坡失稳,必须合理选择和利用边坡的地质环境,消除引起边坡失稳的因素,改善边坡岩(土)体的应力状况,因地制宜采取适当措施提高不稳定边坡的抗滑力。 相似文献
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由于黄土地区地下水埋藏较深,降水因此成为影响公路黄土边坡稳定性的主要因素。根据饱和-非饱和土的渗流理论,考虑降水入渗的影响,利用有限元的方法,对阎良—禹门口高速公路的黄土边坡在百年一遇降水强度下的入渗规律和稳定性进行了数值模拟,同时根据现场人工降水试验证明:强降水条件下水分入渗的深度有限,一般为表层2m深度范围,且入渗深度随着降水时间的增加而增加,边坡安全系数逐渐减小,但对边坡的整体稳定影响不大;坡面出现冲刷破坏,如果不采用坡面防护措施,随着降水次数增加,将会出现局部破坏,最终导致整体边坡的失稳。而对于失稳状态下的危险边坡或老滑坡,滑坡出现频率与降水强度成正比例,并有一定的滞后性。 相似文献
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地质不连续带的破坏往往对岩质边坡的失稳起控制性作用。二阶功破坏准则可以分析除振颤失稳外的所有材料失稳问题,因此,利用该准则分析了岩体不连续带的材料失稳破坏问题。首先从数学上解释了使用二阶功分析二维地质不连续带的优势;而后将二阶功破坏准则引入FLAC有限差分计算软件,并根据相关监测数据对南芬铁矿岩质滑坡进行了二维数值分析。滑坡是一个准静态到动态的转化过程,动能的突然爆发标志着准静态-动态转化的发生。二阶功和二阶动能之间存在直接关系,据此关系估算出的南芬铁矿岩质边坡动能演化曲线可以证明二阶功对岩土材料失稳破坏判别的有效性。 相似文献
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黄土边坡变形失稳机理研究对于黄土滑坡灾害防治具有重要意义。黄土-泥岩接触面滑坡作为黄土滑坡类型之一,研究人员已对其失稳基本过程与形成机理有较为清晰的认识。但对于其在不同降雨类型下,特别是强降雨条件下的变形破坏过程则有待进一步探讨。因此,本文对黄土-泥岩接触面边坡开展室内降雨模型试验,研究其在强降雨条件下斜坡变形破坏模式。试验设计连续强降雨和间断强降雨两种降雨条件,对比分析两种降雨条件下边坡雨水入渗规律及变形破坏模式。结果表明:在两种典型降雨模式下,雨水入渗速率由边坡前缘至后缘逐渐降低;在坡体表层,随着降雨由间断至连续过渡,入渗速率逐渐增加;在坡体深部,入渗速率受边坡结构影响;间断降雨下边坡呈现滑移-拉裂失稳;在连续降雨条件坡体则表现为蠕滑-拉裂破坏。 相似文献
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2017年10月30日,位于秭归县归州镇香溪河右岸的盐关滑坡发生整体滑移破坏,成为近年来三峡库区为数不多的整体破坏变形的滑坡之一。根据现场应急调查,滑坡在不到3天的时间内经历了预警直至完全破坏的过程。本文以盐关滑坡为实例,根据滑坡失稳破坏特征结合有效应力原理提出了孔隙水压力变化速率条件下滑坡失稳破坏的模式,分析出滑坡体内的孔隙水压力对滑坡破坏的影响,最后通过有限元模拟软件予以验证。利用Geo-Studio岩土仿真软件SEEP/W模块模拟盐关滑坡在降雨入渗作用下的渗流场,结合滑坡变形期直至破坏时的实际库水位值计算出孔隙水压力随时间变化曲线,并且将所得结果应用到Slope/W模块,计算出滑坡的安全系数随时间的变化曲线,从而验证出滑坡失稳破坏的主要原因是滑坡内部土体在降雨和库水位的作用下达到饱和后,孔隙水压力激增所导致的。 相似文献
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清江流域是湖北省滑坡高易发区,滑坡灾害频发,造成了较大的经济损失,危害大。该区地质环境复杂,地貌形态以中山为主,河谷深切,岸坡陡峭,构造发育,新构造运动表现为大面积间歇性上升运动; 区内共发育滑坡2843处,其中滑坡2275处,崩塌型滑坡568处,滑坡以小型为主,主要分布在人类工程活动比较频繁的地带。通过统计分析,清江流域滑坡的空间分布规律主要受控于地质环境条件和动力因素,动力因素包括自然动力因素和人为动力因素,前者以降雨为主,后者以切坡为主且日趋发展; 滑坡变形的时间规律主要表现为同发性、滞后性和不稳定的周期性; 滑坡的自身活动规律主要表现为继承性、隐蔽性、突发性和差异性; 针对性地提出了监测预警、搬迁避让、工程治理和地质环境保护等滑坡减灾对策。 相似文献
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通过对白龙江流域大型滑坡的现场调查和遥感解译,共调查大型滑坡259处,对流域内大型滑坡的发育分布有了总体的认识;在此基础上,利用GIS技术对大型滑坡的分布与距断裂距离、高程、岩性等因素的关系进行统计分析。研究认为:（1）流域内大型滑坡分布在区域上表现出沿河流水系呈线状分布和沿断裂带呈带状分布的特点;（2）流域内90%以上的大型滑坡分布在距断层距离小于5.0 km的范围内,距断层越远,大型滑坡发育数量越少;同时,集中分布在断裂交叉、错列及交汇部位;（3）流域内大型滑坡表现出与高程和微地貌很好的对应关系,大部分大型滑坡分布在1200~2600 m（上游2200~2600 m、中游1600~2200 m、下游1200~1600 m）以下的河谷峡谷段,尤其是宽谷向峡谷转折部位;（4）流域内软硬相间层状岩岩组最有利于大型滑坡发育,93%以上的大型滑坡与千枚岩、板岩等浅变质岩相关;（5）流域内大型滑坡主滑方向以NE向、W向为主,但是武都区两水镇至舟曲县腊子口乡一带表现出与断层走向基本一致的特征,即SE向和NW向为主;（6）流域内大型滑坡的滑移距离与滑坡体积有关,随着滑坡体积的增大,大型滑坡的运动性摩擦系数呈指数降低,部分大型滑坡表现出强碎屑流特征。 相似文献
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Landslides triggered by slipping-fault-generated earthquake on a plateau: an example of the 14 April 2010, Ms 7.1, Yushu, China earthquake 总被引：3，自引：1，他引：2
On 14 April 2010 at 07:49 (Beijing time), a catastrophic earthquake with Ms 7.1 struck Yushu County, Qinghai Province, China. A total of 2,036 landslides were interpreted from aerial photographs and satellite images, verified by selected field checking. These landslides cover about a total area of 1.194 km2. The characteristics and failure mechanisms of these landslides are presented in this paper. The spatial distribution of the landslides is evidently strongly controlled by the locations of the main co-seismic surface fault ruptures. The landslides commonly occurred close together. Most of the landslides are small; there were only 275 individual landslide (13.5 % of the total number) surface areas larger than 1,000 m2. The landslides are of various types. They are mainly shallow, disrupted landslides, but also include rock falls, deep-seated landslides, liquefaction-induced landslides, and compound landslides. Four types of factors are identified as contributing to failure along with the strong ground shaking: natural excavation of the toes of slopes, which mean erosion of the base of the slope, surface water infiltration into slopes, co-seismic fault slipping at landslide sites, and delayed occurrence of landslides due to snow melt or rainfall infiltration at sites where slopes were weakened by the co-seismic ground shaking. To analyze the spatial distribution of the landslides, the landslide area percentage (LAP) and landslide number density (LND) were compared with peak ground acceleration (PGA), distance from co-seismic main surface fault ruptures, elevation, slope gradient, slope aspect, and lithology. The results show landslide occurrence is strongly controlled by proximity to the main surface fault ruptures, with most landslides occurring within 2.5 km of such ruptures. There is no evident correlation between landslide occurrences and PGA. Both LAP and LND have strongly positive correlations with slope gradient, and additionally, sites at elevations between 3,800 and 4,000 m are relatively susceptible to landslide occurrence; as are slopes with northeast, east, and southeast slope aspects. Q4 al-pl, N, and T3 kn 1 have more concentrated landslide activity than others. This paper provides a detailed inventory map of landslides triggered by the 2010 Yushu earthquake for future seismic landslide hazard analysis and also provides a study case of characteristics, failure mechanisms, and spatial distribution of landslides triggered by slipping-fault generated earthquake on a plateau. 相似文献
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《Engineering Geology》2007,89(1-2):67-87
Light detection and ranging (LIDAR) data were used to visually map landslides, headscarps, and denuded slopes in Seattle, Washington. Four times more landslides were mapped than by previous efforts that used aerial photographs. The mapped landforms (landslides, headscarps, and denuded slopes) were created by many individual landslides. The spatial distribution of mapped landforms and 1308 historical landslides show that historical landslide activity has been concentrated on the mapped landforms, and that most of the landslide activity that created the landforms was prehistoric. Thus, the spatial densities of historical landslides on the landforms provide approximations of the landforms' relative susceptibilities to future landsliding. Historical landslide characteristics appear to be closely related to landform type so relative susceptibilities were determined for landslides with various characteristics. No strong relations were identified between stratigraphy and landslide occurrence; however, landslide characteristics and slope morphology appear to be related to stratigraphic conditions.Human activity is responsible for causing about 80% of historical Seattle landslides. The distribution of mapped landforms and human-caused landslides suggests the probable characteristics of future human-caused landslides on each of the landforms. The distribution of mapped landforms and historical landslides suggests that erosion of slope-toes by surface water has been a necessary condition for causing Seattle landslides. Human activity has largely arrested this erosion, which implies that landslide activity will decrease with time as hillsides naturally stabilize. However, evaluation of glacial-age analogs of areas of recent slope-toe erosion suggests that landslide activity in Seattle will continue for the foreseeable future. 相似文献
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Yan Tongzhen Li Yun ’an Faculty of Environmental Science Geotechnique China University of Geosciences Wuhan Zhong Yufang Faculty of Earth Sciences China University of Geosciences Wuhan 《中国地质大学学报(英文版)》1998,9(2)
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在快速城镇化背景下,人类活动已成为影响滑坡分布的重要因素。文章以重庆武隆区为例,基于1991—2015年330处历史滑坡数据,运用重力模型和标准差椭圆模型,揭示了武隆区滑坡灾害的时空演变格局;利用地理探测器分析了2001—2005、2006—2010和2011—2015三个时段滑坡分布的驱动因子,解释了滑坡驱动因子演变的机制。结果表明:（1）在时间分布上,武隆滑坡累计曲线呈现出“缓-陡-缓”的特征,2008年之前,滑坡发生速率随降雨量的增加而增长,而后在降雨量保持稳定的情况下,滑坡发生速率明显减缓;（2）在空间分布上,武隆滑坡集聚于西、中、东3个高发区,呈现出由西北—东南方向转向东北—西南方向的变化过程,并表现出方向性减弱和离散化的趋势;（3）在驱动因子上,降雨、地质因子和地形地貌等因子的解释力呈下降趋势,而人类活动因子的解释力不断增强,已逐渐成为影响滑坡分布的关键影响因素之一。研究成果可为三峡库区滑坡灾害防灾减灾工作部署提供依据。 相似文献
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Do landslides follow landslides? Insights in path dependency from a multi-temporal landslide inventory 总被引：1，自引：0，他引：1
Jalal Samia Arnaud Temme Arnold Bregt Jakob Wallinga Fausto Guzzetti Francesca Ardizzone Mauro Rossi 《Landslides》2017,14(2):547-558
Landslides are a major category of natural disasters, causing loss of lives, livelihoods and property. The critical roles played by triggering (such as extreme rainfall and earthquakes), and intrinsic factors (such as slope steepness, soil properties and lithology) have previously successfully been recognized and quantified using a variety of qualitative, quantitative and hybrid methods in a wide range of study sites. However, available data typically do not allow to investigate the effect that earlier landslides have on intrinsic factors and hence on follow-up landslides. Therefore, existing methods cannot account for the potentially complex susceptibility changes caused by landslide events. In this study, we used a substantially different alternative approach to shed light on the potential effect of earlier landslides using a multi-temporal dataset of landslide occurrence containing 17 time slices. Spatial overlap and the time interval between landslides play key roles in our work. We quantified the degree to which landslides preferentially occur in locations where landslides occurred previously, how long such an effect is noticeable, and how landslides are spatially associated over time. We also investigated whether overlap with previous landslides causes differences in landslide geometric properties. We found that overlap among landslides demonstrates a clear legacy effect (path dependency) that has influence on the landslide affected area. Landslides appear to cause greater susceptibility for follow-up landslides over a period of about 10 years. Follow-up landslides are on average larger and rounder than landslides that do not follow earlier slides. The effect of earlier landslides on follow-up landslides has implications for understanding of the landslides evolution and the assessment of landslide susceptibility. 相似文献
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2008年汶川地震滑坡详细编目及其空间分布规律分析 总被引：3，自引：0，他引：3
最新研究成果表明, 2008年5月12日汶川MS 8.0级地震触发了超过197000处滑坡。首先,基于GIS与遥感技术构建了汶川地震滑坡的3类编目图,分别为单体滑坡面分布数据、滑坡中心点位置和滑坡后壁点位置。构建方法为基于地震前后高分辨率遥感影像的目视解译方法,区分单体滑坡并圈定其边界,对滑坡后壁进行识别与定点,并开展了部分滑坡的野外验证工作。这些滑坡分布在一个面积大约为110000km2的区域内,滑坡总面积约为1160km2。选择一个面积约为44031km2的区域作为研究区,区内滑坡数量为196007个,滑坡面积为1150.622km2,这是最详细完整的汶川地震滑坡编录成果,也是单次地震事件触发滑坡最多的记录。其次,开展研究区内的地震滑坡空间分布规律的研究。基于滑坡面与滑坡中心点分别构建滑坡空间分布面积密度图与点密度图,结果表明:滑坡多沿着映秀北川断裂分布,多发生在断裂的上盘。滑坡的高密度区位于映秀北川同震地表破裂的南西段(映秀镇与北川县之间)的上盘区域,这一区域恰对应着逆冲分量为主的断裂上盘,表明逆冲断裂对上盘区域发生滑坡的极强烈的控制作用,而该区域正是形变最大的区域,因此说明是地震滑坡发生的强烈控制作用。基于滑坡面密度(LAP)、滑坡中心点密度(LCND)与滑坡后壁点密度(LTND)这3个衡量指标,使用统计分析方法,评价了汶川地震滑坡与地震参数、地质参数、地形参数的关系。结果表明:LAP、LCND与LTND这3个衡量指标与坡度、地震烈度与PGA存在明显的正相关关系; 与距离震中、距离映秀北川同震地表破裂存在负相关关系; 斜坡曲率越接近0,滑坡越不易发生; LAP、LCND与LTND的高值高程区间为1200～3000m; 滑坡发生的优势坡向为E、SE、S方向; 滑坡发育的易发岩性为砂岩与粉砂岩(Z)、花岗岩; 滑坡与坡位的相关关系不太明显。统计结果还表明LCND与LTND两个衡量指标的差异对地震与地质因子不敏感,而对地形因子较敏感。最后将本文的统计结果与以往的汶川地震滑坡空间分布规律统计成果进行了一些对比,对比结果表明,对于某些因子,如高程、岩性、距离震中、距离映秀北川断裂的统计分析结果,采用不完整的滑坡分布数据或点数据,与采用较完整的滑坡分布面数据会有一定的差异,这种差异并未出现在针对坡度与坡向等因子的统计对比结果中。总之,作者认为一个完备、详细的地震滑坡分布面要素编目图是地震滑坡空间分布规律定量分析、危险性定量分析与滑坡控制的地震区地貌演化研究的重要基础,否则,与实际情况相比,得到统计结果会有一定的偏差,本文的研究成果与以往成果的对比结果证明了这一点。 相似文献
19.
金沙江干热河谷区滑坡遥感解译研究 总被引：7，自引：1，他引：7
“三江”(即金沙江、澜沧江及怒江)地区自然条件恶劣,交通不便,解决该地区水电大开发地质灾害调查中一条切实可行的方法是利用遥感。论文分析了金沙江干热河谷气候环境和地形条件的特点及他们对滑坡解译产生的影响。通过研究这一地区的滑坡在多种遥感影像上的图斑特征配合实地考察,分析并列举了干扰滑坡识别的图斑,总结出该地区的古滑坡、活动滑坡和典型滑坡的识别特征。同时对该地区滑坡不发育,所占地质灾害比例低的现象进行了分析。指出当地气候、地形、构造特征、岩土类型对滑坡发育存在的影响。为该类型地区的遥感地质调查提供借鉴。 相似文献
20.
David K. Keefer 《Engineering Geology》2000,58(3-4):231-249
The 1989 Loma Prieta, California earthquake (moment magnitude, M=6.9) generated landslides throughout an area of about 15,000 km2 in central California. Most of these landslides occurred in an area of about 2000 km2 in the mountainous terrain around the epicenter, where they were mapped during field investigations immediately following the earthquake. The distribution of these landslides is investigated statistically, using regression and one-way analysis of variance (ANOVA) techniques to determine how the occurrence of landslides correlates with distance from the earthquake source, slope steepness, and rock type. The landslide concentration (defined as the number of landslide sources per unit area) has a strong inverse correlation with distance from the earthquake source and a strong positive correlation with slope steepness. The landslide concentration differs substantially among the various geologic units in the area. The differences correlate to some degree with differences in lithology and degree of induration, but this correlation is less clear, suggesting a more complex relationship between landslide occurrence and rock properties. 相似文献