Large debris flows in Chosica,Lima, Peru: the application of hydraulic infrastructure for erosion control and disaster prevention     

S. P. Villacorta  K. G. Evans  K. Nakatani  I. Villanueva 《Australian Journal of Earth Sciences》2020,67(3):425-436

Abstract

Large debris flows in steep-sloped ravines debouching to the Rimac River, in metropolitan Lima (Peruvian capital), have resulted in considerable loss of life and property adversely impacting communities in the region. Temporal, spatial and volumetric features of debris flows are difficult to predict, and it is of utmost importance that achievable management solutions are found to reduce the impact of these catastrophic events. The emotional and economic toll of these debris flows on this increasingly densely populated capital city in South America is devastating where communities must live in such inadequate and dangerous conditions. To address this problem, the application of advanced Japanese technology, Sustainable Actions Basin Orientation (SABO), has been investigated using a geomorphological modelling to develop an implementation plan. Rayos de Sol stream basin in Chosica, was selected as a pilot to develop the proposal, as it is considered high risk due to the presence of ancient debris flows and recent flows in 2012, 2015 and 2017. The recurrence of debris flows in this location has resulted in numerous deaths and catastrophic property losses. This study combines geologic and geomorphic mapping and hydraulic and landform evolution numerical modelling. The implementation of a SABO Master Plan based on the multidisciplinary assessment hazard scenarios, will allow the implementation of feasible mitigation actions. The SABO technology has been applied successfully in Japan and other countries in areas with steep short slopes, similar to the conditions surrounding the Peruvian capital. Results from this study will be presented to the Peruvian Government as part of an action plan to manage debris-flow impact.

1. KEY POINTS

2. High-risk mass slope failure is linked to poor urban planning in urban developing regions of Lima the capital of Peru.

3. A multidisciplinary study including geotechnical and hydrological analysis, engineering design, and socio-economic research is required to implement a SABO Master Plan, and this basin is pilot study basin.

4. At the present time, a maintenance programme for existing hydraulic structures should be implemented, and a flood risk management plan developed may propose the relocation of some communities and infrastructure.

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土质滑坡格构锚杆抗滑机制及受力试验研究     

韩冬冬  门玉明  胡兆江 《岩土力学》2020,41(4):1189-1194

通过滑坡防治格构锚固大型物理模型试验，分析了土质滑坡格构锚杆体系在坡顶荷载下的变形和位移，揭示了格构锚杆的抗滑机制，探讨了锚固力与坡体位移及锚杆变形的关系，提出了极限锚固力的计算方法。结果表明：滑坡滑动时，格构梁与坡体整体发生旋转滑移，锚杆在滑面处发生了弯曲变形，处于弯曲和轴向拉伸组合变形状态；格构锚杆的抗滑作用表现为锚杆在滑面处的抗剪抗滑和锚杆格构梁的挡土阻滑；格构锚杆的极限锚固力由初始预应力、锚杆弯曲变形引起锚拉力、坡体位移引起锚拉力三部分组成，可通过公式 计算。该研究结果可为格构锚固体系的优化设计提供一定的参考。  相似文献   

Strain analysis of a seismically imaged mass‐transport complex,offshore Uruguay     

Michael J. Steventon  Christopher A.‐L. Jackson  David M. Hodgson  Howard D. Johnson 《Basin Research》2019,31(3):600-620

Strain style, magnitude and distribution within mass‐transport complexes (MTCs) are important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally driven passive margins have been shown to approximately balance between updip extensional and downdip contractional domains; such an exercise has not yet been attempted for MTCs. We here interpret and structurally restore a shallowly buried (c. 1,500 mbsf) and well‐imaged MTC, offshore Uruguay using a high‐resolution (12.5 m vertical and 15 × 12.5 m horizontal resolution) three‐dimensional seismic‐reflection survey. This allows us to characterise and quantify vertical and lateral strain distribution within the deposit. Detailed seismic mapping and attribute analysis shows that the MTC is characterised by a complicated array of kinematic indicators, which vary spatially in style and concentration. Seismic‐attribute extractions reveal several previously undocumented fabrics preserved in the MTC, including internal shearing in the form of sub‐orthogonal shear zones, and fold‐thrust systems within the basal shear zone beneath rafted‐blocks. These features suggest multiple transport directions and phases of flow during emplacement. The MTC is characterised by a broadly tripartite strain distribution, with extensional (e.g. normal faults), translational and contractional (e.g. folds and thrusts) domains, along with a radial frontally emergent zone. We also show how strain is preferentially concentrated around intra‐MTC rafted‐blocks due to their kinematic interactions with the underlying basal shear zone. Overall, and even when volume loss within the frontally emergent zone is included, a strain difference between extension (1.6–1.9 km) and contraction (6.7–7.3 km) is calculated. We attribute this to a combination of distributed, sub‐seismic, ‘cryptic’ strain, likely related to de‐watering, grain‐scale deformation and related changes in bulk sediment volume. This work has implications for assessing MTCs strain distribution and provides a practical approach for evaluating structural interpretations within such deposits.  相似文献   

DATABASE OF LANDSLIDES TRIGGERED BY 2015 GORKHA(NEPAL) M_W7.8 EARTHQUAKE     

XU Chong  TIAN Ying-ying  SHEN Ling-ling  MA Si-yuan  XU Xi-wei  ZHOU Ben-gang  HUANG Xue-qiang  MA Jun-xue  CHEN Xi 《地震地质》2018,40(5):1115-1128

In this study, a detailed database of landslides triggered by the 25 April 2015 Gorkha (Nepal)M_W7.8 earthquake is constructed based on visual interpretation of pre- and post-earthquake high-resolution satellite images and field reconnaissance. Results show the earthquake triggered at least 47 200 landslides, which have a NWW direction spatial distribution, similar with the location and strike of the seismogenic fault. The landslides are of a total area about 110km² and an oval distribution area about 35 700km². On the basis of a scale relationship between landslide area (A)and volume (V), V=1.314 7×A^{1.208 5}, the total volume of the coseismic landslides is estimated to be about 9.64×10⁸m³. In the oval landslide distribution area, the landslide number density, area density, and volume density were calculated and the results are 1.32km^-2, 0.31%, and 0.027m, respectively. This study provides a detailed and objective inventory of landslides triggered by the Gorkha earthquake, which provides very important and essential basic data for study of mechanics of coseismic landslides, spatial pattern, distribution law, and hazard assessment. In addition, the landslide database related to an individual earthquake also provides an important earthquake case in a subduction zone for studying landslides related to multiple earthquakes from a global perspective.  相似文献   

国家安全发展示范城市建设的震灾预防对策研究     

申文庄  贾启超  李峰 《震灾防御技术》2018,13(4):997-1002

我国地震多、强度大、分布广，强地震的现实危害和潜在威胁是我国城市安全发展所面临的重大挑战。国内外城市地震灾害惨痛经验表明，震灾预防能力建设不足的城市往往在强震中毁于一旦。实现我国城市安全可持续发展，必须高度重视和持续推进城市震灾预防能力建设，切实防控和消除地震灾害风险。本文在深入分析城市地震灾害影响因素的基础上，从震灾预防能力建设、城市地震灾害风险防控工作、法规及技术标准和评价体系等方面入手，提出了进一步加强城市震灾预防能力建设的对策建议。  相似文献   

2014年鲁甸M_S6.5地震后地质灾害发育分布特征          下载免费PDF全文

杨秀元  姚亚辉 《地震工程学报》2018,40(5):1078-1083

2014年云南鲁甸“8·03”M_S6.5地震造成了重大人员伤亡和财产损失，诱发了大量滑坡、崩塌、泥石流等地质灾害。基于对鲁甸县龙头山幅（G48E006006）地质灾害调查数据和对典型地质灾害的剖析，震后地质灾害发育分布有特征如下：（1）震后地质灾害较震前成倍增长，震前地质灾害多以中小型浅层崩滑为主，地震诱发了诸如甘家寨、红石岩等大型—特大型滑坡、崩塌，大量沟谷崩滑堆积物为泥石流储备了丰富的物源；（2）震中高烈度区域地质灾害密度大，沿发震断裂带NNE—NE向构造密集发育，震中区龙头山镇地质灾害发育最为集中；（3）地质灾害呈带状分布，明显受控于河流水系（牛栏江、沙坝河、龙泉河等）、公路（昭巧二级公路、沙乐公路）等线性地貌单元和线性工程，人类活动影响明显。  相似文献   

灾区恢复重建后效评估研究进展          下载免费PDF全文

赵亮  何凡能  杨帆 《干旱区地理》2020,43(5):1337-1347

随着全球变化加剧，世界各地自然灾害的频发，国际社会为应对自然灾害进行了不懈努 力，历届世界减灾大会不断强调对应急管理全流程的研究，恢复重建作为应急管理的重要环节而 得到广泛重视。积极开展灾区恢复重建后效评估有利于保障灾区恢复重建实施与区域可持续发 展。灾区恢复重建后效评估研究时间较短，首先比较分析了国内外恢复重建的内涵，明确了恢复 重建后效评估的基本概念，并梳理了灾区恢复重建后效评估的在中国的发展演变。由于灾区恢复 重建内容复杂多样，本文结合灾区恢复重建后效评估的发展历程、研究范围与关注时段，分别从项 目、要素与可持续性三个关键视角对后效评估的理论方法等展开评述，结果表明：（1）项目后效评 估在灾区恢复重建后效评估中起步较早，现有评估多集中于居民住房、基础设施、公共设施等工程 质量的评估，但缺乏对项目设计过程中社会居民参与度、公众满意度以及社会经济效益等的评 估。（2）要素后效评估在灾区恢复重建后效评估中涉及范围最广，具体包括社会、经济与环境等要 素，这些要素的评估受政策绩效影响较大，后期需要构建综合的评估体系以开展科学评估。（3）可 持续性后效评估以联合国可持续发展目标与地方国民经济与社会发展计划为基础构建评估框架， 有利于促进灾区的可持续发展。通过综合分析《仙台减轻灾害风险框架》中“重建的更好”(BBB)理 念，联合国可持续发展目标（SDGs）以及《巴黎协定》适应全球变化等诉求，结合当前灾区恢复重建 后效评估现状进行展望，以期为灾区恢复重建与可持续发展提供一个更为系统、综合的技术参考。  相似文献   

西南煤系地层山区采动型崩滑灾害研究关键问题     

李军  褚宏亮  李滨  贺凯  高杨 《中国岩溶》2020,39(4):453-466

文章在分析采矿型崩滑灾害发育特征的基础上，得出西南煤系地层山区地下采动型崩滑灾害常发生在层状碳酸盐岩与碎屑岩地层组成的褶皱翼部和核部的陡崖带上，与地形地貌、地层结构与地下采矿工程活动等因素关系密切，并指出薄矿层开采诱发大型山体崩滑灾害的具体过程:①采空后覆岩顶板塌落—覆岩顶板离层，采空区上覆岩层内部及层间自下而上应力传递；②地下水运移通道形成，并加快更大范围岩体结构破坏及扩展，加速了岩体结构面的松动与破坏；③上覆岩层不均匀沉降导致坡脚压裂，山体大型岩体结构面逐渐拉剪或压剪变形扩展，最终山体发生累积损伤与大规模崩滑灾害。此外，传统经验公式的计算方法对此类采矿型崩滑灾害已不适用，建议开展西南煤系地层山区地质结构与地下采动诱发崩滑灾害的相互作用关系、薄矿层采空区上部山体累积断裂损伤—岩体松动、裂隙扩展-岩溶管道流、裂隙流变化的链式响应机制、地下采动型崩滑灾害评价方法等关键科学问题的研究，以推动采矿型地质灾害防灾减灾工作的发展。   相似文献   

基于D-InSAR技术的金沙江地区滑坡形变监测与分析     

齐麟  孔祥意  袁鑫  姜岩 《测绘与空间地理信息》2020,(2):175-177,181

滑坡是发生在我国山区的主要地质灾害类型,金沙江地区由于地势较高、地形复杂、多云多雨的特点,给传统的滑坡监测增加了难度。合成孔径雷达差分干涉测量技术(Differential interferometry synthetic aperture radar,D-InSAR)已在滑坡地面沉降监测中得到了广泛应用。本文选取金沙江上游沿岸作为研究区域,基于2018年8月11日与9月28日的Sentinel-1A影像及SRTM1数据,利用GAMMA软件及D-InSAR技术监测到金沙江地区的地表形变,成功识别出金沙江右岸的一处滑坡灾害。研究结果显示,在此滑坡的坡顶部分出现了约2.5 cm的沉降,而在坡底部分由于崩塌物的累积,地面出现了约3 cm的抬升。从实验结果可以得出,InSAR技术是一种有效的滑坡变形监测手段,利用Sentinel-1A卫星的SAR数据对滑坡区域进行形变监测,可以得到较好的干涉结果。  相似文献   

堆积阶地古老滑坡识别方法及其在线状工程地质勘察中的应用     

安玉科  樊江  马胜午  马建全  高娟  毛立军 《吉林大学学报(地球科学版)》2020,50(6):1787-1794

阶地型古老滑坡体形成后，长期受各种营力影响，导致古老滑坡地貌形态破坏严重甚至消失。目前遥感技术和普通工程地质调绘很难发现这些滑坡的存在，给工程建设和后期运营造成较大安全隐患。为准确识别形态特征不明显的古老滑坡体，从阶地物质结构特征演变入手，找到阶地受剪切破坏产生的典型物质结构特征，将地层结构错断、卵砾石异常定向排列、摩擦镜面和泥包粒的眼球构造等作为滑坡准确识别依据。首先采用沿沟谷进行工程地质测绘的纵横交错追踪法确定滑坡体纵向范围和滑面形状，再结合地貌特征推测各级、块滑坡平面范围和分布，最后用点状勘探工程验证和校正推测结论。可将其总结为由"地貌异常、沿沟追踪、面上推断、点状校验"组成的阶地型滑坡识别方法，即物质结构异常推断法。结合线状工程勘察设计各阶段工作特点，提出线状工程前期工作中阶地型滑坡识别步骤，并在临渭高速公路工程建设项目中取得成功应用。  相似文献