IMHE OpenIR  > 山地灾害与地表过程重点实验室
典型震后滑坡灾害演化特征及时空规律研究—以银洞子沟滑坡泥石流灾害为例
Alternative TitleResearch on the Disaster Evolution Characteristics and Spatio-temporal Laws of Typical Post-earthquake Landslide: A Case Study of the Yindongzi Landslide-debris Flows
Language中文
王礼勇
Thesis Advisor杨宗佶
2020
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name硕士
Degree Discipline建筑与土木工程
Keyword震后滑坡 水-力耦合 土-水参数 时空规律 演化机制
Abstract2008年汶川大地震使得西南震区山体普遍松动,形成大量的地震滑坡堆积体。震后滑坡最主要的特征表现为降雨滑坡敏感性增加、规模增大、临界雨量降低和滑坡堆积物转化为泥石流的特征,并成为震区新的威胁。震后滑坡灾害的持续效应根本上表现在降雨激发震后滑坡泥石流频繁发生。针对地震“后效应”下震后滑坡灾害演化特征及时空规律展开研究,对震后滑坡的预警预报和长期防控十分必要。本研究以5.12汶川地震极震区中国西部山区的白沙河流域银洞子沟震后滑坡泥石流灾害为研究对象,首先通过多时相遥感影像差分技术分析典型震后滑坡震后10年地表演化过程及衰减的时空特征;采用震后滑坡现场水-力多参数实时监测,并结合非饱和水–力耦合理论方法开展了基于实测数据的震后滑坡物理机制研究及长时间序列边坡稳定性分析;基于滑坡现场实测数据和室内物理模型试验建立土-水参数演化模型。在土-水参数预测模型基础上选取2次典型震后滑坡极端降雨事件,预测了震后滑坡持续效应下在未来10年的稳定性演化趋势。最后通过TRIGRS模型,将震后滑坡持续效应稳定性预测模型扩展至三维空间环境下,进一步量化并揭示了震区恢复效应下地表演化的时间、空间规律。本论文主要取得以下研究成果:1、通过野外取样调查、无人机航拍以及多时相卫星遥感影像差分等方法,揭示了银洞子震后滑坡灾害为期10年的地表演化特征、衰减时间和空间分布规律;结合震后滑坡事件的触发降雨量建立了触发日降雨量演化模型。2、基于长时间序列现场实测数据,采用非饱和滑坡稳定性分析方法揭示了滑坡现场长时间序列的土体含水量、基质吸力、吸应力和稳定性的连续变化;揭示了震后滑坡长时间序列雨-水-力-稳定性耦合变化规律,为判别和揭示震后滑坡失稳及转化为泥石流的成灾模式提供了理论基础。3、通过银洞子震后滑坡现场采样和室内人工降雨试验揭示了震后滑坡细颗粒迁移现象,并量化震后土体结构及土体强度参数的演化趋势。同时,结合滑坡现场5个水文年的实时监测水文数据,反演了包括饱和导水率、残余含水率、Van Genuchten模型参数α和n土-水特征参数的时变效应和演化趋势。建立了土-水参数时间尺度上的预测模型。4、基于土-水参数预测模型,开展了一维降雨入渗时变特性研究。结果表明,降雨入渗导致土体吸力消散是震后滑坡失稳的核心机制,堆积体基质吸力和吸应力随地震后时间效应呈降低趋势,而导水性呈增强趋势。结合两次震后滑坡事件“8.28”和“6.26”的极端降雨过程,量化了土-水参数变化对滑坡稳定性的影响,揭示了地震后效应和震后恢复效应双重作用下的典型震后滑坡稳定性变化机制及其持续效应的演化特征和规律。5、基于TRIGRS模型预测了震后滑坡持续效应下时间尺度的边坡稳定性空间演化规律。震后滑坡持续效应下边坡稳定性逐年增强,3年后、5年后、7年后和10年后边坡失稳面积呈降低趋势,所占总面积比例分别为6.73%、1.67%,0.91%和0.12%。体现了震后良好的恢复效应,预计在2027年后基本达到整体稳定状态。最后基于量化的震后滑坡持续效应,修正了雨量-概率预警指标。本研究中的研究方法和研究结论可为震后滑坡持续效应下变形破坏时空演化规律、形成机理和预警预报的研究提供了重要的理论基础和实践参考,并旨在为汶川震区震后地质灾害的长期预测和防控提供新的参考和基础。
Other AbstractThe 2008 Wenchuan earthquake caused the mountain masses in the southwestern earthquake area to loosen, forming a large number of earthquake landslide deposits. The main characteristics of post-earthquake landslides in the earthquake area are increased sensitivity to rainfall, increased scale, reduced critical rainfall, and the conversion of landslide deposits into debris flows, which have become new threats. The sustained effects of mountain disasters after a large earthquake are usually reflected in the frequent occurrence of landslides and debris flows caused by rainfall. The research on the evolutionary characteristics of post-seismic landslides and spatio-temporal laws under the post-earthquake effect is necessary for the long-term defense and early warning of landslide disasters in earthquake regions. This study focuses on a typical post-earthquake landslide of Yindongzi gully in Dujiangyan County, Sichuan Province, after the Wenchuan earthquake. The evolution of temporal variation and spatial distribution on post-seismic landslide deposits under the sustainable effect of geohazards are studied by multi-temporal satellite images. A hydro-mechanical multi-parameter real-time monitoring system is applied in the post-seismic landslide. The stability and failure mechanism of the slope were investigated in a long period by combining the real-time monitoring data of five hydrological years and hydro-mechanical coupling theory. Combined with the real-time monitoring data of the landslide site and the rainfall-induced landslide physical model test, the evolution trend of soil-hydro parameters of landslide deposits was creatively inverted. Based on the soil-hydro parameter evolution model, the stability evolution of post-earthquake landslide under the sustained effects of mountain disasters is quantified and predicted in the next 10 years. Through the TRIGRS model, the prediction of the stability of the post-earthquake landslides was extended to a three-dimensional space environment, and further quantified and revealed the spatio-temporal evolution process of the land surface under the continuous recovery effect after the earthquake.This thesis mainly achieved the following research results:1. Based on field investigations, unmanned aerial vehicle (UAV) images, and multi-temporal satellite images,the evolution characteristics, time variation, and spatial distribution pattern of landslide disasters during the 10 years period after the earthquake in Yindongzi gully are revealed. A preliminary model of daily rainfall threshold for triggering landslides is proposed based on the rainfall triggering of disaster events.2. Based on the analysis of the long-term monitoring data and the unsaturated slope stability method, the change of soil moisture content, matric suction change, suction stress change, and stability change of the landslide site in a long period are established, and the rainfall-hydro-mechanical-stabality coupling mechanism of post-earthquake landslides is revealed. It provides a theoretical basis for identifying and revealing the hazard model of post-seismic landslides and transformed into debris flows.3. The migration of fine particles in slope is proved by combining on-site sampling of the post-earthquake landslides and the rainfall-induced landslide physical model tests, and the evolution trend of soil structure and soil strength parameters is quantified in post-earthquake landslides. Combined with the real-time monitoring data of 5 hydrological years, the evolution trend of soil-hydro characteristic parameters of landslide deposits is creatively inverted, including saturated hydraulic conductivity, residual moisture content, Van Genuchten model parameters α and n. A prediction model with time is established.4. Based on the prediction model of soil-hydro parameters, the one-dimensional rainfall infiltration characteristics of post-seismic landslide are studied. It is proved that the suction dissipated due to rainfall infiltration is the main mechanism of post-seismic landslide instability. The matrix suction and suction stress of the slope showed a decreasing trend with the time after the earthquake, while the hydraulic conductivity showed an increasing trend. The stability analysis under two extreme rainfall conditions by soil-hydro parameters at different times is carried out to quantify and predict the stability evolution of post-earthquake landslide under the sustained effects of mountain disasters. A method for predicting the stability of post-seismic landslides under the effects of mountain disasters and post-earthquake recovery is constructed.5. The spatial evolution process of slope stability on the time scale under the continuous effect of post-earthquake landslides was predicted by the TRIGRS model. Under extreme rainfall conditions, the safety factor of slope in the space gradually increases year by year, and the slope failure area decreases gradually in time. After 3 years, 5 years, 7 years, and 10 years, the slope instability area accounted for 6.73%, 1.67%, 0.91%, and 0.12% of the total area respectively. A well post-earthquake recovery effect is manifested, and it is expected that the slope will reach an overall stable state after 2027. The quantified post-earthquake recovery effect results are applied to the modification of the rainfall intensity-probability threshold.The research methods and conclusions in this thesis provide an important theoretical basis and practical reference for the study on the temporal and spatial evolution, formation mechanism, and early warning and forecast of post-earthquake landslides under the sustained effects of mountain disasters and post-earthquake recovery. It aims to offer a reference and basic theory for the long-term prevention of post-earthquake geological disasters in the Wenchuan earthquake area.
Pages152
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/55004
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
王礼勇. 典型震后滑坡灾害演化特征及时空规律研究—以银洞子沟滑坡泥石流灾害为例[D]. 北京. 中国科学院大学,2020.
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