四川汶川地震-滑坡-泥石流灾害链形成演化过程

2008年“5·12”汶川Ms 8.0级地震之后,地震灾区表现出显著的强震地质灾害后效应。地震造成山体分水岭及山脊部位产生大量的崩塌和滑坡,崩滑体大多散落在山体的中上部,在强降雨作用下大量松散堆积物沿陡峻的沟道汇聚、加速,形成破坏性极大的高位泥石流,从而构成典型的地震-滑坡-泥石流灾害链。在回顾汶川地震灾区同震地质灾害的基础上,调查分析了震后汛期地质灾害的主要类型及其6种表现形式,将地震-滑坡-泥石流灾害链形成、演化过程划分为4个阶段：孕育阶段、地震同震滑坡阶段、震后滑坡-泥石流发育阶段、高位泥石流的动态演化阶段,提出高位泥石流的判识指标,并探讨其分布特征、动态变化趋势及其防治对策。     

Characteristics and numerical runout modeling of the heavy rainfall-induced catastrophic landslide–debris flow at Sanxicun,Dujiangyan, China,following the Wenchuan Ms 8.0 earthquake

The 2008 Ms 8.0 Wenchuan earthquake triggered a large number of extensive landslides. It also affected geologic properties of the mountains such that large-scale landslides followed the earthquake, resulting in the formation of a disaster chain. On 10 July 2013, a catastrophic landslide–debris flow suddenly occurred in the Dujiangyan area of Sichuan Province in southeast China. This caused the deaths of 166 people and the burying or damage of 11 buildings along the runout path. The landslide involved the failure of ≈1.47 million m³, and the displaced material from the source area was ≈0.3 million m³. This landslide displayed shear failure at a high level under the effects of a rainstorm, which impacted and scraped an accumulated layer underneath and a heavily weathered rock layer during the release of potential and kinetic energies. The landslide body entrained a large volume of surface residual diluvial soil, and then moved downstream along a gully to produce a debris flow disaster. This was determined to be a typical landslide–debris flow disaster type. The runout of displaced material had a horizontal extent of 1200 m and a vertical extent of 400 m. This was equivalent to the angle of reach (fahrböschung angle) of 19° and covered an area of 0.2 km². The background and motion of the landslide are described in this study. On the basis of the above analysis, dynamic simulation software (DAN3D) and rheological models were used to simulate the runout behavior of the displaced landslide materials in order to provide information for the hazard zonation of similar types of potential landslide–debris flows in southeast China following the Wenchuan earthquake. The simulation results of the Sanxicun landslide revealed that the frictional model had the best performance for the source area, while the Voellmy model was most suitable for the scraping and accumulation areas. The simulations estimated that the motion could last for ≈70 s, with a maximum speed of 47.7 m/s.     

The 12 May Wenchuan earthquake-induced landslide lakes: distribution and preliminary risk evaluation

The Wenchuan earthquake, measured at M _s 8.0 according to the China Earthquake Administration, occurred at 14:28 on 12 May 2008 in the Sichuan Province of China. It brought overwhelming destruction to eight provinces and cities. Landslides and rock avalanches triggered by the earthquake produced 257 landslide lakes which were distributed along the fault rupture zone and river channels. The authors traveled to the disaster zone immediately after the earthquake to examine some of the features of the debris dams and performed a quick evaluation of the potential for outburst of earthquake-induced landslide lakes for the purpose of disaster relief. The preliminary analysis indicated that the landslide lakes could be classified as those exhibiting extremely high risk, medium risk, and low risk according to field observations and remote sensing, to determine material composition, dam structure, dam height, maximum water storage capacity, and size of the population potentially affected area. The failure risk of 21 debris dams were evaluated as follows: one dam with an extremely high danger risk, seven dams with a high danger, five dams with a medium danger, and eight dams of low danger. More concern was given to the Tangjiashan Lake and different scenarios for the potential sudden failure of its dam were assessed. The risk evaluation result was accepted in full, by the earthquake disaster relief office. A successful emergency dam treatment for risk reduction was planned, based on our assessments, and these measures were quickly carried out. According to this research, the earthquake destabilized the surrounding mountains, resulting in a prolonged geohazard for the area. Landslides and debris flows will continue to develop for at least 5 to 10 years after the Wenchuan earthquake and will produce additional dammed lakes. Recommendations and plans for earthquake–landslide lake mitigation were proposed, based on past successful practices.     

沟道型滑坡-碎屑流运动距离经验预测模型研究

沟道型滑坡-碎屑流具有隐蔽性强、危险性高、力学机理复杂的特点,研究其运动距离预测模型具有重要的理论意义和实践意义。本文基于遥感GIS技术,结合野外调查,获取了汶川地震触发的38个沟道型滑坡-碎屑流的基础数据。通过相关性分析确定沟道型滑坡-碎屑流最大水平运动距离L的影响因素从大到小依次是滑坡体积V、最大垂直运动距离H、滑源区高差Hs、沟道段坡度β。采用逐步回归方法建立了滑坡-碎屑流最大水平运动距离L的最优多元回归模型,检验结果表明模型具有较高精度。将最优多元回归模型与国际上应用较多的滑坡运动距离和泥石流运动距离预测模型进行对比,表明考虑滑坡体积、地形落差和沟道段坡度的运动距离预测指标体系,具有最高的拟合优度和较好的物理含义,可为沟谷山区滑坡-碎屑流危险性评价提供参考依据。     

汶川八级地震地质灾害研究

汶川地震触发了15000多处滑坡、崩塌、泥石流,估计直接造成2万人死亡。地质灾害隐患点达10000余多处,以崩塌体增加最为显著,反映出地震对山区高陡斜坡的影响差异性非常大,在山顶上的放大作用非常显著。通过综合分析堰塞湖库容、滑坡坝高以及坝体物质组成和结构,对地震形成的33处坝高大于10m的滑坡堰塞湖进行了评估,划分出极高、高、中和低4种溃决危险。汶川地震滑坡滑床往往不具连续平整的滑面,尖点撞击是极震区滑坡的一大共性,可以分为勺型滑床、凸型滑床和阶型滑床等类型。据实地调查,滑坡附近震毁建筑物垂向震动非常明显,具有地震抛掷撞击崩裂高速滑流三阶段特征。在高速滑流中,发生3种效应:(1)高速气垫效应,滑坡体由较大块石和土构成,具有一定厚度,飞行行程可达1~3km;(2)碎屑流效应,撞击粉碎的土石呈流动状态,特别是含水丰富时,形成长程流滑;(3)铲刮效应,巨大撞击力导致下部岩体崩裂,形成新滑坡、崩塌,但是,其厚度不大,滑床起伏不平。本文以北川城西滑坡和青川东河口滑坡为例,分析了地震滑坡高速远程滑动及成灾机理。北川县城城西滑坡导致1600人被埋死亡,数百间房屋被毁,是汶川地震触发的最严重的滑坡灾难,举世罕见。青川东河口滑坡碎屑流是汶川地震触发的较为典型的高速远程复合型滑坡,滑程约2400m,高速碎屑流冲抵清江河左岸,形成滑坡坝,致使7个村庄被埋,约400人死亡。     

Activity and distribution of geohazards induced by the Lushan earthquake,April 20, 2013

An Ms7.0 earthquake, focal depth 13 km, struck Lushan on April 20, 2013, caused 196 deaths and 21 missing, 13,484 injuries, and affected more than two million people. A field investigation was taken immediately after the quake, and the induced hazards were analyzed in comparison with the Wenchuan earthquake. We have identified 1,460 landslides and avalanches and four dammed lakes, which were generally small and concentrated on high elevation. Avalanches and rockfalls developed in cliffs and steep slopes of hard rocks, including Jinjixia of Baosheng Town and Dayanxia of Shuangshi Town, Lushan, and the K317 section the Xiaoguanzi section north to Lingguan Town along the provincial highway S210. Landslides were relatively less, mainly in moderate and small scales, developing in sandstone, shale, and loose colluviums. Only one single large landslide was observed to turn into debris slide-flow. Dammed lakes were formed by avalanches and landslides, all in small size and of low danger degree. The earthquake-induced hazards distributed in belt on the hanging wall along the faults, and their major controlling factors include tectonics, lithology, structure surface, and landform. More than 99 % landslides were within 30 km to the epicenter, and 678 within 10 km, accounting for 46 % of the total; about 50 % landslides were distributed on slopes between 35° and 55°, and 11 % on slope exceeding 75°; 60 % on slopes at the altitudes between 1,000 and 1,500 m, 77 % on slopes between 900 and 1,500 m; and 24 and 62 % in hard rocks and section between hard and soft rocks, respectively. Compared with the case of Wenchuan earthquake, both the number and extension of landslides and avalanches in Lushan earthquake-affected area are much smaller, only 5.53 % in number and 0.57 % in area. The earthquake has increased the instability of slope and potentiality of landslide and debris flow. Accordingly, the active period is expected to be relatively short comparing with that in Wenchuan earthquake-hit area. However, the insidious and concealed hazards bring difficulty for risk investigation.     

再论大光包滑坡特征与形成机制

摘 要 大光包滑坡是汶川地震触发的规模最大的巨型滑坡。滑坡位于安县高川乡、汶川地震发震断裂上盘,滑动距离4.5 km,堆积体宽度2.2km,面积7.8 km2,估算体积7.5亿m3。与地震灾区178处特大滑坡相比,大光包滑坡除了强震触发崩滑灾害具有的震动溃裂、溃滑失稳、超强动力和大规模高速抛射与远程运动等特征之外,其存在一个长度大于1km的长大滑面,是其余滑坡绝无仅有的！作者在去年研究的基础上,又多次到现场调查、测绘并取样分析,初步认为大光包滑坡发生过程为一次性完成,滑带物质组成较为复杂,主体为震旦系（Zd）风化程度较高的泥质灰岩,局部夹泥盆系沙窝子组（Ds）磷矿及其伴生矿。滑坡形成机理主要分为以下3个阶段:即(1)坡体震裂阶段:在强震作用下后缘拉裂边界及上游拉裂边界形成,并与下游侧的岩层层面构成巨大的V型楔形体;(2)滑面碎裂化,摩阻力急剧降低阶段:滑坡下游边界（主控滑动面）滑床被震裂、松弛、剪胀-扩容并碎裂化,产生滚动摩擦效应,导致滑面摩阻力急剧降低;(3) 前部锁固段剪断,高速溃滑阶段:滑体前部滑面上的锁固段在强震持续作用下,产生突发性剪断,从而导致整个巨大的楔形体,如同拉抽屉一样,沿岩层走向高速溃滑而下;（4）震动堆积阶段,滑体冲过黄洞子沟,受到迎面山体的强力阻挡,逆冲爬高500余m后,表部惯性极大的松散岩土体快速折返并震动堆积、荡平,余势不减的碎屑流汇入滑坡扩容抛撒体,向黄洞子沟下游流动1km,止于大偏桥。     

An empirical model for landslide travel distance prediction in Wenchuan earthquake area

Sliding mass of landslides highly endangered the area along travel path, especially landslides with long travel distance. It is necessary to develop an effective prediction model for preliminarily evaluating landslide travel distance so as to improve disaster prevention and relocation. This paper collected 54 landslides with 347–4,170 m travel distance triggered by the 2008 Wenchuan earthquake to discuss the effectiveness of various influential factors on landslide travel distance and obtained an empirical model for its prediction. The results revealed that rock type, sliding source volume, and slope transition angle were the predominant factors on landslide travel distance. The validity of proposed model was verified by the satisfactory agreement between observations and predictions. Therefore, this model might be practically applicable in Wenchuan earthquake area and other similar geomorphological and geological regions.     

Using Bayesian networks in analyzing powerful earthquake disaster chains

Substantial economic losses, building damage, and loss of life have been caused by secondary disasters that result from strong earthquakes. Earthquake disaster chains occur when secondary disasters take place in sequence. In this paper, we summarize 23 common earthquake disaster chains, whose structures include the serial, parallel, and parallel–serial (dendroid disaster chain) types. Evaluating the probability of powerful earthquake disaster chains is urgently needed for effective disaster prediction and emergency management. To this end, we introduce Bayesian networks (BNs) to assess powerful earthquake disaster chains. The structural graph of a powerful earthquake disaster chain is presented, and the proposed BN modeling method is provided and discussed. BN model of the earthquake–landslides–barrier lakes–floods disaster chain is established. The use of BN shows that such a model enables the effective analysis of earthquake disaster chains. Probability inference reveals that population density, loose debris volume, flooded areas, and landslide dam stability are the most critical links that lead to loss of life in earthquake disaster chains.     

强震区高位滑坡远程灾害特征研究——以四川茂县新磨滑坡为例

近年来,在汶川地震等强震区常发生一种特大的高位滑坡地质灾害,它从高陡斜坡上部位置剪出并形成凌空加速坠落,具有撞击粉碎效应和动力侵蚀效应,导致滑体解体碎化,从而转化为高速远程碎屑流滑动或泥石流流动,并铲刮下部岩土体,使体积明显增加。新磨滑坡就是这种典型,它发生于2017年6月24日,滑坡后缘高程约3450m,前缘高程约2250 m,高差1200 m,水平距离2800 m,堆积体体积达1637×10~4m~3,摧毁了新磨村村庄,导致83人死亡。新磨滑坡地处叠溪较场弧形构造带前弧西翼,母岩为中三叠统中厚层变砂岩夹板岩,是1933年叠溪Ms7.5级震中区(烈度X度)和汶川Ms8.0级强震区(烈度IX度),形成震裂山体。滑源区分布多组不连续结构面,将厚层块状岩体分割成碎裂块体,在高程3150~3450 m区间形成明显的压裂鼓胀区,特别是存在2组反倾节理带,具有典型的"锁固段"失稳机理。滑坡体高位剪出滑动,连续加载并堆积于斜坡体上部,体积达390×10~4m~3,导致残坡积岩土层失稳并转化为管道型碎屑流;碎屑流高速流滑至斜坡下部老滑坡堆积体后,因前方地形开阔、坡度变缓,转化为扩散型碎屑流散落堆积,具有"高速远程"成灾模式。据此,可建立强震山区高位滑坡的早期识别方法,当陡倾山脊存在大型岩质高位滑坡时,应当考虑冲击作用带来的动力侵蚀效应和堆积加载效应,特别是沿沟谷赋存丰富的地下水时,发生高速远程滑坡的可能性将明显增加。因此,在地质灾害调查排查中,在高位岩质滑坡剪出口下方的斜坡堆积体上的聚居区等应划定为地质灾害危险区。在强震山区地质灾害研究中,不仅应采用静力学理论分析滑坡的失稳机理,而且应采用动力学方法加强运动过程的成灾模式研究。     

汶川地震强震区地震诱发滑坡与后期降雨诱发滑坡控制因子耦合分析

本文以汶川地震强震区北川县典型研究区为例,利用高分辨率航片、SPOT5卫星图像对北川县典型研究区进行了512地震之后和924降雨之后诱发的滑坡解译,解译结果显示:512地震诱发滑坡1999个,924强降雨诱发滑坡828个,924强降雨导致原有地震滑坡面积扩大的滑坡150个。研究表明:地震和强降雨都是诱发滑坡的动力成因,924强降雨诱发的滑坡面积是512地震诱发滑坡面积的1/4倍,强降雨诱发滑坡的数量增加了41.4%; 强降雨不仅诱发新的滑坡,而且促使原来地震滑坡复活,并扩大其面积,强降雨导致地震诱发的滑坡面积扩大了原面积的68.7%。同时,在遥感解译数据基础之上,开展地震诱发滑坡与降雨诱发滑坡规模对比和控制因子耦合分析及地震与降雨耦合灾害链模式研究,为进一步分析研究地震灾区滑坡的产生、发展趋势、危险性和风险评价等预测预报提供科学依据,也为汶川震区恢复重建中的减灾防灾提供决策参考。     

The Wenchuan Earthquake (May 12, 2008), Sichuan Province,China, and resulting geohazards

On Monday, May 12, 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenchuan area, northwestern Sichuan Province, China. The focal mechanism of the earthquake was successive massive rock fracturing 15 km in depth at Yingxiu. Seismic analysis confirms that the major shock occurred on the Beichuan–Yingxiu Fault and that aftershocks rapidly extended in a straight northeast–southeast direction along the Longmenshan Fault zone. Fatalities approaching a total of 15,000 occurred, with a significant number resulting from four types of seismically triggered geohazards—rock avalanches and landslides, landslide-dammed lakes (“earthquake lakes”), and debris flows. China Geological Survey has identified 4,970 potentially risky sites, 1,701 landslides, 1,844 rock avalanches, 515 debris flows, and 1,093 unstable slopes. Rock avalanches and landslides caused many fatalities directly and disrupted the transportation system, extensively disrupting rescue efforts and thereby causing additional fatalities. Landslide-dammed lakes not only flooded human habitats in upstream areas but also posed threats to potentially inundated downstream areas with large populations. Debris flows become the most remarkable geohazards featured by increasing number, high frequency, and low triggering rainfall. Earthquake-triggered geohazards sequentially induced and transformed to additional hazards. For example, debris flows occurred on rock avalanches and landslides, followed by landslide-dammed lakes, and then by additional debris flows and breakouts of the landslide-dammed lakes and downstream flooding. Earthquake-induced geohazards occurred mainly along the fault zone and decreased sharply with distance from the fault. It can be anticipated that post-earthquake geohazards, particularly for debris flows, will continue for 5–10 years and even for as long as 20 years. An integrated strategy of continuing emergency response and economic reconstruction is required. The lesson from Wenchuan Earthquake is that the resulted geohazards may appear in large number in active fault regions. A plan for geohazard prevention in the earthquake-active mountainous areas is needed in advance.     

Characteristics and geomorphic effects of earthquake-initiated landslides in the adelbert range, Papua New Guinea

On November 1, 1970, an earthquake of magnitude 7.0 occurred 32 km north of Madang on the north coast of Papua New Guinea, and on the fringes of the Adelbert Range. Dense landsliding occurred over an area of 240 km². Debris avalanches removed shallow soil and forest vegetation from slopes of 45°. Earthflows occurred on deeper soils and lower-angled slopes. The nature of the landslides and disposition of the vegetation debris suggest that falling trees triggered the landslides during the earthquake. Logs in the deposits were an important influence on the movement of landslide debris in the channel systems.     

Spatio-temporal evolution of mass wasting after the 2008 M<Subscript>w</Subscript> 7.9 Wenchuan earthquake revealed by a detailed multi-temporal inventory

Strong earthquakes in mountainous areas can trigger a large number of landslides that generate deposits of loose and unconsolidated debris across the landscape. These deposits can be easily remobilised by rainfalls, with their movement frequently evolving into catastrophic debris flows and avalanches. This has been the fate of many of the 200,000 co-seismic deposits generated by the 2008 M_w 7.9 Wenchuan earthquake in Sichuan, China. Here we present one of the first studies on the post-seismic patterns of landsliding through a detailed multi-temporal inventory that covers a large portion of the epicentral area (462.5 km²). We quantify changes of size-frequency distribution, active volumes and type of movement. We analyse the possible factors controlling landslide activity and we discuss the significance of mapping uncertainties. We observe that the total number of active landslides decreased with time significantly (from 9189 in 2008 to 221 in 2015), and that post-seismic remobilisations soon after the earthquake (2008–2011) occurred stochastically with respect to the size of the co-seismic deposits. Subsequently (2013–2015), landslide rates remained higher in larger deposits than in smaller ones, particularly in proximity to the drainage network, with channelised flows becoming comparatively more frequent than hillslope slides. However, most of the co-seismic debris remained along the hillslopes and are largely stabilised, urging to rethink the way we believe that seismic activity affects the erosion patterns in mountain ranges.     

“5．12”大地震前后汶川县地质灾害发育研究

汶川大地震对地质环境影响很大,由于大地震的影响,其震前震后的地质灾害类型、数量等发生了很大的改变。本文通过搜集前人资料,现场调查,分析了汶川大地震前后汶川县地质灾害的变化。结果表明,地震前汶川县地质灾害类型主要以泥石流为主,地震后,汶川县地质灾害类型主要为崩塌,其次为泥石流和滑坡。地震使汶川县地质灾害数量极大增加,同时,也使得其主要地质灾害类型发生改变。     

都江堰市龙池镇黄央沟泥石流特征与防治工程效果分析

黄央沟位于"5.12"汶川地震的极重灾区四川省都江堰市龙池镇,地震使沟内山体发生大规模的滑坡和崩塌,其为泥石流的形成提供了丰富的松散固体物质。地震后黄央沟泥石流十分活跃,2010年8月13日、8月18日和2013年7月9日均暴发了泥石流,造成了严重的经济损失。笔者通过对黄央沟泥石流灾害现场进行实地调查,详细分析了黄央沟泥石流的形成条件和发育特征,并对已有防治工程效果进行了分析和探讨。针对防治工程存在的问题和黄央沟泥石流的特点,建议在沟道下游和堆积区修建排导沟,使泥石流顺畅排入龙溪河;采取工程和生物措施来稳定沟道内的崩滑堆积体和不稳定斜坡,减少泥石流物源;沟口公路采用高架桥跨越方式通过泥石流堆积扇。该研究结果可为强震区泥石流灾害的防治提供参考。     

Surface recovery of landslides triggered by 2008 <Emphasis Type="Italic">Ms</Emphasis>8.0 Wenchuan earthquake (China): a case study in a typical mountainous watershed

The Ms8.0 Wenchuan earthquake that occurred on 12 May 2008 in southwestern China and triggered numerous landslides is one of the stronger ones in the steep eastern margins of the Tibetan Plateau. The surfaces of these landslides have recovered gradually with vegetation, which provide useful information about the evolution of geologic environment as well as the long-term assessment of landslides after earthquake. The Mianyuanhe watershed shows many co-seismic landslides. The active fault passing through its center is selected as a study area aiming to analyze the annual surface recovery rate (SRR) of landslides by interpretation of remote-sensing images in five periods from 2008 to 2013. The results are here described. (1) Although a large amount of loose deposits were transformed into debris flows, the surfaces of the landslides recovered rapidly with vegetation and almost no landslides occurred at new sites after the Wenchuan earthquake. In the year 2008, the exposed surface projected area (ESPA) of the landslides showed a total area of 56.3 km² and covered 28.9 % of the study area, which was reduced rapidly to 19.1 % in 2011 and 15.8 % in 2013. (2) The study area was divided into four geologic units, including clastic rocks, melange zone, carbonate rocks, and magmatic rocks. Smaller ESPAs and higher SRRs were found in the former two units versus the latter ones. (3) A single large landslide shows an SRR lower than a group of smaller ones having an equal total surface, while the SRRs of debris flows are lower than those of rockfalls and landslides. (4) The vegetation cover would return to the pre-earthquake level in 2020 approximately, which indicates that the impact of the Wenchuan earthquake on landslides and debris-flows activities would cease almost completely.     

Characteristics and remediation of a landslide complex triggered by the 2008 Wenchuan, China earthquake-case from Yingxiu near the earthquake epicenter

During the 2008 Wenchuan earthquake, the river valley from Yingxiu to Wenchuan experienced numerous landslides and became a prominent area of landslide complexes. The present large landslide complex near the earthquake epicenter consisted of Laohuzui slide 1, Laohuzui slide 2 and Douyaping slide. The scale, geology, morphology, sliding process, and failure mechanism of the landslide complex are analyzed by means of field investigation, aerial photograph and stereographic projection technique. Characteristics of these three slides including seismic response of slope, landslide debris, damage and potential failure are discussed: the convex slope and the upslope of fractured granitic rock at high altitude are highly prone to landsliding under earthquake; the high source altitude and long travel path determine grain sizes and the deposit angle of the slide debris; the landslide complex completely buries the G213 roadway and dams up the Minjiang River in these sections; after the earthquake, rainfall, aftershocks and river erosion may retrigger new failures, such as retrogressive slide of weathered fractured rock, colluvial landslide, debris flow, embankment failure and rockfall. The following are presented as suggested remedial measures to protect the roadway and stabilize the slope: the removing and trenching, protective concrete/rock blocks against erosion, retaining structure, rockfall stopping wall, rockfall restraining net, rock bolt, and the planting of vegetation.     

四川安县高川乡政府滑坡特征及稳定性分析

2008年汶川"5.12"特大地震诱发了为数众多的崩塌、滑坡、泥石流等次生地质灾害,安县高川乡政府滑坡就是其中之一。本文在综合分析滑坡区地质环境条件、滑坡灾害体特征的基础上,进行了滑坡稳定性计算,给出了滑坡稳定性影响因素。     

低山丘陵区典型滑坡-泥石流链生灾害特征与成灾机理

2019年6月10—13日,龙川县发生持续强降雨,导致全县境内发生大量滑坡、泥石流灾害,贝岭镇米贝村是三个重灾区之一。本文以贝岭镇米贝村6号沟发生的滑坡-泥石流链生灾害为研究对象,在野外精细化调查测量基础上,结合数值模拟分析与计算,对链生灾害特征与成灾机理展开研究。研究发现:①6号沟内共发育7处浅层土质小型滑坡,仅3号滑坡体与部分6号滑坡体转化为泥石流,构成泥石流主要物源,其余滑坡未构成持续性影响;②持续降雨下渗,坡体由非饱和向饱和状态转变,坡表形成连续饱和区,孔隙水压力的增加与孔隙水的软化促使土体强度降低,加之坡体饱和自重的增大,斜坡发生浅表层失稳破坏;③降雨的持续下渗与支沟沟源“漏斗状”地形下的地表汇水快速增大滑坡松散堆积体内的含水率,促使其物理性质发生变化,在重力势能下呈流态状启动、运动转化为泥石流。降雨结构影响滑坡-泥石流链生过程,前期降雨引发滑坡、后期降雨启动形成泥石流,滑坡与泥石流的发生表现出阶段性特征。研究成果有助于指导当地政府进一步开展滑坡-泥石流链生灾害的防灾减灾工作,也为该地区未来区域预警研究工作提供理论支撑。