Slope Debris Flows Research Articles

The Application of Remote Sensing Technology in Post-Disaster Emergency Investigations of Debris Flows: A Case Study of the Shuimo Catchment in the Bailong River, China

The Bailongjiang River Basin is a high-risk area for debris flow in China. On 17 August 2020, a debris flow occurred in the Shuimo catchment, Wen County, which blocked the Baishui River, forming a barrier lake and causing significant casualties and property damage. In this study, remote sensing, InSAR, field surveys, and unmanned aerial vehicle (UAV) techniques were used to analyze the causal characteristics, material source characteristics, dynamic processes, and disaster characteristics after the debris flow. The results showed that the Shuimo catchment belongs to low-frequency debris flows, with a recurrence cycle of more than 100 years and concealed features. High vegetation coverage (72%) and a long main channel (11.49 km) increase the rainfall-triggering conditions for debris flow occurrence, making it more hidden and less noticed. The Shuimo catchment has a large drainage area of 31.26 km2, 15 tributaries, significant elevation differences of 2017 m, and favorable hydraulic conditions for debris flow. The main sources of debris flow material supply are channel erosion and slope erosion, which account for 84.4% of the total material. The collapse of landslides blocking both sides of the main channel resulted in an amplification of the debris flow scale, leading to the blockage of the Baishui River. The scale of the accumulation fan is 28 × 104 m3, and the barrier lake area is 37.4 × 104 m2. The formation mechanism can be summarized as follows: rainfall triggering → shallow landslides → slope debris flow → channel erosion → landslide damming → dam failure and increased discharge → deposition and river blockage. The results of this study provide references for remote sensing emergency investigation and analysis of similar low-frequency and concealed debris flows, as well as a scientific basis for local disaster prevention and reduction.

Review of research on testing and models of the trigger mechanism of slope debris flows

Review of research on testing and models of the trigger mechanism of slope debris flows

Dynamic numerical simulation and risk predictive assessment of the slope debris flow for the rear mountain at the management office of the Erlang Mountain Tunnel

The Erlang Mountain Tunnel Management Office is located in Luding County, Sichuan Province, China. A long-term open-pit limestone mine is located on the rear mountain, 1 km from the west entrance of the Erlang Mountain Tunnel Management Office for the Sichuan-Tibet Highway. Dangerous rock masses and a large accumulation of mine waste slag are present o-n the hillside, which can easily produce slope debris flow disasters. This paper analyzes the formation causes of slope debris flow through field investigation and uses RAMMS (Rapid mass movement simulation) software to study the influence of base friction coefficient μ and ξ on slope debris flow. Numerical simulation predicted level of danger of the movement process from the aspects of Velocity, deposition height, flow, topography. When the dry Coulomb friction value μ increased from 0.3 to 0.4, the debris velocity decreased and began to spread out along the slope. The flow process can be divided into four parts, and found that the velocity and discharge are different in the upstream and downstream of the slope constriction. The slope constriction has a significant amplification effect on the velocity and discharge. The velocity is amplified by 31.1%, and the discharge is amplified by 14.5%. In addition, based on the dynamic characteristics and the frequency of rainstorms, the risk of debris flow is divided into four levels: low, medium, high, and extremely high. The hazard map of slope debris flow in the rainstorm return period (20 years) is established, which provides a basis for the assessment and prediction of debris flow.

New insights into the occurrence of the catastrophic Zhaiban slope debris flow that occurred in a dry valley in the Hengduan Mountains in southwest China

New insights into the occurrence of the catastrophic Zhaiban slope debris flow that occurred in a dry valley in the Hengduan Mountains in southwest China

Dynamic process of a typical slope debris flow: a case study of the wujia gully, Zengda, Sichuan Province, China

Dynamic process of a typical slope debris flow: a case study of the wujia gully, Zengda, Sichuan Province, China

Disaster control and effect evaluation of high and steep slope based on the landslide mass chain disaster model

According to the investigation on the distribution of surface geological hazards in Maoping Mine, Yunnan Province, the stability calculation and discrete element numerical simulation of Meitanyakou landslide were carried out. The result shows that under the action of earthquake and rainfall, the Meitanyaku landslide has a chain disaster mode of high source start-up, acceleration slippage on the steep slope, gentle slope debris flow scattering and accumulation, and block rolling and throwing. Based on this, the reinforcement and treatment scheme in the landslide source area was formulated: the surface soil and vegetation in the gentle slope area were used to block the landslide, the passive protective net was installed at the bottom, and the reinforcement and treatment facilities were monitored. Meanwhile, a complete set of advanced and reliable slope online monitoring and early warning systems was established. After treatment, there was no unstable landslide, and the slope and its engineering structures in the monitoring area were stable, which shows that the chain disaster mode of landslide geological disaster and the complementary scheme of prevention and control countermeasures are effective.

Slope Failures and Debris Flow Caused by 2018 July Heavy Rain along Katsuradani, Hida City, Gifu Prefecture, Japan

Slope Failures and Debris Flow Caused by 2018 July Heavy Rain along Katsuradani, Hida City, Gifu Prefecture, Japan

Природные наледи селевых бассейнов Среднего и Южного Сахалина

The article deals with the ice mounds formation processes in the mudflow basins. Small natural frosts are widespread on the territory of Middle and Southern Sakhalin within the slope and small valley debris flow basins, along with dangerous slope exogenous processes (debris flows, landslides, erosion, etc.), often having a paragenetic nature of the current. The mechanism of ice data formation is due to the hydro/meteorological features of the territory, as well as disturbance of the thermal, hydrological or hydrogeological regime of the debris flow basin. The main reason for the formation of natural ice mounds in the valley debris flow basins is disturbance of the hydrological regime of the catchment basin during debris flow formation, which mainly contributes to the annual solid runoff of first order watercourses. Scum of slope debris flow basins are formed in case of violation of the thermal regime of the surface and soil of the debris flow basin due to climatic anomalies, as well as damage to natural heat-insulating coverings: snow and soil-vegetable. It is also possible to form sloping ice as a result of a violation of the hydrogeological regime of the catchment basin under anthropogenic impact or the development of dangerous exogenous slope processes with a sufficient depth of rock capture. Cryogenic processes of ice formation affect debris flow and channel processes.

DEBRIS FLOW CHECK CONSTRUCTIONS SITUATED NEAR THE MOUTH OF RIVERS OF THE SAKHALIN ISLAND

The significant part of roads and railways of the Sakhalin Island are located in the coastal zone of the sea, in the lower part of the debris flow transit zone. Debris flows cause blockages and damage to the roadways. In some areas of the island are sites where the number of debris flow basins is 30-40 per km. Basically, these are slope debris flows, which are formed annually during precipitation of liquid precipitation, and whose volume can reach 500 m3. At the same time, debris flows can play an important role in the formation of beaches and protection from abrasion due to the removal of material to the mouth of the rivers. Transport of debris flow material to the coastal zone on the Sakhalin Island is carried out on the coasts of the Gulf of Patience, the Gulf of Aniva, the Tatar Strait, etc. Beach savings are the best of its natural protection against destruction. Therefore, the need to build seepage facilities is due not only to the need to protect the roadway, but also the importance of transporting debris flow material to the beach area. Characteristics of debris flows in the coastal zone of the island differ in a number of parameters, such as the volume of debris slides, the frequency of formation of debris flows, the type of debris flows, the size of carried fragments of rocks; therefore, when choosing a debris flow protection facility, it is necessary to be guided both by the parameters of debris flows and by the role of debris flows in the formation of beaches. The paper examines the current state of water chute and debris flows chute under the roads in the near-mouth parts of debris flow rivers, as well as the expediency of selecting debris flow protection structures depending on the characteristics of debris flows.

Effects of loose deposits on debris flow processes in the Aizi Valley, southwest China

Loose deposits, rainfall and topography are three key factors that triggering debris flows. However, few studies have investigated the effects of loose deposits on the whole debris flow process. On June 28, 2012, a catastrophic debris flow occurred in the Aizi Valley, resulting in 40 deaths. The Aizi Valley is located in the Lower Jinsha River, southwestern Sichuan Province, China. The Aizi Valley debris flow has been selected as a case for addressing loose deposits effects on the whole debris flow process through remote sensing, field investigation and field experiments. Remote sensing interpretation and laboratory experiments were used to obtain the distribution and characteristics of the loose deposits, respectively. A field experiment was conducted to explore the mechanics of slope debris flows, and another field investigation was conducted to obtain the processes of debris flow formation, movement and amplification. The results showed that loose deposits preparation, slope debris flow initiation, gully debris flow confluence and valley debris flow amplification were dominated by the loose deposits. Antecedent droughts and earthquake activities may have increased the potential for loose soil sources in the Aizi Valley, which laid the foundation for debris flow formation. Slope debris flow initiated under rainfall, and the increase in the water content as well as the pore water pressure of the loose deposits were the key factors affecting slope failure. The nine gully debris flows converged in the valley, and the peak discharge was amplified 3.3 times due to a blockage and outburst caused by a large boulder. The results may help in predicting and assessing regional debris flows in dry-hot and seismic-prone areas based on loose deposits, especially considering large boulders.

Fusulinids from slope debris flow beds in the Word Formation (Guadalupian, Middle Permian), Gilleland Canyon, northwestern Glass Mountains, West Texas

Three Guadalupian allochthonous debris flow beds in a slope-to-basin facies succession in northern Gilleland Canyon of the northwest Glass Mountains were sampled for fusulinid biostratigraphic age-dating. The deeper water allochthonous debris flow beds underlie the shelf-margin packstone-grainstone facies of the Willis Ranch Member of the Word Formation (3rd Word Limestone Bed of King 1931) (middle Guadalupian, early Wordian), which forms a distinct bench all along the west wall of Gilleland Canyon (114–169m above base of measured section). The uppermost GV-RC1 sample, from 104 m in the measured section, contained the fusulinids Parafusulina sellardsi, P. antimonioensis, P. deliciasensis, P. rothi, P. trumpyi, and P. boesei. SampleGV-CM1, from 83min the section, contained P. sellardsi, P. deliciasensis, P. rothi, P. boesei, and P. lineata. The lowest sample GV-CM20, from 76 m in the section, contained only P. deliciasensis and P. wildei. According to previous studies, most of these species appear in Roadian-aged strata and range upward into early Wordian-aged strata, but the common occurrence of P. sellardsi in the upper two samples, and the occurrence of P. antimonioensis in the uppermost sample confirm an early Wordian age.

Waldentwicklung und flachgründige Rutschungen: eine grossflächige GIS-Analyse

Forest dynamics and shallow landslides: a large-scale GIS-analysis Through continuous and abrupt changes in the forest and particularly in its root area, the disposition for shallow landslides also changes. The aim of this article is to learn more about the relationships between long-term forest dynamics and the risk of landslides with the help of large spatial data sets. A total of 6670 shallow landslides were selected from the natural event register StorMe, the event register of the Canton of Obwalden and the WSL database for shallow landslides and slope debris flows and overlaid with GIS data on the current and former forest situation (Siegfried maps of approx. 1880) and with windthrow areas (Vivian and Lothar). Shallow landslides occurred less frequently in the forest than outside of it at inclinations of less than 35 degrees. Higher landslide densities occurred in coniferous and mixed forests (compared to deciduous forests) and in relatively young forests (ingrown after 1880). Landslides in younger forests occurred on slopes less steep than in older forests. More shallow landslides occurred on former windthrow areas during the first 3 to 17 years after the event, however these landslides occurred on comparatively steep slopes. The analyses show that the disposition towards shallow landslides defined by slope inclination and subsoil can change strongly due to reforestation processes and natural disturbances. Silvicultural interventions may contribute to an improvement of the protective effect in the long term if they are carried out carefully and if they contribute to an increased adaptability to natural disturbances.

Early warning model for slope debris flow initiation

Early warning model of debris flow is important for providing local residents with reliable and accurate warning information to escape from debris flow hazards. This research studied the debris flow initiation in the Yindongzi gully in Dujiangyan City, Sichuan province, China with scaled-down model experiments. We set rainfall intensity and slope angle as dominating parameters and carried out 20 scaled-down model tests under artificial rainfall conditions. The experiments set four slope angles (32A degrees, 34A degrees, 37A degrees, 42A degrees) and five rainfall intensities (60 mm/h, 90 mm/h, 120 mm/h, 150 mm/h, and 180 mm/h) treatments. The characteristic variables in the experiments, such as, rainfall duration, pore water pressure, moisture content, surface inclination, and volume were monitored. The experimental results revealed the failure mode of loose slope material and the process of slope debris flow initiation, as well as the relationship between the surface deformation and the physical parameters of experimental model. A traditional rainfall intensity-duration early warning model (I-D model) was firstly established by using a mathematical regression analysis, and it was then improved into ISD model and ISM model (Here, I is rainfall Intensity, S is Slope angle, D is rainfall Duration, and M is Moisture content). The warning model can provide reliable early warning of slope debris flow initiation.

Warning model study of debris flow slope source starting based on experimental method

To further realize the correlation between rainfall and the starting mechanism of the slope debris flow in the source area of Yindongzi gully, a typical model was selected after a detailed fieldwork and engineering investigation. The rainfall intensity and gradient were set as control variables using 20 large artificial rainfall physical model tests under four gradients and five rainfall intensity conditions to research the instability mechanism and failure patterns of the slope debris flow. The experimental results revealed the starting and failure model of the source of the loose slope and the response relationship of the surface deformation and the underground physical mechanical parameters. Then, a traditional I-D (rainfall intensity-duration) early warning model was established. Next, reliable warning parameters (i. e. gradient and moisture content) were extracted and the exponential model and means of the mathematical regression analysis were used to determine the IGD and IGM multi-parameter forecast model, while the traditional model was effectively modified for dependability and practical utility.

A Detail on Landslide & its Types

The term landslide or, less frequently, landslip, refers to several forms of mass wasting that include a wide range of ground movements, such as rock falls, deep-seated slope failures, mudflows and debris flows. Landslides occur in a variety of environments, characterized by either steep or gentle slope gradients: from mountain ranges to coastal cliffs or even underwater, in which case they are called submarine landslides. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability which produce specific conditions that make a slope prone to failure. In many cases, the landslide is triggered by a specific event (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable.

Identification of Slope Debris Flow Based on Fisher Discriminated Criterion

On the basis of analyzing formation condition of slope debris flow, optimize four indexes as the discriminated factors: the loose material reserves weighted by area (),effective particle size of the loose material ,geomorphic super entropy (),meteorological and hydrological index which is composed of indirect and direct antecedent precipitation and short duration rainfall (),use the basic data of slope debris flow in Beishan of Longnan City, build the Fisher discriminated analysis model , find out the discriminated function of debris flow and non-debris flow on slope is,critical value is 1.305,give the new method of identification on the slope debris flow.

日本の山地斜面における豪雨に起因した斜面崩壊・土石流の発生頻度

日本の山地斜面における豪雨に起因した斜面崩壊・土石流の発生頻度

平成21年7月に山口県防府市で発生した土砂災害における源頭部崩壊と土石流の状況とその地形的特徴

平成21年7月に山口県防府市で発生した土砂災害における源頭部崩壊と土石流の状況とその地形的特徴

The Preliminary Study on Definition of Slope Debris Flow

So far, the definitions of slope debris flow are cinders and divergent, even, some scholars equate it with the hill slope debris flow/landslide-induced debris flow and other similar terms. This article summarizes research on the slope debris flow, from the definition and classification of debris flow, study on the classification of slope debris flow , analyzes the formation conditions, properties and characteristics of slope debris flow, at last, use the definition method of attribute and kind, tentatively give the preliminary definition of the slope debris flow .

Assessment of secondary mountain hazards along a section of the Dujiangyan-Wenchuan highway

Conducting a hazard assessment for secondary mountain hazards is the technical basis for reconstructing destroyed highways and for disaster prevention. It is necessary to consider the role and influence of structural engineering measures as an important assessment factor. In this study, based on six substantial field investigations conducted between July 2008 and July 2012, a 2 km wide zone along both sides of the Dujiangyan-Wenchuan (Du-Wen) Highway was selected as the study area. Microgeomorphic units and small watersheds in the study area were extracted with GIS software and used as basic assessment units. Through field investigations, remote sensing surveys and experimental analysis, a structural engineering effectiveness assessment was conducted using the technique of principal component analysis. The results showed the following: 1) A total of 491 collapses, 12 landslides, 32 slope debris flows and 17 gully debris flows were scatted across the study area. The total overall areal density of all mountain hazards was 25.7%. The distribution of secondary hazards was influenced mainly by seismic intensity, active fault zones, lithology, slope and altitude. More than 70% of secondary hazards occurred in zones with a seismic intensity of XI, a distance to the fault zone of between 0 and 25 km, a slope between 25° and 50°, and an altitude of between 1,000 m and 1,800 m. 2) Different structural engineering measures play different roles and effects in controlling different types and scales of secondary mountain hazards. 3) With a secondary mountain hazard area of 128.1 km2 and an areal density of 34.9%, medium, high and very high hazard zones accounted for 74% of the study area and were located on the high, steep slopes along both sides of the highway. The low hazard zone was located mainly in the valley floor, on gentle slope platforms and at locations 1.5 km away from the highway ? the hazard area was 45 km2 and the areal density was 3.3%. 4) The methodology for hazard assessment of secondary mountain hazards, which is based on five factors, solves such key technical problems as the selection of assessment units, multi-source data fusion, and the weight calculation for each assessment index. This study provides a new and more effective method for assessing secondary mountain hazards along highways, and the proposed models fit well with validation data and field observations. The findings were applied to reconstruction and disaster mitigation in the case of the Du-Wen Highway and proved to be feasible.