Landslide Problems Research Articles

Numerical modeling of earthquake-induced landslides using updated Lagrangian nonlocal general particle dynamics method

Developing a robust numerical method to model earthquake-induced landslides has long been a persistent challenge in the field of computational geotechnical engineering. Recently, the meshless methods based on nonlocal theory have piqued the interest of researchers. However, the application of nonlocal theory in seismic analysis is currently limited. This paper proposed a numerical framework based on the updated Lagrangian nonlocal general particle dynamics (UL-NGPD) method to analyze earthquake-induced landslide problems. The UL-NGPD method benefiting from the update support domain can capture the whole process of slope run-out induced by earthquakes. To enhance the numerical stability of the proposed method, several optimizing strategies are proposed. In the current framework, the seismic waves are input through the proposed boundary treatments of nonlocal form. Besides, a nonlocal friction model with velocity-weakening is proposed to accurately simulate the movement process of soils on a rocky sliding bed. The proposed framework is validated by the simulations of several classic problems, including the collapse of sand and the shake table test. The performance of the proposed approach is further demonstrated through simulating the landslides induced by earthquakes. The numerical results consistent with recorded data indicate that the UL-NGPD method has an excellent capacity to deal with earthquake-induced landslide problems.

GIS-based MCDM approach for landslide hazard zonation mapping in east Gojjam zone, central Ethiopia

Landslides are prevalent in the Ethiopian highlands, particularly in the east Gojjam zone, which is highly affected by landslide problems. This research was carried out in the east Gojjam zone, northwestern Ethiopia. The study area is part of an economically important area in the country, and it is the main source of water for the Grand Ethiopian Renaissance Dam (GERD). The main objective of this work was to undertake a detailed inventory of past landslide locations and prediction of present and future landslide hazards, as well as the preparation of a landslide zonation map in the East Gojjam zone by using the Analytical Hierarchy Process (AHP) with the GIS technique. The parameters used for this study were slope degree, slope aspect, land use and land cover, road proximity, rainfall, lithology, altitude, and river proximity. The various causative parameters were collected from the field, and suitable modifications were made to the thematic maps. Finally, the ratings for various parameters were used as the basis to prepare the LHZ map in GIS windows. The landslide susceptibility and inventory mapping were produced in the GIS environment. The results of the study show that the main driving factors for the landslide hazards in the area were river proximity, rainfall, and manmade activities. Validation of this LHZ map revealed that more than 80% of past landslides match within the "high hazard zone" and reasonably accepted the rationality of the adopted methodology. The considered parameters, as well as their evaluation of the production of LHZ-Map, were confirmed. The produced landslide inventory map is very important for urban planners, agricultural studies, environmentalists, and future landslide hazardous prevention and mitigation strategies.

A Systematic review of machine learning based landslide susceptibility mapping

The landslide problem is one type of geohazard which damages both economic and human life loss. This problem needs awareness and creating zonation’s to prevent its effect. This study reviews in locations Brazil, India, China, Italy, Turkey, Denmark, Vietnam, Iran, Bhutan, Pakistan, Peru, and Ecuador. These countries are facing landslide problems because their topography is more hilly terrain types. During the studies, different criteria are set to review articles published in the last 5 years from 2018 to June 9, 2023. The research is more focused on a machine learning model to map landslide problems in these selected areas. A field survey is used to validate this landslide susceptible mapping results. Future researchers utilizing machine learning methods to map the area's susceptibility to landslides will benefit from this research. Deep learning and ensembled machine learning will give good results for more datasets.

SOSIALISASI SISTEM AGROFORESTRI UNTUK MENINGKATKAN KESUBURAN TANAH DAN PENDAPATAN MASYARAKAT DESA WAAI KECAMATAN SALAHUTU MALUKU TENGAH

Waai Village in Salahutu District, Central Maluku, is an area with diverse topography which poses challenges for agriculture and fisheries, such as soil erosion and landslides. To overcome this problem, an agroforestry system is implemented as a sustainable land management solution. This research aims to socialize and evaluate the implementation of agroforestry in Waai Village, with a focus on reducing erosion, increasing soil fertility, and diversifying community income. The implementation method involves lectures, presentations, practical training, and distribution of plant seeds. This activity was carried out on 11-12 August 2023 by the Forestry Study Program, Faculty of Agriculture, Pattimura University with the participation of the local community. An initial survey was conducted to understand soil conditions, slope and community knowledge about agroforestry. Lectures and presentations provide basic information and techniques for implementing agroforestry, while practical training introduces vegetative methods in growing agroforestry crops. The results of the activity show that the community has a high interest in implementing agroforestry, with a significant increase in understanding and skills. The evaluation shows a good level of satisfaction and strong commitment from the community to develop agroforestry systems. The implementation of agroforestry is expected to reduce erosion, increase soil fertility and diversify people's income through high-value products such as wood and fruit. Agroforestry offers an effective solution to overcome the problem of erosion and landslides in Waai Village, while improving the economic welfare and food security of the community.

Comparative study between active and passive soil nailing using PLAXIS software

Abstract Many researchers have proposed several solutions to minimise the landslide problem. One proposed solution is stabilising the slope by installing nail reinforcement through simulation analysis in PLAXIS software. The study aims to analyse the stability of nailed slopes in two different types of parameters by using numerical study. The result of the parametric study was performed at various effects of moisture content and slope angle. Mohr-Coulomb and Hardening Soil models were adopted to analyse the behaviour of soil failure subjected to loadings condition of moisture content and slope angle effects. The finding results regarding the slope stability (FOS) study show that values of the FOS decreased as the slope angle and moisture content increased. This can be seen during the Mohr-coulomb model for passive soil nail system, that the FOS of moisture content at 7.1 % is 1.107, while the FOS of moisture content at 25 % is 1.063. The finding also shows that the active soil nail system is better than the passive soil nail system. This can be seen when the highest value of FOS in the Mohr-Coulomb model for active soil nail is 1.336 at 7.1 % moisture content, while passive soil nail has a FOS value of 1.107 at 7.1 % moisture content. The significance of the study has also impacted preserving the original geometry structure of nature, while people can enjoy the scenery. It also can be beneficial in terms of the cost-effectiveness of soil for nailed structures to prevent unnecessary problems in the future.

Erosion in the coastal areas of the Vietnamese Mekong Delta: Current challenges and solutions

Coastal erosion is one of the types of geological disasters that is occurring quite commonly and seriously in the Mekong Delta. The problem of landslides and erosions is one of the major concerns for coastal stability. Currently, along 9 coastal provinces, there are over 115 serious erosion and landslide points; each year, a total of 300 –500 hectares of coastal land can be lost. Erosion and landslides narrow the area of mangrove forests, residential land, and aquaculture land of local people. The Mekong Delta has to spend billions of VND yearly to build breakwaters and sea dikes and restore mangrove forests. Many structural and non-structural measures have been implemented to reduce the risk of erosion over the past two decades. However, there is not much assessment of the sustainability of landslide prevention projects. The research question is what are the challenges and difficulties in the ongoing fight against erosion in the coastal plain. Through a practical approach from surveying works in coastal areas, the results show that choosing an effective solution depends mainly on the cost factor and the terrain of the ground. Water resource management policy on the Mekong River system is difficult to find a satisfactory answer.

INTERFACE SHEAR STRENGTH DEGRADATION IN PROGRESSIVE LANDSLIDE OF WEATHERED CLAY SHALE OVERBURDEN ON UNDISTURBED CLAY SHALE

In accomplishing Sustainable Development Goals (SDGs), the construction of roads played a substantial role in achieving economic equity. However, landslides due to problematic soil would hinder its construction process. Thus, it is essential to understand the mechanism of slope movement to reduce landslide problems. A landslide that happened during the construction of the Semarang-Bawen toll road was analyzed in this research. The landslide was known to fail between the interface of the tuff breccia overburden and the problematic clay shale soil. This research proposed the direct shear test to determine the interface shearing behavior. Before the test, the overburden was differentiated as various sand and weathered clay shale ratios. After the overburden soils were compacted, a multistage interface direct shear test was conducted with three different loadings. Water was added to the overburden layer to model the infiltration at the interface by increasing the water content. From the test, results such as the interface cohesion, friction angle, and average stress ratio were obtained. Overall, the interface shear strength decreased as the water content increased. The decreasing value was due to the wetting at the interface. Thus, it would moisten the interface and disrupt the structure of both the top and bottom layers of the sample. In conclusion, the interface direct shear test was able to describe the shear behavior at the clay shale interface. It also indicated that water had a considerable role in triggering interface landslides for two different soil layers.

Ground Water of Himalayan Region, Due to Landslides Impact on Himalayan Folk Life

Looking at the life of the Himalayan people, the ground water level there is continuously decreasing. The problem of landslides is affecting the life of the people there. The speed with which the perennial streams are drying up, the Himalayan people life is in danger due to disasters, due to which the solution is very important. Geologists are conducting surveys from time to time to clarify the cause of landslides and drying up of streams. There are indications of a serious accident. Due to the rivers originating from the Himalayas, the pressure of water and sediment increases, due to which the pressure on the slopes also increases, whereas the rivers of the Western Ghats have less sediment as compared to the Himalayan rivers.

Optimasi Geometri Lereng dengan Evaluasi Nilai Faktor Keamanan Menggunakan Software Geostudio

The slopes of the Widas watershed in Kutorejo Village, Bagor District, Nganjuk Regency were hit by a landslide, damaging a 50-meter-long road. This damage has an impact on the activities and mobility of residents. The impact of landslides caused enormous losses, both infrastructure damage and loss of life. Several studies have been carried out, in determining slope stability it is necessary to observe at the research location and determine the type of soil, soil consistency, and soil shear strength parameters. This research aims to determine the value of the safety factor (FK) on the slopes of the Widas River. This research began by conducting a case study, including interviews, collecting field survey data, taking soil samples, and laboratory testing. Slope stability analysis was carried out using Geostudio software. The research results show that the soil type is classified as Poorly Graded Sand (SP), and the soil consistency is classified as Non-Plastic soil with a liquid limit of 26.093 and a shear angle of 20° - 30°. Slope improvements were carried out by changing the slope geometry until a slope ratio of 1V:2H was obtained by creating two slope core models. The FK value increased from 1.007 to 1.107 and 1.437 to 1.585 under pore water pressure conditions. Thus, the slope modeling obtained can be used to overcome landslide problems.

Investigation of the Impact of Leaching Agent Concentration and pH on the Stability of Agglomeration of Ion-Absorbed Rare Earth Deposits

Ion-absorbed rare earth deposits react with the leaching agent during the in situ leaching process through ion exchange and hydration, which change the stability of ore agglomerates and even result in mining slopes or landslides. Indoor simulated column leaching assays were conducted on ion-absorbed rare earth deposit samples by using magnesium sulfate solution as the leaching solution. Surface zeta potential, double electric layer thickness, particle gradation, and pore structure were analyzed to measure the different concentrations and pHs of leaching solutions’ impact on the stability of ore agglomerates. Results show that the critical magnesium sulfate solution concentration and pH affecting the stability of deposit sample agglomerates are 3.5% and 4, respectively. The chemical replacement reaction between the leaching agent and rare earth ions occurs during column leaching when it reaches its zero-point potential at a pH of 3.5168. This breaks the balance between the van der Waals gravitational force and double-layer repulsion in clay particles and induces the disruption of agglomerates, which causes the difference in the pore radius ratio of the ore samples before and after column leaching. It is of great engineering guidance to solve the problems of slope instability and landslides that may occur in the ore body during the mining process of ionic rare earth ore.

EPS-Geofoam as Lightweight material for Replacement of Embankment Fill to Overcome Landslide Problems at STA 40+200 of Cisumdawu Toll Road, West Java

Toll Road construction takes a vital role to connects cities in Indonesia. Cisumdawu toll road which is constructed to connects Cileunyi, Sumedang and Dawuan, pass through a complex geological formation and suffers a number of slope failures during construction. At STA 40+200, the toll road is constructed by using 20m height embankment by using local soil. Prior to reaching the final elevation, significant land movement was observed. In order to rehabilitate the embankment, the fill is excavated in order to reduce driving loads acting on the sliding plane and EPS geofoam is used as lightweight material to replace soil fill in order to reduce the driving forces acting on the soil. In this paper, the mechanism of slope failure and discussion on the EPS-Geofoam and pavement system employed to solve the slope failure problem will be discussed.

An integrated geotechnical and geophysical investigation of landslide in Chira town, Ethiopia

Landslides pose a significant threat to infrastructure, property, and human lives in many regions worldwide, including Chira town in Ethiopia. This study presents an integrated geotechnical and geophysical investigation aimed at identifying the contributing factors to landslides in Chira town, Ethiopia, with a focus on a recent landslide event. The methodology employed a combination of geotechnical and geophysical techniques to comprehensively analyze the landslide problem. The geotechnical investigation involved a detailed analysis of the soil characteristics in the area, including the composition of fine-grained soil and the determination of cohesion and angle of internal friction through triaxial testing. The geophysical investigation utilized electrical resistivity tomography to assess the subsurface soil profile. The findings revealed the presence of a massive basaltic tertiary volcanic rock layer underlying a very low resistivity layer of sticky clay soil. Through this study, it was established that rainfall, soil type, land use, elevation, and proximity to streams, slopes, and aspects were the main factors contributing to the landslide, accounting for 22.03%, 18.89%, 15.75%, 15.46%, 10.87%, 9.7%, and 7.5% of the overall influence, respectively. Based on these findings, the study proposes a range of interventions to enhance resilience against landslides, including surface drainage, the implementation of appropriate land use management practices, and the introduction of vetiver vegetation. The integration of geotechnical and geophysical methodologies provided a comprehensive understanding of the landslide problem in Chira town. The proposed interventions aim to inform future land use planning, infrastructure development, and disaster risk reduction efforts in the region. By expanding our knowledge of the mechanisms driving landslides, this study offers valuable insights that can be utilized in similar regions facing comparable geotechnical and geophysical conditions.

An implicit 3D nodal integration based PFEM (N-PFEM) of natural temporal stability for dynamic analysis of granular flow and landslide problems

The particle finite element method (PFEM) is a robust approach for modelling large deformation problems with free surface evolution. The classical PFEM, however, requires variable mapping from old to new quadrature points when adopting history-dependent material models in granular flow and landslide problems. Although the nodal integration technique circumvents this issue, it makes the PFEM temporal instable in dynamic analysis when using a displacement-based formulation. In this study, we developed a new version of a three-dimensional (3D) Nodal integration based PFEM (N-PFEM) using a mixed variational principle with the final problem resolved in mathematical programming. The proposed N-PFEM not only inherits the benefit from the nodal integration scheme that no variable mapping is required for handling history-dependent models but also is naturally temporal stable requiring no ad-hoc stabilization technique. We simulated a series of benchmark problems to demonstrate its nature of temporal stability as well as other admirable features such as the volumetric-locking free property and capability for tackling extreme configuration changes. Additionally, its application to a 3D landslide with a sensitive clay layer is shown to highlight its robustness.

Experimental Studies on Some Clays Leading to Instability

The landslide problem in the city of Constantine (Algeria) is mostly due to clayey soil, which is covering the whole area. Therefore, all the structures and foundations built over such soil are quite vulnerable. The sensitivity of this soil increases during the rainfall season, which might reach an extreme magnitude and cause damage to the structures. To understand some aspects of the failure of the mentioned soil and its mechanism, a large campaign of geotechnical characterization was undertaken using samples from the area. The specific gravity, Atterberg limits, and coefficient of lateral earth pressure at rest were determined. Samples were tested in triaxial stress path cells over a range of stresses, with the test being either stress- or strain-controlled, leading to sliding phenomena under different stress levels. The clays can be classified as over-consolidated soils. The test program and the characterization study indicated that Kois directly related to the stress history of the soil and also dependent upon the state of the sample before the test (i.e., undisturbed or disturbed). The clay minerals in the Mio-Pliocene landslide zones in Constantine are mostly montmorillonite and kaolinite, which have the lowest frictional resistance. As the montmorillonite content increases, the angle of internal friction decreases. The present study focuses on the critical state analysis since all the behavior problems of these tested samples show a peak shear strength, which is characteristic of over-consolidation materials that could lead to instability in this area. Doi: 10.28991/CEJ-2023-09-02-012 Full Text: PDF

Factores exógenos en la evaluación de rentabilidad de proyectos de inversión para gestión de carreteras

In recent years, of the 31 Public Private Associations (APP), developed by the MTC, more than 100 addenda have been accepted. Only in 15 road APPs, they presented more than 60 addenda; Of which 22 corresponded to the Initiative for the Integration of the South American Regional Infrastructure (IIRSA) due to problems of landslides and soil erosion, not foreseen in the project. That is why by integrating exogenous factors into the methodology for evaluating the profitability of investment projects, synergies and hierarchies are determined that shorten the gap between projected and executed costs. For this reason, the profitability of these projects, evaluated on the invierte.pe platform, (formerly SNIP) using financial factors such as VAN and IRR, but does not consider exogenous actors in the area of influence such as rain, forests, soils, populations, etc., that affect the social profitability of the project. In addition, the unmeasured factors are not manageable during the execution and service time of the work.

Multi-storey precast retaining walls to prevent landslides: derivation of the basic formula

Landslides can involve both large and small soil masses. Many geotechnical researchers focus on large-scale landslide problems. The retaining walls required for large landslides also involve large dimensions. The national standards also only cover the dimension of retaining needed to prevent large landslides. There are landslides that only involve small masses of soil. For this reason, the needed retaining walls are also in small dimensions. Small retaining wall dimensions do not need to follow national standards for maintaining the efficiency and effectiveness of application. In this paper, a precast retaining wall is designed which is used to retain soil on a relatively small scale. The designed retaining wall can be used also in multi-level to restrain the larger landslide. There are three main elements of the retaining wall: base plate, wall plate, and connector beam. The retaining wall elements are made of concrete material with bar reinforcement and wire mesh. The weight of each wall element is less than 50kg so it is portable. The wall prototype has been made and is ready to be applied in the areas with potential landslides.

Machine learning and landslide studies: recent advances and applications

Upon the introduction of machine learning (ML) and its variants, in the form that we know today, to the landslide community, many studies have been carried out to explore the usefulness of ML in landslide research and to look at some classic landslide problems from an ML point of view. ML techniques, including deep learning methods, are becoming popular to model complex landslide problems and are starting to demonstrate promising predictive performance compared to conventional methods. Almost all the studies published in the literature in recent years belong to one of the following three broad categories: landslide detection and mapping, landslide spatial forecasting in the form of susceptibility mapping, and landslide temporal forecasting. In this paper, we present a brief overview of ML techniques, provide a general summary of the landslide studies conducted, in recent years, in the three above-mentioned categories, and make an attempt to critically evaluate the use of ML methods to model landslide processes. The paper also provides suggestions for future use of these powerful data-driven techniques in landslide studies.

Multiscale nonlinear analysis of failure mechanism of loess-mudstone landslide

The sliding mechanism of loess landslides is unique and complex; a single-scale and linear mechanical model cannot describe their failure process scientifically, thus necessitating a multiscale and nonlinear research idea. In order to monitor and observe the whole failure process of loess landslide more conveniently, a physical model test (2.0 × 0.6 × 1.5 m) is designed to simulate the landslide failure process under rainfall condition. Twelve pore water pressure sensors and twelve soil pressure sensors were arranged in three loess layers, and were used to record the numerical variation characteristics of pore water pressure and soil pressure during the failure process of Landslide physical model. The results show that, the failure process of loess landslides and the data from sensors are very random, making it impossible to use a single-scale or linear mechanical model to analyze their mechanics. However, we can well describe the failure process of loess landslide through the micro, meso, and macro scales. Therefore, the mechanical problems of loess landslides should be analyzed from six aspects, including the liquid bridge, force chain, soil mechanics test, a physical model, real landslides, and tectonic stress. In the future, nonlinear and multiscale research ideas can make loess landslide studies more scientific and effective.

Landslide vulnerability of the Debre Sina-Armania road section, Central Ethiopia: Insights from geophysical investigations

Geophysical investigations using 2D electrical imaging and magnetic methods have been conducted to study the landslide problem on the road located at Dokakit Kebele near Sar Amba Kidane Mhiret locality between Debre Sina and Armania towns in Central Ethiopia. From field observations, the landslide problem in the Debre Sina-Armania road section at Dokakit is due to a combination of factors, the most important of which are topography, the high degree of weathering, hydrology of the area, and human activities. Among these factors, human activities that include deforestation for housing, agricultural activities, search for building materials, and road construction are generally assumed to be the triggering factors for slope failure in the area. From the interpretation of the geophysical results, the near-surface geology of the study area is found to be composed of massive deposits of fragmented basalts and structurally disturbed layers together with expansive clay soils, which considerably contribute to the sliding problem. Another contributing factor to the subsurface instability is the high gradient slope in the area and the lack of vegetation/wooded tree cover. From the geophysical survey results, it has further been possible to map zones of weakness in the subsurface over which the geologic layers slide as well as their vertical and lateral extents. Areas of active sliding surfaces and extensive subsurface cracks, especially at the two ends of the profiles, were mapped. A combination of numerous weak zones, deep weathering conditions of the lithologic units, the action of rainfall, springs, and the high slope gradient of the study area were the contributing factors for this sliding problem. Remedial measures to stabilize a section of the affected area and construction of a detour road are proposed as mitigation measures for the road segment's recurrent and rather expensive failure over the locality.

Determination of Shear Strength Parameters by Multistage Triaxial Tests in the Long-Term Analysis of Slopes

Accurate determination of soil parameters is of great importance in the analysis of landslides, which is a common type of natural disaster. In the solution of landslide problems, the direct shear box test is generally preferred as a laboratory test type for the determination of the shear strength parameters of soils. However, the need for drained parameters in long-term problems reveals a disadvantageous aspect of this experiment, especially in clayey soils, because pore water pressures cannot be measured in the direct shear box test, which is widely used in the laboratory to determine the shear strength of the soils.Multistage triaxial compression tests used to obtain shear strength parameters in the laboratory are advantageous compared to conventional triaxial compression tests because of the time and financial concerns, as well as the avoidance of differences between the samples to be tested. In this study, a new method was tried in addition to the methods used to obtain shear strength parameters with consolidated-drained multistage tests in normally consolidated clayey soils and the results were promising. Thus, since it increases the usability of multistage tests, it will be helpful in terms of preventing possible disasters by enabling analysis in many more sites.