Papers by Keyword: Slope Stability

Abstract: The Jeneberang watershed area is known for being susceptible to landslides. A field survey conducted in the Jeneberang watershed basin revealed that the slopes of andesite rock inclined up to 66°. Additionally, the rocks forming the slopes were found to be jointed. It is necessary to analyze slope stability and potential landslides at the study site. Some of the required data for this study include geological conditions, slope geometry, physical and mechanical properties of the rock from laboratory tests, and previous research findings. Slope modeling was conducted using Bishop’s limit equilibrium method in the Slide software to determine the Safety Factor (FS) value. Additionally, the Dips software was used to perform kinematic analysis and identify the type of landslides via stereographic projections. The slope is made up of andesitic and igneous rocks based on the analysis. The kinematic analysis of the stereographic projection results suggests that landslides on the research slope will occur in the direction of N 302° E. The type of slide that can occur on the slope is a plane (planar) type of slide. The safety factor of 4.1 indicates slope stability at the site, with little chance of sliding.

Abstract: Landslide is a major geological hazard and poses high risk to most countries in the tropical regions. This problem is more severe in places like Malaysia where residual soil is abundant. High temperature and humidity will easily disintegrate soil particles and therefore loosen the bonding between the soil and the root system. The main goal is to elucidate the interaction mechanism of bio-inspired soil anchorage system to enhance bonding between residual soil matrix in tropical region. Hence, this research aims to establish correlation between the pattern of root and its tensile strength to reinforce tropical residual slope. Basic soil property tests and classification protocols were carried out in the laboratory. Root tensile test results from the laboratory was correlated with field pull-out test data. Slope stability in the area where the plant roots were introduced have been disturbed. The factor of safety of slope with bio-anchorage system was one third of the slope with grass. The findings provide the best solution from the bioinspired soil anchorage system for tropical slope. Hence, the plant species that works well in residual soil for the purpose of reinforcing tropical slope was identified and recommended. As a result, many serious landslides and slope failures in residual soil could be avoided in the tropical region. Therefore, slope stabilization technique such as the bio-inspired soil anchorage system once established can reduce the dependency on conventional concrete wall.

Abstract: Numbers of large scale polders are constructed to protect low-lying coastal area of Sundarban in Bangladesh during 1960s. At present, there are number of polders occupying an area of about 1.2 million hectares, which are vulnerable to breach and cause immense misery to millions of people every year. The purpose of this study is to assess the safety factors (FoS) of those Polder embankments during diurnal tidal cycle in coastal area and provide solution to improve the stability of embankment through installation of geogrid layers. To investigate vulnerability of the embankment failure, soil samples are collected from several borehole locations in Satkhira, a coastal site of Sundarban area. Field test—SPT and several Laboratory tests—direct shear test and Sieve analysis test have been carried out to determine shear strength, angle of internal frictions and grain size distribution. Slope stability analysis are performed using Geo5 software under several conditions—high water table (HWT), low water table (LWT) and rapid drawdown (RD) with side slope are 1:1, 1:1.5 and 1:2 and embankment height are 5m, 7.5m and 10m. The safety factor has been found lowest at rapid drawdown condition because of rapid recession of external water level. The lower FoS have been found 0.68, 0.89 and 0.92 which can be improved to 1.23, 1.34 and 1.24 respectively by installing several geogrid layers. Simplified Bishop Method have been used in Geo5 to perform the stability analysis under various conditions. In our investigation, HDPE biaxial geogrid have been taken to strengthen of polder embankments, which are timesaving, cost effective and efficient, side by side suitable for Sundarban area. The findings and solutions proposed by the study will help geotechnical engineers to reduce the vulnerability of Polder embankment under similar coastal conditions.

Abstract: In this paper, the material characteristics of field applied green slope soil for the development of vegetation shotcrete using mineral additive are evaluated. And, the effect of the moisture content of fertilizer on properties of the shotcrete soil using the mineral additives are investigated. From the results, it was found that when the compaction level increase, soil hardness and soil strength are increased. Moreover, after a certain level of consolidation is proceeded, soil hardness and soil strength are not affected by ages. However, in order to ensure slope stability, the cohesion of the field applied soil should be improved. When the mineral additive is mixed as a green shotcrete soil materials, it could be attributed to the increment of adhesion between green slope soil and slope face. And, when the moisture content of fertilizer increases, the soil hardness and soil strength is decreased. The moisture content of fertilizer increases, shrinkage decrease at early ages, however, shrinkage increased with ages. The optimum moisture content of fertilizer was about 60% from the view point of shrinkage and soil hardness of green shotcrete soil.

Abstract: In this paper, the variation of safety factor of unsaturated soil slope with temperature and matric suction was simulated. The simulation was performed using modified ordinary method of slices for unsaturated soil slope including temperature and suction effects. The expression for factor of safety of unsaturated soil slope at elevated temperature under undrained condition was derived. The ranges of temperature and suction in simulation were 25 to 60 degree Celsius and 0 to 100 kPa, respectively. The simulation was performed using soil parameters presented in literature. The simulation results shows the variation in factor of safety of soils slope with matric suction and temperature. The factor of safety of soil slope with circular failure surface increased with increasing matric suction for all values of temperature but decreased with increasing temperature for all values of matric suction.

Abstract: Slope stability analysis is one of the ancient tasks in the geotechnical engineering. There are two major methods; limit equilibrium method (LEM) and finite element method (FEM) that were used to analyze the factor of safety (FOS) to determine the stability of slope. The factor of safety will affect the remediation method to be underdesign or overdesign if the analysis method was not well chosen. This can lead to safety and costing problems which are the main concern. Furthermore, there were no statement that issued one of the analysis methods was more preferred than another. To achieve the objective of this research, the soil sample collected from landslide at Wang Kelian were tested to obtain the parameters of the soils. Then, those results were inserted into Plaxis and Slope/W software for modeling to obtain the factor of safety based on different cases such as geometry and homogenous of slope. The FOS obtained by FEM was generally lower compared to LEM but LEM can provide an obvious critical slip surface. This can be explained by their principles. Overall, the analysis method chosen must be based on the purpose of the analysis.

Abstract: Slope stability is very important on designing a safe slope. If this were to be taken lightly by the engineer, major disaster will occur that results in lost of lives. Each engineer is responsible to evaluate all aspects of design, especially when designing a slope gradient on the surface of soft clay. Soft clay containing high water content and if not planned properly, water from the soft clay will seep into the slope and causes reduction in soil strength. The purpose of this research was to investigate the effect of water absorption of soft clay on the stability of the slope. The objectives of this study were to analyze the soil strength when the soil were soaked in water to a set of different time range and to analyze slope stability on soft clay based on the infiltration of water from underground using PLAXIS software. In this study, soil samples were taken and laboratory experiments were carried out to obtain the unit weight, cohesion, and friction angle of the soil samples. The experiments involved were grain size analysis test and unconfined compression test. Data from the experiments will be used in PLAXIS software to obtain the factor of safety.

Abstract: Peridynamic simulations have been carried out to perform the slope stability analysis. A slope is first modelled with discretized particles in 2D. Then the non-ordinary state-based Peridynamic model is utilized. In order to obtain a more realistic behavior of the soil, Drucker-Prager constitutive model is used to describe the mechanic properties of soil. Results show great agreements with the FEM results, while provides the dynamic slide progress in the post-failure process.

Abstract: This paper presents a numerical study that performs the stability of slopes on bedrock reinforced with single pile row at different locations. The slope is formed of top sliding soil layer that underlies over rock. The numerical analysis has been implemented by employing the three dimensional analysis using FLAC3D. The results indicate that as the pile location is moved towards the slope crest the displacement increases.In the single row of pile application, the factor of safety reached its maximum value when the pile located at the top middle of the slope. Considering the failure mode the results has conclude three failure modes; above, in front, and through the pile according to the location of the pile. Failure mode is also affected by socketed length of pile in bedrock layer. It is believed that the findings of this study contribute to the engineers performing slope stability analysis in practice.

Abstract: Main goal of this article is to introduce an used methodology of analyses for excavation of surge tank enlargement of HEC MATKA1. The way of combining of the methods for analyses of discontinual and continual media are explained. The main information’s about existing geological and geotechnical properties are also given, as a basis for analytical and numerical analyses. Some of the results from the stability analyses of structural controlled instabilities during excavation of water tank are presented. The newly secondary stress – deformation state as a result from enlargement (excavation) is analysed with program Z-SOIL.