scholarly journals The Effect of Initial Groundwater Table and Rainfall Wetting Towards Slope Stability (Case Study of Landslide in Tangkil Hamlet, Banaran Village, Pulung Subdistrict, Ponorogo Regency)

2019 ◽  
Vol 5 (2) ◽  
pp. 149 ◽  
Author(s):  
Diana Ariesta

Landslide is a natural phenomenon that can be controlled by a combination of various factors, such as topography, lithological condition, geological structure, water table, etc. Landslide is stated as a natural disaster if it causes casualties, direct losses and subsequent impacts of the initial destruction, as happened in Banaran Village, Ponorogo Regency. This study is aimed to examine the effects of initial groundwater table conditions and rainfall wetting on Banaran Village landslide. This study was conducted by assuming scenarios of initial groundwater table conditions. Soil parameters were obtained by testing soil samples in the laboratory. Infiltration parameters were acquired through permeability tests using the Philip-Dunne method, while areal rainfall was calculated using the Thiessen polygon method. In addition, slope stability modeling was calculated by using SLOPE/W while rainfall wetting analysis was carried out through SEEP/W. The analysis of Banaran Village landslide through these two numerical models was conducted by considering two conditions: 1) without rainfall and 2) with rainfall and infiltration. The analysis results imply that the landslide occurred in the initial groundwater table condition in scenario 3 with a safety factor of 1.008, and in a similar scenario with a safety factor of 0.973 when taking into account rainfall and infiltration. The results from SEEP/W and SLOPE/W indicate that the initial condition of the groundwater table highly influenced the decrease of the safety factor, while the wetting process did not cause a significant decrease of the safety factor.

2021 ◽  
Vol 248 ◽  
pp. 03024
Author(s):  
Yuan Zhang ◽  
Haifeng Lu

Taking a homogeneous double-layer soil slope as an example, the SEEP/W module and SLOPE/W module in the finite element analysis software GeoStudio were used in this paper. Then, the changes of pore water pressure and stability under different rainfall patterns and soil parameters were studied. Finally, the variation curves of pore water pressure and slope safety factor with rainfall time were obtained. The results show that: Soil parameters a and m are directly proportional to the slope safety factor, while n is inversely proportional to the slope safety factor. Under the condition of continuous rainfall, the decreasing rate of slope safety factor is directly proportional to the rainfall intensity.Under different rainfall patterns, the continuous rainfall in the advanced and normal rainfall patterns will cause the slope stability to decline and then gradually recover, while delayed and averaged rainfall patterns rainfall will cause the slope stability to decline continuously.In addition, there is a lag period in the change of slope safety factor, and the whole lag period lasts about 6 hours. During the lag period, the pore water pressure inside the soil began to decrease, while the slope safety factor continued to decrease. The safety factor starts to recover after the lag period ends.


2012 ◽  
Vol 575 ◽  
pp. 70-74 ◽  
Author(s):  
Ying Xia Huo ◽  
Hong Fei Zhai

Slope stability represents an area of geotechnical analysis in which finite element method provides a lot of benefits over limit equilibrium. In this paper, the authors apply a finite element code, PLAXIS, on slope stability analysis with various conditions to state out sensitivities of not only the soil parameters, slope configuration and groundwater condition but also numerical condition that one would encounter when making a FE slope design. It demonstrates that slightly conservative safety factor is obtained using FEM over the ones from limit equilibrium method. Intensity of mesh for simulation domain shall be selected as a fine level for an acceptable accuracy and economical computation time. Element nodes slightly affect the result of safety factor and final deformation of the slope.


2021 ◽  
Vol 778 (1) ◽  
pp. 012018
Author(s):  
D W Apriani ◽  
U Mustofa ◽  
M Azhary

Abstract Slope stability analysis was carried out in the Institut Teknologi Kalimantan which is an area with educational facilities that have a high risk of soil movement. The research area consists of slopes that often reported landslides, especially during the rains time. Evaluation is carried out to the important factors that affect slope stability such as slope geometry consist of 23 zones, soil parameters consist of 7 drilling holes, and past landslide occurrence. Slope stability was evaluated using back analysis based on soil parameters under critical conditions and field investigation and slope geometry using SLOPE/W software to obtain the safety factor (SF) of a certain slope. Landslide vulnerability maps are created based on the risk and potential landslide or landslide occurrence. Based on the results of the stability analysis, there are 6 zones with unstable conditions and a high potential for landslides and 4 zones in critical conditions with moderate landslide potential. The modeling also shows that in the same soil parameter value with a steep slope, the value of the safety factor is getting smaller. This means that the potential for soil movement is greater. Besides, the loading at the top of the slope also causes a reduced safety factor.


Author(s):  
Sriyati Ramadhani ◽  
Ahmad Rifa'i ◽  
Wahyu Wilopo

Poboya area has many geological structures that result in distribution of strength and stress of rocks not evenly distributed, as a result, the rock mass strength becomes disturbed and slopes become unstable. The objective of the study was to determine the geological structure effect on slope stability and tunnel conditions on metamorphic rocks at the Poboya gold mine. The study was conducted in the Mantikulore sub-district, Palu, Central Sulawesi. Lithology composing study area is metamorphic rocks consisting of gneiss and schist, therefore, the analysis was carried out on both locations which have many geological structures. Numerical analysis was performed applying the finite element method with the RS2 program assistance. The findings show that the safety factor value of the existing slope at gneiss and schist location under static loading is 4.6 and 2.72, if there is an earthquake it becomes 1.07 and 0.77. The safety factor value under static loading with the joint is 4.58 and 2.03, while under dynamic loading with joint, it becomes 0.94 and 0.64. The geological structure effect which represented by the joint gave a big impact with a decrease of safety factor at gneiss about 0.43% under static loading and 80% under dynamic loading. Meanwhile, at schist, safety factor decreased 25% under static loading and 76% under dynamic loading. For tunnel stability, the existence of joint will increase the displacement of 65% at gneiss under static loading and 84% under dynamic loading, while at schist, it increases 25% under static loading and 54% under dynamic loading. This illustrates that geological structures under dynamic loading affect significantly slope stability of Poboya gold mine.


Author(s):  
Ririn Hartini ◽  
I W. Redana ◽  
I.G.N. Wardana

Slope stability analysis along roads Denpasar – Singaraja have been calculated using Felenius Method and Software Plaxis 8.2. This calculation was conducted using  material model Mohr - Columb, soil cohesion (c) and tan f soil parameters. Calculations safety factor using phi – c reduction value, condition until structural failure occurs. The results of computation Felenius Method give stability value Fs < 1.5 which mean landslide would be accurred in this slope. Calculation using Plaxis 8.2 produce Fs > 1,5. This study has been on optimization of soil parameters, so that plaxis gives better result. This study may conclude that plaxis should be used with caution and with proper soil parameters


Author(s):  
V. E. Perekutnev ◽  
V. V. Zotov

Upgrading of hoisting machines aims to improve their performance, to reduce risk of accidents, and to cut down operational and capital costs. One of the redesign solutions is replacement of steel cables by rubber cables. This novation can extend life of pulling members, decrease diameters of drive and guide wheels and, consequently, elements of the whole hoisting machines: rotor, reducing gear, motor. This engineering novation needs re-designing of hoisting machines; thus, the new design should be validated, in particular, strength characteristics of the machine members. This article considers a drive wheel of a hoisting machine with a pulling belt. In order to justify the potential range of design parameters with regard to safety factor, the numerical models of different-design drive wheels are developed and their operation with pulling belt (rubber cable) is simulated in the SolidWorks environment. The data on the stress state of the wheel elements are analyzed, the most loaded points are identified, and the maximal stresses on the sidewall surface and in the spokes of wheels of different designs are plotted.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić

The design code Eurocode 7 relies on semi-probabilistic calculation procedures, through utilization of the soil parameters obtained by in situ and laboratory tests, or by the means of transformation models. To reach a prescribed safety margin, the inherent soil parameter variability is accounted for through the application of partial factors to either soil parameters directly or to the resistance. However, considering several sources of geotechnical uncertainty, including the inherent soil variability, measurement error and transformation uncertainty, full probabilistic analyses should be implemented to directly consider the site-specific variability. This paper presents the procedure of developing fragility curves for levee slope stability and piping as failure mechanisms that lead to larger breaches, where a direct influence of the flood event intensity on the probability of failure is calculated. A range of fragility curve sets is presented, considering the variability of levee material properties and varying durations of the flood event, thus providing crucial insight into the vulnerability of the levee exposed to rising water levels. The procedure is applied to the River Drava levee, a site which has shown a continuous trend of increased water levels in recent years.


2014 ◽  
Vol 501-504 ◽  
pp. 8-11
Author(s):  
Jing Sheng Bian ◽  
Chao Sheng Bian ◽  
Zhi Ming Zhu

Rainfall is one of the most important factors of the slope stability. After the "5.12" earthquake, there are a large number of loose solid produced by earthquake on the mountain, which leads to the soils strength loss in the earthquake disaster zones. and induces landslides and collapses easily in the heavy rainfall condition. The soil parameters obtained from the tests, the scene investigation of the Erman mountain landslide of Han Yuan County, the new developed control of ArcGIS to obtain intuitive landslide warning graphs have been carried out. Results show that the picture of hazard grade is consistent with the actual situation of landslide on Erman mountain. It will provide a scientific way to analyze the influence of heavy rainfall on slope stability.


2013 ◽  
Vol 275-277 ◽  
pp. 1423-1426
Author(s):  
Lin Kuang ◽  
Ai Zhong Lv ◽  
Yu Zhou

Based on finite element analysis software ANSYS, slope stability analysis is carried out by Elastic limiting equilibrium method proposed in this paper. A series of sliding surface of the slope can be assumed firstly, and then stress field along the sliding surface is analyzed as the slope is in elastic state. The normal and tangential stresses along each sliding surface can be obtained, respectively. Then the safety factor for each slip surface can be calculated, the slip surface which the safety factor is smallest is the most dangerous sliding surface. This method is different from the previous limit equilibrium method. For the previous limit equilibrium method, the normal and tangential stresses along the sliding surface are calculated based on many assumptions. While, the limit equilibrium method proposed in this paper has fewer assumptions and clear physical meaning.


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