Stability Analysis Of Embankments Research Articles

ANALISIS STABILITAS TIMBUNAN DENGAN MEMBANDINGKAN BRANKAL DAN GEOTEKSTIL

Construction activities in road infrastructure development are never separated from earthworks which often become obstacles due to differences in land contours due to excavation and embankment work which is closely related to geotechnical engineering. Embankment and excavation are very interesting things to study because they are closely related to slope safety factors and require special handling. In this research, we examine the use of geotextiles by comparing the handling using safes on embankment stability using PLAXIS Version 8.2 software. The results of embankment stability analysis with safes, settlement at 1 year consolidation was 5.6 cm and settlement at 10 years consolidation was 5.7 cm. in accordance with applicable criteria. The results of the analysis using 2 layers of geotextile showed that the settlement at 1 year consolidation was 4 cm and at 10 years consolidation was 4.1 cm, which is in accordance with the applicable criteria.. Meanwhile, the results of the slope safety factor using bract treatment at 1 year consolidation were 1.475 and the safety factor for 10 year consolidation was 1.478, not in accordance with the design criteria of 1.5. The results of the safety factor using 2-layer geotextile treatment at 1 year consolidation was 1.853 and the safety factor for 10 year consolidation was 1.855, which is in accordance with the design criteria of 1.5.

Correction to: Undrained Stability Analysis of Embankment on Ordinary and Encased-Granular Columns in Soft Clay

Correction to: Undrained Stability Analysis of Embankment on Ordinary and Encased-Granular Columns in Soft Clay

Undrained Stability Analysis of Embankment on Ordinary and Encased-Granular Columns in Soft Clay

Undrained Stability Analysis of Embankment on Ordinary and Encased-Granular Columns in Soft Clay

Slope Stability Analysis for the Phosphogypsum Stockpiles: A Case Study for the Sustainable Management of the Phosphogypsum Stacks in Aqaba Jordan

The process of making phosphates fertilizer involves taking the soft rock phosphate and mixing it with sulphuric acid. This process creates a gypsum by-product (phosphogypsum). Although gypsum is a widely used material in the construction industry, most of the produced phosphogypsum is not processed around the world and is stacked into large piles over the land, especially near coastal areas, which raised concerns about their stability. Such a disposal scheme creates man-made slopes in the surrounding areas which are prone to failure, which represents a common challenge for engineers. A slope failure will lead to a significant risk not only to human lives and activities but to the topographic and geological location of the stacks. In this paper, the geotechnical properties of the phosphogypsum in Aqaba, Jordan are determined and embankment stability analysis is carried out, as the purpose of this study is to evaluate the phosphogypsum stockpiles’ stability, and therefore, avoid any possible environmental disasters. Limit equilibrium methods and finite element methods were utilized in the analysis of this study. The required topographic and geological characteristics were obtained during the site visits and the contour plot of each phosphogypsum pile was produced by the Jordan Phosphate Mines Company (JPMC). Several laboratory tests were conducted to estimate the geotechnical properties of the stacked material due to the limited information on the Jordanian Phosphogypsum characteristics. Based on the results of this study, the above-ground slopes for the stacking of Phosphogypsum in Aqaba were found to be stable under both static and earthquake loading. Therefore, this study proved that the disposal process of the current stockpiles in Aqaba is sustainably managed for providing stable stockpiles and that the process has a generally low environmental risk.

Characterization of Stationary and Nonstationary Random Fields with Different Copulas on Undrained Shear Strength of Soils: Probabilistic Analysis of Embankment Stability on Soft Ground

Soil properties are known to have high spatial variability and often fluctuate with depth. The objective of this study was to investigate the effects of using different models to simulate the spatial variability of undrained shear strength (su) to calculate the failure probability of an embankment on soft ground. Two-dimensional random fields of su were generated based on one Gaussian and two non-Gaussian copulas, with stationary and nonstationary assumptions. Statistical parameters of su variation—mean, coefficient of variance, and scale fluctuation (correlation length)—were estimated from simulated and field data. Monte Carlo probabilistic analyses were performed on embankment stability based on both stationary and nonstationary random fields and all copula approaches; results showed more frequent embankment failures at low water levels in the embankment ditch. In particular, the nonstationary random field (su increases with depth) simulations more closely reflected real observed data, with higher probabilities of slope failure and lower mean factor of safety than the stationary random field simulations. Additionally, the non-Gaussian copulas provided simulated data that more accurately reflected observed field data, highlighting the importance of copula selection when characterizing soil parameter random fields.

Pengaruh Geotekstil Terhadap Stabilitas Timbunan Jalan

Infrastructure development, especially roads are closely related to geotechnical activities. The difference of contours at construction site forces embankment and excavation work. Embankment is an interesting thing to study more deeply because embankments have characteristics such as slopes that have safety factor and must be handled specifically. Geotextiles as an alternative to handling embankment stability are populary used for embankment construction. Many types of geotextile need to calculate and analyze in determining the type of geotextile that are suitable to the characteristics of the subgrade and embankment construction. Embankment stability analysis in this study was calculated using PLAXIS version 8.2 software and Mohr-Coulomb method as basic for calculation. Base on the result of this studie, use of geotextiles, whether woven, non-woven or geogrid, can increase the safety factor and accelerate consolidation time. There will be secondary consolidation consequence of the plastic adjustment of soil grains and geotextiles. The ideal of stress percentage for geotextile to be suitable for use is 56.957% - 37.194%.

An Embankment Stability Analysis Using Finite Element Method Constructed over Soft Consolidating Soil Improved from Lime Columns and Prefabricated Vertical Drains

An Embankment Stability Analysis Using Finite Element Method Constructed over Soft Consolidating Soil Improved from Lime Columns and Prefabricated Vertical Drains

Establishment the program and mathematical diagrams of embankment stability analysis on soft soil reinforced by soil cement columns

In the calculation of improvement of embankments on soft soils, the geometrical parameters of soil cement columns such as the length L, diameter d, the distance between the columns D, greatly affect to the stability of embankments (settlement S, coefficient of stability Fs) and treatment efficiency. On the basis of the multivariate correlation equation predicting total settlement (S), residual settlement after treatment (DS) based on the unit weight of soil , the height of embankments H, the length L, diameter d, the distance between the columns D after statistical analysis on p_value index and R2 with the following models: Linear, Quadratic combined with the Bishop method on slope stability analysis, the authors have built the code of stability analysis for the embankment on soft ground reinforced with soil cement columns system. At the same time, we have developed mathematical diagrams for the analysis of the influence of each pair of column geometry factors on the settlement of the roadbed.

Deformation and Stability Analysis of Embankment over Stone Column-Strengthened Soft Ground

Compacted granular columns are commonly used to support embankments over soft soils. Using a reinforcement layer under the embankment causes the total stress to be further transferred to the column rather than soft soil, thus reducing total deformations of the subsoil. In this paper two dimensional (2D) numerical analysis was used to study the influence of stone columns and basal geosynthetic on deformations and stability of an embankment over soft deposit by means of Plaxis 2D finite element code. Unit cell to plane strain conversion approach was applied to transform columns into equivalent walls thus allowing to simulate a full embankment over a group of columns. Comprehensive parametric analysis was then performed to investigate the role of different critical parameters on embankment behavior. Results showed that the use of stone columns yielded the total deformations of the subsoil to significantly reduce, while its influence was less remarkable as a high stiffness geogrid was placed under the embankment. It was also found that the stone column length was the most influential parameter on the embankment total deformations, so that increasing columns length from 0.25Hs to 0.75Hs reduced the vertical and horizontal deformations by about two and five times, respectively. In addition, the use of a high stiffness basal geogrid caused the stability of the embankment to remarkably improve as the value of safety factor at the end of construction increased from 1.25 to about 1.9.

Slope Stability of Embankments on Soft Soil Improved with Vertical Drains

The overloads of structures or embankments built on clayey soft ground are generally applied gradually, respecting a specific phasing. This phasing on construction allows the undrained shear strength of clay increasing over consolidation in order to avoid the risk of collapse during loading. In this work, the undrained shear strength of clay over the consolidation was estimated following SHANSEP method of which parameters proposed by eight researchers have been employed, as well as the slope stability analysis of embankments on soft soils during staged construction. Assessment of factor of safety for slope stability was conducted basing on the Bishop method. Additionally, the variations of undrained shear strength and factor of safety were presented. In order to validate the methods discussed in this study, slope stability analysis of five embankments constructed on clayey soft soils improved by the vertical drain technique in a high-speed railway construction project in Morocco was performed. For these embankments, field measurements about lateral displacement are presented. It was found that some of the adopted methods is in a good agreement with field measurements. Hence, generalization of these methods to many soft ground cases can be proposed.

Analysis of a full-scale slope failure test on a sludge embankment

In the framework of the reorganisation of several historical wet deposits of a chemical processing plant, one of the oldest wet deposits was cleared because of environmental and economic considerations. The stored sludge (around 350 000 m3) was transported to the neighbouring environmentally controlled deposit, Veldhoven (Ham, Belgium), and stacked on top of existing sludge, using the sludge itself as dyke construction material. To calibrate the embankment stability analysis procedure, a full-scale slope failure test was conducted on an embankment built with industrial calcium fluoride (CaF2) sludge. The Norwegian Geotechnical Institute–active, direct simple shear, passive (NGI–ADP) material model was used to perform a finite-element back-analysis of the full-scale slope failure test. Anisotropic conversion factors are suggested to convert the in situ measured vane shear strengths to shear strengths at different anisotropic stress states, which can then be implemented in the NGI–ADP model. The simple and quickly executable in situ vane shear test was used to master the uncertainties linked to the heterogeneity of the sludge. Sludge heterogeneity not only depends on sludge composition, but also on manipulations during transport and handling of the sludge at the construction of the elevations. The results of the full-scale slope failure test support the proposed modelling of the embankment stability problem.

Analisis Stabilitas Tanah Timbunan dengan Perkuatan Turap Kayu Galam di Daerah Rawa Kalimantan Selatan

South Kalimantan is one of the areas that has a lot of swamps. The use of galam wood is an alternative to the construction of landslide resistors on the roadside in swamp areas. Landslides often occur on the edge of road piles in swamp areas. Not infrequently damage due to landslides on several roads. This study aims to determine the effect of galam wood plaster reinforcement on increasing soil carrying capacity and stability of embankment due to the operation of external forces. The factor of manual embankment slope safety with the fellenius slice method shows that SF = 0.857 <1.0 "is not safe" so there will be a collapse on the slope of the embankment. Then the embankment stability analysis is carried out gradually, so that an increase from cu = 1.04 t/m2 to cu = 1.8 t/m2. The results of the analysis carried out manually revealed that the total decrease was = 284.62 cm � 285 cm. For the simulation results with the PLAXIS program, it shows that there is a decrease of 3.1 cm.

Stability Analysis of Embankment with Squeezing Thick Silt by Blasting

Blasting squeezing silt technology plays an important role in the marine reclamation and tidal power station seawall project construction. The thickness of soft clay gradually deepening with the ocean engineering progresses to offshore and underwater shoals. The suspended seawall structure appears in over 12m deep soft clay. Carrying out stability analysis of these seawall structures has important significance and application value. In this paper, aim at a revetment engineering stability analysis, the traditional stability analysis method and numerical simulation method were applied. Furthermore, applicability and rationality were analyzed for these methods. Studies have shown that, the safety coefficient obtained by the Swedish strip method is low, and it cannot even meet the requirements of the overall anti sliding stability in the construction period and the earthquake condition. The assumptions of Bishop, Janbu and FLAC based finite element method were closer to the actual engineering conditions. The calculated results were reliable and could be applied to the calculation of the suspended seawall.

Undrained stability analysis of embankments supported on geosynthetic encased granular columns

A systematic series of slope stability analyses were performed on embankments supported on soft clay soils treated with ordinary granular columns (OGCs) and geosynthetic encased granular columns (EGCs). The effect of various parameters such as the undrained shear strength of soft clay, friction angle of fill materials and aggregate in granular columns, area replacement ratio and the secant modulus of geosynthetic encasement on the factor of safety (FS) is analysed. A higher FS value is observed for EGC-supported embankments compared to embankments supported on OGC. In addition to full three dimensional (3D) modeling, an equivalent method is also presented in order to compare the solution accuracy and the relative computational efforts. The equivalent method yields similar FS values to 3D column models in the case of OGC, with lower computational costs. In the case of EGC, both methods give different FS values when the critical slip surface passes through the foundation soil, owing to the absence of the confinement effect provided by the geosynthetic in the equivalent method. For the same FS value, a significant reduction in area replacement ratio is observed when using geosynthetic encasement, which can reduce the consumption of natural resources.

Analysis of embankment stability: a case study at Awaso mine, Ghana

Ghana Bauxite Company Ltd operates an open cast bauxite mine at Awaso in the western region of Ghana. As part of its mining activities, a 36 000 m3 water storage facility has been constructed to store water for use in the processing plant. The facility consists of a 4 m high embankment built across a valley on a silty sandy gravel foundation. Seepage forces and pore pressures in the foundation and embankment have raised some stability concerns. The principal objective of this study is to carry out an assessment of the stability of the water storage facility embankment and foundation and propose measures to improve it. The stability assessment procedures include: (a) investigating the geological, geotechnical and engineering properties of the embankment and foundation material, (b) evaluating possible failure factors such as piping, erosion, sliding and seepage; and (c) reviewing operational parameters of the facility. From the qualitative and quantitative assessments, it was concluded that the embankment of the facility was susceptible to failure resulting from inadequate compaction, seepages and overgrown tree roots. The foundation, on the other hand, was found to be susceptible to failure resulting from seepages. Recommendations for improving the embankment integrity include the construction of a toe drain, implementation of a vegetation cover management scheme and documented periodic monitoring.

PVA 섬유보강 시멘트-점토 혼합토의 휨강도 특성에 관한 연구

Currently, the stability analysis of embankments founded on soft ground stabilized with DCM (Deep Cement Mixing) columns has been performed based on a limit equilibrium analysis by using a shear strength of composite ground. Recent research efforts based on centrifuge tests, numerical analyses, and case studies revealed that the group of DCM columns might fail by several failure modes governed not only by shear failure but also by bending failure. So, the applicability of current practice for the stability analysis of embankments founded on soft ground stabilized with DCM columns is uncertain. Therefore, the bending moment capacity of DCM columns needs to be incorporated in the stability analysis. In this study, PVA fiber has been added to improve the bending moment capacity of DCM columns. This paper presents the effects of cement contents, PVA fiber contents and lengths, and curing periods on the flexural strength characteristics of PVA fiber reinforced soil-cement mixtures through a series of third point bending tests.

Use of Graphical Technique for Stability Analysis of Embankment

Use of Graphical Technique for Stability Analysis of Embankment

Use of Graphical Technique for Stability Analysis of Embankment

To authenticate the stability of homogeneous slopes, a simplified version of the friction circle method is presented in the proposed investigation. By introducing few simplified assumptions, the original friction circle method has been modified to provide a simpler and user-friendly technique for slope stability analysis of finite slopes. The graphical technique has been incorporated for the stability analysis of embankments in (c-) soils. The use of this method recompenses the drawbacks of other methods of their suitability for performing stability analysis in the field. The endeavor has been made in this work to make available the most critical slip surface that occurs in the field for the particular conditions. By using computer program these critical slip surfaces are originated and their correlation with the height, slope, and seepage conditions of the embankment has been established. Both toe circles and slope circles that envisage above the toe have been analyzed using this technique. Base circles are less critical unless the friction angle is less than 3 0 ( Terzaghi and Peck, 1984). Therefore, this method is most appropriate for analyzing slopes in c- soils. This method itself lends to back of the envelope type calculations useful for back calculating the geo-mechanical parameters such as c,,  and ru of known slides or imminent slides. Keywords: c - cohesion,  - friction angle of soils,  - density of soil, ru - pore pressure ratio.

Failure of infrastructure embankments induced by flooding and seepage: a neglected source of hazard

Abstract. The risk of failure of transportation embankments due to seepage induced by temporary and occasional impoundments taking place on the upstream side as a consequence of exceptional rainfalls is frequently underestimated. These failure events result from a combination of three main factors, i.e. the flooding event, the hydraulic weakness and the geotechnical weakness of the embankment. Based on the case study of a railway embankment in Southern Italy that collapsed in 2005 due to an upstream impoundment that occurred after few hours of a very intense rainfall, the paper describes a methodological approach aimed at assessing hazard of failure of transportation embankments induced by flooding and seepage. In particular, according to hydrological, hydraulic and geotechnical studies performed to define the factors affecting the process of the embankment failure, three subsequent activities are proposed: the historical analysis of flood damages at the watershed scale; and the assessment of the upstream peak impoundment based on hydrological analysis and the embankment stability analysis, these latter to be carried out at the site specific scale. The approach here proposed is planned to be further validated and improved by means of the application to other case studies, characterised by different contexts and embankment structures.

PC-River – reliability analysis of embankment stability

PC-River is a program to evaluate the reliability of river embankments taking into account different failure mechanisms incorporating the uncertainty of input load and resistance parameters. The application of PC-River is shown within a case study at the Elbe river. The results of this reliability analysis are compared with the traditional approach of the freeboard. To show another application of PC-River, the results of this case study are used for a systematic judgement of flood risk taking into account cost-benefit aspects. For the purpose of this article, flood risk is defined as the product of failure probability and the allocated vulnerability of the flooded area.