Improvement of Slope Stability as a Result of Combining Diverse Reinforcement Methods (original) (raw)
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The article is an answer proposal for the conclusion stated in European regulations regarding the environment friendly and more sustainable development, which among others includes utilising secondary and recycled material in order to obtain durable and stable cuttings and embankments. Bearing in mind that the slope stability and erosion control on embankments are the issues rising the nowadays geotechnics awareness through all around the world, the paper content provides the alternative engineering solutions to such problems. The techniques proposed in the paper mainly consist of the proper vegetation cover implementation on embankment slopes, the reinforcement of earth structures by utilising geotextiles and a combination of those two. Additionally, it is presented how secondary materials could be used as a vegetation development accelerating and enhancing material. In order to prove the reliability and efficiency of such activities the laboratory material tests and numerical mode...
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The analysis of landslide slope stability since 1960s is the development of a 2-D structure proposed by various experts, through the 3-D method. Most of these previous studies stated that the ratio of 3-D and 2-D safety factors was more than one for cohesive and less than one for non-cohesive soils. These were because several required slope reinforcements were affected by the safety factors, with the analytical differences of the 2-D and 3-D methods causing a distinction in the requirements. These differences further cause problems by underestimating or overestimating the design. Therefore, this study aims to determine a comparative analysis of 2-D and 3-D slope stability on several required reinforcements. The analyses of the 2-D and 3-D structures were carried out using the LEM proposed by Fellenius and Hovland, respectively. The comparison of the several required reinforcements was also conducted using geotextile with Tult = 200 kN/m. The results showed that the reinforcements re...
Journal of Infrastructure & Facility Asset Management
Slope stability analysis is very important in slope design so it can manage and maintain the infrastructure assets. If the slope is unstable, it can damage the infrastructure around the slope. The method commonly used in slope stability analysis is 2D modeling which assumes the length of the landslide area is not limited or continuous. Landslides that occur in the field are limited and not continuous, so 3D modeling is more suitable than 2D modeling. 3D slope stability analysis has been developed by various researchers. Most of the results of previous studies stated that the 3D and 2D factor of safety ratio were more than one for cohesive soils and less than one for non-cohesive soils. This safety factor affects the amount of reinforcement needed. Differences in 2D and 3D safety factors will cause differences in the amount of reinforcement needed. Therefore, this study was conducted to determine the differences in the 2D and 3D slope stability analysis result. Slope stability analysis was carried out using LEM, where the 2D slope stability used the Fellenius method while the 3D slope stability used the Hovland method. Calculate the required reinforcement amount using geotextiles with Tilt = 250 kN/m. The results obtained from this study are the 2D safety factor is smaller than the 3D safety factor. The 3D and 2D safety factor ratios range from 1.09-1.397. While the amount of reinforcement required in the 3D analysis is less than in the 2D analysis with the ratio of 3D and 2D reinforcement requirements ranging from 0.5 to 0.955 depending on the width and height of the embankment.
Analysis of Effect of Curtailment of Reinforcement on Stability of Steep Slopes
Proceedings of the 19th International Conference on Soil Mechanics and Geotechnical Engineering, Seoul , 2017
Steepening of slopes for construction of rail/road embankments or for widening for other civil engineering structures is a necessity for development. Use of geosynthetics for steep slope construction or repair of failed slopes considering all aspects of design and environmental considerations could be a viable alternative to this problem. Literature survey indicates that some efforts were made for optimization of length of reinforcement. The present paper details an analysis to optimize the length of geosynthetics from the face or near end of the slope with respect to its location, length and combination of multiple layers of reinforcement to obtain the desired minimum factor of safety for a steep slope. Steep unreinforced and reinforced slopes are analyzed to obtain critical factors of safety. The effect of providing geosynthetic layer in shifting the critical slip circle has been identified and studied. The effect of interaction between layers of reinforcement has been identified and quantified.
A procedure for the design and analysis of geosynthetic reinforced soil slopes
Geotechnical and Geological Engineering, 1992
A procedure for the stability analysis and design of geosynthetic reinforced soil slopes over a firm foundation is described. Firstly the unreinforced slope is analysed, and for this a circular failure method is used which allows a surcharge load to be taken into account. Any method of slip circle analysis could be used to identify the coordinates of the centre of the slip circle, its radius and the minimum factor of safety. In this study, both internal and external stability analysis of the reinforced slope is presented. Internal stability deals with the resistance to pullout failure within the reinforced soil zone resulting from the soil/reinforcement interaction. The external stability is considered by an extension of the bilinear wedge method which allows a slip plane to propagate horizontally along a reinforcing sheet. The results for total tensile force, internal and external stability are presented in the form of charts. For given properties of soil and slope geometry, the required strength of the geosynthetic and the length of reinforcement at the top and bottom of the slope can be determined using these charts. The results are compared with the published design charts by Schmertmann et al. (1987).
A state-of-the-art review of geosynthetic-reinforced slopes
International Journal of Geotechnical Engineering, 2011
Geosynthetic-reinforced slopes are generally compacted fill embankments that incorporate geosynthetic layers as tensile reinforcement to enhance stability. The reinforcement holds together the soil mass from both sides of the failure surface, thus increasing the factor of safety of the existing slope. Several analytical, numerical and experimental research works, and many case studies on geosynthetic-reinforced slopes have been reported in literature; however, no attempt has been made in recent years to give an insight into such slopes and to present an overview of these developments. This paper presents a comprehensive overview of geosynthetic-reinforced slopes, including suitability of geosynthetics, modes of failure, methods of slope stability analysis and design, model studies, and typical slope stabilization methods and some specific recommendations. The readers, especially students and practicing engineers, will find the concepts presented in this paper very useful.
The role of geosynthetics in slope stability
Geosynthetics are fibrous materials made of elements such as individuals fibers, filaments, yarns, tapes, etc. that are long, small in cross section and strong in tension. It must be sufficiently durable to last a reasonable length of time in the hostile environment. Use of geotextile in civil engineering structures are rapidly expanding in terms of volume, types of products and range of applications. The largest area of application of these materials in Civil Engineering is Geotechnical Engineering. Based on a few laboratory work and numerical analysis, few investigators reported geosynthetics in slope reinforcement, a review of related last works shows that not much research has been done to define performance of geosynthetics in slopes, a problem that is often encountered in field. The paper observed the performance of geosynthetics in slope reinforcement.
Geoysynthetic Reinforced Embankment Slopes
2020
Slope failures lead to loss of life and damage to property. Slope instability of natural slope depends on natural and manmade factors such as excessive rainfall, earthquakes, deforestation, unplanned construction activity, etc. Manmade slopes are formed for embankments and cuttings. Steepening of slopes for construction of rail/road embankments or for widening of existing roads is a necessity for development. Use of geosynthetics for steep slope construction considering design and environmental aspects could be a viable alternative to these issues. Methods developed for unreinforced slopes have been extended to analyze geosynthetic reinforced slopes accounting for the presence of reinforcement. Designing geosynthetic reinforced slope with minimum length of geosynthetics leads to economy. This chapter presents review of literature and design methodologies available for reinforced slopes with granular and marginal backfills. Optimization of reinforcement length from face end of the sl...
Construction and post-construction behaviour of a geogrid-reinforced steep slope
Geotechnical and Geological Engineering, 2003
A geogrid reinforced steep slope was built and monitored during construction and during the first ten months of service. The slope is located between Régua and Reconcos in the new Portuguese main itinerary, IP3, and is a part of reestablishment 2. The reinforced slope has an extension of about 206.2 m, is in curve and the reinforced area reaches a maximum height of about 19.6 m in the outside curve slope at 150.0 m of extension (km 0+150). The monitored slope cross section is at km 0+150. The reinforcements are high density polyethylene geogrids;. materials with different tensile strength values were used. The reinforcement strains were measured at three reinforcement levels using linear extensometers. The soil vertical stresses were recorded using load cells. The internal horizontal displacements of the slope were recorded using two inclinometer tubes. The face displacements were recorded topographically in points spaced approximately 1.2 m vertically along the face of the slope on the km 0+150 cross section. The reinforced slope behaviour was observed during a period of about 13 months, which includes three months of construction period. This way it was possible to obtain information about the slope behaviour during and after construction (the first 10 months of service). The behaviour of the observed reinforced slope is characterized by: low values of face displacements, slope internal horizontal displacements and reinforcement strains; change of the face displacements configuration at the end of construction during service;tendency to stabilization of the horizontal displacements in a relatively short period of service; change, during service, of the position of the line passing through the points of the reinforcements where maximum strains were recorded. The reinforced slope behaviour express the conservative design of Equilibrium Limit methods and encourage the research on new design methods for geosynthetic reinforced soil systems.