What is the most effective way to Reinforced fine soils like clay ?
for example could strip reinforcement used for fine soils??? As reinforced walls should be backfilled with coarse materials like coarse sand or gravels
Regards
Dear Mohamad,
The following two links contain publication which demonstrate reinforced wall for fine soils:
1-Flume Tests on Fine Soil Reinforced with Geosynthetics: Walls of the Salt Pans (Aveiro Lagoon, Portugal)
Abstract
This paper presents exploratory work on the use of geosynthetics for reinforcing fine soils, particularly for applications in the Aveiro lagoon, Portugal. The behaviour of local fine soil reinforced with geosynthetics under hydraulic actions was studied using flume tests. The case study was a typical cross section of the walls of the salt pans of the Aveiro lagoon. A preliminary design of a structure was done, for different reinforcements (geogrid, geocomposite, association of geogrid and geotextile). Local soil was collected and characterised using laboratory tests. The flume tests included performing permeability, erosion and overtopping tests, for actions typical of the lagoon environment. The models reinforced with geogrid GGR exhibited the highest global permeability, due to the difficulty of soil lumps to penetrate the geogrid openings. Although this type of reinforcement provides low resistance to erosion, promoting vegetation growth or including other elements can reduce surface erosion. The other reinforcements (sheets) enabled containing the soil. Non-uniformity of the soil compaction caused local differences of permeability. Thus, ensuring uniform compaction on site is necessary; however it can be challenging, particularly for fine soils. The results indicate that seepage is likely to induce some clogging of the reinforcements. The reinforced soil models tested exhibited higher permeability and lower resistance to erosion and overtopping than the traditional solution (soil matrix with vegetation). The results indicate that a possible alternative solution for the walls could use fibre reinforcement. Further work is necessary to ensure adequate (low) permeability of new solutions for these walls.
http://link.springer.com/article/10.1007/s40891-015-0014-6
2-Performance of a Nonwoven Geotextile Reinforced Wall with Unsaturated Fine Backfill Soil
Abstract: The use of marginal backfills in GSE (geosynthetic stabilized earth) walls has not been recommended by different standards specifications. Restrictions are motivated by the poor hydraulic conductivity of fine soils that are capable of developing of water pressures. However, the use of granular materials can expend the cost of the construction. As a result, local soils, granular or not, have been increasingly used. Unsaturated conditions of fine soils may result in convenient performance even using extensible reinforcements. This paper evaluates the performance of a full scale model of a nonwoven geotextile reinforced wall constructed with fine grained soil backfill. The unsaturated condition was maintained and matric suctions, displacements and reinforcement strains were
monitored during the test. Results have shown that the unsaturated condition of the backfill allowed maximum reinforcement peak strain of 0.4 %. For the case of a wrap faced wall on a firm foundation the performance and good agreement between measured strains and factors of safety from limit equilibrium analyses have shown the maintenance of unsaturated conditions as an economical
alternative to the use of high quality fill.
http://www.ce.utexas.edu/prof/zornberg/pdfs/AJ/Portelinha_Bueno_Zornberg_2013b.pdf
Hoping this will be helpful,
Rafik
Dear Mohamad, we have been using Buriti (Mauritia Fluxuosa), as a good geotextile tecnique, to recuperate/protect sandy, clayey and loamy gully walls and this technique has been working very well. Have a look on my Research Gate and also on Prof. Antonio Jose Teixeira Guerra´s Research Gate, where you will find several papers regarding this issue.
I hope this information will be useful for you.
Best wishes,
Maria do Carmo
Dear Mohamad,
I suggest to find Brazilian publications. Is common to us use fine soils to build reinforced walls.
Dr. Karaman has suggested an interesting instrumented GRS. In the sequence are others that you can read.
Regarding your questions, I do not reccomend to use strips in fine soils because of the interface shear strenght. I also do no reccomend to use vertical face walls (84° or 10V:1H is recommended).
- BENJAMIM, C. V. S. ; ZORNBERG, Jorge Gabriel ; BUENO, B. S. . Field monotoring evaluation of gotextile-reinforced soil-retaining walls. Geosynthetics International, New York, v. 14, p. 100-118, 2007.
- RICCIO, MARIO ; EHRLICH, MAURICIO ; DIAS, DANIEL . Field monitoring and analyses of the response of a block-faced geogrid wall using fine-grained tropical soils. Geotextiles and Geomembranes, v. 42, p. 127-138, 2014.
- SANTOS, EDER C.G. ; Palmeira, Ennio M. ; BATHURST, RICHARD J. . Behaviour of a geogrid reinforced wall built with recycled construction and demolition waste backfill on a collapsible foundation. Geotextiles and Geomembranes, v. 39, p. 9-19, 2013.
- GOMES, R. C. ; PALMEIRA, E. M. ; LANZ, D. . Failure And Deformation Mechanisms In Model Reinforced Walls Subjected To Different Loading Conditions. Geosynthetics International, London: Thomas Telford Publ., v. 1, n.1, p. 45-65, 1994.
- Fonseca, E. C. A. ; PALMEIRA, E. M. ; Santos, E.C.G. . Numerical Analysis of a Geogrid Reinforced Retaining Wall Built with Non-Conventional Backfill Material. In: 10th International Conference on Geosynthetics, 2014, Berlin. Proceedings. Essen: Deutsche Gesellschaft für Geotechnik e.V., 2014. v. 1. p. 1-8.
- MIRMORADI, S. H. ; EHRLICH, M. . Numerical Evaluation of the Behavior of GRS Walls with Segmental Block Facing under Working Stress Conditions. Journal of Geotechnical and Geoenvironmental Engineering, v. 141, p. 04014109, 2015.
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