Research & Innovation: Seismic Performance of Various Tough-Cell Earth-Retention Systems (Leshchinsky, 2009)
This article discusses how innovation and research work together to drive new technologies, in this case, to develop Neoloy Tough-Cells best suited for earth retaining walls
Summary
This article by Prof. Leshchinsky (et al) summarizes testing of Neoloy earth retention walls on the large shake table at the National Seismic Research Institute in Japan. The tests on a variety of wall types replicated seismic activity similar to a severe earthquake. The study concluded that novel polymeric alloy geocells – more suitable for long-term use than HDPE Soft-Cells – can be used successfully to form gravity walls as well as reinforcement layers even when subjected to a very high seismic load beyond that of the Kobe earthquake.
- The Editors of Geosynthetics Magazine noted that this article departs from policy by focusing on a specific product….”in an effort to offer a guideline, an example, of how product development for the geosynthetics industry can be done effectively (to)…advance the geosynthetics industry into the 21st century with much success.”
Challenge
Ideally, the design of any structure subjected to earthquakes should be based on tolerable recoverable and/or permanent displacements, but this approach is difficult to implement for many reasons. The objective of this study was to quantify a reasonable reduction factor (RF) on the as peak ground acceleration (PGA) for geocell retention structures. The RF can then be integrated with limit equilibrium (LE) stability analysis to conduct seismic and static design.
Conclusions
The study resulted in recommended seismic reduction factors (0.3-0.4) that are used in the design of gravity and reinforced walls. Tests 1 and 2 show that gravity walls made of Tough-Cell can perform well under seismic loading. Such gravity systems may be economical for walls up to 3-4m high. Tests 3 and 4 show that a reinforced system, made entirely of geocell and soil, can be effective and likely economical.
Prof. Leshchinsky noted, however, that Tough-Cells made from HDPE are unsuitable for long-term applications, and guidelines were given to PRS to further the development of its Neoloy based Tough-Cell for demanding applications requiring long-term performance.
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