Research & Innovation: Seismic Performance of Various Geocell Earth-Retention Systems (Leshchinsky, 2009)

This article discusses how innovation and research work together to drive new technologies, in this case, to develop Neoloy Geocells 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 geocells – 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.

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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 geocell 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 geocells made from HDPE are unsuitable for long-term applications, and guidelines were given to PRS to further the development of its Neoloy based geocell for demanding applications requiring long-term performance.

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Click here to read more about Neoloy reinforcement under seismic pressure