Advances and remaining challenges for geosynthetics in geoenvironmental engineering applications

R Kerry Rowe

doi:10.14195/2184-8394_110_1

Abstract

Nine issues of importance to the use of geomembranes (GMs) and geosynthetic clay liners (GCLs) as part of composite liners in geoenvironmental applications are examined. These issues include the effect of: GCL-leachate compatibility on hydraulic conductivity; freeze-thaw on GCL performance; internal erosion on GCL hydraulic conductivity; temperature on advection and diffusion as well as desiccation of GCLs and compacted clay liners (CCLs); the choice of protection layer on the strains developed in GMs; wrinkles on strains developed in GMs and the thinning of GCLs; holes in GMs on leakage through composite liners; winkles in GMs on leakage through composite liners; diffusion through GCLs and GMs; and temperature and leachate exposure on the service life of GMs. It is suggested that GCLs and GMs can play a very beneficial role in providing environmental protection. However, like all engineering materials they must be used appropriately and consideration should be given to factors such as those addressed in this paper. There is a need for site specific design, strict adherence to construction specification, and appropriate protection of the geosynthetics after construction. In particular, given the diversity of available GCLs and their different engineering characteristics, GCLs should be selected based on the required engineering properties, not just price.

Highlights

In recent years there have been many advances in the understanding of issues related to the use of geosynthetics such as geosynthetic clay liners (GCLs) and geomembranes (GM) as contaminant barriers
The objective of this paper is to highlight some of the recent advances in geosynthetic engineering, illustrate some of the important considerations related to design and construction using geosynthetics, and flag some of the remaining challenges related to the use of geosynthetics in geoenvironmental applications
Petrov & Rowe (1997) showed that if there is a low applied stress at the time of permeation, there can be an order of magnitude increase in hydraulic conductivity to about 6 x 10-10 m/s as the permeant was changed from water to municipal solid waste (MSW) leachate (Table 1)

Summary

Introduction

In recent years there have been many advances in the understanding of issues related to the use of geosynthetics such as geosynthetic clay liners (GCLs) and geomembranes (GM) as contaminant barriers. When placed on the geonet, four of the five GCLs tested (BWD, NWD, WD, SNWD; see Table 3) experienced internal erosion (bentonite loss) and an increase in hydraulic conductivity by at least one order of magnitude for heads ranging from 8 m to 45 m.

Objectives

Results

Conclusion