Abstract

The study for closure and monitored natural attenuation/stabilization of industrial waste deposits plays a fundamental role in the process of groundwater quality management, providing information for understanding the contaminants evolution and enabling decision-making, with the purpose of isolating waste, contaminant concentrations, toxicity and mass and/or volume reduction to levels adequate to protect human health and the environment, within a reasonable period of time. The aim of this study was to propose an environmental remediation solution for a contaminated material disposal area using the case study of a metallurgical industry located in Bahia, Brazil. To this purpose, four conditions were provided for compliance: i) control of dust, odor and erosion, ii) control of contaminant release, iii) chemical stabilization of waste and iv) soil recovery. Based on the results obtained in environmental investigation studies and information from the area, the best solution in an attempt to naturally stabilize the area would be the use of geosynthetics as a physical barrier between the contaminated material disposed in the area and the rainwater. In this way, infiltration of rainwater into the landfill and the migration of percolated liquid with risk of contamination to the soil, groundwater table and surface water bodies is avoided. It is still possible to monitor the effectiveness of the proposed solution with the installation of instrumentation such as water level indicators and piezometers.

Abstract

Geosynthetics-reinforced soil (GRS) walls have gained immense popularity among other reinforced soil walls. In recent times, case studies have highlighted several GRS walls facing problems such as cracking on the facia, breakage of connection pins in the segmental block, breakage of connection between facia and reinforcement, and relative settlement between facia and backfill, all leading to the serviceability issues or failure of the wall. The existing design methods estimate connection loads using laboratory pull-out tests, which do not incorporate the effect of on-site conditions, such as differential settlement, compaction-induced stresses, and facia geometry, and the stress mobilization in the connection system. This study examines the stress distribution in the facia connection system of segmental reinforced soil walls subjected to site conditions such as inadequate backfill compaction and differential settlement between facia and backfill. A finite element (FE) approach has been adopted to predict the stresses in the reinforcement for the connection loads in the reinforcement-facia connection system subjected to the above-mentioned conditions. The modular block facia, along with geogrid reinforcement connections, was studied, incorporating appropriate geometrical and interface properties (viz. geosynthetics-block interfaces). Based on the study, the obtained variation in the von Mises stresses in the geogrid, embedded in the modular block, due to connection load at the service state was analysed. A comparative analysis of the performance of three different segmental block facia-reinforcement connections was also performed to understand their suitability in a particular site condition