Design Criteria and Construction of a Capillary Barrier Cover System: The Rocky Mountain Arsenal Experience

摘要

Capillary Barrier Cover Systems were recently designed and constructed over contaminated materials at the Rocky Mountain Arsenal (RMA) located near Denver, Colorado. The design and compliance of the infiltration control component of the covers at the site are governed by a quantitative percolation criterion. During an initial field demonstration for evaluation of alternative cover systems in achieving the criterion, formation of a capillary barrier was found to play a critical role. This paper discusses design studies, construction criteria and construction approaches that were developed for this capillary barrier cover system, as well as initial information from the long-term monitoring of the cover system performance. The use of index soil properties for the soil storage component of the cover was found to be suitable for construction specifications, but required implementation of a comprehensive borrow source characterization. The use of a laboratory column test program proved relevant to identify the different capillary barriers suitable for the full-scale cover system.