Laboratory Techniques for Evaluating Effectiveness of Sealing Voids in Rubble-Mound Breakwaters and Jetties with Grouts and Concretes

摘要

Many US Army Corps of Engineers (USACE) breakwaters and jetties have become permeable to sand transport and wave transmission, a condition which results in increased operation and maintenance dredging costs and increased risks and delays to navigation. Causes of the permeability may be wave damage to armor and concomitant loss of core material, differential settling of rubble material below a monolithic cap, or the use of only large blocks to construct the original section. Whatever the cause, the engineering problem facing a coastline planner or engineer is to economically rehabilitate a coastal rubble-mound structure by permanently closing the large voids in a specified zone of its interior. This report is the second milestone in a multiyear project to better understand cementitious, chemical, and bituminous materials, and injection techniques applicable to USAGE projects that are experiencing detrimental levels of sediment infiltration or wave energy transmission. Other products of this research investigation will include results of field monitoring of recommendations and tests arising from these laboratory evaluations, and development of guidance for field use of cementitious, chemical, and bituminous sealants specifically directed toward coastal projects. Laboratory investigations consisted of tests for injecting sealant materials in a model structure to describe their flow behavior and sealing ability inside a scaled, submerged, rubble-mound structure. (sdw)