Slurry Walls-Construction Quality Control

Structural slurry walls have become a standard method for the construction of deep underground structures in the United States. Structural slurry walls have been excavated to great depth and have been installed to plan dimensions from approximately 10 meters in diameter for circular shafts to hundreds of meters for walls for tunnels or large commercial basements. Slurry walls have been installed through a variety of difficult geological formations with varying success, and have been used as temporary walls, permanent walls, water cutoff walls, load bearing elements or in lieu of underpinning. Currently there are no United States standards for the design and/or construction of slurry walls. Government agencies, private consultants, contractors and trade groups have prepared and, from time to time, published and distributed specifications for the construction of slurry walls [1]. These specifications vary in degree of complexity and quality standards. Some specifications place excessive emphasis on the preparation and control of bentonite slurry used for excavation, with insufficient emphasis placed on quality control of the tremie concrete placement or requirements for the finished product. This paper will discuss the slurry wall construction process, identifying those areas which require special scrutiny by the contractor and owner.