Soil bentonite (SB) slurry trench cutoff walls are widely used to control the movement of ground water and subsurface contaminants. This paper presents findings from in situ tests conducted on an SB wall using the Marchetti Dilatometer Test (DMT). This paper also describes a modified lateral squeezing model that accounts for loading associated with a dike built shortly after construction of the wall was completed. Data from the DMT were obtained during slurry wall construction as well as three, six and nine months after construction to evaluate changes in the lateral stress state with time. The dilatometer provided a unique opportunity for relatively direct measurement of the in situ horizontal earth pressure. The DMT was conducted in both perpendicular and parallel orientations (relative to the trench line) to investigate stress anisotropy within the wall. Dilatometer data revealed modest differences in the lateral stress state as a function of both orientation and time. The transverse stresses are slightly greater than the longitudinal stresses. Both transverse and longitudinal stresses increase with time. The lateral stresses computed from the DMT results compared favourably with those predicted by the modified lateral squeezing model that was adapted to include the influence of the dike.
Strength and Permeability of a Deep Soil Bentonite Slurry Wall
In 2006, a Soil Bentonite (SB) slurry wall was constructed at a brownfield redevelopment of a former steel mill site in Mayfield, NSW Australia. At this site, the slurry wall is designed to block groundwater