ABSTRACT
The soil-cement mixed wall technique consists of mixing in-place soils with cement grout or other binders by means of multiple axis augers and mixing paddles to construct sets (or panels) of overlapped soil-cement columns. The grout is mixed at a central plant, pumped down the hollow shaft of the augers and injected through their tips. The auger flights break the soil loose, which the paddles then blend with the grout. As the augers advance to greater depth the mixing paddles continue to mix the soil. When the design depth has been reached, the mixing shaft rotation is reversed and mixing continues as the shafts are brought to the ground surface. Some machines are capable to change the sense of rotation individually for each of the augers, both in the upward and downward directions. By overlapping the column sets, extensions to form a continuous soil-cement wall for use as a cutoff for seepage control, or as a support wall for an excavation can be constructed. Wall elements can be arranged in different configurations to suit various applications, for example, liquefaction stabilization of loose foundation soils. Soils have been mixed in-situ to more than 60 m in depth by this technique.
