Soil mixing improves the engineering properties of soil by injecting cementitious grout and blending the materials in-situ. Soil mixed walls are constructed by overlapping elements of soil mixed ground, and inserting structural piles for reinforcing. Soil mixed walls offer a relatively low cost option to construct continuous, deep, low-permeability walls, and recent developments in construction technology have allowed even more widespread and cost effective applications. Lateral support options for soil mixed walls include reinforced cantilever systems, tieback anchors or internal bracing. In circular or elliptical layouts, unreinforced hoop action can provide shaft support. Malcolm offers three soil mixing technologies applicable to retention systems:

CUTTER SOIL MIXING (CSM) employs two sets of counter rotating vertically mounted cutter wheels to form rectangular panels of soil mixed ground, 21 to 60 inches wide. The cutter head is advanced into soil or soft rock as grout or similar fluid agent is injected, cutting and blending the ground with the injected cementitious slurry. Panels are overlapped end to end and reinforced with steel piles to create a continuous wall. CSM systems can install walls In diverse ground conditions including cohesive and non-cohesive soils as well as soft rock. The system offers a high level of quality control with the capability of down-hole steering which allows CSM support walls to be used for access shaft and wall construction to depths exceeding 100 feet.

JET MIXING is unique to Malcolm Drilling and combines mechanical paddle mixing with high pressure hydraulic energy to shear and blend soil In-situ. This system offers high-speed installation while forming soil mixed columns of 30 to 42 inches in diameter. Continuous walls are constructed by overlapping adjacent soil cement elements, and installing steel pile reinforcement. Jet mixing is ideally suited for wall installation to depths of 40 to 65 feet In weak to moderately strong ground which can be efficiently cut and mixed by the jetting action of high pressure grout injection.

MULTI-AXIS MIXING simultaneously advances three vertical overlapped mixing shafts to create a soil cement panel. The system, routinely referred to as Cement Deep Soil Mixing (CDSM), mechanically cuts and blends the soil with injected grout using interlocked cutting heads and mixing paddles on the shafts. Continuous walls are constructed by overlap­ping panels end to end, and frequently the construction sequence will completely re-mix the end column of adjacent panels to ensure wall continuity. Multi-axis soil mix walls are installed at depths up to 120 feet.