The strength and soil water characteristics for subsurface clays under low suction

A firm standing ground is always required for vehicles to move around in areas of green parks or vegetations zones where access is needed. Expansive soils or landfill cover materials include smectite-rich mineral soils which are sensitive to water. Saturated and near-saturated soils are normally of low shear strength and may not be capable of supporting pavements or traffic loads. The type and constituents of soil play a significant role in determining the appropriate top layer to be used for this purpose. Granular components which include sand and fine gravel play a significant role in providing the required subgrade strength. Soil water characteristic curves predicted for Tabuk clays are compared to the clay slurry behaviour under low suction. Clay sand mixtures compaction characteristics were examined to establish the maximum dry density and optimum moisture content. Stress partitioning between clay and sand concept is used to recommend an appropriate clay sand mixture for top layers or access roads over muddy ground. Landfill cover layers are generally intended to support plants, grass and shallow root vegetation. When water is introduced in a flooding mode to a landfill cover or a top clayey ground, it is likely to cause the fine material to lose strength, wash away or show excessive settlement.