Saturated hydraulic conductivity (Ks) of earth materials in the weathering profile over quartz-mica schists of the Seremban area, Negeri Sembilan

The weathering profile at the slope cut at Km 67.9 of the Kuala Lumpur – Seremban Highway, can be differentiated into two broad zones; an upper pedological soil (Zone I) and a lower saprock (Zone II). The pedological soil (some 4.8 m thick) comprises firm to stiff, clayey sands and silts with many gravel-sized, lateritic concretions and vein quartz clasts and can be subdivided into the solum (IA and IB soil horizons) and saprolite (IC horizon). The aprock is more than 16.2 m thick and consists of in situ, moderately to highly weathered quartz-mica schists marked by steeply dipping to vertical bands of variable thickness of firm to hard, pink to light grey and white silts and sandy silts. Foliation and fracture planes as well as quartz veins and pods are distinctly preserved as relict structures in the saprock. Laboratory constant head permeability tests show clayey silts from sub-zone IIB with distinct relict foliation planes to have saturated hydraulic conductivities (Ks) of 0.0611, and 0.0838, cm/hr with flow perpendicular, and about perpendicular, to the foliation. Sandy silt from sub-zone IIA with indistinct relict foliation planes has a saturated hydraulic conductivity of 0.2977 cm/ hr, whilst silts from sub-zone IIC with distinct relict foliation planes have conductivities of 0.7365, and 0.3864, cm/hr with flow parallel, and steeply inclined, to foliation, respectively. It is concluded that the saturated hydraulic conductivity (Ks) of earth materials within the weathering profile over quartz-mica schists is dependent upon the orientation of the inherent relict foliation planes.