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Soft clay becomes remoulded around wick drains during their installation. The effects of remoulding can be taken into account in design by adopting an analytical method incorporating the radius of smear and the permeability of the remoulded soil in the smear zone. However, these parameters are usually not known and are estimated largely based on experience and guidance provided in the technical literature. Back analysis of settlement data from an embankment constructed on soft Pimlico Clay in Australia with a wick drain spacing of 1·5 m in an equilateral triangular configuration is performed to assess the potential smear parameters. A chart showing variations of permeability with smear radius is presented to assist with selection of design parameters for wick drains installed in soft Pimlico Clay. Effects of wick drain spacing on the permeability of the remoulded soil are investigated through back analysis of embankments constructed on wick drains spaced at 1·0 m and 1·35 m in an equilateral triangular configuration. Although the embankments are not constructed in identical ground conditions, there is no evidence that reducing the spacing between the wick drains causes the average permeability ratio to increase. [ABSTRACT FROM AUTHOR]

The pile designer in a seismically active region will generally need to estimate the maximum seismically induced internal moment and shear of the pile in order to provide adequate strength to maintain the structural integrity of the pile. In this paper an effort has been made to provide a simple means of carrying out such an estimation for a single pile embedded in a homogeneous clay layer. The results have been presented in the form of design charts that can be used directly by designers with no or little computational effort. The variables in the design charts include the length and diameter of the pile, the Young's modulus of the pile material, the strength and stiffness of the soil, and the factor of safety against axial failure of the pile. The charts have been obtained from a time domain analysis of pile-soil interaction, and are based on the response of the piles to a range of earthquakes recorded in North America and Australia. [ABSTRACT FROM AUTHOR]