https://www.jstage.jst.go.jp/article/sandf/47/5/47_5_873/_pdf

Comparative study on the behavior of encased stone column and conventional stone column

This paper investigates the influence of geosynthetic encasement on the performance of stone columns floating in soft clay. It was found that with unencased columns the bearing capacity improvement...

Influence of geosynthetic encasement on the performance of stone columns floating in soft clay

Improved performance of soft clay foundations using stone columns and geocell-sand mattress

The paper examines the influence of soil strength and stiffness on the end resistance mobilised by a cone or displacement pile in a two-layered soil profile (i.e. strong soil overlying or underlying weak soil). The investigation involved a series of numerical analyses that idealise pile/cone penetration assuming the spherical cavity expansion analogue. It is shown how the end resistance mobilised by a penetrometer in a dense sand (i.e. strong soil) varies with the number of penetrometer diameters (D) from a weak soil (assumed here to be either a loose sand or soft clay), and depends on the ratio of the steady-state penetration resistances of the strong and weak layers. The penetrometer resistance in the weak soil is not affected by an adjacent strong layer at penetrations greater than 2D. A design procedure based on a numerical parametric study is proposed, and this is subsequently shown to compare well with centrifuge test data and with previous numerical research.

Pile and penetrometer end bearing resistance in two-layered soil profiles

This paper identifies some of the causes of imperfections in real pile foundations and then examines their possible effects on pile behavior. The imperfections considered arise from two main sources, natural imperfections caused by the geological circumstances and imperfections related to the construction of the piles. In each case, single piles are considered first, and then pile groups are addressed separately. Case histories are presented to illustrate the effects on pile performance which are predicted by theoretical analyses. The analyses with which these examinations are carried out will still inevitably involve some degree of idealization, but at least attempt to incorporate the key “nonideal” aspects. The paper also discusses the particular problems involved in investigating and analyzing underperforming pile foundations and reviews some methods by which the consequences of imperfections may be overcome or ameliorated.

Pile Behavior — Consequences of Geological and Construction Imperfections

The previous Part 1 of this paper deals with the bearing capacity of piles penetrating through clay into sand. In the present Part 2 the case of piles penetrating into a sand stratum overlying clay...

V. V. R. N. Sastry

Papers

Bearing capacity of piles in layered soils. Part 2. Sand overlying clay