Abstract
In order to analyze the effect of vertical drains in plane strain condition, a new matching procedure based on well resistance is proposed. The advantage of this procedure is that it not only matches the average degree of horizontal consolidation in axisymmetric by plane strain condition, but also yields a more realistic excess pore pressure distribution in horizontal direction. The method was incorporated into finite element analysis, and it was demonstrated that half of the drain spacing could be modelled by one-column of elements. Then, an actual case history of an embankment on vertical drain improved subsoil was analyzed by the proposed method. It was shown that vertical drains have two effects on subsoils response : (1) increasing settlement rate, and (2) reducing lateral displacement. For the case analyzed, the vertical drain used was without a filter. For matching the surface settlement, a low discharge capacity of about 1.5 m3/year was found (fixed smear effect). The analysis results were compared with measured values, and it was found that discharge capacity may be reduced significantly with an increase of confining pressure on the sleeve (wall) of the drain.
