Consolidating the relationship between the two
A simple one-dimensional consolidation model consists of rectilinear element of soil subject to vertical changes in loading and through which vertical (only) seepage flow is taking place. iso = equal; kronos = time) The figure shows a set of supposed standpipes inserted into a consolidating layer.
There are three variables: Solutions to the one-dimensional consolidation equation can be obtained by plotting the variation of with the depth in the layer at given elapsed times. Before loading, the pore pressure in the drain is zero.
A laboratory test has yielded a coefficient of consolidation for the appropriate loading range of 0.675 mm²/min.
The final consolidation settlement has been calculated to be 120mm.
an open layer in which the drainage path length, d = H/2) axis scale is linear.
The basic equation used is: where d = drainage path length [d = H for one-way drainage, d = H/2 for two-way drainage] T Back to Calculation of settlement times Example The final consolidation settlement of a layer of clay 5.0 m thick is calculated to be 280mm.From the changes in thickness at the end of each load stage the compressibility of the soil may be observed, and parameters measured such as Compression Index (C Back to The oedometer test The saturated specimen is usually 75 mm diameter and 15-20 mm thick, enclosed in a circular metal ring and sandwiched between porous stones.Vertical static load increments are applied at regular time intervals (e.g. The load is doubled with each increment up to the required maximum (e.g. During each load stage thickness changes are recorded against time.Back to The process of consolidation and settlement A general theory for consolidation, incorporating three-dimensional flow vectors is complicated and only applicable to a very limited range of problems in geotechnical engineering.