A very thorough paper on site investigation techniques, such as SPT's, CPT's and more, as well as laboratory testing. Written in 2002 for NHI by Doctors Mayne, Christopher, and DeJong.
The influence of discharge capacity on vertical drain performance is studied by computer simulation. Effects of variation in soil compressibility with depth, nonuniform stress increase with depth, and discharge capacity variation with depth and with strain are studied and reported.
Consolidation equations for vertical prefabricated drains which consider finite vertical strain of the soil are derived. Estimated consolidation times are shorter when finite soil strain is considered, and this effect becomes greater as the strain becomes greater. A method of proportioning composite drains used for lateral drainage is proposed.