Evaluation of consolidation parameters in CL tests; theoretical and practical aspects

The paper presents theoretical solutions of the consolidation problem with respect to the different conditions of continuous loading and its application. The author introduces modified consolidation parameters and dimensionless parameters characterizing the course of the consolidation process. Therefore it is possible to calculate the theoretical pore water pressure distribution for various loading procedures in continuous loading (CL) consolidation tests occurring in constant rate loading (CRL), constant rate of strain (CRS) or controlled gradient (CG) tests. The calculation results allow presentation of the attributes that differentate CL consolidation and classical incremental loading (IL) consolidation. A new method of calculation cv (coefficient of consolidation) is proposed using theoretical diagrams of porewater pressure distribution and results of laboratory measure ments during the CL test. A comparative analysis of the methods currently used for cv calculation and the new method is presented here. The cv values estimated by means of method referring only to the seepage factor of consolidation, are usually higher than those based on the strain course. Proper projection of the seep age factor of consolidation makes it possible to shorten the time of consolidation tests in accordance with results of many field observations. The methods described herein can be useful in studying physical conditions of sedimentation, glacial geology, early diagenetic process and applied geology.