Determination of coefficient of consolidation with rowe cell

Abstract

Consolidation is one of the most important aspects in soil engineering. Since deformation is one of the important criteria for design purpose, consolidation test is important. Structures built over soft clay will create large settlement on the clay layer. The rate of settlement is an important part in design, because the time for total settlement can be estimated by the rate of settlement. It is as well important for the design of soil improvement, which is meant to reduce the time of total settlement. The rate of settlement is represented by coefficient of consolidation, both in vertical and horizontal direction. In this study, measurement of coefficient of consolidation in each direction is done by means of consolidation testing with Rowe cell with single drainage, double drainage, and radial outward drainage condition. Kaolin was used for the experiment, prepared with consolidation tank with a pre-consolidation pressure of 100 kPa. The consolidation test was done by applying a load increment of 25 kPa, 50 kPa, 100 kPa, and 200 kPa. Back pressure of 30 kPa was maintained throughout the experiments. Coefficient of consolidation in vertical direction was calculated based on three methods: Taylor‟s method, Casagrande‟s method, and rectangular hyperbola method. Coefficient of consolidation in horizontal direction was calculated based on method proposed by McKinlay. The trends and the values of both cv and ch were compared to previous researches. It was found that Rowe cell that the values of cv has a range of 8.05×10-7 to 4.33×10-6 m2/s for single drainage, and 5.09×10-7 to 1.65×10-6 m2/s for double drainage, and ch has a range of 4.29×10-7 to 7.85×10-7 m2/s. However, some improvements can be made in the method or the cell arrangement to give more accurate results.