| Popis: |
A significant problem, especially in long-term tests, is leakage through the fittings and membrane. To avoid the first of these two sources of error, a cell with fittings enclosed in a back pressure chamber has been developed. To reduce leakage through the membrane, various cell fluids have been considered and tested in normal triaxial test conditions but with a dummy in place of the specimen. The results show that silicone oil minimizes the leakage. Filter papers are used in triaxial testing to accelerate the consolidation process and the equalization of effective stresses within the specimen during shearing. The drainage capacity of five different filter papers was measured, and their effect on the consolidation and shear processes was evaluated by comparative tests. The results show that in the overconsolidated range, the filter papers are efficient; however, due to the high coefficient of consolidation of natural clays in this range, they are not really useful. In the normally consolidated range, the efficiency of the filter drains during consolidation is considerably less than expected; contrary to what has been observed by other researchers, no effect of the filter drains on shear strength was found. |
