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|Title:||SHEAR STRENGTH. OF COMPACTED SOILS|
|Authors:||Katiyar, R. P.|
|Abstract:||The use of modern heavy equipments for compaction of soils result in 'over compaction'. Vdith the result that the soil develops anisotropy on account of orientation of clay particles. Unconfined compression tests were conducted on ver-tical samples and samples inclined at a = 300 with the vertical. it did not reveal any significant anisotropy presumably due to low clay content and low compaction effort. Total stress fail-ure envelopes for vertical samples were also obtained for a wide variation of moisture content from 7 to 15% and at 90%, 95% and 100% maximum dry density. It was found that shear strength is higher at lower moisture contents for a given dry density but strength reduced after some water content. This tendency was obtained for all densities investigated. These results have wide field application. Strict control of placement moisture content is necessary for embankments of height 30 to 40 from the stability point of view. Consolidated undrained tests were also conducted with pore pressure measurement for above noted moisture contents and at 95 maximum dry density. Effective stress parameters were found to be invarient to compaction moisture content. This suggests that the cause of low strength is not the reduction in cohesion and friction. A further work is necessary in this direction. Difficulty was experienced in taking out the 12" dia-meter and 3" high samples from 4" x 8" mould. Soil sample used to break at the junctions of compacted layers. Further, the control of dry density and moisture content was not easy. Satisfactory samples were obtained from split mould, 1~" dia- mater and 5" high with 1" high loadinc caps at both ends giving 3" clear spacing for soil sample.. Samples were extracted from bigger mould with the help of screw controlled Universal Extra- ctor. In this way dynamic stresses were eliminated in the soil sample.|
|Appears in Collections:||MASTERS' DISSERTATIONS (Civil Engg)|
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