SHEAR FAILURE IN THE STIFFER CLAYS IS IMMEDIATE, HOWEVER IN CASE OF SOFT PLASTIC CLAYS IT FAIL VERY SLOWLY

The bearing capacity of a soil depends upon the physical characteristics of the soil particles (ie, size, shape, cohesive properties, frictional resistance and the power to retain moisture, etc) moisture content and the changes brought in by the atmosphere influences (heat, rain etc) . The finer the soil particles, the more variable the cohesive and frictional properties of the soil under field conditions. In general, the heavier the unit weight of soil the greater the strength, and also the lesser the voids, the greater the strength. With structures built on sands and gravels the settlement is likely to be partically completed at the end of construction, but when the site is underlain by clays or silts, settlement is likely to continue for a long time after construction and cracks may appear many years after completion. All foundations settle under  load and the general tendency is for some parts of a structure to settle more than others causing relative movement. The critical factor in the settlement of a structure is not the amount of settlement but the differential settlement between the different parts of a structure itself. Excessive pressure is comparatively uncommon cause of settlement. Investigation of all layers under a foundation should be made as even thin layers which are weak in shear can cause settlement. As per report of the investigation obtained from the founding area the design of the foundation is accordingly prepared for the required construction. Shear failure in the stiffer clays is immediate, but some soft plastic clays fail very slowly and short term loading tests on them may be deceptive:-- Er Fateh chand Guleria, Director RTI welfare Association registered number HPCD, 3552 , Bilaspur Himachal pradesh phone number, 9459334377