Soil mechanics by bc punmia pdf free download

Any soil mass may contain the particles of both types of soils, a combined analysis comprising both sieve analysis and sedimentation analysis may be required for any soil mass. Water present in the voids of a soil mass is called soil water.

The soil water is broadly classified into two categories:. Free water moves in the pores of the soil under the influence of gravity. Free water flows from one point to the other wherever there is a difference of total head. The rate at which the head is lost along the flow passage is equal to the hydraulic gradient.

The held water is retained in the pores of the soil and it cannot move under the influence of gravitational force. Held water is further divided into three types.

The structural water is chemically combined water in the crystal structure of the mineral of the soil. This water cannot be removed without breaking the structure of the mineral. In soil engineering, the structural water is considered as integral part of the soil solid. The water held by electrochemical forces existing on the soil surface is known as adsorbed water.

The quantity of adsorbed water depends upon the colloidal fraction in the soil, chemical composition of the clay mineral and the environment surrounding the particle. The adsorbed water is important only for clayey soils. For coarse grained soils, its amount is negligible or zero. Hygroscopic water or contact moisture or surface bound moisture is that water which soil particles freely adsorb from atmosphere by the physical forces of attraction at held by the forces of adhesion.

This form of moisture is in a dense state and surrounding the surfaces of individual soil grains as a very thin film. Film moisture is attached to the surface of soil particles as a film on the layer of hygroscopic film. This film forms because of condensation of aqueous vapour. Film moisture is also held by molecular forces of high intensity but not as high as in the case of hygroscopic film.

Film moisture can migrate on the application of external energy potential i. The greater the specific surface soil, the more is the film moisture that can be contained.

It is that water which is lifted up by surface tension above free ground water surface. This water is in suspended condition within the interstices pores of capillary size of the soil. The capillary water fills all the pores to a certain distance above the water table - this distance being known as zone of saturation. So, excavation requires the knowledge of slope stability analysis, the idea of soil elasticity, isotropic properties. Hence, to gain knowledge about these properties of soil knowledge of soil mechanics is must require.

Besides this, soil mechanics is required to solve the problem relatthe ed to the soil like soil heave, soil subsidence, frost heave, shrinkage, and swelling. Differences between compaction and consolidation process of Soil mass. Relation between Discharge velocity and Seepage velocity in soil mass. Numerical to calculate the plastic limit of soil Plasticity index. Save my name, email, and website in this browser for the next time I comment. Notify me of follow-up comments by email.

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