1. Engineering properties of rock Prepared by :- Kumari Pooja 3 rd sem civil department 13oo40106036

2. study of engineering properties of rocks very important during the engineering planning's such as:-  Evaluations of geological hazards(rock slide, tunnel stability)  Selection and preparation of rock material  Evaluation of cutting and drilling ability  Analysis of rock deformation  Design of support system  Selection of site for structures

3. Properties of rock are of two types  Rock material property  Rock mass property

4. Rock material property  This includes:-  Rock type  Colour  Particle size  Texture  Hardness  Strength  It is described by using qualitative methods and simple classification test

5. Rock mass property  Discontinuities' are distinct breaks or interruption in the integrating of rocks mass that converts a rock mass into discontinuity assembly of blocks, plates or irregular rock particles.  Naturally occurring ex are stream cobbles,talus,and glacial boulders etc.

6. Common properties which are shared by both:-  Seismic velocity  Weathering  Secondary cavities

7. Engineering properties of rock  Rock types:- it is simplified geological classification of rock based on its genetic categories, structures, composition and grain size.  Rock strength:- (i)Tensile strength (ii) Hardness (iii) Impact strength

8. Tensile strength  This is the maximum conventional stress that can be sustained by the material.  It is the ultimate strength in tension and corresponds to the maximum load in a tension test.  It is measured by the highest point on the conventional stress-strain curve. In engineering tension tests this strength provides the basic design information on the materials.

9. hardness  Hardness is the resistance of material to permanent deformation of the surface. It is the property of a metal, which gives it the ability to resist being permanently deformed (bent, broken or shape change), when a load is applied.  The hardness of a surface of the material is, a direct result of inter atomic forces acting on the surface of the material.

10. hardness  Hardness is not a fundamental property of a material, but a combined effect of compressive, elastic and plastic properties relative to the mode of penetration, shape of penetration etc.  The main usefulness of hardness is, it has a constant relationship to the tensile strength of a given material and so can be used as a practical non-destructive test.

11. Impact strength  Impact strength is the resistance of a material to fracture under dynamic load.  It is a complex characteristic which takes into account both the toughness and strength of a material.  In S.I. units the impact strength is expressed in Mega Newton per m 2 (MN/m 2 ).  It is defined as the specific work required to fracture a test specimen with a stress concentrator in the mid when broken by a single blow of striker in pendulum type impact testing machine.

12. Impact strength  Impact strength is the ability of the material to absorb energy during plastic deformation.  Brittleness of a material is an inverse function of its impact strength.  Impact strength is affected by the rate of loading, temperature and presence of stress raisers in the materials.  It is also affected by variation in heat treatment, alloy content, sulphur and phosphorus content of the material