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Module 2 : Theory of Earth Pressure and Bearing Capacity

Lecture 10 : Point of Application of Passive Earth Pressure [ Section10.1 Rankine's & Coulomb's Theory ]


10	POINT OF APPLICATION OF PASSIVE EARTH PRESSURE
1	Rankine’s theory
	In Rankine’s earth pressure theory the intensity of earth pressure at each depth is known. So, point of application of the passive earth pressure is known at any depth as shown in fig. 2.36.

	Fig. 2.36 Point of application of passive earth pressure (Rankine’s theory)
2	Coulomb’s theory
	In the coulomb’s method only the total earth pressure value acting on the retaining structure can be calculated. The point of application of the earth pressure can be calculated from coulomb’s assumption that all points on the back of the retaining wall are essentially considered as feet of the failure surface. So, for each failure surfaces as shown in fig. 2.37, earth pressure intensity can be calculated. Let the earth pressure intensity for failure surface 1-1’ is p a at depth z from top of retaining wall and the earth pressure intensity for failure surface 2-2’ is p a’ at depth (z +dz) from top of retaining wall.