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Abstract Foundations constructed on swelling clays are subjected to pressure which are manifested in the form of uplifting force pushing the foundations upwards. These pressures are generated due to the increase of the clay volume as it absorbs water The main aim of this thesis is to investigate the response of surface footing resting on expansive soil due to flow of surface footing resting on expansive soil due to flow of water utilizing laboratory and field test results. The variables considered are: a) footing stress, b) unit weight of soil, c) direction of water flow, d) dimensions of footing, e) soil thickness,f) surcharge pressure,g) dimension of sand cushion and h) inertia of the tie beam. The experimental results are reduced in terms of : a) heave - time relationshi~s for the footing and free soil surface, b) generated pressure - time relationships, c) water profile at the end of each test and d) the active and the critical soil depth. The laboratory experiments are performed using an expansive sandy - clay soil extracted from Nasr City Cairo. The footing models dimensions are: i) Circular footing with diameters 4.0,6.0 and 10.4 cm ii) Rectangular footing 3*10 cm and two square footings 3*3 cm. |