DELAY OF PORE PRESSURE IN OEDOMETER AND ITS EFFECT ON DETERMINATION OF COEFFICIENT OF CONSOLIDATION

From common consolidation tests,a new oedometer which can measure the pore pressure from the bottom of specimen is employed. A phenomenon is found that the pore pressure in the specimen inclines to delay. Compared curves of the pore pressure and the displacement,it can be concluded that around the appearance of the of peak value pore pressure,the displacement curve finds its first turn. When the pore pressure reaches its total dissipation,the displacement curve finds its second turn. Because the pore pressure has strong relationship with the displacement,research work is carried out to reveal the cause of the delay. With further experiments under various conditions,it can be found that the side friction and the degree of saturation have strong influences on the delay of pore pressure in the specimen. So the delay rance of pore pressure should be considered in determining the consolidation coefficient,and at last,the measuring relative methods are discussed.