A different approach and result to the measurement of K_o of granular soils

An in-soil version of the null soil pressure measurement system has been used in the measurement of lateral earth pressures of granular soils for at-rest K_o conditions. Four uniformly graded soils were tested, from particle diameter 0·15 mm through to 15 mm. Two significant observations were made based upon the data presented. For initial loading, the coefficient of lateral earth pressure, K_o, was found to be higher for soil placed in a dense packing arrangement in comparison to that measured for the same soil placed in a loose packing arrangement. The development of horizontal pressure during unloading and reloading was found to be very similar to that of initial loading.