Development of a new device for measuring contact pressure distribution of geomaterials

A new nondestructive test is developed for evaluating mechanical property of improved soil as well as sand and cohesive soil. Focus on the subgrade reaction differences between sandy soil and cohesive soil, a stress distribution ratio between inside and outside parts on rigid loading plate is measured by the new test device. Used samples are Toyoura sand, decomposed granite soil, kaolin, Ariake clay and cement-improved soils, which are typical sandy soils and cohesive soils. The purpose of this study is to develop a new device for measuring contact pressure distribution of geomaterials and estimate internal friction angle by correlation with the result of the triaxial compression test. It is also expected that this method is applied to the quality control in the surface layer ground. According to the loading test, the coefficient of subgrade reaction ratio between inside plate and outside plate is defined in terms of the relationship between settlement and average load intensity. And a relationship among the distributions of subgrade reaction with φ obtained from the triaxial compression test is discussed.