Abstract
This paper covers a development of volume reducing method for natural cohesive soil ground by disturbance, generated by mixing machinery as utilized for cement deep mixing method. This method is based on the basic knowledge that compressibility of natural clay will be changed by sample disturbance. This paper summarizes basic effect of compressibility of natural clay on artificial disturbance by a series of laboratory oedometer tests. Through the tests using undisturbed clay samples taken in Japan, effects of disturbance on compressibility is examined. Then, simple estimation of potential settlements due to ground disturbance by mixing machinery is studied using liquid limit of clay sample, as basic clay intrinsic parameter. In addition, effect of coefficient of consolidation due to the disturbance is confirmed to control the consolidation speed in subsequent soil improvement work by pre-fabricated vertical drain. Finally, some probable application of this proposed method is mentioned.
