EXPERIMENTAL STUDY ON IMPROVEMENT OF ORGANIC SOIL WITH CEMENT AND FLY-ASH

The soft soils which contain high organic matters usually lead to a low-strength cement-soil. This paper mainly studies the influence of fly ash as an additive on cement-soil. By comparing the unconfined compressive strength of the cement fly-ash soil mixtures with different cement contents, fly ash content and concreting time, the strength and deformation behavior of the mixtures are analyzed. Moreover, the improving mechanism of the organic soil is discussed. The results show that the unconfined compressive strength of the mixtures changed slightly at the beginning. However, the unconfined compressive strength increased remarkably after concreting. The optimal content of the fly ash was about 12%. At this fly ash content, the failure strain and E50 reached the smallest and maximum value, respectively. If the fly ash content exceeded 12%, the unconfined compressive strength of the mixtures decreased.