2016 年 4 巻 5 号 p. 97-100
The development of ground improvement technology by means of permeation grouting using recently developed ultra microfine cement has been underway by the authors’ group, especially for mitigating effects of soil liquefaction on existing structures built on liquefiable soil deposits. From the experiences gained from the field tests carried out at the different two sites, this method works well for relatively clean fine sand deposits, though it may still need some refinement for silty sand deposits. Some supplementary methods assisting permeation of cement solutions through silty sand deposits were pursued based on laboratory permeation tests, and one method was found promising. This method employs the injection of water, following infiltration of relatively dense cement solutions which would be terminated by cement particles trapped within micro-scaled silty sand skeletons. In the present study, a series of laboratory one-dimensional permeation tests are conducted to examine this supplementary method in more detail, especially from the viewpoint of cost-effectiveness and performance.