Mitigation of environmental risk of waste ground for contribution to sustainable society

由于日本国土面积有限，因此有必要利用封闭的垃圾填埋场和自然污染土壤作为资源。本研究对废弃地、底层粘土层和污染土壤进行了试验研究。主要验证以下项目：1）由于从初始刚度和内摩擦角的观点来看，废弃地面可以具有与桑迪地面一样高的强度，因此根据结构类型，扩展基础是适用的，2）当桩基础被安装以到达底部粘土层下面的承载层时，在正常固结条件下，由于粘土变形的影响，钢和粘土之间的通道足够封闭;以及3）铁铝榴石阻挡材料，例如GCL，即使在含有重金属的酸性岩石排水中也能保持极低的水力传导率，并能减少重金属的向外泄漏。

Since Japan has limited land space, it it essential to utilize closed waste landfills and naturally contaminated soil as resources. In this research, experimental studies were conducted to characterize waste ground, bottom clay layer and contaminated soil. The following items are mainly verified: 1) since waste ground can has as high strength as sandy ground from the viewpoint of initial stiffness and internal frictional angle, spread foundations are applicable according to type of structures, 2) when pile foundations are installed to reach the bearing layer beneath a bottom clay layer, the channel between the steel and the clay closed enough under the normally consolidated condition by the effect of clay deformation, and 3) the bentonitic barrier material, such as GCL, can maintains extremely low hydraulic conductivity even against acid rock drainage containing heavy metals, and can mitigate outward leakage of heavy metals.