A local soil called “Polishing soil, Migaki-suna” (hereafter called as Polishing sand) is found in Handa district, Tsu city of Mie Prefecture. As we could easily surmise after its name, the sand in old days was utilized as polishing powder, tooth/washing powder, etc. The engineering properties of Polishing sand were in detail examined in the laboratory, bearing in mind mitigating any disasters in the Polishing sand ground or making use of it as fill material. The sand is stiff enough in natural state. However, it turns out uniform and fine sand with greyish white color. The sand exhibits the engineering characteristics similar to those of Shirasu, despite that Shirasu and the sand is categorized as sand and clay, respectively. In spite that the sand contains fines more than 90 percent, it shows alike sand behavior, since most of fines refer to silty grains (i.e., nearly 80 %) and those grains are made of volcano-originated glass. The shear strength characteristics of the in-situ sand are c
cu≒100-200 kPa, φ
cu≧40-50°, whereas those of reconstituted sample are c
cu=10kPa, φ
cu=36° on average. Since the reconstituted sample is vulnerable against submergence, some improvement with cement is needed when the sand is used as fill material.
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