抄録
Sand grains of uniform size were sieved out of natural and crushed quarz sand. Series of synthetic sand were prepared by mixing the sand grain and a fixed amount of binder, Kibushi-clay, in which the water content was varied. Permeability and strength of sand were examined and the following results were obtained. Some considerations were given on the results. The maximum permeability of sand is given by the formula P=kdn, where d is the average diameter of sand grain. n is the index, whose numerical valve lies between 1.4∼1.7, according to the kind of sand. With a fixed amount of binding meterial, strength of sand is higher with coarse grain size. On the other hand, when grain size becomes finer than 100 mesh, the strength of sand has a higher value. This phenomena are explained by two factors of sand strength, binding power of clay and contact resistance of sand grain. Strength of sand with coarse grain varies rapidly with water content, and in such sand, care must be teken to control the moisture in the practice.
