To promote a uniform kneading between additives and earth-sand by making a mass of earth and sand to be conveyed in a pressure pipe by dint of compressed air in a state of repeating the formation and disruption of a plug, into such a state that pressure in the pressure pipe is lowered, thereby checking the formation of any earth-sand plug, and after adding the additives to the earth-sand, repeating the formation of disruption of the plug again.
A pressure regulating diffuser 4 with an airvent valve 3 is installed in the point midway in a pressure pipe 2, while pipe pressure is lowered to some extent, and pressure pulsation is averaged, whereby a supply of soil S is stabilized. A pipe diameter of the pressure pipe 2 is contracted again and, after installing a damper diffuser 6, the pipe diameter is reconnected, and the soil S, in a state of checking the formation of any soil plug at the upstream side of this damper diffuser 6, is moved into this damper diffuser 6. The pipe diameter of the pressure pipe 2 is further reconnected, and a pressure regulating diffuser 8 with a filler hole 7 of an additive X is installed there, through which the additive X is supplied by way of blowing it to earth and sand in the pipe with pressure air higher than that in the pipe. Thus the soil plug is formed there as the pressure pipe 2 whose diameter is contracted again and again.
MASUDA MINORU
SAKAMOTO AKINORI
TAKEUCHI MOTOYUKI
YOSHIDA SATOSHI
