Caking Agent for Soft Mud Chemical Plug Shield (CPS) Method 　The Shield Method is widely adopted in construction of under-ground　tunnels, sewer systems and under-ground passages etc. Excavating with a rotating propeller equipped blades at the edge, which is protected by pouring muddy water, at the same time it facilitates operation. In construction under ground with high hydraulic pressure, there is a risk of spouting excavated soil. Under CPS system, to prevent from spouting muddy soil and to achieve smooth excavating working, the muddy soil containing profuse water is coagulated into plugs on the screw-conveyer during transporting up to the ground. We have developed a solidifying agent “ERFRESH” based on natural plant ingredient. This facilitates carrying out the waste soil from the working site and returns to nature. This is uniqe slurry treatment agent and widely being applied to Chemical Plug Shield Method as the officially resistered agent at The Shield Method Engineering Association.