Noriyuki NISHI

Study on Mud Pumping of Foam Composite Light-weight Soil

Takaya KAINO

The design compressive strength of Foam Composite Light-weight Soil (abbr. FCL) that is used for the banking material of the railroad is set up to 1,500kPa at the present day. I researched about the mix of the strength 1,000kPa & 500kPa for the purpose of lightening furthermore the specific gravity. I carried out the cyclic loading test on model of the FCL banking under humid condition increasing the pressure step by step to inspect the pressure which mud pumping occurred on FCL banking. It is thought that the main cause of mud pumping occurrence is the presence of water, because no destruction and no progress of subsidence occur under low cyclic pressure if the water was not supplied. Thereupon, I carried out the element test of the saturated and also unsaturated specimens of FCL to make clearly the mechanical characteristic. The occurrence mechanism mud pumping was able to be approximately clarified from the result of the cyclic loading test and element test.