COUNTERMEASURE FOR LIQUEFACTION AND TEMPORARY WORKS IN NIIGATA PORT ROAD TUNNEL

For the foundation of the left bank retaining wall part in Niigata Port road tunnel, in orderto improve work efficiency and reduce construction cost and period, cantilever earth-retaining usingreinforced deep mixing (DM) method was adopted for the purpose of temporary earth-retaining, imperviousground, outer form of the main structure, and liquefaction countermeasure.In order to design this type of soil improved and H steel reinforced composite structured earth-retaining, which has no preceding case, reinforced concrete (RC) design method for acantilever beam based on Bernoulli-Euler theory was introduced combining with conventional DM designmethod.As a result of various type of researches, analyses, laboratory and in-situ tests, this methodwas proved to be feasible in terms of both design and execution.