Abstract: Gridding concrete retaining wall(GCRW) is a new-type supporting structure usually used in excavation of foundation pit in soft soil region; and interaction between GCRW and soft soil is the key issue to be studied profoundly. Centrifugal model and test plan were made firstly by means of background engineering; then the interaction between GCRW model and soft soil was successfully simulated through centrifugal model test of step by step excavation; finally, we made a comparion between measured results of earth pressures and ones based on Rankine theory. The results show that nearly all of the earth pressures take on linear distribution characteristic increasing along depth; GCRW produces deformation and displacement because of earth pressue on the inside of front wall caused by excavation. GCRW and soft soil in the gridding as a whole keep balance under the action of earth pressues, of which the stressed characteristics are similar to those of gravity supporting structures. While this structure is in its most unfavorable conditions, the earth pressures in active region are between earth pressure at rest and active pressure; but those in passive region are bigger than passive earth pressures. One of the reasons that front wall doesn’t overturn is the pulling force from partition wall prevent the front wall from overturning

Key words: gridding concrete retaining wall (GCRW), centrifugal model test, soft soil, earth pressure, excavation, gravity supporting structure