Model tests on supporting mechanism of soil nailing wall in silty clay deep foundation

Based on the similarity theory, the similitude ratio of model tests is confirmed, the similar materials are selected according to the similitude ratio, and the physical model for soil nailing wall is established. The reasonable test system, loading system and precipitation testing procedure are designed. The horizontal displacement of soil nailing wall top, axial force of soil nails and earth pressure are tested and analyzed. The results show that the primary factor that affects the displacement of soil nailing wall is the soil stress redistribution caused by pit excavation, and every excavation makes the horizontal displacement of the wall top present stepped increases. The horizontal displacement reaches 2.3‰ of excavation depth at the excavation and supporting stage. The rainfall is an important factor of the horizontal displacement. If the loading on the top of the wall is not very large, the horizontal displacement of the wall top increases with the growth of excavation depth. With the pit excavation the lateral earth pressure of soil nailing wall first increases and then decreases but its overall trend is to increase. During the pit excavation, the forces on soil nails develop from the end to the inside.