Numerical Analysis Of The Soil Nailed Retaining Structure For The Excavation In Soft Soil

Recently, the soil nailed retaining structure has been popular for the excavation not only in the northern hard-soil but in the coastal soft soil. However, the theories about the soil nailed retaining structure are lagging behind the engineering practice. In this thesis, the studies listed below were carried out, considering current research and design status of the soil nailed retaining structure.1. The lateral displacement, settlement and plastic aera of excavation were analyzed numerically when the soil nailed retaining structure was applied to the excavation. By the numerical simulation, the failure process of the structure was showed and thus the retaining effect was obtained.2. The effect to the excavation with regard to various parameters of the soil nailed retaining structure was studied, including the nail length, the pattern of arrangement, the slope angle, etc.3. The retaining mechanism of composite nails and the relationship between the parameters of soil and pile and the composite nails was analyzed in this thesis. The analysis shows that the modulus of soil and Poisson ratio greatly affect the Soil Nailed Retaining Structure and that the depth and width of mixed-in-place pile both have critical values.4. The stability of the passive soil around the excavation was studied with regard to various improved aera by composite nails, such as their depth and width. The study shows that the appropriate width and depth of improved area should be 0. 8 to 1.0 time and 0.2 to 0.4 time of the depth of excavation respectively.