Simulation Of Deep Excavation Considering Spatial Effect And Studies Of Effect Of Stress Path Of Soil On Mechanical Properties

Urban constructions of Tianjin are developing greatly. A great deal of deep excavation engineering has been coming forth. In addition, the geo-environmental problems become more and more important in design and construction of substructures with the scale and depth of excavation increasing. Especially, the environment response due to adjacent excavation-induced soil movements gets more and more attentions from the engineer. How to reduce the environment effect of excavation, Spatial effect is applied to foundation excavation in Tianjin, deformation of the support structure and the building settlement near the foundation pit are observed, and Finite Element Analysis is used to simulate the spatial effect on foundation excavation, the results show obvious spatial effect during excavation, Spatial effect using reasonably can reduce deformation of the support structure and effect on environments around the foundation.Mechanical properties of clay are related to stress variation and stress state. By using the conventional triaxial shear test, the effect of stress paths on it can not be reflected actually. With the self-made triaxial equipment, a series of Ko consolidation and undrained shear tests has been carried out to study the effect of stress paths in excavation of considering spatial effect on the deformation and shear strength properties of a typical soil in Tianjin city. According to the experimental results, the deformation and shear strength properties are different from that of conventional triaxial test. This shows that, in an actual project, the stress paths should be determined according to load case and stress state so that the mechanical parameters of clay can be measured correctly and reasonably.