Study On Mechanism Of Soft Soil Crack's Propagation Under Strata Movements And Engineering Applications

ABSTRACT:In the light of the strategic position of Binhai new area in Tianjin, it is a good opportunity for Binhai new area to build up well-developed modern economy zone. However, Binhai new area is one of the major coastal seismic areas, which locates in the southeast of north China seismic belt, to the west of Yanlu strong seismic belt and in the meeting place of Hebei plain seismic belt and Zhangjiakou-Bohai seismic belt. And foundation soil belongs to typical sedimentary soft soil of littoral-alternative sea and river facies, so it is full of serious challenge to be faced with the threat from earthquake. As the most threatening and high-frequency incidence earthquake, one of Tectonic earthquake's rupture ways is the failure of structure resulted from strong deformation of soil under strata movements resulted from fault movements, so it is very important to discuss the soil crack's propagation and engineering application in Binhai new area under strata movements. They're discussed by finite difference method, which is one of numerical analysis methods. The main contents contain the following sections:1. Collect and analyse the former document relating to fault movements, and then absorb the research results.2. In order to improve the simulation accuracy, it is studied that numerical simulation of strata movements. According to the dislocation characteristics, the analytical models are made.3. In order to understand the characteristics of actual site better, two kinds of monolayer soil are chose to analyse the soil crack's propagation mechanism under different dip angles.4. Based on the analytical results of monolayer soil, models of Tianjingang site and Hangu site are made, and then they're done a comparative analysis that the soil crack's propagation characteristics under different dip angles and different movement types.5. Engineering applications. Two situations of tunnel models are made, and they're analysed comparatively that the deformation characteristics of tunnel lining and crack's propagation of surface soil and soil near the tunnel.By means of modeling the different analytical models in Tianjingang site and Hangu site and analyzing the influencing of multi-parameter effect factor on the same model, some useful conclutions on soil crack's propagation characteristics are obtained. These conclutions could be guide for anti-seismic research of underground structure in Tianjin and reference for later research for seismic resistance of structure.