Research On The Influence Of The Existing Building Composite Foundation On Earth Pressure Of Foundation Pit

With the development of the society, the constant speed of city construction, city center area land scarcity increasingly apparent, distance between buildings in the city, but the heart of the city buildings are generally tall buildings, new buildings are generally at the bottom of the basement, so in the later stages of the old city transformation and the surrounding buildings were deep foundation pit, will inevitably encounter new buildings become limited soil surrounding soil, and is no longer the past of infinite soil.Foundations of a new building around the house when using composite foundation, because of the building at the bottom of the basement of the homework, all of the load will be borne by the composite foundation of pile and soil together, rather like pile foundation used by or borne by the friction in the form of the vast majority of the load, in this way, can let the back earth pressure of retaining structure under its own gravity, will also take some additional stress. As the deformation of foundation pit support in these additional stress affected slowly, near the pit construction of composite foundation soil will change the original state of rest, pressure into to the launch of a foundation pit; These factors combined to make foundation pit surrounding soil stress is very complicated. In this case, the proposed building around the basement and composite foundation of the influence of excavation of foundation pit supporting is worth to study.In this paper, the first part is to ask questions, the paper mainly expounds the research purpose and meaning, and the research achievements of domestic and foreign experts and scholars and literature review. Is the second part introduces the foundation pit engineering of soil pressure calculation theory, first of all, this paper expounds the classical earth pressure theory, secondly, analyses the equivalent treatment method of pile composite foundation, at the same time, according to the equivalent treatment of composite foundation method simplify the calculation of foundation pit is proposed. The third part is the main line, mainly for existing buildings under the condition of composite foundation excavation are numerically simulated, first of all, the elastic-plastic model of ANSYS software, ANSYS, and analyses the ANSYS nonlinear problem of processing method, on this basis, the numerical analysis model is established and presented for existing buildings, natural foundation, composite foundation based numerical simulation method of three kinds of model. The fourth part is the in-depth analysis, deeply discusses the pit cement-soil pile composite foundation of foundation pit soil pressure. The fifth part is conclusion.