Analysis And Forecast For The Law Of Horizontal Displacement In Soil Nailing Supporting

Soil nailing supporting is a new technology developed from abroad in recent years,to be used in excavation of soil and slope stability. The technique had been wide used in engineering for its merit such as simple technics,cheap cost and lesser time limie for a project. Stability of soil nailing supporting is one of the most advertment questions along with increase of deepness.So it is necessary to detailed research the strength mechanism of soil nailing. However,the strength mechanism of soil nailing was not knew yet at present,so the theory is behind the application,especially the study of deformation of soil nailing supporting is lesser.The deformation theory of soil nailing was dissertated in this paper,including drawing-resistance function mechanism during pulling-resistance test of soil nailing,friction reinforcement principle of earth,soil arching effect and apparent cohesion theory.Based on lots of documents and collecting test result of stress-strain,summarize stress characteristic of soil nailing,and validate academic analysis of soil nailing.Though geological condition and ambience of every project is disaffinity,their level displacement curve is well-regulated. The paper collects meterage data of level displacement in Beijing area and summarizes variational rule.It helps to safety project.The paper founds GM(1, 1) model of gray prediction theory in order to predict level displacement,and forecast horizontal displacement of 8-8 section of the Olympic Games project with it and compares forecast data and actual data.The result is that GM(1, 1) model may forecast short-term horizontal displacement after the model is proved eligibility. In order to manage long-term horizontal displacement,the paper founds metabolism GM(1, 1) model.At first, founding GM(1,1) model with known data and forecast next numerical value,next renewing founded GM(1,1) model with numerical value at the same time abnegating first data,and then forecast nest numerical value with same method.The paper forecasts horizontal displacement according to every step of soil nailing supporting with the model and validate feasibility of model with engineer example. The result is that metabolism GM(1, 1) model may better forecast every step of soil nailing supporting.