Disintegration Behavior Of Residual Soil And Nonlinear Time Series Analysis For Its Slope Displacement

There is granite residual soil widely distributing in Fujian province. For long time, the influencing factors and sliding behavior of residual soil slope have been largely studied, whereas it has not manage to identical understanding for the formation mechanics and influencing factors. In particular the research of slope destabilitation affected by the disintegration of residual soil has been lessly dealt with. Some samples of granite residual soil are used to take indoor slaking test. The results indicate that they cause disintegration as soon as they contact water. And the process of disintegration consists mainly of three seedtimes namely initial stage of low speed, metaphase of speediness and anaphase of slow speed over again. The disintegration speed is rapider when the moisture content becomes greater. The soil with more coarse grain is of rapider disintegration speed and vice versa. There are large quantities of blebs coming during the course of tests, which shows that the granite residual soil contants some ingredients that are prone to be dissolved by water and take place chemical reaction, accelerating the disintegration in a way. Thereby during any slope engineering, it should be taken recognition to heavens to the disintegration character of residual soil and correspond control measure should be adopted. Whereas there are close relationships between rainfall and the disintegration as well as the displacement of residual soil slope, the effective rainfall which bring the soil on slope into saturation is studied. It is indicated that when it reaches the effective rainfall, the slope comes into saturation and the shear strength becomes minimum value, and consequently the safety factor of slope is minimuming. The result can provide gist for adopting control of slope destabilization. The displacement is one of important information feeding back from evolvement of slope deformation. The displacement supervising is used to take modeling to forecast future evolvement trend of slope, which is of import significance in engineering. Based on the displacement monitoring data and rainfall information, the model of nonlinear time series analysis namely threshold auto-regression model is set up and three instances are taken into account. The results are reconciled with the actual data when the current rainfall is considered. By compared the actual monitoring data with the calculated values, it is showed that the model can be used to predict the displacement of resemble slope, which makes the observation more effective.