Theoretical Research On Real Time Stability Of Landslides

The study of slope stability has been an important topic in the field of geotechnical engineering. As an important basis for the evaluation of the slope safety state, slope monitoring can reflect the slope motion state intuitively, so it is widely used in slope engineering. However, the current discrimination and prediction methods of the slope stability are based on the field monitoring data and start with the trend of analysis data, which cannot build a deeper inner relationship between the slope displacement monitoring data and the mechanical stability mechanism of landslide. Therefore, we need to strengthen the theoretical study on the prediction of slope stability which is based on the monitoring data.On the basis of spot investigation throughout the part of Hainan Province Forest Park, we found small collapses and shallow landslides occurred frequently in the park due to increased human activities (economic crops planting, mountains excavation, scenic road construction, etc.) and years of typhoon heavy rainfall erosion. This is not only a great destruction to the natural ecological environment of the park, but also a serious security risk. Therefore, it is essential to strengthen the slope observation, the forecast and warning and the slope treatment in these areas.Combined with the slope displacement monitoring information analysis, the soil stress state and the stress-strain relationship analysis, the real-time calculation of slope stability is proposed in this paper, which is based on the displacement monitoring data. First, the index parameters and variation oftypicalHainan red loam, which are necessary in the theoretical research,are obtained by conventional physical property tests, triaxial tests and direct shear tests under different saturation; Then, the displacement of virtual deep inclinometer measuring point is extracted from the calculation results of slope stability finite element displacement field. According to the relative displacement of the two adjacent monitoring points, the strain of the sliding surface in this section is calculated, and analyzing the soil stress state of the analog monitoring points in the model at the same time; Next, according to the stress strain curve and shear displacement curve, which can be got by triaxial and shear test, the corresponding shear and strain is defineded and its relation curve is obtained; Finally, combined with the real-time strain on the slope sliding surface and the shear strain curve of soil sample under corresponding stress state, the real-time shear stress on the slope sliding surface is obtained, and compared with the peak of soil shear strength to define the slope real-time stability factor.Real-time safety factor method proposed in this paper can build the relationship between slope displacement monitoring data and landslide internal mechanical stability mechanism, so as to realize the real-time tracking forecast of slope stability. This method overcomes thedisadvantagesof the traditional slope stability analysis theory, which ignored the deformation process and just get the single stability factor. Compared with numerical analysis of slope stability, real-time safety factor methodavoid the problems of rainfallinfiltration intensity determination and fluid-structure interaction analysis, etc. It can be comprehensively reflected by the displacement of sliding surface directly, and reduce the difficulty of slope real-time stability analysis.Comparative calculations show that: the results of real-time stability coefficient method, traditional slope stability and strength reduction of slope stability analysis method are basically consistent, so the real-time stable slope stability coefficient method which is suggested in this paper is theoretically feasible.