Study On The Stability Of Island Rock Slope Under Rainfall And Toe Quarrying

Island is an important composition of Marine ecosystems. The slope instabilityof island is one of the geological disasters. Rainfall and toe quarrying play importantroles in the instability of island rock slope. Because of the complexity of the islandenvironment and the perniciousness of landside, the real-time monitoring of islandslope is needed in order to obtain the instant message, and the stability of islandslope is also needed to be analysized and evaluated qualitatively andquantificationally. Rainfall and toe quarrying always trigger the instability of slope,so their influence on the stability of island slope should be studied deeply, and thecorresponding early warning value should be given. The paper takes the landslide ofChangshan northern island as the research background. Based on the actualmonitoring displacement of island rock slope and by using the finite elementstrength reduction method, the evaluation and analysis of the stability of island rockslope have been studied. The main work done in this paper is as follows:1、The large nonlinear finite element software ABAQUS is briefly introduced atfirst. The principle of strength reduction method and the slope failure criterion arealso presented. Meanwhile, the theory and method based on real-time monitoring inslope engineering is briefly introduced.2、 Based on the engineering geologic condition of landslide located onChangshan northern island, with the large-scale nonlinear finite element softwareABAQUS, a number of practical island finite element analytical models are modelingby means of considering the influence of the inherent structural surface of rock. Thesafety factor of slope, the position of sliding surface, displacement and otherinformations are obtained.3、An equivalent reduction approach is proposed to consider the influence ofrainfall on slope stability. The key of this method is that the slope displacementincrement caused by rainfall is equal to the displacement increment caused by thereduction of slope strength parameters. Based on the relationship between dailyrainfall and daily incremental displacement and the relationship between reductionfactor and displacement, taking the displacement as the intermediate variable, the corresponding relationship between daily rainfall intensity and slope equivalentreduction coefficient is established and early warning values of slope instability due torainfall are proposed.4、For the influence of toe quarrying, eleven calculation schemes are presented.Based on the analysis of computing result, the influence of toe quarrying on the safetyfactor has been obtained, and the early warning value of toe excavation on stability ofisland slope are also proposed. At the same, rainfall after toe quarrying for thestability of island slope and the estimation of the volume are also studied.