Centrifuge Model Tests On The Engineering Soil Slope Under Rainfall Condition

With the development of human society and technology progress, the engineering slope has become even higher and steeper. Due to the slope instability caused by the landslide, collapse and other geological disasters can cause huge personal and property loss, slope engineering instability problem has attracted more people’s attention.The centrifugal model test is not only one of the important means of test in geotechnical engineering,but also the best similarity in all kinds of physical model test in various types of test method. Centrifuge model test technology can simulate the gravity field by changing the centrifugal acceleration, in order to realize the simulation of many geotechnical structures related to working conditions.This thesis takes unsaturated cohesive soil engineering slope as research subject, with the geotechnical centrifuge model test technique, study unsaturated cohesive soils engineering instability mechanism of slope under the condition of rainfall.1. On the Rainfall infiltration theory and The mechanism of rain-falling induced slope instability is analyzed.2. Developed a new centrifugal model rainfall test system, including high pressure eddy current centrifugal atomizing spray system, centrifugal fiber grating integrated test system, centrifugal field measurement data acquisition system, etc., and then tested the validation of this system, calibration, assembly. The method can get a better test results than the electrical test component.3. Based on the similarity principle, the similarity parameters of centrifugal rainfall of slope were derived, and the comparison, selection and testing of the relevant materials were carried out. a comprehensive set of test processes of selecting material, selecting monitoring original, original layout, and loading, monitoring of the test of the slope rainfall centrifuge test were formed.4. Combined with the new centrifugal rainfall devices and the fiber grating integrated test system, a group of10soil slope centrifugal rainfall model tests were carried out under conditions of different rainfall conditions, retaining conditions, slope conditions, stratum conditions, etc. The evolution characteristics of the factors of the displacement change during the test slope, moisture content change, pore pressure change, retaining force structure change, and the typical slope failure mode were obtained with time changing.5. The test analysis showed that the heavy rains the sliding surface of slope under the condition of short time depth is shallow, generally with in the slope under4m, and the rain for a long time the sliding surface of slope can be reached under the condition of slope under6-10m; Compared with the ordinary slope, slope with weak intercalated in rainfall can rendering multi-layer sliding surface。6. Retaining structure can effectively reduce the deformation of slope, providing anti-slide force, increasing the stability of the slope, lower the risk of instability. Also we should pay attention is that retaining structure can reduce the flow velocity of water applied in slope, increased the water holding capacity,so that the shallow landslide risk transfer to the deep side.