A multi-scale study on the evolution mechanism of micro-structure and macro-mechanics of soil in sliding zone under drying-wetting cycles with loads
[Objective]The slip zone of landslides can be affected by changes in water levels in the reservoir,leading to cycles of wetting and drying with loads that can impact the stability of landslides.However,this complex issue involves the evolution of mi-crostructure and macroscopic mechanical properties at multiple scales.[Methods]The study focuses on the sliding zone soil of the Shuping landslide in the Three Gorges Reservoir area.Under loaded conditions,direct shear tests,scanning electron microscopy(SEM),and nuclear magnetic resonance(NMR)tests were conducted on reshaped sliding zone soil that underwent different wet dry cycles.The strength and microstructure evolution of reshaped sliding zone soil under loaded wet dry cycles were analyzed.[Results]With the increase in wetting and drying cycles under loading,the cohesion of the soil gradually increases(with a degra-dation degree of approximately-30％),while the internal friction angle of the soil shows a decreasing trend(with a degradation de-gree of approximately 22％);Microscopically,the small pores gradually connect to form large pores,but macroscopically,the po-rosity decreases exponentially(with a decrease of approximately 7％).Additionally,the micro-characteristics indicate a gradual disintegration of clump-like aggregates with each cycle,and a transformation in the way clay particles associate,from edge-to-face and edge-edge flocculation to face-to-face aggregation.These changes ultimately result in the friction angle deterioration.Mean-while,there is a significant positive correlation between moisture content and cohesion of dry soil,indicating that increased cohesion is closely related to the presence of water in clay minerals.[Conclusion]This study reveals the mechanism of soil microstructure's multiscale evolution,which is significant for studying geological hazards because of soil structure deterioration.
soil in sliding zonedrying-wetting cycles with loadsmicrostructuremuti-scale structure evolutionclay mineralslandslidesmodel testing
万方数据
维普
