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中国东南沿海山地丘陵地区气候湿润,每年梅雨季和台风侵袭时都伴随有大量土质滑坡,研究降雨诱发土质滑坡的失稳模式和机理对该类滑坡预警预报及防治具有重要意义。笔者自行研制了离心机机载降雨模拟装置,在50g条件下模拟和再现了非饱和粉土边坡在不同强度降雨条件下的失稳破坏过程,揭示了降雨诱发粉土边坡的失稳模式为坡脚局部失稳—向上扩展—整体浅层滑动,滑动面深度介于1~3 m。3组试验获得了降雨强度与边坡失稳时降雨历时关系数据,与李鹤等针对东南沿海地区残积土边坡提出的雨强–历时警戒曲线(I–D曲线)最为接近,验证了该降雨量警戒曲线的有效性。对离心模型试验结果进行反分析表明:非饱和土渗流分析能有效模拟边坡降雨入渗过程,而现有极限平衡分析方法难以准确捕捉降雨诱发边坡由局部向整体发展的失稳过程。基于所揭示的失稳模式,指出了该类降雨诱发滑坡的有效防治措施主要包括坡脚加强排水和支护、坡面防渗和防护。
The climate in mountainous hilly area of southeastern China is humid. Every year during the rainy season and typhoon invasion, there are a lot of soil landslides. It is of great significance to study the failure modes and mechanism of rainfall-induced soil landslide on the prediction and prevention of such landslides. The author developed a centrifuge airborne rainfall simulator to simulate and reproduce the failure process of unsaturated silt slope under different intensities of rainfall under 50g conditions and reveal the instability mode of rainfall induced silty slope For the slope foot local instability - upward expansion - the overall shallow sliding, sliding surface depth between 1 ~ 3 m. The data of rainfall intensity and rainfall duration in slope instability were obtained by the three groups of experiments. It is the closest to the rainfall-duration warning curve (I-D curve) proposed by Li et al. For the residual soil slope in the southeastern coastal area. Effectiveness of rainfall alert curve. The inverse analysis of the centrifuge model test results shows that the unsaturated soil seepage analysis can effectively simulate the rainfall infiltration process, while the existing limit equilibrium analysis method can not accurately capture the instability process of rainfall-induced slope from the local to the overall development. Based on the revealed instability model, it is pointed out that effective measures to prevent and control this kind of rainfall-induced landslide mainly include slope foot strengthening drainage and support, slope seepage prevention and protection.