库水位骤变下滑坡–抗滑桩体系作用三维分析

库水位上升产生的浮力作用和库水位骤降时产生的渗透动水压力，将改变原有的水–边坡作用环境与条件，不利于库区边坡稳定。结合三峡库区马家沟I号滑坡的现场监测成果以及库水位波动数据，利用数值模拟方法，建立真三维模型。采用有限差分程序软件内置的Fish语言将分别考虑库水位上升和下降对坡面产生的静水压力作用、动水压力作用耦合于有限差分程序软件，对滑坡在库水位骤然上升与下降的位移和应力场进行分析，研究应力–渗流耦合作用下抗滑桩加固库区滑坡位移和受力特征，探讨滑坡–抗滑桩相互作用体系的防治效果。结果表明：抗滑桩与土体形成土拱效应以及抗滑桩阻滑效应相互作用下防治滑坡效果明显；库水位骤降产生的动水压力相比于库水位骤升产生的静水压力对滑坡–抗滑桩作用体系的减弱作用更大；数值模拟方法为对库水位骤变下滑坡–抗滑桩体系相互作用三维分析具有一定的指导意义。

3D ANALYSIS OF INTERACTION OF LANDSLIDE AND ANTI-SLIDE PILE SYSTEM UNDER SUDDEN CHANGE OF RESERVOIR WATER LEVEL

Due to the buoyancy produced by reservoir level rising and the dynamic stress produced by the descent of the water level，the intrinsic water-slope interaction circumstance and condition will be changed，which may results in the instability of the slope. Combined with the site monitoring results of the landslide #1 in Majiagou in the Three Gorges reservoir area and the water level fluctuation data，the true 3D model was established by using numerical simulation method. With finite difference program software and the Fish language programming considering the static water pressure effect to slope surface due to the rising of water level and the dynamic seepage pressure produced by the drawdown of reservoir water level，the displacement and the stress field of landslide during the evolutionary process of the changing of the water level were analyzed. Under the fluctuation of the water level，the seepage-stress fields，the displacement and mechanical characteristics of landslide in reservior area with the anti-slide pile reinforced were analyzed. In addition，the control effect of landslide-anti-slide pile system was discussed. The results indicate that：the combination of soil arching effect forced by the anti-slide pile and soil formation and the resistance slip effect of anti-slide pile，the landslide prevention and control effect are obvious. Compared to the hydrostatic pressure，the weakened effect of the dynamic water pressure produced by the reservoir water level drawdown on the landslide-anti-slide pile system is larger. The numerical simulation method may be applicable for 3D analysis of interaction of landslide and anti-slide pile system during sudden change of reservoir water level.