模拟库水位变化的抗滑桩加固边坡离心模型试验研究

 抗滑桩是边坡深层抗滑最为有效的措施之一，以三峡库区边坡抗滑桩加固工程为背景，利用离心模型试验手段，模拟库区蓄水和水位循环变化条件下失稳边坡的抗滑桩加固机制。详细介绍相应的离心模型试验方法，通过对一系列自然边坡和不同桩间距条件下的模型试验，获得库水位变化影响下的边坡变形、破坏模式和抗滑桩受力，探讨滑坡推力的分布以及不同桩间距条件下的抗滑桩–边坡相互作用机制。测试结果表明，受抗滑桩加固的边坡在水位升降作用下仍发生一定程度的变形并产生裂缝，随着抗滑桩的直接支挡和桩后土体由于不均匀位移产生土拱效应后，边坡变形逐渐得到较好的控制。在本试验条件下，随着桩间距的增大，边坡变形总体上表现为增大趋势，但抗滑桩的受力呈现出先增大后减小的抛物线型变化形态，在某一最适桩间距情况下抗滑桩的抗滑性能得到了最充分的发挥，而滑坡推力表现出复合三角形分布特征。该研究结果为桩土相互作用和库区边坡抗滑桩加固机制分析提供了直接的试验依据，对丰富抗滑桩设计理论和库区边坡的防灾减灾研究具有较为重要的意义。

CENTRIFUGAL TESTS ON SLOPE REINFORCEMENT BY ANTI-SLIDING PILES MODELLING CHANGE OF RESERVOIR WATER LEVEL

Anti-sliding pile is one of the most effective measures for slope reinforcement. On the basis of centrifugal tests modeling the impoundment and cyclical change of water level in the Three Gorges Reservoir，this paper pays attention to the reinforcement mechanism of unstable reservoir slope by anti-sliding piles；and the corresponding test techniques of centrifuge modelling are introduced. A series of centrifuge tests including natural slopes and reinforced slopes with different pile layouts are conducted；slope displacement，failure modes and bending moments of piles are obtained during the testing procedure；the distribution of landslide pushing force，mechanism of pile-slope interaction and arching effect are discussed as well. Results indicate that the deformation of reinforced slope will still occur during the first stage of change of reservoir water level；it will be gradually controlled during the form of arching effect due to different soil displacements behind the piles. Moreover，the bigger the pile spacing is，the weaker reinforced effects are，which leads to the larger slope deformation. However，the maximum pile bending moment of each test shows parabolic character，so there must exist an optimal pile spacing under which the reinforcing effect will be the best. In addition，the pushing force acted on the anti-sliding pile obeys multi-triangle configuration. This study provides not only the direct data for the investigation of interaction mechanism between pile and slope，but also the new idea of optimal pile spacing for slope reinforcement design. It will contribute a lot to the theory of slope stabilization by piles and prevention of landslide disaster in the Three Gorges Reservoir area.