A new type of compound anti sliding system with retaining and anchoring effect,called "anchor cable micropile structure",was presented through setting oblique prestressed anchor cable on the connection beam at the top of traditional micropile structure.Two groups of model experiments,in which a soil slope was reinforced by the double-row traditional micropiles and anchor cable micropiles respectively,were designed and conducted by graded loading.Besides,the numerical calculation of same experimental conditions was also conducted by FLAC3D.Then,the deformation and stress characteristics of the slope reinforced by anchor cable micropiles,traditional micropiles and both of them were analyzed comparatively,and the anti-sliding mechanism of anchor cable micropiles was further studied.Results indicate that:compared with traditional micropile structure,the deformation of slope and the displacement of connection beam are obviously reduced after being reinforced by anchor cable micropiles.Stress concentration region distributes around anchor cable micropiles and a compound structure-soil skeleton is formed,the slip stress and deformation are prevented from transferring along the landslide direction.The lateral stiffness of the micropile structure is effectively enhanced by the prestressed anchor cable,and the lateral inclined deformation of the structure is decreased.The distribution of internal and external forces of micropiles tends to be uniform,which is advantageous to exert the mechanical properties of pile body timely and fully.With the gradual increase of load,the deformation process of micropile structure can be divided into three stages,including small deformation,large deformation and limit-equilibrium failure.Corresponding to the three stages above,the change law of load sharing ratio of pile over cable is increasing firstly,then decreasing and increasing again lastly,among which the ratio value of the last stage is roughly from 1.3 to 1.5.%在传统微型桩顶部联系梁上加设斜向预应力锚索,构成新型复合挡锚结构的锚索微型桩.采用分级加载方式进行双排传统微型桩和锚索微型桩加固土质边坡的室内模型试验,并结合相同条件的FLAC3D数值计算,对比分析锚索微型桩和传统微型桩以及采用两者加固后边坡的变形和受力特征,进而探讨锚索微型桩的抗滑机理.结果表明:相比传统微型桩,经锚索微型桩加固后边坡的变形和联系梁的位移明显减小;锚索微型桩周围产生应力集中区,形成结构一土体的复合骨架体系,阻滞了致滑应力和变形沿滑坡方向的传递;预应力锚索有效增强了微型桩结构的侧向刚度,结构侧向倾斜变形减小;微型桩的内力和外力分布趋于均匀,有利于及时和充分地发挥桩体的力学性能;随着堆载的逐级增加,微型桩结构的变形过程分为小变形、大变形和极限破坏3个阶段,对应的桩锚荷载分担比呈先增大、后减小和再增大的变化规律,极限破坏阶段的分担比稳定在1.3～1.5之间.
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