某具有软弱夹层的反倾岩坡变形特征探索

Study of the deformation characteristics of an anti-dip slope with soft internal layers

反倾岩坡的结构面倾向与边坡倾向相反,通常认为反倾岩坡的稳定性较强,因此相对于顺倾向坡而言,对反倾岩坡的研究较少,但工程实例表明对反倾边坡的稳定性研究意义重大。当反倾岩坡中有软弱岩层时,软弱结构面会对坡体变形产生影响,因此借助内、外观测成果对一具有软弱夹层的反倾岩坡进行研究,对其变形特征和变形机制进行分析。研究结果表明边坡在开挖过程中变形呈现"点头"现象,且在边坡变形体后缘出现拉裂缝。由于存在较厚的软弱层,坡体在倾倒变形的同时对软弱岩层压缩产生压缩蠕变,所以坡体整体变形模式为压缩-蠕变、倾倒-拉裂复合模式。软弱岩层对坡体变形具有一定控制作用,支护效果说明对穿锚索可以有效地约束坡体变形。

That the dip direction of slope is opposite to the dip direction of the rock strata is a typical feature of anti-dip slopes.In general,an anti-dip slope is considered to be much more stable,so the relevant study is less.However,when the slope rock mass contains soft inter-layers,its deformation behavior will be influenced by the soft inter-layers.An anti-dip slope with soft interlayer is studied for its deformation characteristics and mechanism by using monitoring data.The result indicates that in the excavation process the slope deformation assumes ＂bow and scrape＂,and there is an open fracture in the deformation body of the upper side of the slope.In the excavation process,the slope tilts,and,due to the thick soft interlayer,the slope experiences compressive creep deformation.The slope deformation model should be a composite of compressive-creep and tilt-split models.The slope deformation is controlled by the soft interlayer,which may be effectively restrained using end-fixed cables.