通过大型滑坡物理模型试验,利用计算机辅助检测技术测量坡体表面的位移场,获得抗滑桩加固斜坡坡面位移场分布特征,统计斜坡失稳过程中坡面位移场的特征统计量-方差,根据位移场方差值D(X)的平稳变化和急剧变化对坡体失稳破坏过程进行描述;运用分形理论R/S分析法,确定滑坡位移场时序分形动力学参数-坡面位移场方差的Hurst指数,研究抗滑桩加固斜坡失稳过程中坡面位移场的演化规律。试验结果表明:坡面位移场特征统计量-方差可以用来表征斜坡宏观裂缝的发育、贯通,以及斜坡的失稳破坏;宏观裂缝形成前夕,坡面出现局部变形带,局部变形进一步集中,形成宏观地表裂缝,此统计特征量-方差出现突变,斜坡失稳破坏时,位移场方差出现激增:斜坡失稳过程中位移场时序分形动力学参数-坡面位移场方差的Hurst指数表现出“低值-回升-降维”的演化趋势,坡面位移场方差的Hurst指数随着斜坡由稳定向失稳的演化出现明显降维突变规律。
The surface displacement field of slope stabilized with piles in physical model tests was obtained using the computer aided inspection. The variances D(X) as the characteristics variable of the surface displacement field at different loading levels were calculated and used to describe the whole deformation and failure process of the slope. The dynamic parameter of slope displacement field and the fractals-Hurst index of variance of the surface displacement field were determined by means of R/S analysis. Experimental results show that the variance D(X) of the surface displacement field can be used to describe the formation and penetrating of the cracks and the failure of the slope. The severe deformation localization occurred on the slope surface and the cracks were developed. The varianceD(X) increased sharply when the deformation localization occurred. It is found that the Hurst index of the surface displacement field variance had a trend of low value-increase-dropping during the process of landslide. The Hurst index of variance of the surface displacement field decreases before the destabilization of the slope.