基于位移变化率和强度折减有限元的边坡失稳判定方法

发布时间：2018-01-16 05:23

  本文关键词：基于位移变化率和强度折减有限元的边坡失稳判定方法　出处：《农业工程学报》2017年15期 　论文类型：期刊论文

  更多相关文章： 边坡稳定性 模型 边界条件 强度折减法 有限元法 位移变化率

【摘要】：采用强度折减有限元法计算边坡稳定时,以变形为基础的失稳判据具有显著的物理意义和工程意义。该文采用变步长的折减方法,基于位移变化率-强度折减系数曲线的转折突变作为失稳判据,并研究特征点的敏感性及选取范围。计算结果表明,当折减系数为1.42时,坡顶水平位移变化率、竖向位移变化率和总位移变化率均发生急剧性的转折。与位移相比,位移变化率-强度折减系数的曲线存在明显的转折突变,可更准确、明显地判断边坡稳定的安全度。至坡顶一定距离范围内的特征点,如位于非塑性区域且非滑动土体时,其位移变化率-强度折减系数的曲线发生转折突变,但曲线在转折点附近存在振荡现象。通过位移变化率计算得到的54个安全系数,平均值为1.420,变异系数为0.005 3,不同特征点根据水平位移变化率、竖向位移变化率和总位移变化率得到的安全系数基本一致。当特征点至坡顶的距离≤1倍坡高时,特征点的位移12 mm,且位移变化率均较大,此时特征点对位移变化率较敏感;当特征点至坡顶的距离1倍坡高时,特征点位移在5~18 mm之间,但位移变化率大幅度降低,此时特征点对位移变化率的敏感性大幅度降低。考虑边界约束的影响及特征点的敏感性,建议特征点的选取范围为:与坡顶距离为1倍坡高的范围。
[Abstract]:When the strength reduction finite element method is used to calculate the slope stability, the deformation-based instability criterion is of great physical and engineering significance. In this paper, the variable step reduction method is adopted. Based on the abrupt change of displacement rate-strength reduction coefficient curve as the criterion of instability, the sensitivity and selection range of characteristic points are studied. The calculation results show that when the reduction coefficient is 1.42. The change rate of horizontal displacement, vertical displacement and total displacement of the top of the slope have a sharp turning point. Compared with the displacement, the curve of displacement change rate and strength reduction coefficient has obvious abrupt change and can be more accurate. The characteristic points within a certain distance from the top of the slope, such as in the non-plastic region and non-sliding soil, the curve of displacement change rate and strength reduction coefficient has a turning and abrupt change. But there is oscillation near the turning point, 54 safety factors calculated by displacement change rate, the average value is 1.420, and the coefficient of variation is 0.0053. According to horizontal displacement rate, vertical displacement change rate and total displacement change rate, the safety coefficient of different characteristic points is basically the same. When the distance from the feature point to the top of the slope is 鈮，

本文编号：1431733