Analysis on sliding displacement of slope with muddy intercalation considering blasting cumulative damage effect
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摘要: 反复爆破振动是诱发滑坡的重要因素,特别是含泥化夹层的复杂岩质边坡。为揭示多次爆破振动下含泥化夹层复杂岩质边坡失稳破坏机制,根据能量守恒定律,基于Newmark滑块位移法,考虑爆破累积损伤效应,引入泥化夹层强度折减系数,建立了多次爆破振动下含泥化夹层边坡累积滑移量计算和临界爆破振动次数预测方法。探讨了剪切模量、倾角和连续率等泥化夹层参数对多次爆破振动下边坡累积滑移量的影响,并对泥化夹层参数敏感性进行了分析。研究结果表明:(1)考虑爆破累积损伤效应引起的泥化夹层强度参数劣化,边坡累积滑移量计算和临界爆破振动次数预测结果更加合理。(2)泥化夹层参数对多次爆破振动下边坡累积滑移量具有显著影响。随泥化夹层剪切模量的增大,边坡抵抗变形能力增大,累积滑移量减小。随泥化夹层倾角的增大,边坡剪切段滑移量无明显变化,但蠕滑段滑移量明显增大,总的累积滑移量随之增大。泥化夹层连续率越高,边坡累积滑移量越大。(3)参数敏感性分析表明,泥化夹层剪切模量对多次爆破振动下边坡累积滑移量影响最显著,其次是泥化夹层倾角,再次是泥化夹层连续率。Abstract: Repeated blasting vibrations are one of important triggers of landslides, especially those developed on complex rock slopes with muddy intercalation. To reveal the failure mechanism of complex rock slope with muddy intercalation under repeated blasting vibrations, a novel method was proposed to evaluate cumulative sliding displacement and critical blasting times for this type of slopes based on the law of conservation of energy and Newmark sliding block method. In this method, the cumulative damage effects of repeated blast vibrations were characterized through multiple strength reduction factors of muddy intercalation parameters, e.g. shear modulus, dip angle and continuity. The importance of those parameters on slope cumulative sliding displacement was also addressed using sensitivity analysis. The proposed method generally shows more reasonable results regarding estimation of cumulative sliding displacement and critical blasting vibration times. The parameters of muddy intercalation show significant controls on the cumulative sliding displacement of slope under many times of blasting vibration. With the shear modulus increased, the cumulative displacement declines as the slope resistance gets enhanced. Steeper dip angle of muddy intercalation increases the slope displacement of creep section and has no obvious influence on the displacement of shear section. Higher continuity of muddy intercalation induces larger cumulative sliding displacement as expected. The sensitivity analysis results show that the cumulative sliding displacement under repeated blasting vibrations is influenced by shear modulus, followed by dip angle and continuity of muddy intercalation.
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表 1 滑体与泥化夹层的有关物理力学参数
Table 1. Physical and mechanical parameters of sliding mass and muddy intercalation
名称 重度/(kN·m−3) 剪切模量/MPa 泊松比 内摩擦角/° 黏聚力/kPa 倾角/° 泥化夹层连续率/% 滑体 24 60 0.36 39 150.00 45 —— 折减前的泥化夹层 21 50 0.40 26 15.00 30 100 折减后的泥化夹层 21 50 0.40 9 5.36 30 100 表 2 1次爆破振动下各条块滑移量
Table 2. Sliding displacement of each block under one blasting
单位:mm 条块 剪切段
滑移量剪切段水平
滑移量剪切段竖向
滑移量蠕滑段
滑移量蠕滑段水平
滑移量蠕滑段竖向
滑移量总滑
移量1 18.52 16.04 9.26 —— —— —— —— 2 17.65 15.29 8.83 —— —— —— —— 3 16.32 14.13 8.16 —— —— —— —— 4 —— —— —— 16.51 14.30 8.26 —— 5 —— —— —— 17.92 15.52 8.96 —— 6 —— —— —— 19.35 16.76 9.68 106.27 表 3 泥化夹层参数分析计算工况
Table 3. Parameter analysis and calculation of muddy intercalations
工况编号 剪切模量/MPa 倾角/° 连续率/% 1 43 20 100 2 51 15 100 3 56 10 100 4 56 15 67 5 51 20 67 6 43 10 67 7 43 15 33 8 51 10 33 9 56 20 33 表 4 坝址区滑体与泥化夹层的有关物理力学参数
Table 4. Physical and mechanical parameters of sliding mass and muddy intercalation at the dam site
名称 重度/(kN·m−3) 泊松比 内摩擦角/° 黏聚力/kPa 滑体 25 0.3 40.00 150 折减前的泥化夹层 21 0.5 22.00 14 折减后的泥化夹层 21 0.5 7.86 5 -
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