Stability Analysis and Treatment Measures of Lujiawan Bridge Accumulation Landslide
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摘要: 堆积体边坡普遍结构松散，稳定性差，多处于基本稳定或者临界滑动状态，在降雨、地震、施工开挖扰动等条件下，边坡极易因变形过大而失稳。以大永高速卢家湾大桥堆积体滑坡为例，通过地质调绘结合勘探成果，在掌握地层岩性、地质构造及水文地质条件等地质背景基础上，用传递系数法和刚体极限平衡法分析了卢家湾大桥滑坡堆积体的稳定性，并提出抗滑桩+锚杆的支护治理方案。利用有限元软件对加固后的边坡进行数值模拟，结果表明：边坡为复合型边坡，长时间强降雨水下渗至地下，地形上受工程建设开挖形成的临空面影响，导致了该边坡的失稳；经过计算，综合治理后坡体稳定性系数为1.2；滑坡监测数据表明，治理后坡体位移迅速收敛并趋于稳定，表明滑坡治理方案有效。工程研究成果可为今后类似工程提供参考。Abstract: The slope structure of accumulation body in southwest mountainous area is generally loose, and its stability is low. Most of them are in the basic stable or critical sliding state. Under the conditions of rainfall, earthquake, construction and excavation, the slope is prone to instability due to excessive deformation. Taking Lujiawan Bridge landslide of Da-Yong Expressway as an example, the stability of Lujiawan Bridge landslide accumulation was analyzed by the transfer coefficient method and rigid body limit equilibrium method based on the geological background of stratum lithology, structures and hydrogeological conditions through geological mapping and exploration results, and the anti-slide pile+anchor bolt support treatment scheme was proposed. The numerical simulation of the reinforced slope was conducted using finite element software, and the results showed that the slope was a composite type, with long-term heavy rainfall water seeping underground. The terrain was affected by the free surface formed by engineering construction excavation, resulting in the instability of the slope. After calculation, the stability coefficient of the slope after comprehensive treatment is 1.2. The landslide monitoring data shows that the displacement of the slope after treatment converges rapidly and tends to stabilize, indicating the effectiveness of the landslide treatment plan. The results can provide reference for similar projects in the future.
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Key words:
- accumulation body /
- landslide /
- numerical simulation /
- supporting scheme
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表 1 主滑断面稳定性计算表
工况 条块序号 条块重/
（kN·m−1）滑面
长度/m滑面
倾角/（°）滑带面参数 c/kPa φ/（°） 正常工况 1 966.2 14.4 54 18.0 29.0 2 2131.8 13.1 46 17.0 27.0 3 1827.8 10.4 39 17.0 27.0 4 1751.4 7.8 32 17.0 27.0 5 1811.2 7.3 25 17.0 27.0 6 2165.6 8.2 21 15.5 25.0 7 1725.8 6.8 21 15.5 25.0 8 1106.2 6.3 20 15.5 25.0 9 445.2 7.9 16 15.5 25.0 非正常
工况（暴雨）1 1014.5 14.4 54 16.0 27.0 2 2238.4 13.1 46 15.0 26.0 3 1919.2 10.4 39 15.0 26.0 4 1839.0 7.8 32 14.5 26.0 5 1901.8 7.3 25 14.5 26.0 6 2273.9 8.2 21 14.5 26.0 7 1812.1 6.8 21 14.5 26.0 8 1161.5 6.3 20 14.5 26.0 9 467.5 7.9 16 14.5 26.0 
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表 2 主滑断面稳定性计算结果
滑面 正常工况 非正常工况（暴雨） 稳定系数Fs 剩余下滑力/（kN·m−1） 稳定系数Fs 剩余下滑力/（kN·m−1） 主滑断面 1.050 1121.8 0.972 1254.3
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表 3 滑坡计算参数取值及计算结果
滑面 工况 滑带面参数 稳定
系数Fs安全
系数Fst剩余下滑力
/（kN·m−1）c/kPa φ/（°） 主滑断面 天然 15.5 27.0 1.047 1.30 1160 暴雨 14.5 26.0 0.970 1.20 1220
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表 4 滑坡验算参数取值及验算结果表
滑面 工况 滑带面参数 地震加速度 稳定
系数
Fsc
/kPaφ
/（°）主滑断面 天然 15.5 27.0 1.216 15.5 27.0 0.1g 1.009 暴雨 14.5 26.0 1.207 14.5 26.0 0.1g 1.002
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表 5 天然工况相关参数
材料 滑带面参数 弹性模量E
/（kN·m−2）抗弯刚度EI
/（kN·m2·m−1）轴向刚度EA
/（kN·m−1）c/kPa φ/（°） 主滑面土 15.5 27.0 抗滑桩 3×107 2.68×108 2.625×108 土工格栅 3000
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