Axisymmetric simplified method for stability analysis of an circular-like mine slope
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摘要:
为响应国家“绿水青山就是金山银山”的发展理念, 对废弃矿坑的开发再利用成为热点, 而采用合理的稳定性评价方法对废弃矿坑边坡加固设计是后续工作的关键。但这类矿坑边坡通常形状近似圆形或椭圆形, 三维空间效应不容忽略, 基于传统平面应变假设的简化方法对其进行稳定性分析似乎不太合理。在FLAC3D强度折减法的基础上, 提出了一种针对近似圆形矿坑边坡稳定性分析的轴对称模型简化计算方法。基于计算结果的对比分析表明:①对于这种类似圆形凹坡, 轴对称模型计算的安全系数比传统平面应变模型更准确, 减少了计算时间, 并且轴对称模型对于各种复杂程度不同的边坡类型同样适用;②轴对称模型计算的安全系数与三维模型计算的安全系数非常接近, 而传统平面应变模型计算的安全系数偏于保守;③将轴对称模型计算结果与现有研究对比, 表明两者结果相符, 并将其进一步应用于长沙冰雪世界项目矿坑边坡加固工程的稳定性分析中, 证明其可为类似工程的边坡稳定性评价提供参考。
Abstract:To follow the national development concept of "Lucid waters and lush mountains are invaluable assets", the reuse of abandoned mines has become a hotspot. A reasonable stability analysis method to reinforce the slope must be proposed. However, the shape of common mine slope is close to a circle or an ellipse, and thus the three-dimensional space effect of stability cannot be ignored. Based on the strength reduction method of FLAC3D, an axisymmetric numerical analysis method was proposed. Through comparative calculation and analysis, some conclusions can be obtained as follows: (1)For concave slopes with circular-likeshape, the safety factor calculated by the axisymmetric model is more accurate than that of the traditional plane strain model, the calculation time of the proposed model is less, and the proposed model is also applicable to various types of slopes. (2)The safety factor obtained from the axisymmetric model is close to the results obtained from the 3-D model, while the safety factor obtained from the traditional plane strain model is conservative.(3)The calculation results of the axisymmetric model are also consistent with the results from the literature. The proposed model is further applied to the stability analysis of a mine slope reinforcement in Changsha Ice World, which can also be applied in the slope stability evaluation of similar projects.
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Key words:
- mine slope /
- FLAC3D /
- axisymmetric model /
- plane strain model
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表 1 土体力学参数表
Table 1. Mechanical parameters of soil
密度ρ/ (kg∙m-3) 弹性模量E/GPa 泊松比μ 黏聚力c/kPa 内摩擦角φ/(°) 2 400 4.3 0.2 28 27 表 2 边坡土体力学参数
Table 2. Mechanical parameters of slope
土体类型 ρ/(kg·m-3) E/MPa μ c/kPa φ/(°) 软弱夹层 1 850 20 0.4 10 10 土层 1 800/2 000 80 0.3 28.5/26.0 20.0/18.0 注:“/”前后分别为土层的天然参数和饱和参数 表 3 不同方法的安全系数计算结果
Table 3. Safety factor obtained from different methods
三维模型 轴对称模型 平面应变模型 极限平衡法[10] 0.988 0.939 0.69 0.739 表 4 安全系数计算结果对比
Table 4. Comparison of safety factor
λ 坡角β/ (°) 文献[21] 结果 三维模型 轴对称模型 平面应变模型 0.2 30 1.91 1.97 1.87 1.60 45 1.58 1.57 1.50 1.25 75 1.08 1.14 1.04 0.81 1.0 30 2.38 2.37 2.26 1.60 45 2.06 2.02 1.95 1.55 75 1.51 1.61 1.56 1.21 表 5 长沙冰雪世界项目边坡岩土体力学参数
Table 5. Mechanical parameters of the slope in Changsha Ice World
土体类型 ρ/(kg∙m-3) E/GPa μ c/kPa φ/(°) 粉质黏土 1 800 1.0 0.22 50 19 微风化灰岩 2 400 6 0.32 280 27 -
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