Stress Analysis of Three-row Pile Rigid Frame Retaining Structure in High Slope with Deep and Thick Backfill Soil
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摘要: 针对深厚填土高边坡中单排悬臂桩、桩锚支护、双排桩、h型桩等支护结构存在的不足,分析探讨了三排桩刚架支挡结构。研究表明,三排桩刚架支挡结构用于支护深厚填土高边坡,可以同时起到“收坡”、“固脚”作用,既能节约用地,又可以有效发挥支挡作用。通过工程实例,分别采用位移法、MIDAS GTX NX有限元软件进行计算分析,对比结果表明,采用位移法简化方法可近似计算三排桩刚架支挡结构的弯矩。三排桩钢架支挡结构设计时应加强前排桩和连梁的截面刚度,保证节点位置刚性连接,刚架结构分级高度应大致均匀布置,且应尽量减少后排桩悬臂段高度。Abstract: The supporting structures of single row cantilever pile, pile-anchor support, double row pile, H-type pile and other supporting structures have deficiencies in high slope with deep and thick backfill soil. In view of the deficiencies, three-row pile rigid frame retaining structure was analyzed. In supporting deep fill high slope, the three-row pile rigid frame retaining structure can simultaneously play the role of "retracting slope" and "reinforce the foot of the slope". The application of this structure could save land and realize retaining effectively. Through engineering examples, displacement method and MIDAS GTX NX finite element software were used for calculation and analysis. The comparison results show that the simplified displacement method can be used to approximate the bending moment of three-row pile rigid frame retaining structure. The section rigidity of front pile and connecting beam should be strengthened in the design, and ensure that the nodes are rigidly connected. The grading height of rigid frame structure should be roughly uniform and the cantilever height of rear pile should be reduced as much as possible.
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Key words:
- three-row pile /
- rigid frame /
- retaining structure /
- displacement method /
- high slope with backfill soil
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表 1 有限元计算参数
材料 重度γ/
(kN·m−3)黏聚力
c/kPa内摩
擦角
φ/(°)弹性
模量
E/
MPa泊松比
ν材料计算模型 压实填土 19.2 8 25 9.6 0.36 修正莫尔–库伦 强风化凝灰岩 19.5 60 30.0 32.2 0.32 修正莫尔–库伦 中等风化凝灰岩 26.5 120 35.0 136.5 0.28 修正莫尔-库伦 微风化凝灰岩 26.9 250 38.0 182.4 0.26 修正莫尔–库伦 抗滑桩、连梁 25.0 30000 0.25 弹性 表 2 计算结果对比表
计算方法 桩身最大弯矩M/(kN·m) 后排桩(中部) 中排桩(上部) 中排桩(下部) 前排桩 位移法 2692 4317.8 2186 3774.4 有限元 3128 4252 2508 4504 相对误差 16.2% 1.5% 14.7% 19.3% 表 3 台阶分级高度类型
台阶分级高度类型 h1 h2 h3 台阶分级高度类型 h1 h2 h3 类型1 3 5 7 类型1 5 5 5 类型2 3 6 6 类型2 5 6 4 类型3 4 5 6 类型3 6 4 5 类型4 4 6 5 类型4 6 5 4 -
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