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摘要: 针对西南地区软弱地基, 运用GEO-SLOPE软件, 对在斜坡软弱地基上填筑路堤时路堤与地基的应力与变形进行了仿真计算, 比较了水平软弱地基与倾斜软弱地基路堤填筑的差异, 并分析了在不同地层坡度、软弱土层厚度及路堤填筑高度下路堤地基的应力与变形响应, 尤其是下坡脚处等重要部位的关键响应。并结合渝怀线一代表性断面, 对有无工程措施、各种工程措施的效果等进行了模拟。研究结果为工程设计与施工提供了进一步的科学指导。Abstract: Numerical analysis was conducted to simulate the deformation behavior of subgrade embankment on sloped weak ground using commercial software GEO SLOPE.Critical structural responses such as strain and stress at the toe of embankment slope were abstracted to evaluate the effectiveness of engineering measurement used to improve stability potential of the filled embankment.Cross sectional factors influencing the deformation behavior of embankment were also explored. Research results show that numerical simulation can provide reliable and rigorous guide in the design and construction phases in infrastructure development.
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Key words:
- sloped ground /
- weak ground /
- subgrade embankment /
- FEM /
- numerical simulation
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图 2 地基表面任一点与荷载中心点竖向位移差值曲线
Figure 2. Difference curve of vertical displacement between any point and load central point on ground surface layer
图 5 代表性断面计算示意图
Figure 5. Sketch of typical cross-section of Yu-huai railway embankment
图 6 代表性断面不同工况下的有限元计算模型
Figure 6. FEM model of typical cross-section under different conditions
图 7 软弱水平地基填方工程变形前后网格示意
Figure 7. Deformation grid of embankment on horizontal weak ground
图 9 软弱水平地基与软弱倾斜地基地层表面水平位移曲线
Figure 9. Horizontal displacement curve of ground surface layer on horizontal and sloped weak ground
图 10 软弱水平地基与软弱倾斜地基地层表面竖向位移曲线
Figure 10. Vertical displacement curve of ground surface layer on horizontal and sloped weak ground
图 11 下坡脚竖向剖面水平位移随地层坡度变化曲线
Figure 11. Relation between the horizontal displacement of sections of embankment slop toe and the ground slope
图 12 坡脚处地层表面水平位移随地层坡度变化曲线
Figure 12. Relation between the horizontal displacement of ground surface layer on embankment slope toe and the ground slope
图 13 路堤中心线处地层表面竖向位移随地层坡度变化曲线
Figure 13. Relation between the vertical displacement of ground surface layer on embankment slope center and the ground slope
图 14 下坡脚竖向剖面水平位移随软弱土层厚度变化曲线
Figure 14. Relation between the horizontal displacement of sections of embankment slope toe and the thickness of weak layer
图 15 坡脚处地层表面水平位移随软弱土层厚度变化曲线
Figure 15. Relation between the horizontal displacement of ground surface layer on embankment slope toe and the thickness of weak layer
图 16 路堤中心线处地层表面竖向位移随软弱土层厚度变化曲线
Figure 16. Relation between the vertical displacement of ground surface layer on embankment slope center and the thickness of weak layer
图 17 下坡脚竖向剖面水平位移随路堤高度变化曲线
Figure 17. Relation between the horizontal displacement of sections of embankment slope toe and the height of embankment
图 18 坡脚处地层表面水平位移随路堤高度变化曲线
Figure 18. Relation between the horizontal displacement of ground surface layer on embankment slope toe and the height of embankment
图 19 路堤中心线处地层表面竖向位移随路堤高度变化曲线
Figure 19. Relation between the vertical displacement of ground surface layer on embankment slope center and the height of embankment
图 20 代表性断面4个典型剖面在不同工况下的水平位移
Figure 20. Horizontal displacement of 4 typical sections under different conditions
表 1 土层物理力学参数
Table 1. Mechanical parameters of soil
土层类型 泊松比μ 重度γ/kN·m-3 弹性模量E/MPa 粘聚力c/kPa 内摩擦角φ/ (°) 路堤填料 0.3 19 30 25 25 软弱土层 0.4 18 5 10 10 稳定土层1 0.3 20 100 100 40 稳定土层2 0.2 21 200 150 45 稳定土层3 0.1 22 300 200 50 
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表 2 代表性断面土层参数
Table 2. Soil parameters of typical cross-section
土层编号 重度γ/kN·m-3 粘聚力c/kPa 内摩擦角φ/ (°) 弹性模量E/MPa 泊松比μ 1 19 20 20 30 0.25 2 18 12 10 5 0.40 3 18 20 15 15 0.30 4 20 50 40 10000 0.10
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表 3 抗滑桩、碎石桩设置位置处土层参数
Table 3. Soil parameters of location using anti-slide pile and granular pile
工程措施 重度γ/kN·m-3 粘聚力c/kPa 内摩擦角φ/ (°) 弹性模量E/MPa 泊松比μ 抗滑桩 25 — — 20000 0.1 碎石桩 20 0 30 1000 0.2 注: 抗滑桩设置位置处局部采用线弹性本构关系, 对其它部分仍采用理想弹塑性本构关系。
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表 4 不同工程措施条件下路堤地基的响应
Table 4. Some critical mechanical responses under different engineering measurements
参数 类型 不采取任何加固措施 地基用碎石桩加固 左侧坡脚设置抗滑桩 同时采取碎石桩和抗滑桩 umax/m 0.983 0.157 0.171 0.150 uH/m max 0.016 0.016 0.016 0.017 min -0.872 -0.104 -0.112 -0.084 uV/m max 0.633 0.030 0.049 0.008 min -0.426 -0.133 -0.139 -0.129 γmax max 0.357 0.049 0.062 0.043 min/10-7 0.529 1.114 3.515 4.692 σ1/kPa max 364.464 767.225 1916.670 1725.260 min -49.5621 -28.999 -229.490 -232.375 σ3/kPa max 223.153 329.249 726.077 768.751 min -54.012 -863.530 -744.465 -634.742 τmax/kPa max 122.457 650.849 600.566 508.030 min 0.240 0.214 0.179 0.202
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[1] WEI Yong -xing. An disquisition for the safety of earthwork in the floopy-tip ground[J]. Journal of Geological Hazards and Environment Preservation, 2001, 12(2): 73-79. [2] 铁道部第四勘测设计院. 软土地基试验文集[M]. 武汉: 中国地质大学出版社, 2001. [3] TB 10001-99, 铁路路基设计规范[S]. -
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