Numerical Analysis of Effect of Jacked Pile on Performance of Buried Pipes
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摘要: 为了分析静压沉桩过程对邻近埋地管道性能的影响，基于位移贯入法模拟静压沉桩的二维有限元数值方法，建立了桩-土、管-土接触面并在桩顶施加位移荷载实现动态压桩过程，并综合分析了压桩过程中沉桩深度、桩径大小、管道中心与桩体中心的水平距离以及管道的埋深等因素对管道变形与力学性能的影响.研究结果表明：同等条件下，增加管-桩水平距离，管道水平位移、径向变形和管周应力相应减小，近桩侧管周土体的最大水平应力约为不设置管道时的1.5倍；随着沉桩深度增大，初始使管道产生明显水平位移的临界沉桩深度约为管道上方1 m处，随后管道水平位移呈现先增大后略微减小，并最终趋于稳定的趋势，且当沉桩深度为2倍埋深时管道水平位移最大；管道埋深越大，管道受沉桩挤土效应的影响越明显；当埋深为5倍管径时，沉桩桩径减少25%时管道最大水平位移减少27.8%，表明减小桩径可显著降低沉桩对周边管道性能的影响.Abstract: To analyse the influence of the driving process of jacked piles on the performance of adjacent buried pipes via the planar finite element method numerical simulation based on the displacement penetration method and achieve the dynamic pile driving process by establishing the pile-soil and pipe-soil contact surfaces and applying the displacement load at the top of the pile, comprehensive analysis was carried out to investigate the effect of the pile penetration depth, pile diameter, horizontal centre distance between the pile and buried pipe, and buried depth, on the performance of buried pipes during pile driving. The calculation results showed that when keeping other parameters identical and first increasing the horizontal distance, caused a decrease in the horizontal displacement, radial deformation, and stresses of pipes. The maximum horizontal stress of the soil surrounding the pipes is 1.5 times that of the soil without pipes. Secondly, with the increase in the pile penetration depth, there exists a critical penetration depth, after reaching it, the horizontal displacement of pipes increases significantly, then somewhat decreases, and finally becomes steady. Moreover, the maximum horizontal displacement of pipes can be reached when the penetration depth is equal to 2 times the buried depth of the pipe. Thirdly, increasing the buried depth of the pipe results in remarkable change in the deformation and mechanical performance of the pipes. For a buried depth of 5 times the diameter of pipe, the maximum horizontal displacement of the pipes reduced by 27.8% when the pile diameter decreased by 25%. This implied that reducing the diameter of jacked piles can considerably weaken its effect on buried pipes.
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Key words:
- buried pipes /
- jacked pile /
- finite element method /
- displacement penetration method
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图 2 不同L值时管道水平位移随沉桩深度影响
Figure 2. Horizontal displacement of pipe varying with penetration depth of pile for different L
图 3 管道垂直和水平径向变形比随沉桩深度的变化
Figure 3. Variation of ratio of deformation of pipes in vertical and horizontal direction with depth of penetrating pile
图 5 Hp=10 m时有、无管道时沿管周土应力比
Figure 5. Ratio of stress around pipe and W/O pipes while Hp=10 m
图 7 无管道时不同深度距桩中心2.4 m处水平方向位移
Figure 7. Horizontal displacements at 2.4 m away from centre of pile without pipe
图 10 沉桩过程中管道水平位移随H和Dp的变化
Figure 10. Variation of pipe horizontal displacements with different combinations of H and Dp
图 11 Hp为6 m和10 m时管道水平和垂直径向变形
Figure 11. Horizontal and vertical deformation of pipes when Hp is equal to 6 and 10 m
图 12 沉桩结束时不同H和Dp对管道径向变形的影响
Figure 12. Effect of H and Dp on radial displacement after pile penetration
图 13 沉桩结束时不同H和Dp对管周环向应力的影响
Figure 13. Effect of H and Dp on pipes' hoop stresses after pile penetration
表 1 砂土模型参数
Table 1. Model parameters for sand
土体 密度/
(g·cm-3)弹性模
量E/MPa相对密
实度%泊松
比μ内摩擦
角β/(°)塑流应
力比K膨胀角
ψ/(°)桩土摩擦
因数f1管土摩擦
因数f2屈服强度
σc/kPa砂土 1.750 15 50 0.4 22.5 0.87 21.24 0.1 0.4 54.1 
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表 2 埋地管道力学与变形分析的数值计算方案
Table 2. Plan for analysing mechanical performance and deformation of buried pipes via numerical calculation
模拟组数 影响因素 L/D Hp/m H/D 桩径Dp/mm 9 3, 4, 5, 6 0~10 5, 6, 7, 8 600, 800
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