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摘要:目的 主要对海上风电嵌岩桩的桩基尺寸与竖向荷载等因素对其水平承载特性的影响进行研究。方法 文章采用有限差分的数值方法，基于一处现场试验建立数值模型并进行参数分析。结果 结果表明：嵌岩桩基存在一个临界嵌岩长度（长径比），桩基尺寸的改变会影响桩-岩的相对刚度，进而使临界嵌岩长度随之改变，随着桩径的减小，嵌岩桩临界嵌岩长径比逐渐增加；在桩的承载能力范围内，在竖向荷载与水平荷载共同作用下，桩基的水平位移和桩身弯矩有较大程度的减小，如果认为竖向荷载引起的侧摩阻力在桩的两侧大小与方向相同，或将竖向侧摩阻力简化为作用在桩的轴线则会忽略这一效应的影响，会对计算结果造成误差。结论 论文结果对于临界嵌岩长度以及竖向荷载影响的分析将有助于水平承载嵌岩桩的合理设计和深入研究。Abstract:Introduction The aim of this paper is to analyze the influence of the size and the vertical load of the pile foundation on the horizontal bearing capacity of rock-socketed piles.Method Based on a field test of the rock-socketed concrete pile under horizontal load， a 3-D finite difference numerical model was established and parametric analyses were performed.Result The results show that there is a critical rock-socketed length （ratio of length and diameter） for rock-socketed piles. Changes of the size of the pile will influence the relative stiffness of the pile and the rock， which will affect the critical rock-socketed length. With the decrease of the pile diameter， the critical socket length will increase. Within the scope of the bearing capacity of the pile and under the condition of combined vertical and horizontal load， the horizontal displacement and bending moment of the pile will have a pretty large decrease. This influence will be neglected if the vertical friction is assumed to be the same on the both sides of the pile or simplified to be at the center of the pile， which will cause error to the calculation results.Conclusion This study is supposed to provide contribution to the reasonable design and further research of the horizontal load of rock-socketed piles.
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图 3 数值模拟与试验桩桩顶荷载-位移曲线对比
Figure 3. Comparison of load-displacement curves at pile top between numerical simulation and field test
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图 4 数值模拟与试验桩的桩身位移曲线对比
Figure 4. Comparison of displacement curves between numerical simulation and field test
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图 5 数值模拟与试验桩的桩身弯矩曲线对比
Figure 5. Comparison of moment curves between numerical simulation and field test
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图 7 不同嵌岩长度下桩顶的荷载-位移曲线
Figure 7. Load-displacement curves of piles with different lengths
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图 8 H=3.496 MN时不同嵌岩长度桩基弯矩曲线
Figure 8. Moment curves of piles with different lengths when H= 3.496 MN
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图 9 H=3.496 MN时不同嵌岩长度桩基桩侧基岩反力曲线
Figure 9. Bedrock reaction curves of piles with different lengths when H=3.496 MN
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图 10 不同桩径条件下桩顶位移随长径比的变化
Figure 10. The variation of displacement of piles with length-diameter ratios under different pile diameters
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图 11 不同桩径条件下桩顶位移变化率随长径比的变化
Figure 11. The variation of displacement gradients of piles with length-diameter ratios under different pile diameters
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图 12 H=5 MN时竖向荷载对水平承载桩水平位移的影响
Figure 12. Influence of vertical loads on horizontal displacement of the horizontal bearing pile when H=5 MN
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图 13 H=5 MN时竖向荷载对水平承载桩弯矩的影响
Figure 13. Influence of vertical loads on moment of the horizontal bearing pile when H=5 MN
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图 14 不同水平荷载下竖向荷载对桩顶水平位移的影响
Figure 14. The influence of vertical load on horizontal displacements of piles under different levels of horizontal loads
表 1 基岩RMR值和GSI值计算
Table 1
The RMR and GSI values of bedrock 深度/m 强度等级 RQD等级 节理间距 节理状况 地下水状况 RMR均值 GSI 0~2.13 4 3~5 5~15 5~20 15 46 41 2.13~5.48 4~7 13 5~15 20~25 15 66 61 
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表 2 Hoek-Brown准则中各参数取值
Table 2
The values of the parameter in Hoek-Brown failure criterion 深度/m GSI mi mb s a Em/GPa 0~2.13 41 6 0.730 0.001 0.511 0.695 2.13~5.48 61 6 1.490 0.013 0.503 2.208
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