基于孔压静力触探的大直径单桩p-y曲线分析  

The p-y curve analysis of large diameter monopiles based on piezocone penetration test

作　　者：陈雨露 欧阳仲坤 郑向远 CHEN Yulu;OUYANG Zhongkun;ZHENG Xiangyuan(Shenzhen International Graduate School,Tsinghua University,Shenzhen 518055,Guangdong,China)

机构地区：[1]清华大学深圳国际研究生院,广东深圳518055

出　　处：《水利水电技术（中英文）》2024年第8期141-151,共11页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金项目(52071186)。

摘　　要：【目的】水平受荷桩的p-y曲线法已广泛用于描述桩-土相互作用并预测桩在水平荷载下的行为,特别是在海上风电机大直径单桩的理论分析中。孔压静力触探试验(piezocone penetration test,简称CPTu)作为一种效率高、精确度好的原位测试手段,克服了传统室内试验获得土工参数的过程中土样存在扰动、结果准确性较差的缺点。该试验可以通过测量三个基本参数(修正锥尖阻力qt、侧壁摩阻力fs以及孔隙水压力u2)随深度变化的连续剖面来解译土体的物理力学参数,从而在p-y曲线模型的建立中提供关键数据。【方法】利用渤海海域某场区的CPTu数据,完成了以下研究任务:(1)基于CPTu触探响应结果,对该场区海洋土体进行分类,以及物理与力学参数的反演,包括土体密度、弹性模量、有效内摩擦角及有效黏聚力;(2)将CPTu反演参数代入三维有限元分析模型中,模拟直径为5 m的钢管桩在最大荷载为20 MN时的水平受荷响应;(3)基于CPTu测试数据,提出一套土抗力计算公式;(4)将现有p-y曲线模型中相关参数通过CPTu触探响应结果进行反演,之后对比分析上述p-y曲线模型。【结果】形成了一套基于CPTu且适用于土体分层情况较为复杂的p-y曲线公式,该公式与有限元方法对比结果良好。【结论】结果表明,提出的基于CPTu的土抗力公式经过有限元模拟检验后能快速、准确地反映大直径单桩的水平受荷响应。该公式不仅为渤海海域内大直径单桩的工程实践提供了有力的理论支持,还为相似海洋环境的工程设计与分析提供了完全基于CPTu研究大直径单桩的新思路。[Objective]The p-y curve method for laterally loaded piles has been widely used to describe pile-soil interactions and predict pile behavior under lateral load,especially in the theoretical analysis of large-diameter monopiles for offshore wind turbines.As an in-situ test method with high efficiency and good accuracy,piezocone penetration test(CPTu)overcomes the short-comings of disturbance and poor accuracy of soil samples in the process of obtaining geotechnical parameters in conventional laboratory tests.CPTu records three continuous measurements(modified cone tip resistance qt,sleeve friction resistance fs and pore water pressure u2)and evaluates physical and mechanical properties of the soil strata,which can be incorporated into p-y curve model.[Methods]This paper uses the CPTu data from a certain area in the Bohai Sea,China,and the following study tasks were completed:(1)Classification of the marine soil of the site and determination of the physical and mechanical properties by CPTu including soil density,elastic modulus,effective friction angle and cohesion intercept,(2)Aforementioned CPTu-interpreted properties served as the input in a three dimensional finite element analysis to model a 5-meter diameter laterally loaded steel pipe pile′s response with a maximum load of 20 MN,(3)A new CPTu based formula to calculate the ultimate soil lateral capacity is proposed and;(4)The relevant parameters in the existing p-y curve model are interpreted by CPTu,and then the above p-y curve model is compared and analyzed.[Results]In this paper,a CPTu based p-y curve formula for complicated soil stratification is established and validated through comparison with FEA,and showed a reasonably agreement.[Conclusion]The result show that the soil resistance formula based on CPTu proposed in this paper can quickly and accurately reflect the horizontal load response of large-diameter monopiles.This formula not only provides strong theoretical support for the engineering practice of large-diameter monopiles in the Bohai Sea,but

关 键 词：P-Y曲线 静力触探试验 有限元方法 水平受荷桩 大直径单桩 土抗力 土体有效应力参数 力学性能 

分 类 号：TU473.1[建筑科学—结构工程]