海上风电勘察中用于获取黏土原位参数的静力触探试验,其现有黏土解译方法基于理想弹塑性模型,未充分考虑黏土的小应变非线性刚度特性。该文通过开展数值研究,剖析黏土应力-应变非线性、小应变参数对圆锥贯入锥尖阻力的影响关系,饱和黏土采用双曲线硬化弹塑性模型和小应变弹塑性本构模型,并在ABAQUS有限元软件中模拟圆锥贯入过程。采用ALE重划分技术防止大变形分析中的网格畸变。有限元数值分析表明：土体刚度、土层原位应力、锥面粗糙度和破坏准则等因素均对锥尖承载系数有影响;土体破坏比越大锥尖系数越小;考虑小应变刚度后,锥尖系数有明显的增大,其增幅与小应变刚度、参考剪应变和大应变刚度之间的相对关系有关。对现场工程案例进行分析,表明考虑黏土小应变刚度的锥尖系数评估方法有较好的适用性。
Abstract
The current interpretation methods for the cone penetration test (CPT), which is used to obtain in-situ parameters of clay in offshore wind power investigations, are based on the elastic-perfectly plastic soil model and do not adequately account for the small-strain nonlinear stiffness characteristics of clay. This paper conducts numerical studies to investigate the impact of clay stress-strain nonlinearity and small-strain parameters on cone tip resistance. Saturated clays are modeled using the hyperbolic hardening elastoplastic model and the small-strain elastoplastic constitutive model, simulating the cone penetration process within the ABAQUS finite element software framework. To mitigate mesh distortion during large deformation analyses, the Arbitrary Lagrangian Eulerian （ALE） remapping technique is adopted. Finite element numerical simulations indicate that soil stiffness, in-situ stress of soil strata, cone surface roughness, and failure criteria significantly influence the cone bearing factor. Moreover, an increased soil failure ratio corresponds to a decreased cone factor. Importantly, accounting for small-strain stiffness leads to a marked augmentation of the cone factor, with the extent of this increase being closely related to the interplay among small-strain stiffness, reference shear strain, and large-strain stiffness. Finally, the proposed method for evaluating the cone factor, which incorporates the small-strain stiffness of clay, is validated through a field engineering case, demonstrating robust applicability.
关键词
海上风电场 /
静力触探 /
软黏土 /
大变形有限元 /
小应变刚度 /
锥尖系数
Key words
offshore wind farms /
cone penetration test /
soft clay /
large deformation finite element /
small-strain stiffness /
cone factor
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基金
国家自然科学基金（52101334）; 中国电建集团华东勘测设计研究院有限公司科技项目（KY2022-KC-01-10）
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