广东阳江海洋砂性土小应变硬化土模型参数的试验研究

Experimental Study on Parameters of Hardening Soil Model with Small Strain Stiffness for Marine Sand in Yangjiang, Guangdong

摘要:

海上风机结构在风、浪、流等复杂循环荷载作用下需严格控制其振动频率和基础变形，设计时需考虑土体的小应变模量特性。使用固结仪、GDS应力路径三轴仪和弯曲元设备波速测试，获得了广东阳江典型海洋砂土的小应变硬化土模型（HSS）的主要参数，包括砂土的有效应力强度指标和刚度参数等。结果表明：海洋砂土刚度参数G₀^ref、E₅₀^ref、E_oed^ref和E_ur^ref之间存在倍数关系，可通过经验公式相互转换；天然海洋砂土的小应变剪切模量G₀明显低于已有研究中的洁净砂土，最终给出了广东阳江地区海洋砂性土HSS模型参数的取值建议。

关键词:小应变硬化土模型;海洋砂土;三轴试验;固结试验;小应变模量;弯曲元

Abstract:

The resonant frequency and the tilt of the offshore wind turbine foundation should be strictly controlled at natural cyclic load such as wind， wave and current， resulting in the fact that the characteristics of small strain modulus of soil should be considered in the design. The hardening soil model with small strain stiffness （HSS） parameters of typical marine sand in Yangjiang， Guangdong， including the effective stress strength parameters and stiffness parameters， were obtained by using conventional oedometer， GDS triaxial and bender elements. The relationships among stiffness parameters of marine sand were also analyzed. It is found that the measured small strain shear modulus G₀ is much smaller than the predictions made by empirical equations based on clean sands. The method to predict the HSS model parameters of marine sands in this area are furthermore suggested.

Key words:hardening soil model with small strain stiffness (HSS);marine sand;triaxial test;oedometer test;small strain modulus;bender element