上海地区软土HSS模型参数的试验研究

HSS模型可以考虑小应变范围内土体剪切模量随应变增大而衰减的特点,在基坑开挖数值分析中逐渐得到较多的运用。通过基于GDS系统的三轴仪、常规固结仪和共振柱仪完成系列的室内试验,获得了上海地区典型软土层(也即黏土层2、淤泥质粉质黏土层3、淤泥质黏土层4和粉质黏土层5)的硬化土小应变本构模型(HSS模型)参数c',φ',E_(oed)~(ref),E_(50)~(ref),R_f,G_0~(ref)和γ_(0.7),以及模型参数之间的比例关系,并将试验结果与已有文献的相关结果进行对比分析。通过工程实例的数值分析表明,围护墙体水平变形计算值和实测值大致相等,验证了HSS本构模型以及本文提出的参数确定方法在上海软土地区基坑开挖分析中的适用性,具有工程参考价值。

Experimental study on parameters of HSS model for soft soils in Shanghai

The HS-Small model, which can reflect the attenuation of shear modulus of soils with strain in tiny strain range, has been gradually utilized in excavation engineering. The laboratory tests using triaxial apparatus, oedometer apparatus and resonant column device are conducted to obtain the prime parameters of HSS model, such as c’, E_oed^ref,E₅₀^ref,R_f,G₀^ref and γ_0.7 for typical silty clay of layer No. 2, muddy silty clay of layer No. 3, muddy clay of layer No. 4 and silty clay of layer No. 5 in Shanghai. The measured parameters are compared with those in other cities in China and verified through practical engineering. The simulated results of horizontal displacement of retaining wall approximately equal to the measured data. The HSS model and the determination method for parameters are proved to be applicable in numerical simulation of excavation engineering in Shanghai. It is of reference value to similar engineering.