原状软粘土各向异性及其对工程影响研究

Anisotropy of Undisturbed Soft Clay and Its Influence on Practical Engineering

利用空心圆柱扭剪仪(HCA),通过设置不同的应力路径对杭州原状软粘土进行了系列试验,研究了原状软粘土的应力-应变-强度各向异性。通过试验研究发现原状软粘土的强度、变形模量等特性都存在强烈的各向异性,且在应力水平较低时(q=5 kPa),主应力轴旋转条件下土体应力应变的特性主要体现了原生各向异性的影响,应力引起的次生各向异性对其影响很小。结合路堤填筑问题的分析发现,存在主应力轴显著旋转的实际工程问题,由于原状软粘土应力-应变-强度各向异性的存在,采用常规的不考虑主应力轴旋转(土体各向异性)影响的设计方法可能偏于不安全。

The stress-strain-strength anisotropy behaviour of undisturbed soft clay in Hangzhou is studied based on a series tests carried out with HCA by setting certain stress paths.It can be found from the experiments that the strength and deformation module of the clay have strong anisotropic behavior.The stress―strain characteristic of the soil under rotation of principal stress axie with low shear stress level（q=5 kPa）mainly reflect the influence of initial anisotropy,while the stress-induced anisotropy impact on the soil is small.As the existence of stress-strain-strength anisotropy,the design for practical engineering with significant rotation of principal stress axie may be unsafe if using conventional method without considering the effect of principal stress rotation.