基于功能系统分析技术的葵岗隧道围岩施工方案选择研究

 基于价值工程中的功能系统分析技术，结合专家知识和群决策(DSS)技术，对高速公路隧道施工方案的优化选择方法进行研究，建立一个针对不同围岩类别的施工方案优化理论模型。然后结合一个具体案例(葵岗隧道施工优化)来阐述该模型的应用。实践证明，这种模型很适合大型隧道工程的施工方案优化选择决策。

DEMONSTRATION ON DEPENDENCY OF CONSTITUTIVE RELATIONS OF SOILS WITH STRESS PATHS

Based on the triaxial compression tests of clays and sands under different stress paths，it is theoretically proven according to the principle of interaction between plastic volumetric and shear strains that the constitutive relations of soils are dependent on stress paths，and the dependency of stress path is the combination of effects of the interaction between plastic volumetric and shear strains. The dependence of stress path includes not only the effect of pressure sensitivity but also shear-induced dilatancy. The results of triaxial compression tests for clays and sands under three different stress paths show that the shear yield surfaces and volumetric yield surfaces rotate with the change in stress paths. At the same time，the sizes of yield surfaces in the stress space vary with stress paths. This phenomenon is called rotational hardening. The mechanism of yield surface rotation is analyzed and it is explained that the rotational hardening is resulted from the dependency of stress path，which is essentially a reflection of the interaction between plastic volumetric and shear strains.