针对西安某地铁车站基坑Q3原状黄土,开展偏应力恒定的循环球应力加/卸载试验,对不同固结应力与不同动应力幅值条件下原状黄土的轴向变形与体应变发展规律进行分析.结果表明:循环球应力作用下,黄土会产生一定的不可逆塑性变形与可逆弹性变形,其变形增长规律与偏压程度和动应力幅值成正比,与固结应力成反比;轴向变形规律符合Monismith C L幂函数模型,且其模型参数与固结应力条件具有显著的相关性;原状黄土在加载初期体应变累积较明显,之后逐渐趋于稳定;固结应力比对体应变影响较小,固结球应力对体应变发展具有抑制作用,表明浅层土体更容易产生压缩变形.
Research on Deformation Characteristics of Loess under Cyclic Spherical Stress
For the Q3 undisturbed loess at the foundation pit of a metro station in Xi'an,cyclic spherical stress loading and unloading test with constant deviatoric stress was carried out to analyze the development laws of axial deformation and volumetric strain of undisturbed loess subject to different consolidation stress and different dynamic stress amplitude.The result shows that,under the action of cyclic spherical stress,there occur certain irreversible plastic deformation and reversible elastic deformation on the loess,and the development law of the deformation is proportional to eccentric compression degree and dynamic stress amplitude,and inversely proportional to consolidation stress.The law of axial deformation conforms to Monismith C L power function model,and the model parameters are of significant correlation to consolidation stress conditions.The undisturbed loess exhibits obvious accumulation of volumetric strain in the initial stage of loading,and then tends to be stable gradually.Consolidation stress ratio has small effect on volumetric strain,and consolidation spherical stress has inhibition effect on development of volumetric strain,indicating that shallow soil mass is subject to compressive deformation more easily.
万方数据
维普
