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深厚覆盖层土体原位结构性强,原状样取样困难,且由于粒径、级配的改变,室内重塑样试验确定的力学参数不能反映原位土体的实际性质,如何准确确定深厚覆盖层土体的力学参数是工程建设中的难题。本文联合室内和现场试验,研究了考虑原位结构效应确定深厚覆盖层砂土动力变形特性参数的方法。研究结果表明,可以通过联合现场波速试验和室内共振柱试验综合确定的最大动剪模量Gmax反映深厚覆盖层砂土动力变形特性的原位结构效应;基于室内共振柱试验确定的砂土归一化G/Gmax-γ/γr曲线和λ-γγr曲线受颗粒大小、级配和结构性的影响很小,用其可以分别较为接近地表征原位土体动剪模量G随动剪应变γ的衰减关系及阻尼比λ随动剪应变γ的增长关系。联合现场剪切波速和室内重塑样动力变形特性试验成果,能够较好地考虑原位结构效应确定深厚覆盖层土体的动力变形特性参数。
The deep overburden soil is structurally in situ and difficult to sample in the original shape. Due to the change of particle size and grading, the mechanical parameters determined by the indoor remodeling test can not reflect the actual properties of the in situ soil, and how to accurately determine the deep covering Layer of soil mechanical parameters is the construction of the problem. In this paper, combined with laboratory and field tests, the method to determine the dynamic deformation parameters of deep overburden sand considering the in situ structure effect is studied. The results show that the maximum dynamic shear modulus, Gmax, which is determined synthetically by field wave velocity test and indoor resonance column test, can reflect the in-situ structure effect of dynamic deformation of deep overburden sand. Based on the results of indoor resonance column test, The curves of G / Gmax-γ / γr and λ-γγr are smallly affected by particle size, gradation and structure, and can be used to characterize the dynamic shear modulus G of the in-situ soil in close proximity to each other. Attenuation relationship and damping ratio λ with dynamic shear strain γ growth relationship. Combined with the field shear wave velocity and the experimental results of dynamic deformation characteristics of indoor remodeling samples, the dynamic deformation parameters of deep overburden soil can be well considered in situ structure effect.