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。
How to accurately determine the mechanical parameters of deep alluvial soils with strong struc- ture is a difficult issue in construction of projects with deep alluvial soils, and this paper focuses on the problem by studying how to determine the dynamic deformation parameters through comprehensively consider- ing the in-situ tests and the laboratory tests. Research results indicate that the in-situ structure effects can be reflected by the maximum shear modulus tested from joint tests of in-situ wave tests and laboratory reso- nant column tests, and the in-situ dynamic deformation properties can be accessible by the normalized curve of G/Gmax-γ/γ and )--γ /γtested from reconstituted samples in laboratory. Therefore, the dynamic deformation parameters of deep alluvial soils can be determined by comprehensively considering the test re- sults of field wave tests and the laboratory tests, which can reflect the in-situ structural effects.