考虑主应力轴旋转的基坑开挖土体应变与非共轴性试验研究

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中图分类号：TU431 文献标志码：A

Experimental Research on Soil Strain and Non-coaxiality in Foundation Pit Excavation Considering Principal Stress Axis Rotation

1.School of Civil Engineeringand Architecture，University of Jinan，Jinan 25OO22，Shandong，China 2.School of Civil Engineering，Heilongjiang University，Harbin 15Oo80，Heilongjiang，China）

Abstract：To predictsoildeformationcharacteristicsduring foundation pitexcavationunder theconditionof principal stressaxisrotationmoreaccurately，foundationpitexcavationprocesswiththetypical supportformof undergrounddiaphragm walswasnumerically simulated byusing finite element analysissoftware FLAC3D.Thre-dimensional stress paths considering principal stressaxis rotation were determined，and aseries ofthree-dimensional stress path tests were conductedon the basis of thisbyusing hollow cylinder torsional shear apparatus to investigate influences of principal stressaxis rotation on soil strainandnon-coaxialityduring foundation pit excavation.Theresults show thatas the principal stress axis rotation angle increases during foundation pit excavation，stress -- strain curves of soil in pit show a faster upwardtrend，sodo both normal straincomponents and shear strain，leading to gradual increaseof strain.Horizontal strainincreases graduallyand eventually decreases withthe increase of distance between observation points in pit and the centerof pit bottmsurface.Non-coaxialityshows relativelysmall diferences，withnosignificant influenceobserved from initial effective stress and unloading method. The change trend of soil stress strain curves remains stable along the side wallof pit，where increase ofeach normal straincomponentand shear strain accelerate from the ground surface to thepit bottom surface，and the strain reaching yield increases gradually.

Keywords：foundation pit excavation；soil deformation characteristic；three-dimensional stresspath test；principal stress axis rotation；non-coaxiality

随着城镇化进程的发展及城市建设需求的增大，我国进入了大规模的地下工程建设阶段。（剩余6742字）