扁铲侧胀试验在杭州地铁工程勘察中的应用研究

The Application Research of Dilatometer Test in Hangzhou Metro Engineering Survey

地铁勘察中水平基床系数是一个非常重要的参数,而扁铲侧胀试验(DMT)是一种现场横向原位测试,存在着快速、准确、土体扰动少等特点,有着现有试验手段无法达到的优势,它可以获取四个基本参数(侧胀模量ED、材料指数ID、水平压力指数KD及孔隙水压力UD)和进行水平基床系数的估算。本文对杭州地铁工程勘察中的28个扁铲测试孔的回归统计分析,初步总结出划分地层界线的土类指数ID的范围值,建立了铁路规范中水平基床系数估算公式的折减修正系数的相关公式,在地铁勘察中作了有益的尝试。

Horizontal coefficients of subgrade reaction is a very important parameter in metro survey.And DMT is one in situ horizontal measurement,with rapid,accurate and less soil disturbance characteristic and so on.It has the advantage that existing experiment method could not attain.Four basic parametres could be obtained through it (dilatometer modulus ED,material index ID,horizontal pressure index KD and excess water pressure UD) and Horizontal Coefficient of Subgrade Reaction could be estimated.According to the regression statistical analyses of 28 DMT holes in Hangzhou metro engineering survey in this paper,preliminary summarized of the scope value of soil index ID that used to plot soil layer boundary,and established relevant formula to reduction revised factor of railway Horizontal coefficient criterion estimated formula,it made useful attempt in metro survey.