砂土内摩擦角与静探锥尖阻力的相关性研究

Study on the Relevance between Angle of Internal Friction and Cone Resistance

随着原位综合测试技术在深厚覆盖层区工程勘察中的推广,剑桥型旁压和静力触探试验对砂土体的物理及力学指标测试效果较好。本文结合孟加拉某工程场地剑桥型旁压试验,根据Hughes建议的砂类土理论计算获取其内摩擦角,同时通过深层静探试验获取锥尖阻力值,分类统计并绘制出该场地细-中砂、含有圆砾的中-粗砂内摩擦角-锥尖阻力的关系曲线,并获取具有良好相关性的关系式。对比欧美基于含大量黏粉粒或含粗颗粒(圆砾)等除外的砂类土静探锥尖阻力的内摩擦角相关经验取值,本文研究的细-中砂关系曲线与相关经验的表现吻合较好,在相同锥尖阻力情况下,含有圆砾的中-粗砂类土内摩擦角则相比细-中砂大1°~3°。通过本文基于剑桥型旁压和深层静力触探的综合原位测试结果分析表明,根据旁压试验理论计算及静探锥尖阻力经验获取砂类土内摩擦角值结果可靠。

With the promotion of the In-situ comprehensive test to the deep cover layer in the engineering survey,Cambridge pressuremeter test and Cone penetration test have a good effect on the physical and mechanical indicators test.According to the suggestion from Hughes that the Angle of internal friction obtained by the the theoretical calculation of sand soil,combining with the Cambridge pressuremeter test on a project in Bangladesh,At the same time,the Qcvalue obtained through CPT,finally,the relation curves between the inner friction Angle and Cone resistance of the fine to medium sand,medium to coarse sand containing round gravel was drawn after classifying and counting,and a goodrelation of correlation was deduced.Compared with Europe and the United States,based on relevant empirical value of the Angle of internal friction from deep PCPT on sand,except sand containing large amounts of silt & clay or coarse particles(pebbles),the study onthe relation curve of the fine to medium sand in this article matches well with the the relevant empirical performance.Under the same cone resistance,the Angle of internal friction of the medium to coarse sand containing pebbles is bigger than fine to medium sand from 1° to 3°.Through the analysis of the result of the in-situ comprehensive test on the basis of Cambridge pressuremeter test and Cone penetration test in this article,it indicates that the data obtained from the Cambridge pressuremeter test and deep PCPT of the Angle of internal friction of the sand is dependable.