基于钙质砂土的CPT与SPT经验转换关系研究

Study of empirical CPT-SPT correlation for calcareous sand

目前现有的CPT与SPT经验转化关系研究主要基于硅质砂土,而在钙质砂土中比较少见。钙质砂土由于其本身具有较高的可压缩性及可破碎性质并不一定适用现有经验关系,因此有必要在钙质砂土中延伸和拓展2种测试方法之间经验转换关系。通过搜集中东卡塔尔多哈新港区域334组钙质砂土数据,对比和分析既有经验关系钙质砂土中的适用性。分析结果显示,基于单因素的平均粒径D50或细颗粒含量FC(%)(<0.063 mm)经验关系并不适合钙质砂土;基于CPT土类划分法的经验系数偏高;而基于土性指数Ic经验关系在钙质砂土中表现出较好一致性。同时通过研究分析,提出基于多因素修正参数的经验关系,并在多哈新港区域钙质砂土的相关性分析中得到较高的拟合度,从而为钙质砂土中2种测试参数之间转换提供一种更可靠经验关系。

The existing CPT and SPT correlations are mostly limited on silica sands.It is seldom to seen the correlation are based on calcareous sand.Since the calcareous sand are mostly characterized a higher crushability and compressibility,the existing correlation is not applicable.Therefore,it is necessary to extend the CPT-SPT correlation in calcareous sands.334 group high quality data were collected from New Doha Port project in Qatar and applied to the existing correlations to compare their applicability.The comparative results indicated that the correlation with single factor,either mean diameter D50 or fine content FC（%）（0.063 mm）is not applicable to calcareous sand,and the coefficient factors based on CPT soil type method is relatively higher,whereas the typical correlation based on soil behave type index Ic shows a good consistency in calcareous sand.Meanwhile,one correlation method based on corrective factor is proposed and the analysis result shows a better correlation coefficient.Hence one more reliable correlation based on calcareous sand can be provided in future research.