饱和砂土中不同钻探工艺下SPT击数的关系研究  

Study on relationship between SPT blow counts in saturated sandy soils using different drilling techniques

作　　者：夏志远 聂莉琴 孟维一 XIA Zhiyuan;NIE Liqin;MENG Weiyi(AVIC Institute of Geotechnical Engineering Co.,Ltd.,Beijing 100098,China)

机构地区：[1]中航勘察设计研究院有限公司,北京100098

出　　处：《安徽地质》2023年第2期153-157,179,共6页Geology of Anhui

基　　金：中航勘察设计研究院有限公司科研课题项目“南昌赣江南支流域浅部饱和承压砂层SPT方法对比及地下水对SPT击数的影响研究”(课题编号:201507)资助。

摘　　要：对南昌赣江(南支)与抚河(故道)入湖尾闾河道之间的湖积冲积平原区域内采用冲击钻进和回转钻进所做的SPT击数进行对比分析,得出两类钻探工艺的击数差异;并采用对砂层扰动较轻的静力触探试验(CPT)作为标准贯入试验(SPT)的对比试验,用以检验两种钻探工艺的SPT击数所反映的砂土密实度与真实密实度的差异,同时得到三点认识:(1)在饱和砂层中采用冲击钻进做SPT,对砂层的扰动很大,建议采用回转钻进进行SPT;(2)冲击钻进对粗颗粒砂土的扰动程度大于细颗粒砂土;(3)冲击钻进对浅部砂土的扰动影响较大,随着埋深增大,冲击造成的扰动影响越来越小。最终建立两种钻探工艺不同深度段各砂土的SPT击数经验关系式。Through comparative analysis of standard penetration test(SPT)blow counts made by percussion drilling and rotary drilling in the lacustrine-alluvial plain area between the Ganjiang River(south branch)and the Fuhe River(old course)in Nanchang,the difference in the blow counts between the two types of drilling processes is obtained.At the same time,cone penetration test(CPT)with less disturbance to the sand layer is used as the comparative test to check the difference between sand compactness and real compactness reflected by the SPT blow counts of the two drilling techniques.Three conclusions are reached:(1)It is recommended to use rotary drilling to make SPT in saturated sand layer because of the great disturbance to sand layer by percussion drilling;(2)The disturbance of percussion drilling to coarse-grained sand is greater than that to fine-grained sand;(3)Percussion drilling has greater disturbance to shallow sand.The disturbance caused by percussion weakens with the buried depth.Finally,the empirical relationships of SPT blow counts in different sandy soils at different depths are established for the two drilling techniques.

关 键 词：饱和承压砂土 冲击钻进 回转钻进 标准贯入试验(SPT) 静力触探试验(CPT) 

分 类 号：TU42[建筑科学—岩土工程]