【摘要】 黄河三角洲粉土主要为第四纪散河流堆积物。结合现场钻探取样、旁压试验(PMT)、扁铲试验(DMT)和室内试验,综合研究黄河三角洲粉土的原位力学特性。室内试验结果表明,黄河三角洲粉土粒径集中在0.075～0.005mm,粒径均匀,级配较差且黏粒含量极低,导致难以压实;孔隙率较高,压缩性大。原位旁压试验结果表明,黄河三角洲地区地基的容许承载力为300kPa左右,且土体的临塑压力随着深度的增加逐渐增大,但在13.0m以下有减小的趋势;随后给出该地区地基旁压模量Em随深度的变化关系式,提出该地区土层旁压模量建议值为1800kPa,并进一步分析变形模量与旁压模量之间的定量关系。扁铲试验进一步论证该地区土层的类别主要为粉土,给出静止侧压力系数K0和水平应力指数KD随深度的变化图。最后讨论侧胀模量ED与压缩模量Es的关系,以及ED,Es随深度的变化情况。更多还原

【Abstract】 The silt in the Yellow River Delta mainly belongs to the quaternary deposits. Based on the in-situ drilling test,pressuremeter test(PMT),dilatometer test(DMT) and laboratory test,the mechanical properties of silt are studied. Laboratory test results show that there are many special characteristics of silt soil,such as the homogeneous particle size(grain sizes of silt centralized in 0.075–0.005 mm),poor gradation and little clay content in the silt,therefore,it is hard in compaction. In addition,the porosity of the silt is very high,which leads to large compressibility. The results of PMT demonstrate that the allowable bearing capacity of foundation in the Yellow River Delta is 300 kPa. In addition,the critical edge pressure of silt increases with the depth,and decreases in the depth greater than 13.0 m. The quantitative relationship between modulus of lateral pressure test and depth is also presented. Moreover,the suggested value of modulus of lateral pressure test is 1 800 kPa in the Yellow River Delta. As for DMT,the results reveal that most strata in the area belong to silt ones except for some rock flour or silt clay in some layers. Then,the changes of static lateral pressure coefficient K0 and horizontal stress index KD with depth are studied. Finally,the relationship between dilatational modulus ED and compression modulus Es is discussed;meanwhile,the variations of ED and Es with depth are analyzed.更多还原