摘要
以广东某钢厂建设项目为背景，通过现场试验测试锤击管桩打人后在距桩不同距离及距地面不同深度处的各地层标贯击数和锤击数等的变化情况，分析预制管桩打入后各地层挤（土）密效应影响范围、程度及变化规律；结果表明锤击管桩进入砂层具有明显挤（土）密效应，粘土层不明显；同一地层，挤（土）密效应影响程度随水平距离增大而减小；同一桩体，砂层挤密效应程度随深度变化呈先增后减趋势；挤密（土）效应具有时间效应，随着应力的重分布，主要影响范围由O～3d可扩大到O～4d；次影响范围为4～8矗，8d之外基本不考虑挤（土）密效应。根据上述研究成果，可避免挤（土）密效应在深厚砂层中带来的不利影响、选择合理的桩间距、充分发挥地基承载力潜能，节约投资提高经济效益，对正确认识挤（土）密效应的发生机理及规律，给类似工程具有很好的借鉴意义。
The installation compactive effects of the impacting Installed closed end, pre--casted reinforced concrete pipe piles in a steel factory in Guangdong are studied throughout a field testing program. The compaction effect after the installation of the closed--end pipe pile is studied by measuring the Standard Penetration Testing （SPT） blow cmmts at different distances from the pile. The results indicate that an obvious compactive effect can be found in sandy soil layers and the compactive effect in the cohesive soil layer is not significant. In the same soil layer, the compactive effect decreases with the increase of distance away from the installed pile. Along the pile, the compactive effect in the adjacent soil increases with depth first and then decreases with the depth. Further, time effect of an increase major influence zone from 0 - 3d （d.. diameter） initial to 0-4d with time can be found in the comapctive effect. The secondary influence zone is existed between 4d and 8d. No compactive effect can be found in distance beyond 8d. The above study results can be used in avoiding the adverse compactive effect of pile installed in thick sand by arranging the optimized pile spacing and utilizing the axial capacity potential.
出处
《土工基础》
2015年第5期62-66,75,共6页
Soil Engineering and Foundation
关键词
锤击管桩
挤(土)密效应
原位测试
现场试验
Impacting Installed Piles
Compactive Effect
In-situ Tests
Field Tests
