摘要
采用自行研制的十字形振动杆结合共振理论,对液化地基进行了加固处理。基于孔压静力触探(CPTU)试验对共振前后的地基进行测试和分析,指出传统振动密实法适用性评价标准低估了共振法的可加固土类范围。土类指数Ic可用于反映加固处理前后土层状态的改变,进而提出基于土类指数Ic的共振法适用性评价标准。根据标准贯入试验SPT钻孔取样的室内试验结果,建立土类指数Ic与黏粒含量之间的关系式,提出适合于共振法加固的土层中黏粒含量的界限值。分析不同共振方案的抗液化地基处理效果,进一步验证所提出基于土类指数评价标准的可靠性。结果表明,土类指数Ic<2.40或黏粒含量不高于15%时土层可适合于共振法加固处理。加固方案不同,抗液化处理效果存在差异,3桩中心处理效果最好,其次为2点中心和常规点位。共振法扩展了传统振动密实法的应用局限性,可在液化地基处理领域中推广应用。
Combined with resonance theory,improvement of liquefiable foundation with cross-shaped vibration wing is conducted. Piezocone penetration tests are performed on the foundation before and after resonance improvement. It is shown that standards to assess the applicability of traditional vibro-compaction methods are not suitable to resonance method,since silts with fine content larger than 10%can be improved by resonance method. Nevertheless,the change of soil behaviour type index Ic,represents the variation of soil properties after improvement. Therefore,a criterion based on Ic is proposed to evaluate the applicability of resonance method. With results from standard penetration test performed on samples,relationship between Ic and clay content is promoted to determine the maximum clay content in soils to ensure the applicability of resonance method. Finally, variations of improvement to reduce liquefaction potential under different resonance schemes are studied. The reliability of criterion based on Ic is further confirmed. It is concluded that cohesionless soils with Ic<2.40 or clay content less than 15%are suitable to be improved by resonance method. However,the effects of improvement are different depending on resonance schemes. Results show that the center of three resonance columns can be improved best,nest for the center of two resonance columns and routine points respectively. It is shown that resonance method expands the limitation of traditional vibro-compaction method,and can be spreaded in liquefiable foundation improvement.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2013年第S2期4105-4114,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(41202203)
"十二五"国家科技支撑计划项目(2012BAJ01B02)
中央高校基本科研业务费(3221003202)
关键词
土力学
孔压静力触探试验
共振法
土类指数
液化地基
soil mechanics
piezocone penetration test(CPTU)
resonance method
soil behavior type index
liquefiable foundation
