基于孔压静力触探试验的土类指数共振法加固液化地基效果评价.docxVIP

基于孔压静力触探试验的土类指数共振法加固液化地基效果评价邹海峰，蔡国军，刘松玉，杜广印(东南大学 岩土工程研究所，江苏 南京 210096)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。 关键词：土力学；孔压静力触探试验；共振法；土类指数；液化地基中图分类号：TU 44文献标识码：A文章编号：1000–6915(2013)增 2–4105–10EVALUATION OF RESONANCE METHOD FOR IMPROVINGLIQUEFIABLE FOUNDATION BASED ON CPTU SOIL BEHAVIOR TYPE INDEXZOU Haifeng，CAI Guojun，LIU Songyu，DU Guangyin(Institute of Geotechnical Engineering，Southeast University，Nanjing，Jiangsu 210096，China)Abstract：Combined with resonance theory，improvement of liquefiable foundation with cross-shaped vibrationwing 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