振冲挤密法加固液化粉砂地基的试验研究及应用

Experimental Research and Application of Vibroflotation for Silty Sand Foundation Consolidation

近年来,随着振冲技术的发展,业内进行了一些粉细沙无填料振冲挤密的室内及现场试验研究和应用,并取得了可贵的成果。曹娥江大闸枢纽工程根据粉砂土的工程特性,通过改进传统的振冲工具、振冲工艺及施工参数,对中等至严重可液化的粉砂地基进行了无填料振冲加固的现场试验。试验结果经标准贯入及剪切波波速测试,表明无填料振冲挤密法加固粉砂地基的抗震动液化效果显著。同时,试验表明,限于振冲法本身的局限性,振冲后的地基表层尚需结合其他工程措施进行加固处理,以提高其密实度,达到消除液化的目的。

Recently, with the development of vibroflotation technology, some indoor and field experimental research and application of the vibroflotation for silty sand foundation treatment have been made and the valuable results have been gained. Based on the characteristics of the silty sand and the engineering conditions of Cao＇ e River Grand Sluice, the on-the-spot experiments of vibroflotation consolidation without filling material on the middle to severe liquefiable silty sand foundation were made, by renovating traditional vibroflotation tool, technique and construction parameters. The experimental results, tested by standard penetration and shear wave velocity measurement, showed the great effect on resisting shock and liquefaction by adopting vibroflotation without filling material has been realized for consolidation of silty sand foundation. Limited by the vibroflotation method itself, other engineering measures should be taken accordingly to consolidate the surface on the treated foundation, so as to upgrade the compactness of the foundation and to eliminate the liquefaction.