陆域与海域深厚碎石回填地基高能级强夯有效加固深度对比试验研究

Comparative experimental research of effective reinforced depth of high energy dynamic compaction on foundation backfilled by crushed stone in land area and sea area

以广东某石油仓储工程高能级强夯法地基处理为背景,采用平板载荷试验、动力触探试验、标准贯入试验、瑞利波试验及室内土工试验相结合的方法,研究陆域与海域深厚碎石回填地基15 000 k N·m高能级强夯下的有效加固深度。研究结果表明:陆域强夯区的有效加固深度不小于10.0 m,海域强夯区的有效加固深度不小于8.0 m;陆域回填区与海域回填区夯点与夯间处强夯加固效果没有显著差别,说明试验设计参数合理,场地经15 000 k N·m能级强夯处理后地基的均匀性较好,强夯影响深度超过20.0 m,消除了20.0 m深度范围内粉砂层的液化,但对于深厚填土覆盖下淤泥质粉质黏土层的影响不大。在本试验条件下,对于深厚的碎石土杂填土地基,建议采用Menard公式确定有效加固深度时的修正系数α介于0.21~0.26之间。

Based on the foundation treatment of high energy dynamic compaction（HEDC） of a petroleum storage project in Guangdong, the effective depth of improvement of HEDC with 15 000 k N·m on foundation backfilled by crushed stone in the land area and the sea area were studied through plate loading test（PLT）, dynamic penetration test（DPT）, standard penetration test（SPT）, Rayleigh wave test（RWT） and laboratory soil test. The results indicate that the effective depth of improvement is not less than 10.0 m in the land trial ramming area, and the effective depth of improvement is not less than 8.0 m in the sea trial ramming area. The dynamic consolidation improvement effect is not significant between the tamping points and the no-tamping points in the land backfill area and the sea backfill area, and therefore test design parameters are reasonable. The uniformity of the foundation is better after HEDC with 15 000 k N·m, dynamic compaction influence depth is more than 20.0 m, and meanwhile, powder sand liquefaction is eliminated in the depth range of 20.0 m, but it has less effect on the mucky silty clay with the deep-thick fill. Under this experiment condition, the correction coefficient for the effective depth of improvement from 0.21 to 0.26 is recommended according to Menard formula.