(中铁第四勘察设计院集团有限公司， 武汉 430063)

［摘要］大型石化工程地基处理难度高且复杂，开展了15 000，12 000，8 000，5 000kN·m能级单点强夯和群夯的超孔隙水压力现场试验。通过在不同能级试验区内不同位置和深度处埋设孔隙水压力计，观测并分析不同能级下强夯超孔隙水压力变化规律。结果表明：相同地质条件下，15 000，12 000kN·m能级单点强夯超孔隙水压力消散90%需约40min，8 000，5 000kN·m能级需30min；5 000kN·m能级单点强夯水平影响距离约为5～6m，12 000，8 000，5 000kN·m能级单点强夯水平影响距离为7～8m。群夯后，浅层超孔隙水压力基本大于深层超孔隙水压力，超孔隙水压力消散时间也相对较长，且浅层孔隙水压力受群夯影响的水平距离较深层的大；当场地内存在黏性土夹层时，超孔隙水压力消散时间增加，且消散速度与夹层厚度有关，需根据夹层厚度适当调整间歇期（每遍夯击时间间隔），夹层厚度大于2m时，15 000kN·m能级间歇期建议为3d，12 000，8 000，5 000kN·m间歇期建议为2d；群夯15 000，12 000，8 000，5 000kN·m能级有效加固深度分别大于11，10，8，8m。

［关键词］软弱地基土； 单点强夯； 群夯； 能级； 孔隙水压力； 现场试验

中图分类号：TU472-3文献标识码：A文章编号：1002-848X(2020)02-0138-06

Field test of pore water pressure during different energy-level dynamic compactions on soft foundation

Cao Liqiao

（China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430063, China）

Abstract:The foundation treatment of large-scale petrochemical engineering is difficult and complex, and field single point dynamic compaction and group compaction tests of 15 000，12 000，8 000，5 000kN·m level of excess pore water pressure were carried out. By embedding pore water pressure gauge at different positions and depths in different energy level test area, the variation laws of excess pore water pressure in dynamic compaction under different energy levels were observed and analyzed. The results show that under the same geological conditions, the excess pore water pressure dissipation of 90% of 15 000kN·m and 12 000kN·m level single point dynamic compaction takes about 40min, and the excess pore water pressure dissipation of 8 000kN·m and 5 000kN·m level single point dynamic compaction takes about 30min. The horizontal influence distance of 5 000kN·m level single point dynamic compaction is about 5～6m, and the horizontal influence distance of 12 000, 8 000 and 5 000kN·m level single point dynamic compaction is 7～8m. After group compaction, the pressure of excess pore water in shallow layer is basically higher than that in deep layer, and the dissipation time of excess pore water pressure is relatively long, and the horizontal distance of excess pore water pressure affected by group compaction is larger than that in deep layer. When there is a clay interlayer in the field, the dissipation time of excess pore water pressure increases, and the dissipation speed is related to the thickness of interlayer. It is necessary to adjust the interval period according to the thickness of interlayer (interval time of each compaction). When the interlayer thickness is greater than 2m, the interval period of 15 000kN·m energy level is recommended to be 3 days, and the interval period of 12 000, 8 000 and 5 000kN·m is recommended to be 2 days. The effective reinforcement depth of 15 000, 12 000, 8 000 and 5 000kN·m level is greater than 11, 10, 8 and 8m respectively.

Keywords:soft foundation soil; single point dynamic compaction; group compaction; energy level; pore water pressure; field test

*中国石油工程建设公司科学研究与技术开发项目（CPECC2011KJ22）。

作者简介：曹力桥，硕士，高级工程师，Email:caoliqiao52025@163.com。