水下DCM法加固软基关键参数优化  

Optimization on key parameters of soft foundation reinforcement by underwater DCM

作　　者：汪海洋 WANG Haiyang(CCCC Fourth Harbor Engineering Institute Co.,Ltd.,Guangzhou 510230,China;CCCC Key Lab of Environmental Protection&Safety in Foundation Engineering of Transportation,Guangzhou 510230,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China)

机构地区：[1]中交四航工程研究院有限公司,广东广州510230 [2]中交交通基础工程环保与安全重点实验室,广东广州510230 [3]南方海洋科学与工程广东省实验室(珠海),广东珠海519000

出　　处：《水运工程》2024年第12期238-244,共7页Port & Waterway Engineering

摘　　要：陆上和水下软基深层水泥搅拌桩施工参数通常通过试桩确定,水下DCM多为四轴,施工参数难以确定。以某填海工程DCM桩为背景,对水下DCM桩进行试桩,对水泥搅拌桩搅拌切土次数、底部W施工曲线、喷浆工艺等关键参数进行研究,并通过三重管取芯对水泥土强度进行检测。结果表明,淤泥中水泥掺量由320 kg/m3优化为300 kg/m3,固化28 d水泥土搅拌桩无侧限抗压强度大于1.0 MPa,满足设计要求。底部硬黏土层增加2个小W施工曲线进行复搅可以提高水泥桩的强度。为充分将黏土搅散,下贯速度不宜大于0.3 m/min,提升速度不宜大于1.0 m/min。搅拌叶片的旋转速度应与钻头下贯或提升速度匹配,以提高搅拌效果,进而提高成桩质量。The construction parameters of deep cement mixing(DCM)on land and underwater soft foundation are usually determined by test pile,and the underwater DCM is mostly four-axis,so the construction parameters are difficult to determine.In this paper,the DCM piles in reclamation project is studied,the key parameters of the cement mixing pile,such as BRN,W-shaped construction curve at the bottom and cement slurry jet technology are studied,and the cement soil-cement strength is tested through triple tube coring.The results indicate that the cement content in the silt is optimized from 320 kg m 3 to 300 kg m 3,and the unconfined compressive strength of the cement-soil mixing pile is greater than 1.0 MPa after 28 days curing,which meets the design requirements.The pile’s strength can be improved by adding two W-shaped curve to remix the hard clay layer at the bottom.To fully stir the clay,the penetration speed should not be greater than 0.3 m min and the withdraw speed should not be greater than 1.0 m min.The stirring blade rotation speed should match the drill penetration or withdrawing speed to improve the mixing effect and the quality of pile.

关 键 词：深层水泥搅拌法 软基 施工参数 无侧限抗压强度 

分 类 号：U655[交通运输工程—港口、海岸及近海工程] TU47[交通运输工程—船舶与海洋工程]