膨润土泥浆改变砂性土振动密实特性的室内试验研究  

Laboratory test on changing vibration compaction characteristics of sandy soil by bentonite mud

作　　者：宋博文 寇晓强 陈智军[1,2] SONG Bo-wen;KOU Xiao-qiang;CHEN Zhi-jun(CCCC First Harbor Engineering Co.,Ltd.,Tianjin 300461,China;CCCC Tianjin Port Engineering Institute Co.,Ltd.,Key Laboratory of Geotechnical Engineering of Ministry of Communications,Tianjin 300222,China)

机构地区：[1]中交第一航务工程局有限公司,天津300461 [2]中交天津港湾工程研究院有限公司,港口岩土工程技术交通行业重点实验室,天津300222

出　　处：《水运工程》2022年第11期222-226,共5页Port & Waterway Engineering

摘　　要：钢圆筒结构具有施工工期短、经济、耐久性好、施工便捷等特点,目前已在粤港澳大湾区某工程和国内某跨江通道工程中应用。当地基中存在较硬的夹砂层时,钢圆筒在打设过程中会使砂层发生振密效应,造成砂层板结,给钢圆筒振沉带来了很大的困难,强行打设会导致钢圆筒结构产生破坏。因此有必要对夹砂层和砂层地基进行改性,改变砂层土体振动密实特性,使钢圆筒顺利振沉。通过室内膨润土改性砂样的试验研究发现:1)膨润土可以很好地降低砂土的抗剪强度,改性后的黏聚力c有一定的提升,但是内摩擦角φ降低较为明显。2)水土比对砂土抗剪强度的影响较小,膨润土掺量对泥浆改性砂土的抗剪强度有很大的影响。3)膨润土改性砂土选用的泥浆配合比,建议膨润土掺量为5%、水土比选择在8~20。The steel cylinder structure has the characteristics of short construction period, economy, good durability, and convenient construction. It has been applied in a project in the Guangdong-Hong Kong-Macao Greater Bay Area and a cross-river channel project in China. When there is a hard sand layer in the foundation, the vibration density effect of the sand layer will occur during the construction of the steel cylinder, resulting in the compaction of the sand layer, which brings great difficulties to the vibration settling of the steel cylinder. Forcibly installation will cause damage to the steel cylinder structure. Therefore, it is necessary to modify the sand layer and the sand layer foundation to change the vibration dense characteristics of the sand layer and make driven of steel cylinder smoothly.Through the experimental study of indoor bentonite modified sand samples, we find that: 1)Bentonite can reduce the shear strength of sand very well. After modification, the cohesive force c will be improved to a certain extent, but the internal friction angle φ will be significantly reduced.2)The water-cement ratio has little effect on the shear strength of sand. The amount of bentonite has a great influence on the shear strength of mud-modified sand. 3)The mud mix ratio selected for bentonite modified sandy soil is recommended to be 5% of bentonite and the water-cement ratio of 8 to 20.

关 键 词：泥浆 改性 砂性土 振动密实 

分 类 号：U656[交通运输工程—港口、海岸及近海工程]