Experimental Study on CS-DSM Technology Applied in Soft Ground Treatment
-
摘要: 受限于施工装备与传统工法,我国深层搅拌桩技术(DSM)在深厚软土中的大直径长桩施工尚未突破搅拌不均匀与桩身强度不连续的技术瓶颈。多层互剪搅拌桩(CS-DSM)技术通过创新的钻具结构、测控系统及施工工艺消除了搅拌桩均匀性差、强度低、糊钻抱钻、地表冒浆及材料浪费等固有弊病。通过CS-DSM搅拌桩与DDM搅拌桩现场足尺试验,利用钻芯法与静载试验结果,对比了两者在桩身均匀性、完整性、桩身水泥土强度以及单桩承载变形特性方面的差异性,结果表明:CS-DSM工法相对DDM工法,施工质量更为可控可靠,施工时间可缩短44.4%,单桩承载力可提高25%,初始变形刚度可提高97.0%。结合广州城际工程试验研究,展示了CS-DSM工法体系、测控技术应用、桩身均匀性表征及芯样UCS检测数据。实践表明,新技术的“两搅一喷、下钻喷浆”工艺较传统工艺可缩短工期40%以上;框架式双向搅拌钻具能够确保施工搅拌次数T>600次/m,相当于桩身水泥土任一点的累计拌合次数n>40次,直径1 m、长46 m桩的搅拌均匀性良好。地基弱加固区与强加固区水泥掺量分别为8%和18%~20%,强弱加固区桩身芯样21 d强度均超过设计强度4倍。研究结果揭示了CS-DSM工法能够稳定提升桩身搅拌均匀性并大幅度提高全桩长强度。新技术试验研究成果可为CS-DSM工法推广应用提供参考。Abstract: In China, the insufficient capabilities of construction equipment and traditional methods have long limited deep soil mixing (DSM) technology, presenting a bottleneck for constructing large diameter and deep mixing columns with sufficient mixing uniformity and consistent strength in the thick soft soils. The newly developed CS-DSM technology represents a significant improvement in drilling tool structure design, monitoring and control systems, and construction processes to resolve the drawbacks of the traditional DSM, namely poor uniformity, low compressive strength, drilling bit balling, surface spoiling, and waste on binder materials. Full-scale field comparison tests were conducted between CS-DSM columns and DDM columns. By combining core drilling and static load tests, the differences between the two methods were studied in terms of pile integrity, continuity, cement-soil strength, and bearing and deformation characteristics of a single column. The results indicated that the CS-DSM method offered more controllable and reliable construction quality comparing to the DDM method, reducing construction time by 44.4%, increasing single pile bearing capacity by 25%, and improving initial deformation stiffness by 97.0%. Based on field experiments conducted on an intercity transit project in Guangzhou, this paper showcased major aspects of CS-DSM technology including equipment and column installation process, monitoring and controlling technique, characterization of column uniformity, and UCS test data of core samples. The results indicated that the "one mixing cycle with slurry injected during the down stage" process reduced construction time by 40% compared to the traditional method. The frame-type mixing tool achieved an excellent degree of mixing for columns with adiameter of 1 m and a length of 46 m, and ensured a blade rotation number T of 600/m above, equivalent to the soilcrete per unit volume experiencing more than 40 passes of the mixing blade. The cement contents in the weakly and strongly reinforced zones were 8% and 18%~20%, respectively. The 21-day core sample strengths from both zones were minimum 4 times greater than the design strength. In conclusion, the CS-DSM method stably enhances mixing uniformity and develop high strength along the full column length. The field trial studies on this new technology can provide a reference for the promotion and application of the CS-DSM method.
-
Key words:
- deep soil mixing /
- CS-DSM column /
- CS-DSM method /
- soft ground treatment /
- field trial study
-
[1] PORBAHA A. State of the art in deep mixing technology:part Ⅰ. Basic concepts and overview[J]. Proceedings of the Institution of Civil Engineers-Ground Improvement,1998,2(2):81-92. [2] 刘汉龙,赵明华. 地基处理研究进展[J]. 土木工程学报,2016,49(1):96-115. [3] 中国建筑科学研究院. 建筑地基处理技术规范:JGJ 79—2012[S]. 北京:中国建筑工业出版社,2012. [4] 中国电力企业联合会. 深层搅拌法地基处理技术规范:DL/T 5425—2018[S]. 北京:中国电力出版社,2018. [5] 中铁二院工程集团有限责任公司. 铁路工程地基处理技术规程:TB 10106—2023[S]. 北京:中国铁道出版社有限公司,2023. [6] MORI K,UKAJI N,MIYAKAWA M. Invited lecture:recent trends in the development of deep mixing methods in Japan[C]//DUC Long P,DUNG N T. Geotechnics for Sustainable Infrastructure Development. Singapore:Springer,2020:541-554. [7] 刘松玉,宫能和,冯锦林,等. 双向搅拌桩的成桩操作方法:CN1274912C[P]. 2006-09-13. [8] 刘松玉,宫能和,冯锦林,等. 双向水泥土搅拌桩机:CN1274911C[P]. 2006-09-13. [9] 易耀林,刘松玉,赵玮,等. 变径双向水泥土搅拌桩施工技术[J]. 岩土工程学报,2010,32(增刊2):387-390. [10] 刘松玉,易耀林,杜延军,等. 变径搅拌桩处理成层软弱地基的现场试验[J]. 中国公路学报,2012,25(2):1-8. [11] 何开胜,陈泽虎. 高黏性软土中水泥搅拌桩的施工工艺和检测评估方法[J]. 工业建筑,2017,47(2):141-144. [12] 浙江省交通运输厅. 公路软土地基路堤设计规范:DB33/T 904—2021[S]. 杭州:浙江省市场监督管理局,2021. [13] 刘钟,陈天雄,杨宁晔,等. 一种具有双向旋搅机构的智能钻机装备及施工方法:CN114508091B[P]. 2024-01-05. [14] 林明峰,刘钟,张云霖,等. 一种智能制浆供浆的控制装置及其使用方法:CN114840044B[P]. 2024-03-08. [15] GERRESSEN F W,MCGALL R. Single column mixing—double rotary head(SCM-DRH)—first experiences with a new soil mixing tool[C]// Grouting 2017. American Society of Civil Engineers,2017:405-414. [16] NAKAO K,INAZUMI S,TAKAUE T,et al. Visual evaluation of relative deep mixing method type of ground-improvement method[J]. Results in Engineering,2021,10,100233. [17] 葛春巍,刘钟,兰伟,等. 单向与多层互剪搅拌桩性能模型试验对比研究[J]. 岩土工程学报,2024,46(11):2420-2428. [18] 葛春巍,刘钟,余桃喜,等. 多层互剪搅拌桩工法的工艺因素模型试验研究[J]. 岩土力学,2024,45(1):68-76. [19] CEN. Execution of special geotechnical works-Deep mixing:DIN EN 14679—2005[S]. Brussels:CEN,2005. [20] KITAZUME M. Quality Control and Assurance of the Deep Mixing Method[M]. Boca Raton:CRC Press,2022. [21] BRUCE M E C,BERG R R,FILZ G M,et al. Federal highway administration design manual:deep mixing for embankment and foundation support:FHWA-HRT-13-046[R/OL]. 2013. https://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/13046/009.cfm. [22] 广东省交通运输厅. 公路路堤软基处理技术标准:DB44/T 2418—2023[S]. 广州:广东省市场监督局,2023. [23] 福建省建筑科学研究院. 建筑地基检测技术规范:JGJ 340—2015[S]. 北京:中国建筑工业出版社,2015. [24] 广东省建筑科学研究院集团股份有限公司. 建筑地基基础检测规范:DBJ/T 15-60—2019[S]. 北京:中国城市出版社,2019. [25] 东南大学. 变截面双向搅拌桩技术规程:T/ CECS 822—2021[S]. 北京:中国计划出版社,2021. -
点击查看大图
计量
- 文章访问数: 21
- HTML全文浏览量: 4
- PDF下载量: 0
- 被引次数: 0
登录
注册
E-alert
登录
注册
E-alert
下载: