大直径锚杆在深厚软土地区基坑加固中的应用
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摘要
深厚软土地区的基坑支护体系在使用期间,常因勘察质量、施工质量缺陷及环境变化等因素引发险情,故需对其进行加固,选择既安全又经济合理的加固方案是工程师们的主要难题。本文以温州地区某一实际工程为依托,从设计、计算和监测等方面对大直径锚杆在深厚软土地区基坑加固中的应用进行了系统分析与研究。研究结果表明:1)采用旋喷工艺施工的大直径锚杆能有效控制基坑支护结构和土体位移,是一种经济、实用、有效的加固措施。2)因软土的蠕变导致时间效应对基坑变形量影响显著,故基坑开挖后出现险情时应选择能在短时间内达到设计强度的加固方案。
During the use of foundation pit support system in deep soft soil area, it is often necessary to reinforce the foundation pit support system because of the dangerous situation caused by survey quality, construction quality defects and environmental changes. It is the main problem for engineers to choose a safe and economical reinforcement scheme. Based on a practical project in Wenzhou, this paper systematically analyses and studies the application of large diameter bolts in foundation pit reinforcement in deep soft soil area from aspects of design, calculation and monitoring. The results show that: 1) The large diameter anchor constructed by rotary jet grouting technology can effectively control the support structure and soil displacement of foundation pit, and it is an economic, practical and effective reinforcement measure. 2) The time effect caused by creep of soft soil has a significant effect on the deformation of foundation pit, and the reinforcement scheme that can reach the design strength in a short time should be chosen when dangerous situation occurs after foundation pit excavation.
During the use of foundation pit support system in deep soft soil area, it is often necessary to reinforce the foundation pit support system because of the dangerous situation caused by survey quality, construction quality defects and environmental changes. It is the main problem for engineers to choose a safe and economical reinforcement scheme. Based on a practical project in Wenzhou, this paper systematically analyses and studies the application of large diameter bolts in foundation pit reinforcement in deep soft soil area from aspects of design, calculation and monitoring. The results show that: 1) The large diameter anchor constructed by rotary jet grouting technology can effectively control the support structure and soil displacement of foundation pit, and it is an economic, practical and effective reinforcement measure. 2) The time effect caused by creep of soft soil has a significant effect on the deformation of foundation pit, and the reinforcement scheme that can reach the design strength in a short time should be chosen when dangerous situation occurs after foundation pit excavation.
引文
[1]应宏伟,谢康和,潘秋元,等.软粘土深基坑开挖时间效应的有限元分析[J].计算力学学报,2000,17(3):349-354.
[2]夏冰,夏明耀.上海地区饱和软土的流变特性研究及基坑工程的流变时效分析[J].地下工程与隧道,1997(3):11-18.
[3]高文华,杨林德,沈蒲生.软土深基坑支护结构内力与变形时空效应的影响因素分析[J].土木工程学报,2001, 34(5):90-95.
[4]戴运祥,候学渊,李象范.软地层中斜拉群锚特性的研究[J].岩土力学, 1996, 17(2):23-28.
[5]李俊才,岳颖峰,等.软土基坑支护中的锚拉桩结构设计[J].岩土力学, 2008, 29(9):2551-2555.
[6]基坑工程手册(第二版)[M].北京:中国建筑工业出版社, 2009.
[7]加筋水泥土桩锚支护技术规程:CECS147—2004[S].北京:中国计划出版社, 2004.
[8]建筑基坑工程技术规程:DB33/T1096—2014[S].浙江:浙江工商大学出版社, 2014.
[9]建筑基坑支护技术规程:JGJ120—2012[S].北京:中国建筑工业出版社, 2012.
[10]大直径现浇混凝土薄壁筒桩技术规程:DB33/1044—2007[S].北京:中国计划出版社, 2007.
[2]夏冰,夏明耀.上海地区饱和软土的流变特性研究及基坑工程的流变时效分析[J].地下工程与隧道,1997(3):11-18.
[3]高文华,杨林德,沈蒲生.软土深基坑支护结构内力与变形时空效应的影响因素分析[J].土木工程学报,2001, 34(5):90-95.
[4]戴运祥,候学渊,李象范.软地层中斜拉群锚特性的研究[J].岩土力学, 1996, 17(2):23-28.
[5]李俊才,岳颖峰,等.软土基坑支护中的锚拉桩结构设计[J].岩土力学, 2008, 29(9):2551-2555.
[6]基坑工程手册(第二版)[M].北京:中国建筑工业出版社, 2009.
[7]加筋水泥土桩锚支护技术规程:CECS147—2004[S].北京:中国计划出版社, 2004.
[8]建筑基坑工程技术规程:DB33/T1096—2014[S].浙江:浙江工商大学出版社, 2014.
[9]建筑基坑支护技术规程:JGJ120—2012[S].北京:中国建筑工业出版社, 2012.
[10]大直径现浇混凝土薄壁筒桩技术规程:DB33/1044—2007[S].北京:中国计划出版社, 2007.