深基坑复合土钉支护结构稳定性机理研究
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摘要
随着我国国民经济的高速发展,城市规模不断扩大,我国的深基坑工程也日益增多,且工程规模和技术要求的难度越来越大,传统土钉支护技术由于其固有的局限性已不能满足当前时代发展的需要。复合土钉支护技术作为一种灵活多变的新型支护结构,是传统土钉技术的继承和发展,具有广阔的发展前景。但国内外针对复合土钉支护技术的稳定性分析和作用机理的研究还不够完善。
本文以工程实例为背景,结合理论分析和数值模拟的方法,模拟了复合土钉基坑开挖与支护的全过程,对普通土钉与复合土钉的工作机理以及边坡土体位移、应力分布变化规律进行了初步的探讨。
在已有研究成果基础上,首先对复合土钉支护技术的产生和研究现状做了阐述,并指出复合土钉支护技术研究目前存在的一些问题,对预应力锚杆复合土钉支护的作用机理及其失稳模式进行了探讨;利用FLAC3D数值模拟方法,选用Mohr-Coulomb屈服准则对复合土钉支护的工程实例进行研究,对预应力锚杆复合土钉支护结构进行了较为系统的分析,并探讨了复合土钉支护机理以及基坑变形、应力变化存在的规律。
对复合土钉支护全过程的数值模拟研究表明,基坑坡体的最大水平位移发生在坡顶处,预应力锚杆可有效控制基坑坡体的侧向变形;基坑坡体的水平位移随开挖深度的增大而增大,并且位移的增加速度也随开挖深度递增,下层土体的开挖对上层已有支护临空面有较大影响;复合土钉支护结构主要受拉力作用,且内力分布不均匀,土钉和预应力锚杆承担了大部分荷载,从而使支护范围内土体承受较低的应力,充分发挥了其应力传递和扩散的作用,对土体应力集中现象有所改善;基坑坡脚处应力集中较为严重,实际支护设计与施工过程中,对坡脚处应密切监测,严禁超挖并进行及时支护。
With the rapid development of China's national economy and the cities, there are more and more deep foundations, which scales and the difficulty of technical requirements are also increasing. So the traditional soil nailing technology can not meet the current needs because of its inherent limitations. As a new type of the supporting structure, composite soil nailing technology is the development of the aditional soil nailing technology, so it has broad prospects for development. However, the research of the stability analysis and the mechanism at home and abroad is still not enough.
This paper has applied the methods of theoretical analysis and numerical simulation according to one project. Through the simulation of the excavation and protection, there has a preliminary research about the working mechanism of the common soil nailing and the composite soil nailing technology, the law of the slope displacement and the variation of stress distribution.
Based on the existing research results, this paper has described the generation and research of the composite soil nailing technology, and has pointed out some questions which the composite soil nailing technology has, then has discussed the mechanism and unstable mode of the pre-stressed composite soil nailing anchor. It has applied the FLAC3D numerical simulation to make a research about the engineering which use the composite soil nailing by using the Mohr-Coulomb yield criterion. There is a system analysis about the pre-stressed anchor and composite nailing protecting structure. It also discussed the mechanism of composite soil nailing, and the law of the pit deformation and stress vary.
The numerical simulation has indicated that the maximum horizontal displacement occurs at the top of the slope, and the pre-stressed anchor can control the displacement effectively. The horizontal displacement and the deformation velocity can increase with the increase of the depth of excavation. The excavation of the soil below has a greater impact on the supporting of the upper free surface. Composite soil nailing structure is mainly affected by tension, and the force is asymmetry. The nails and pre-stressed anchor has undertaken a greater load, so the soil which stay in the support area has undertake a smaller load, that will make the soil play its role of stress transfer and diffusion, so it improves the soil stress concentration. There is a serious stress concentration at the toe of side slope. So at the process of design and construction, there is a need to monitor the toe of the slope. And it prohibits over-excavation and need support timely.
本文以工程实例为背景,结合理论分析和数值模拟的方法,模拟了复合土钉基坑开挖与支护的全过程,对普通土钉与复合土钉的工作机理以及边坡土体位移、应力分布变化规律进行了初步的探讨。
在已有研究成果基础上,首先对复合土钉支护技术的产生和研究现状做了阐述,并指出复合土钉支护技术研究目前存在的一些问题,对预应力锚杆复合土钉支护的作用机理及其失稳模式进行了探讨;利用FLAC3D数值模拟方法,选用Mohr-Coulomb屈服准则对复合土钉支护的工程实例进行研究,对预应力锚杆复合土钉支护结构进行了较为系统的分析,并探讨了复合土钉支护机理以及基坑变形、应力变化存在的规律。
对复合土钉支护全过程的数值模拟研究表明,基坑坡体的最大水平位移发生在坡顶处,预应力锚杆可有效控制基坑坡体的侧向变形;基坑坡体的水平位移随开挖深度的增大而增大,并且位移的增加速度也随开挖深度递增,下层土体的开挖对上层已有支护临空面有较大影响;复合土钉支护结构主要受拉力作用,且内力分布不均匀,土钉和预应力锚杆承担了大部分荷载,从而使支护范围内土体承受较低的应力,充分发挥了其应力传递和扩散的作用,对土体应力集中现象有所改善;基坑坡脚处应力集中较为严重,实际支护设计与施工过程中,对坡脚处应密切监测,严禁超挖并进行及时支护。
With the rapid development of China's national economy and the cities, there are more and more deep foundations, which scales and the difficulty of technical requirements are also increasing. So the traditional soil nailing technology can not meet the current needs because of its inherent limitations. As a new type of the supporting structure, composite soil nailing technology is the development of the aditional soil nailing technology, so it has broad prospects for development. However, the research of the stability analysis and the mechanism at home and abroad is still not enough.
This paper has applied the methods of theoretical analysis and numerical simulation according to one project. Through the simulation of the excavation and protection, there has a preliminary research about the working mechanism of the common soil nailing and the composite soil nailing technology, the law of the slope displacement and the variation of stress distribution.
Based on the existing research results, this paper has described the generation and research of the composite soil nailing technology, and has pointed out some questions which the composite soil nailing technology has, then has discussed the mechanism and unstable mode of the pre-stressed composite soil nailing anchor. It has applied the FLAC3D numerical simulation to make a research about the engineering which use the composite soil nailing by using the Mohr-Coulomb yield criterion. There is a system analysis about the pre-stressed anchor and composite nailing protecting structure. It also discussed the mechanism of composite soil nailing, and the law of the pit deformation and stress vary.
The numerical simulation has indicated that the maximum horizontal displacement occurs at the top of the slope, and the pre-stressed anchor can control the displacement effectively. The horizontal displacement and the deformation velocity can increase with the increase of the depth of excavation. The excavation of the soil below has a greater impact on the supporting of the upper free surface. Composite soil nailing structure is mainly affected by tension, and the force is asymmetry. The nails and pre-stressed anchor has undertaken a greater load, so the soil which stay in the support area has undertake a smaller load, that will make the soil play its role of stress transfer and diffusion, so it improves the soil stress concentration. There is a serious stress concentration at the toe of side slope. So at the process of design and construction, there is a need to monitor the toe of the slope. And it prohibits over-excavation and need support timely.
引文
Bose S K, Som N N. Parametric study of a braced cut by finite element method.Computers and Geotechnics, 1998, 22(2): 91-107
Bruce, D.A. & Jewell,R.A. Soil Nailing Application and Practice-part 1[J]. Ground Engineering, 1986,19(12), 10～15
Bruce, D.A.&Jewell, R.A. Soil Nailing Application and Practice-part 2[J]. Ground Engineering, 1987,20(1),21～23
Faheem H, Cai F, Ugai K. Two-dimensional base stability of excavations in soft soils using FEM. Computers and Geotechnics, 2003, 11(30): 141-163
FLAC3D.Fst Lagrangian Analsis of Continua in 3 Dimensions,Version2.1[M].Itasca Consulting Group,Inc,USA.
Hong S H, Lee F H, Yong K Y. Three-dimensional pile-soil interaction insoldier-piled excavations. Computers and Geotechnics, 2003, 9(30): 81-107
Juran,et al.Kinematical limit analysis for design of soil nailed structures[J].Journal of Geotechnical Engineering,v 116,n 1,Jan,1990,54-72
Juran.,et al.Kinematical limit analysis for design of soil nailed structures[J].Journal of Geotechnical Engineering,v 116,n 1,Jan,1990,54-72
Marquest J M M C,Owen D R J.Infinite elements in quasi-static materially nonlinear problems.Computers & structures [J].1984, 18(4):739-751
Plumelle,C.&Schlosser,F. French National Resrarch Project CLOUTERRE on Soil Nailing[M], Geotechnical Special Publication, ASCE, 1990, No.25,661～675
Schlosser, F.Behaviour and design of soil nailing [J].A.A.Balkema, 1985,399-413
Stocker,et al.Soil nailing.Proc.Int.conf.On Soil Reinforcement[J].Paris,1979,469-474
陈希哲.土力学地基基础.北京:清华大学出版社,1989
陈育民,徐鼎平.FLAC/FLAC3D基础与工程实例[M].北京:中国水利水电出版社,2009.
陈肇元,崔京浩.土钉支护在基坑工程中的应用[M].北京:中国建筑工业出版社,2000
陈忠汉,程丽萍编著.深基坑工程[M].北京:机械工业出版社,1999
程良奎,杨志银编著.喷射混凝土与土钉墙[M].北京:中国建筑工业出版社,1998
杜飞,钱七虎.土钉支护技术应用中若干问题分析及对策.施工技术,2000,29(1)
韩永强等.土钉墙稳定性计算方法综述.陕西水利,1999第15卷第2期
黄强.建筑基坑支护技术规程应用手册.中国建筑工业出版社,1999.
黄志全.深基坑支护工程可靠度分析与数值模拟[M].郑州:黄河水利出版社,2009
建设部建[1998]200号文件.建筑业10项新技术[M].建筑技术开发,1999,26(1),10～16
李广信.高等土力学[M]北京清华大学出版社,2004.7
李象范,徐水根.复合型土钉挡墙的研究[J].上海地质,1999.3:1～11
梁炯鋆.锚固与注浆技术手册[M].北京:中国电力出版社,2003.4,190～193
林希强.基坑复合土钉支护全过程内力及变形研究[D].中国地质大学博士学位论文.2003.10
刘成宇,主编.土力学和基础工程.北京:中国铁道出版社,1981
刘建航,候学渊.基坑工程手册[M].北京:中国建筑工业出版社,1997
罗晓辉.土体有限变形理论的弹性本构关系之辨析[J].武汉城市建设学院学报,2000.17(2)
孟厦.FLAC3D前处理程序开发及其工程应用研究[D].淮南:安徽理工大学,2009.
彭文斌.FLAC3D实用教程[M].北京:机械出版社,2008.
钱七虎.迎接我国城市地下空间开发高潮[J].岩土工程学报,1998,20(1):112-113
深基坑开挖与支护的数值分析.湖南工程学院学报.2010.06
孙广忠,主编.岩体力学基础.北京:科学出版社,1983
屠毓敏,郑坚,土钉墙基坑支护机理研究,浙江水利水电专科学校学报,2001,13(3)
王安宝等.土钉支护的稳定分析(条分法结合复形调优法)[J].地下空间,1997,17(1):
王建党等,深基坑土钉支护抗拔机理,东北大学学报(自然科学版),1999,20(1)
王梦恕.岩土工程在城区设计、施工的体会[[J].岩土工程界,2000,(1):12-15
王树理.王树仁地下建筑结构设计[M]北京清华大学出版社,2007
肖毅,邹勇.钉锚结合支护的模型试验研究[J].武汉水利电力大学学报,1999,32(1), 73～77
徐伟,苏宏阳.建筑工程分部分项施工手册[M].北京:中国计划出版社,1999
徐正来.复合土钉墙稳定性分析.水文地质与工程地质,2001, (4)
杨弘,钟嘉高,陈启军.数值模拟在土钉支护体系中的实践应用.广州建筑.2011.4
叶书麟,韩杰,叶观宝编著.地基处理与托换技术[M].北京:中国建筑工业出版社,1994,484～
张明聚,郭忠贤.土钉支护工作性能的现场测试研究.岩土工程学报,2001
张明聚,宋二详,陈肇元.基坑土钉支护稳定性分析方法及其应用.工程力学,1998
张明聚.土钉支护工作性能的研究[D].北京:清华大学土木水利学院,2000
张钦喜,朱绪平,潘旭亮.复合土钉的设计和应用实例[J].土木工程学报,2004,37(5)
张旭辉,土钉与锚杆的关系探讨,岩土力学与工程学报,2002.11
赵志晋、应惠清,主编.简明基坑工程设计施工手册,中国建筑工业出版社,2000.
周川杰.FLAC进行复合土钉支护稳定性分析[J].岩土工程界Vol5,No.6.2000
曾宪明,曾荣生编著.岩土深基坑喷锚网支护原理-设计施工指南[J].上海:同济大学出版社,1997,95～105
Bruce, D.A. & Jewell,R.A. Soil Nailing Application and Practice-part 1[J]. Ground Engineering, 1986,19(12), 10～15
Bruce, D.A.&Jewell, R.A. Soil Nailing Application and Practice-part 2[J]. Ground Engineering, 1987,20(1),21～23
Faheem H, Cai F, Ugai K. Two-dimensional base stability of excavations in soft soils using FEM. Computers and Geotechnics, 2003, 11(30): 141-163
FLAC3D.Fst Lagrangian Analsis of Continua in 3 Dimensions,Version2.1[M].Itasca Consulting Group,Inc,USA.
Hong S H, Lee F H, Yong K Y. Three-dimensional pile-soil interaction insoldier-piled excavations. Computers and Geotechnics, 2003, 9(30): 81-107
Juran,et al.Kinematical limit analysis for design of soil nailed structures[J].Journal of Geotechnical Engineering,v 116,n 1,Jan,1990,54-72
Juran.,et al.Kinematical limit analysis for design of soil nailed structures[J].Journal of Geotechnical Engineering,v 116,n 1,Jan,1990,54-72
Marquest J M M C,Owen D R J.Infinite elements in quasi-static materially nonlinear problems.Computers & structures [J].1984, 18(4):739-751
Plumelle,C.&Schlosser,F. French National Resrarch Project CLOUTERRE on Soil Nailing[M], Geotechnical Special Publication, ASCE, 1990, No.25,661～675
Schlosser, F.Behaviour and design of soil nailing [J].A.A.Balkema, 1985,399-413
Stocker,et al.Soil nailing.Proc.Int.conf.On Soil Reinforcement[J].Paris,1979,469-474
陈希哲.土力学地基基础.北京:清华大学出版社,1989
陈育民,徐鼎平.FLAC/FLAC3D基础与工程实例[M].北京:中国水利水电出版社,2009.
陈肇元,崔京浩.土钉支护在基坑工程中的应用[M].北京:中国建筑工业出版社,2000
陈忠汉,程丽萍编著.深基坑工程[M].北京:机械工业出版社,1999
程良奎,杨志银编著.喷射混凝土与土钉墙[M].北京:中国建筑工业出版社,1998
杜飞,钱七虎.土钉支护技术应用中若干问题分析及对策.施工技术,2000,29(1)
韩永强等.土钉墙稳定性计算方法综述.陕西水利,1999第15卷第2期
黄强.建筑基坑支护技术规程应用手册.中国建筑工业出版社,1999.
黄志全.深基坑支护工程可靠度分析与数值模拟[M].郑州:黄河水利出版社,2009
建设部建[1998]200号文件.建筑业10项新技术[M].建筑技术开发,1999,26(1),10～16
李广信.高等土力学[M]北京清华大学出版社,2004.7
李象范,徐水根.复合型土钉挡墙的研究[J].上海地质,1999.3:1～11
梁炯鋆.锚固与注浆技术手册[M].北京:中国电力出版社,2003.4,190～193
林希强.基坑复合土钉支护全过程内力及变形研究[D].中国地质大学博士学位论文.2003.10
刘成宇,主编.土力学和基础工程.北京:中国铁道出版社,1981
刘建航,候学渊.基坑工程手册[M].北京:中国建筑工业出版社,1997
罗晓辉.土体有限变形理论的弹性本构关系之辨析[J].武汉城市建设学院学报,2000.17(2)
孟厦.FLAC3D前处理程序开发及其工程应用研究[D].淮南:安徽理工大学,2009.
彭文斌.FLAC3D实用教程[M].北京:机械出版社,2008.
钱七虎.迎接我国城市地下空间开发高潮[J].岩土工程学报,1998,20(1):112-113
深基坑开挖与支护的数值分析.湖南工程学院学报.2010.06
孙广忠,主编.岩体力学基础.北京:科学出版社,1983
屠毓敏,郑坚,土钉墙基坑支护机理研究,浙江水利水电专科学校学报,2001,13(3)
王安宝等.土钉支护的稳定分析(条分法结合复形调优法)[J].地下空间,1997,17(1):
王建党等,深基坑土钉支护抗拔机理,东北大学学报(自然科学版),1999,20(1)
王梦恕.岩土工程在城区设计、施工的体会[[J].岩土工程界,2000,(1):12-15
王树理.王树仁地下建筑结构设计[M]北京清华大学出版社,2007
肖毅,邹勇.钉锚结合支护的模型试验研究[J].武汉水利电力大学学报,1999,32(1), 73～77
徐伟,苏宏阳.建筑工程分部分项施工手册[M].北京:中国计划出版社,1999
徐正来.复合土钉墙稳定性分析.水文地质与工程地质,2001, (4)
杨弘,钟嘉高,陈启军.数值模拟在土钉支护体系中的实践应用.广州建筑.2011.4
叶书麟,韩杰,叶观宝编著.地基处理与托换技术[M].北京:中国建筑工业出版社,1994,484～
张明聚,郭忠贤.土钉支护工作性能的现场测试研究.岩土工程学报,2001
张明聚,宋二详,陈肇元.基坑土钉支护稳定性分析方法及其应用.工程力学,1998
张明聚.土钉支护工作性能的研究[D].北京:清华大学土木水利学院,2000
张钦喜,朱绪平,潘旭亮.复合土钉的设计和应用实例[J].土木工程学报,2004,37(5)
张旭辉,土钉与锚杆的关系探讨,岩土力学与工程学报,2002.11
赵志晋、应惠清,主编.简明基坑工程设计施工手册,中国建筑工业出版社,2000.
周川杰.FLAC进行复合土钉支护稳定性分析[J].岩土工程界Vol5,No.6.2000
曾宪明,曾荣生编著.岩土深基坑喷锚网支护原理-设计施工指南[J].上海:同济大学出版社,1997,95～105