中国二重集团淬火装置深基坑支护结构研究
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摘要
圆形基坑周围土体具有拱效应,作用于支护结构的土压力与直边基坑直边中部的土压力相比将会大大降低；如果采用弧形或圆形支护结构,在土压力作用下支护结构内力以周向压应力为主,几乎不存在弯曲拉应力,这样能充分发挥了混凝土抗压性能高特性,因此其应用越来越广泛。本文对德阳市二重厂厂房内淬火炉装置圆形基坑的空间效应、支护方案及支护结构内力等进行了较为系统的研究。主要研究内容及获得结果如下：
(1)对圆形基坑可选用的支护结构型式进行了总结与论证分析,结果表明采用“品”字形密排桩墙+内支撑+桩间混凝土充填的半逆做法,同时用旋喷桩作为止水的支护结构方案,是该基坑支护技术可靠、经济合理和实施性强的最佳方案。
(2)圆形支护结构与通常的线状支护结构比较,具有显著的空间结构效应,在同样的土压力作用下支护结构内力以压应力为主,针对土压力随深度增加,若按照平面问题分析其误差较大。本文提出一种厚壁圆筒受等效的线性分布土压力及内支撑力的空间结构力学模型,应用弹性力学得出应力及位移解析解。结果表明,这种计算方法得到的支护结构内力、变形较小,更接近于实测值。
(3)建立有限差分模型,对采用的排桩墙+内支撑圆形支护结构进行三维数值模拟,分析支护结构及周边环境应力场及变形状态。结果显示支护结构变形小,围护桩最大位移约22mm；基坑开挖对周围环境的影响也小,基坑开挖引起的最大沉降约7mm,说明这种支护结构合理可靠。
(4)根据工程实际情况,制定基坑施工监测方案,对基坑开挖过程中土压力值、支护结构内力、围护桩侧向位移等内容实施动态监测,及时掌握基坑支护结构安全情况及周边环境。对实测数据的分析表明,基坑开挖过程中土压力值变化连续,且变化值较小,说明基坑开挖对周围环境的影响处于可控范围内。
(5)将理论计算、数值模拟及实测结果进行对比分析。三者土压力分析结果表明,土压力均呈现“中间大,两头小”的分布规律,且在18m-23m之间达到最大值。数值分析得到的土压力值最大,理论计算值次之,实测值最小,造成这种差异的原因为理论计算与数值分析均进行了一定的简化,数据的提取位置也存在误差；三者分析方法土压力最大值均控制在0.9MPa以内,说明三者又存在一定的统一性,说明本支护结构是合理、可靠的,可为类似工程提供一定的参考。
Earth pressure acting on the retaining structure is reduced greatly comparing to the middle position of straight side, because there is soil arching effect around the circular foundation pit; main stress of the retaining structure is pressure under circular retaining structure, and there is nearly no tensible pressure so the high pressure property of the concrete can work fully, as a result, more and more circular retaining structure appear. In this paper, take the quenching furnace foundation engineering of the China Secondary Heavy Machinery Group as an example, study the space effect, the supporting scheme and the internal force of the retaining structure and so an. Main research contents and results are as follows:
(1) Argue on various retaining structures which can be applied to circular foundation pit, it shows that the retaining structure of piles in row+internal bracing+concrete padding between piles+sealing works of Jet Grouting Piles is dependable, economical, operable and reasonable, and it is the best retaining structure to this foundation pit.
(2) Comparing with the linear retaining structure, space effect is prominent in the circular retaining structure, and the main internal force of the retaining structure is pressure under the same earth pressure; because earth pressure increase with depth rising, the inaccuracy is larger depending on plane problem. In this paper, propose a mechanics model that thick-walled cylinder bearing linear soil pressure and inner supporting, and obtain stress and displacement solution. The result shows that the internal force and the deformation of supporting structure are both smaller and closer to the measured value.
(3) Build a finite-difference model to simulate the foundation pit excavating, and study the stress field changes and deformation of the retaining structure and the environment. The result shows that deformation of the retaining structure is smaller, and the largest deformation is only about 22mm; influence causing by foundation pit excavation is also smaller, and the largest settlement is only 7mm, it shows that this retaining structure is reasonable and dependable.
(4) According to actual situation, establish a monitoring scheme for foundation pit excavation to monitor earth pressure, internal force of retaining structure and so on, so the retaining structure safety and surrounding environment changes can be known in time. The monitoring data analysis shows the value of earth pressure change continuous and changes are smaller, so it is indicated that the influence of foundation pit excavation is controlled in a rational range.
(5) Compare the theoretical, numerical simulation and monitoring results. The results show that earth pressure present distribution of "middle larger, sides smaller", and the largest earth pressure appear at depth range that 18m to 23m. The earth pressure value of numerical simulation is the largest, followed by theoretical value and the monitoring value is the least, the reason leading to this difference is that theoretical calculation and the numerical analysis are both simplified, meanwhile, data position are different a little. The results in three methods are controlled in 0.9MPa so that the results are consistent in some degree, it shows that this retaining structure is reasonable and reliable, and it can prove some experience to the similar project.
(1)对圆形基坑可选用的支护结构型式进行了总结与论证分析,结果表明采用“品”字形密排桩墙+内支撑+桩间混凝土充填的半逆做法,同时用旋喷桩作为止水的支护结构方案,是该基坑支护技术可靠、经济合理和实施性强的最佳方案。
(2)圆形支护结构与通常的线状支护结构比较,具有显著的空间结构效应,在同样的土压力作用下支护结构内力以压应力为主,针对土压力随深度增加,若按照平面问题分析其误差较大。本文提出一种厚壁圆筒受等效的线性分布土压力及内支撑力的空间结构力学模型,应用弹性力学得出应力及位移解析解。结果表明,这种计算方法得到的支护结构内力、变形较小,更接近于实测值。
(3)建立有限差分模型,对采用的排桩墙+内支撑圆形支护结构进行三维数值模拟,分析支护结构及周边环境应力场及变形状态。结果显示支护结构变形小,围护桩最大位移约22mm；基坑开挖对周围环境的影响也小,基坑开挖引起的最大沉降约7mm,说明这种支护结构合理可靠。
(4)根据工程实际情况,制定基坑施工监测方案,对基坑开挖过程中土压力值、支护结构内力、围护桩侧向位移等内容实施动态监测,及时掌握基坑支护结构安全情况及周边环境。对实测数据的分析表明,基坑开挖过程中土压力值变化连续,且变化值较小,说明基坑开挖对周围环境的影响处于可控范围内。
(5)将理论计算、数值模拟及实测结果进行对比分析。三者土压力分析结果表明,土压力均呈现“中间大,两头小”的分布规律,且在18m-23m之间达到最大值。数值分析得到的土压力值最大,理论计算值次之,实测值最小,造成这种差异的原因为理论计算与数值分析均进行了一定的简化,数据的提取位置也存在误差；三者分析方法土压力最大值均控制在0.9MPa以内,说明三者又存在一定的统一性,说明本支护结构是合理、可靠的,可为类似工程提供一定的参考。
Earth pressure acting on the retaining structure is reduced greatly comparing to the middle position of straight side, because there is soil arching effect around the circular foundation pit; main stress of the retaining structure is pressure under circular retaining structure, and there is nearly no tensible pressure so the high pressure property of the concrete can work fully, as a result, more and more circular retaining structure appear. In this paper, take the quenching furnace foundation engineering of the China Secondary Heavy Machinery Group as an example, study the space effect, the supporting scheme and the internal force of the retaining structure and so an. Main research contents and results are as follows:
(1) Argue on various retaining structures which can be applied to circular foundation pit, it shows that the retaining structure of piles in row+internal bracing+concrete padding between piles+sealing works of Jet Grouting Piles is dependable, economical, operable and reasonable, and it is the best retaining structure to this foundation pit.
(2) Comparing with the linear retaining structure, space effect is prominent in the circular retaining structure, and the main internal force of the retaining structure is pressure under the same earth pressure; because earth pressure increase with depth rising, the inaccuracy is larger depending on plane problem. In this paper, propose a mechanics model that thick-walled cylinder bearing linear soil pressure and inner supporting, and obtain stress and displacement solution. The result shows that the internal force and the deformation of supporting structure are both smaller and closer to the measured value.
(3) Build a finite-difference model to simulate the foundation pit excavating, and study the stress field changes and deformation of the retaining structure and the environment. The result shows that deformation of the retaining structure is smaller, and the largest deformation is only about 22mm; influence causing by foundation pit excavation is also smaller, and the largest settlement is only 7mm, it shows that this retaining structure is reasonable and dependable.
(4) According to actual situation, establish a monitoring scheme for foundation pit excavation to monitor earth pressure, internal force of retaining structure and so on, so the retaining structure safety and surrounding environment changes can be known in time. The monitoring data analysis shows the value of earth pressure change continuous and changes are smaller, so it is indicated that the influence of foundation pit excavation is controlled in a rational range.
(5) Compare the theoretical, numerical simulation and monitoring results. The results show that earth pressure present distribution of "middle larger, sides smaller", and the largest earth pressure appear at depth range that 18m to 23m. The earth pressure value of numerical simulation is the largest, followed by theoretical value and the monitoring value is the least, the reason leading to this difference is that theoretical calculation and the numerical analysis are both simplified, meanwhile, data position are different a little. The results in three methods are controlled in 0.9MPa so that the results are consistent in some degree, it shows that this retaining structure is reasonable and reliable, and it can prove some experience to the similar project.
引文
[1]陈志龙柯佳郭东军.城市道路地下空间竖向规划探讨[J].地下空间与工程学报,2009,5(3)：425-428.
[2]陈忠汉程丽萍.深基坑工程[M].机械工业出版社,1999.
[3]朱峰.小直径圆形深基坑的施工监测与分析[p].上海交通大学硕士论文,2007.
[4]任鹏王永翔张华.第二重型机械集团公司热处理车间新增设备基础工程施工监测及动态模拟报告[R].2009.5.
[5]刘建航候学渊等.基坑工程手册[M].建筑工业出版社,1997.
[6]龚晓南等.深基坑工程设计施工手册[M].建筑工业出版社,1998.
[7]周瑞忠邱高翔等.Rankine土压力理论现代改进方法[J].福州大学学报,1999.6,27(3)：89-92.
[8]陈秋南张永兴周小平.三向应力状态下的Rankine被动土压力公式.岩石力学与工程学报,2005.3,24(5)：880-882.
[9]李峰郭院成.基坑工程有限土体主动土压力计算分析研究[J].建筑科学,2008.1,24(1)：15-18.
[10]高大钊.软土深基坑支护技术中的若干土力学问题[J].岩土力学,1995.9,16(3)：1-6.
[11]刘发前.圆形基坑土压力分布模式研究[D].上海交通大学博士学位论文,2008.5.
[12]赵树德.按空间问题计算挡土墙的主动土压力[J].西安建筑科学大学学报,1995,27(4)：407.
[13]Sokolovski. V.V. Statistics of soil media. Pergamon.London,1996.
[14]别列赞采夫著,谢宗梁、黄贻吉译,松散体(土壤)极限平衡的轴向对称问题[M].建筑工程出版社,1956.
[15]Y.M.Cheng HU Ya-yuan. Active earth pressure on circular shaft lining obtained by simplified slip line solution with general tangential stress coefficient[J]. Chinese Journal of Geotechnical Engineering, 2005,27(01):110-115.
[16]刘发前王建华.非均匀堆载作用下圆形基坑主动土压力分析[J].上海交通大学学报2006,12：2134-2136.
[17]许锡昌.土压力问题与基坑变形分析.中国科学院研究生院博士论文[D].2004.6.
[18]夏永承董道洋等.深基坑护壁桩的受力特性和土压力[J].岩土工程学报,1999,21(2)：222-226.
[19]应宏伟谢永利潘秋元等.深基坑挡土结构土压力数值研究[J].西安公路交通大学学报,1998,18(4)：8-11,46.
[20]俞建霖龚晓南.深基坑工程的空间性状分析[J].岩土工程学报,1999,21(1)：21-25.
[21]刑肖鹏.挡土墙土压力有限元模拟分析[J].山西水利科技,2002年第4期,1-3.
[22]钱丽华.基坑拱形排桩支护结构研究[D].西南交通大学硕士论文,2008.12.
[23]秦四清.基坑支护设计的弹性抗力法[J].工程地质学报,2000,8(4)：481-487.
[24]黄强.m法在基坑支护结构设计中的应用[J].深基坑支护工程实例集,中国建筑工业出版社,1999.6.
[25]孙学奎.条分法有限元法在深基坑支护计算中的应用研究[D].辽宁工程技术大学硕士论文,2003.11.
[26]刘红军董淑云.深基坑支护结构设计的平面应变有限元法[J].青岛海洋大学学报,2003.7,33(4)：581-586.
[27]肖宏彬蔡伟铭.多支撑挡土结构考虑开挖过程的计算分析方法[J].中国港湾建设,1992年第5期：25-37.
[28]吕江宏俞季民.考虑分级开挖的深基坑支护计算[J].长江科学院院报,1998,6,15(3)：42-46.
[29]刘红军贾永刚.深基坑支护设计的弹性抗力有限元法[J].青岛海洋大学学报,1999,29(2)
[30]潘泓曹华先吴世明骆雯.深基坑开挖中圆形支护结构性状分析[J].工业建筑,1999,29(5)：1-4.
[31]周健罗筱波.圆形支护结构的拱效应等效支撑计算方法[J].岩土力学,2003.4,24(2)：169-172.
[32]刘玉涛,徐伟.圆形超深嵌岩基坑支护受力特点分析[J].建筑施工,2007,29(3)：165-167.
[33]李劭晖.锚碇基坑嵌岩支护结构受力特性和施工技术研究[D].(博士论文),2007.6.
[34]陈炯曾宪俊.土地基深基坑圆筒支护结构的受力分析方法[J].特种结构,22(2)：6-9.
[35]朱建峰.深基坑支护工程中地下连续墙的设计[J].隧道建设,2005.1,25(1)：27-30.
[36]樊良本段继伟.一种新型的基坑支护方法-人工冻结法[J].浙江建筑,1998,98(6)：23-24.
[37]梁志荣裴捷.排桩冻结法应用于超深基坑围护结构实践[J].地下空间,2004.12,24(5)：704-707.
[38]马芹永.人工冻结法的理论与施工技术[M],人民交通出版社,2004.
[39]曹宝飞.沉井法在复杂基坑支护中的应用[J].山西建筑,2006.10,32(20)：104-105.
[40]周申一张立荣等.沉井沉箱施工技术[M].人民交通出版社,2005.10.
[41]吴铭炳.排桩挡土结构桩净距计算[J].福州建设科技,1997,(4)：8-9,14.
[42]薛艳青.圆形基坑的三维数值模拟[D].同济大学硕士论文,2008.3.
[43]钟阳郭大智张肖宁.轴对称弹性半空间问题一般解的新方法[J].哈尔滨建筑大学学报,1995,28(2)：23-27.
[44]曾又林曹国兴.弹性力学空间轴对称问题通解的研究[J].应用力学学报,1989,6(3)：123-126.
[45]王杰光.弹性动力学空间轴对称问题的传递矩阵法[J].桂林冶金地质学院学报,1994,14(1)：61-68.
[46]王斌曾又林.横观各向同性弹性力学空间轴对称问题的复变函数解法[J].武汉大学学报,2002,35(3)：67-69.
[47]丁红丽.用边界单元法求解空间轴对称弹性接触问题[J].山东建筑工程学院学报,1992,7(2)：17-21.
[48]王光钦丁桂宝等.弹性力学[M].中国铁道出版社,2005.
[49]徐芝纶.弹性力学(第三版)[M].高等教育出版社,1990.
[50]李云璋姚谦峰秦文科.地下圆形连续墙支护机构的水平位移公式[J].力学与实践,2009.2,31(1)：39-42.
[51]梁亚平王惠珍任兴明.两端均布、轴向线性分布压力作用下厚壁圆筒空间轴对称问题的解析解[J].中国科学G辑：物理学力学天文学,2007,37(5)：684-688.
[52]余志成施文华.深基坑支护设计与施工.北京：中国建筑工业出版社,1997.
[53]刘波,韩彦徽编著.FLAC原理、实例与应用指南[M].北京：人民交通出版社,2005.
[54]陈育民徐鼎平编著.FLAC/FALC3D基础与工程实例[M].北京：中国水利水电出版社,2009.
[55]彭文斌编著.FLAC3D实用教程[M].北京：机械工业出版社,2008.
[56]Itasca. FLAC3D version 2.0 User's Manual[M]. Minneapolis:ICQ 1997.
[57]武立波.圆形超深基坑的监测与分析[D].西安建筑科技大学硕士论文2008.3.
[2]陈忠汉程丽萍.深基坑工程[M].机械工业出版社,1999.
[3]朱峰.小直径圆形深基坑的施工监测与分析[p].上海交通大学硕士论文,2007.
[4]任鹏王永翔张华.第二重型机械集团公司热处理车间新增设备基础工程施工监测及动态模拟报告[R].2009.5.
[5]刘建航候学渊等.基坑工程手册[M].建筑工业出版社,1997.
[6]龚晓南等.深基坑工程设计施工手册[M].建筑工业出版社,1998.
[7]周瑞忠邱高翔等.Rankine土压力理论现代改进方法[J].福州大学学报,1999.6,27(3)：89-92.
[8]陈秋南张永兴周小平.三向应力状态下的Rankine被动土压力公式.岩石力学与工程学报,2005.3,24(5)：880-882.
[9]李峰郭院成.基坑工程有限土体主动土压力计算分析研究[J].建筑科学,2008.1,24(1)：15-18.
[10]高大钊.软土深基坑支护技术中的若干土力学问题[J].岩土力学,1995.9,16(3)：1-6.
[11]刘发前.圆形基坑土压力分布模式研究[D].上海交通大学博士学位论文,2008.5.
[12]赵树德.按空间问题计算挡土墙的主动土压力[J].西安建筑科学大学学报,1995,27(4)：407.
[13]Sokolovski. V.V. Statistics of soil media. Pergamon.London,1996.
[14]别列赞采夫著,谢宗梁、黄贻吉译,松散体(土壤)极限平衡的轴向对称问题[M].建筑工程出版社,1956.
[15]Y.M.Cheng HU Ya-yuan. Active earth pressure on circular shaft lining obtained by simplified slip line solution with general tangential stress coefficient[J]. Chinese Journal of Geotechnical Engineering, 2005,27(01):110-115.
[16]刘发前王建华.非均匀堆载作用下圆形基坑主动土压力分析[J].上海交通大学学报2006,12：2134-2136.
[17]许锡昌.土压力问题与基坑变形分析.中国科学院研究生院博士论文[D].2004.6.
[18]夏永承董道洋等.深基坑护壁桩的受力特性和土压力[J].岩土工程学报,1999,21(2)：222-226.
[19]应宏伟谢永利潘秋元等.深基坑挡土结构土压力数值研究[J].西安公路交通大学学报,1998,18(4)：8-11,46.
[20]俞建霖龚晓南.深基坑工程的空间性状分析[J].岩土工程学报,1999,21(1)：21-25.
[21]刑肖鹏.挡土墙土压力有限元模拟分析[J].山西水利科技,2002年第4期,1-3.
[22]钱丽华.基坑拱形排桩支护结构研究[D].西南交通大学硕士论文,2008.12.
[23]秦四清.基坑支护设计的弹性抗力法[J].工程地质学报,2000,8(4)：481-487.
[24]黄强.m法在基坑支护结构设计中的应用[J].深基坑支护工程实例集,中国建筑工业出版社,1999.6.
[25]孙学奎.条分法有限元法在深基坑支护计算中的应用研究[D].辽宁工程技术大学硕士论文,2003.11.
[26]刘红军董淑云.深基坑支护结构设计的平面应变有限元法[J].青岛海洋大学学报,2003.7,33(4)：581-586.
[27]肖宏彬蔡伟铭.多支撑挡土结构考虑开挖过程的计算分析方法[J].中国港湾建设,1992年第5期：25-37.
[28]吕江宏俞季民.考虑分级开挖的深基坑支护计算[J].长江科学院院报,1998,6,15(3)：42-46.
[29]刘红军贾永刚.深基坑支护设计的弹性抗力有限元法[J].青岛海洋大学学报,1999,29(2)
[30]潘泓曹华先吴世明骆雯.深基坑开挖中圆形支护结构性状分析[J].工业建筑,1999,29(5)：1-4.
[31]周健罗筱波.圆形支护结构的拱效应等效支撑计算方法[J].岩土力学,2003.4,24(2)：169-172.
[32]刘玉涛,徐伟.圆形超深嵌岩基坑支护受力特点分析[J].建筑施工,2007,29(3)：165-167.
[33]李劭晖.锚碇基坑嵌岩支护结构受力特性和施工技术研究[D].(博士论文),2007.6.
[34]陈炯曾宪俊.土地基深基坑圆筒支护结构的受力分析方法[J].特种结构,22(2)：6-9.
[35]朱建峰.深基坑支护工程中地下连续墙的设计[J].隧道建设,2005.1,25(1)：27-30.
[36]樊良本段继伟.一种新型的基坑支护方法-人工冻结法[J].浙江建筑,1998,98(6)：23-24.
[37]梁志荣裴捷.排桩冻结法应用于超深基坑围护结构实践[J].地下空间,2004.12,24(5)：704-707.
[38]马芹永.人工冻结法的理论与施工技术[M],人民交通出版社,2004.
[39]曹宝飞.沉井法在复杂基坑支护中的应用[J].山西建筑,2006.10,32(20)：104-105.
[40]周申一张立荣等.沉井沉箱施工技术[M].人民交通出版社,2005.10.
[41]吴铭炳.排桩挡土结构桩净距计算[J].福州建设科技,1997,(4)：8-9,14.
[42]薛艳青.圆形基坑的三维数值模拟[D].同济大学硕士论文,2008.3.
[43]钟阳郭大智张肖宁.轴对称弹性半空间问题一般解的新方法[J].哈尔滨建筑大学学报,1995,28(2)：23-27.
[44]曾又林曹国兴.弹性力学空间轴对称问题通解的研究[J].应用力学学报,1989,6(3)：123-126.
[45]王杰光.弹性动力学空间轴对称问题的传递矩阵法[J].桂林冶金地质学院学报,1994,14(1)：61-68.
[46]王斌曾又林.横观各向同性弹性力学空间轴对称问题的复变函数解法[J].武汉大学学报,2002,35(3)：67-69.
[47]丁红丽.用边界单元法求解空间轴对称弹性接触问题[J].山东建筑工程学院学报,1992,7(2)：17-21.
[48]王光钦丁桂宝等.弹性力学[M].中国铁道出版社,2005.
[49]徐芝纶.弹性力学(第三版)[M].高等教育出版社,1990.
[50]李云璋姚谦峰秦文科.地下圆形连续墙支护机构的水平位移公式[J].力学与实践,2009.2,31(1)：39-42.
[51]梁亚平王惠珍任兴明.两端均布、轴向线性分布压力作用下厚壁圆筒空间轴对称问题的解析解[J].中国科学G辑：物理学力学天文学,2007,37(5)：684-688.
[52]余志成施文华.深基坑支护设计与施工.北京：中国建筑工业出版社,1997.
[53]刘波,韩彦徽编著.FLAC原理、实例与应用指南[M].北京：人民交通出版社,2005.
[54]陈育民徐鼎平编著.FLAC/FALC3D基础与工程实例[M].北京：中国水利水电出版社,2009.
[55]彭文斌编著.FLAC3D实用教程[M].北京：机械工业出版社,2008.
[56]Itasca. FLAC3D version 2.0 User's Manual[M]. Minneapolis:ICQ 1997.
[57]武立波.圆形超深基坑的监测与分析[D].西安建筑科技大学硕士论文2008.3.