骑跨于既有隧道基坑的开挖过程数值模拟
|
摘要
随着城市轨道交通建设迅猛发展,加上城市土地和空间资源的有限性,使得新建基坑骑跨于既有营运隧道的情形时有发生。文章通过三维有限差分软件FLAC3D建立三维基坑模型,研究基坑在分层分块开挖过程中基坑围护结构、混凝土支撑和抗拔桩的力学特性,分析探讨下卧隧道隆起变形规律。数值模拟结果表明,基坑开挖完成后坑底隆起出现2个峰值,与周边建筑物的影响有关;基坑围护结构弯矩最大出现在基坑的中部,与其水平位移最大值出现的位置相一致;文中实例支撑的轴力以及下卧隧道的隆起均符合控制要求。文中模拟的数值结果以及分析的变化规律可以为今后类似工程提供参考。
With the limited land resources and spatial resources and the rapid development of subway tunnels in cities, it becomes common that the new foundation pit crosses over the existing operating tunnel. In this paper, the three-dimensional foundation pit model is established by three-dimensional finite difference software FLAC3 D to study the mechanical characteristics of foundation pit retaining structure, concrete support and uplift piles in the process of stratified block excavation. The deformation law of the lower tunnel is also analyzed. The numerical simulation results show that after the excavation of the foundation pit, the two peaks appear on the bottom of the pit, which is related to the influence of the surrounding buildings. The largest bending moment of foundation pit retaining structure occurs in the middle of the foundation pit, which is consistent with the position of the maximum horizontal displacement. The axial force of the inner support and the uplift of the lower tunnel are in accordance with the control requirements. The presented numerical results and variation law can provide a reference for similar projects in the future.
With the limited land resources and spatial resources and the rapid development of subway tunnels in cities, it becomes common that the new foundation pit crosses over the existing operating tunnel. In this paper, the three-dimensional foundation pit model is established by three-dimensional finite difference software FLAC3 D to study the mechanical characteristics of foundation pit retaining structure, concrete support and uplift piles in the process of stratified block excavation. The deformation law of the lower tunnel is also analyzed. The numerical simulation results show that after the excavation of the foundation pit, the two peaks appear on the bottom of the pit, which is related to the influence of the surrounding buildings. The largest bending moment of foundation pit retaining structure occurs in the middle of the foundation pit, which is consistent with the position of the maximum horizontal displacement. The axial force of the inner support and the uplift of the lower tunnel are in accordance with the control requirements. The presented numerical results and variation law can provide a reference for similar projects in the future.
引文
[1] 谢贻军,钱德玲,魏雪云.紧邻地铁站的超大深基坑逆作法变形规律研究[J].合肥工业大学学报(自然科学版),2014,37(10):1231-1238.
[2] 沈辉,罗先启,李野,等.深基坑施工对地铁车站影响的数值仿真分析[J].地下空间与工程学报,2011,7(5):1018-1023,1028.
[3] 黄宏伟,黄栩,HELMUT S F.基坑开挖对下卧运营盾构隧道影响的数值模拟研究[J].土木工程学报,2012,45(3):182-189.
[4] SON M,CORDING E J.Estimation of building damage due to excavation-induced ground movements[J].Journal of eotechnical and Geoenvironmental Engineering,2005,31(2):162-177.
[5] 汪鹏程,文杰,邵长征,等.基于数值分析的深基坑围护结构优化设计[J].合肥工业大学学报(自然科学版),2016,39(9):1248-1253.
[6] SHARMA J S,HEFNY A M,ZHAOB J,et al.Effect of large excavation off deformation of adjacent MRT tunnels[J].Tunneling and Underground Space Technology,2001,25(3):93-98.
[7] 黄栩,黄宏伟,张冬梅.开挖卸荷引起下卧已建盾构隧道的纵向变形研究[J].岩土工程学报,2012,34(7):1241-1249.
[8] 李平,杨挺,刘汉龙,等.基坑开挖中既有下穿地铁隧道隆起变形分析[J].解放军理工大学学报(自然科学版),2011,12(5):480-485.
[9] 杨伦,朱大勇,袁海平,等.基于FLAC3D地铁车站基坑开挖的变形规律研究[J].合肥工业大学学报(自然科学版),2015,38(10):1363-1368.
[10] 张波,钱德玲,蒋玉敏.深基坑开挖变形控制及对周边建筑物影响的研究[J].合肥工业大学学报(自然科学版),2015,38(11):1513-1517.
[11] 中国建筑科学研究院.建筑基坑支护技术规程:JGJ 120—2012[S].北京:中国建筑工业出版社,2012:9-10.
[12] 王卫东,徐中华.预估深基坑开挖对周边建筑物影响的简化分析方法[J].岩土工程学报,2010,32(增刊1):32-38.
[13] 李志高,刘国彬,曾远,等.基坑开挖引起下方隧道的变形控制[J].地下空间与工程学报,2006,2(3):430-432.
[14] 李东海,刘军,牛晓凯,等.开挖卸荷对下卧初支隧道的纵向变形的影响研究[J].岩土力学,2009,30(2):563-566,571.
[2] 沈辉,罗先启,李野,等.深基坑施工对地铁车站影响的数值仿真分析[J].地下空间与工程学报,2011,7(5):1018-1023,1028.
[3] 黄宏伟,黄栩,HELMUT S F.基坑开挖对下卧运营盾构隧道影响的数值模拟研究[J].土木工程学报,2012,45(3):182-189.
[4] SON M,CORDING E J.Estimation of building damage due to excavation-induced ground movements[J].Journal of eotechnical and Geoenvironmental Engineering,2005,31(2):162-177.
[5] 汪鹏程,文杰,邵长征,等.基于数值分析的深基坑围护结构优化设计[J].合肥工业大学学报(自然科学版),2016,39(9):1248-1253.
[6] SHARMA J S,HEFNY A M,ZHAOB J,et al.Effect of large excavation off deformation of adjacent MRT tunnels[J].Tunneling and Underground Space Technology,2001,25(3):93-98.
[7] 黄栩,黄宏伟,张冬梅.开挖卸荷引起下卧已建盾构隧道的纵向变形研究[J].岩土工程学报,2012,34(7):1241-1249.
[8] 李平,杨挺,刘汉龙,等.基坑开挖中既有下穿地铁隧道隆起变形分析[J].解放军理工大学学报(自然科学版),2011,12(5):480-485.
[9] 杨伦,朱大勇,袁海平,等.基于FLAC3D地铁车站基坑开挖的变形规律研究[J].合肥工业大学学报(自然科学版),2015,38(10):1363-1368.
[10] 张波,钱德玲,蒋玉敏.深基坑开挖变形控制及对周边建筑物影响的研究[J].合肥工业大学学报(自然科学版),2015,38(11):1513-1517.
[11] 中国建筑科学研究院.建筑基坑支护技术规程:JGJ 120—2012[S].北京:中国建筑工业出版社,2012:9-10.
[12] 王卫东,徐中华.预估深基坑开挖对周边建筑物影响的简化分析方法[J].岩土工程学报,2010,32(增刊1):32-38.
[13] 李志高,刘国彬,曾远,等.基坑开挖引起下方隧道的变形控制[J].地下空间与工程学报,2006,2(3):430-432.
[14] 李东海,刘军,牛晓凯,等.开挖卸荷对下卧初支隧道的纵向变形的影响研究[J].岩土力学,2009,30(2):563-566,571.