【作者】 秦辉辉；

【导师】 张顶立；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2012， 硕士

【摘要】 针对城市地下工程的近接施工问题,围绕近接影响分区、地层变形控制、施工方案优化等关键技术,论文依托北京地铁六号线南锣鼓巷站-东四站区间叠落隧道工程,采用工程类比分析、数值模拟与现场监测等方法对小曲线叠落式隧道施工关键技术进行系统研究,主要研究成果如下：(1)结合叠落隧道近接影响分区的理论,提出基于地层附加变形的近接影响分区判断准则,采用数值模拟方法,从地表附加变形、洞周附加变形、地层塑性区分布等角度分析了暗挖、盾构叠落隧道近接施工以及两孔叠落盾构隧道近接施工的相互影响程度,将近接影响分区划分为强、弱和无影响区3个区域。(2)对比暗挖、盾构叠落隧道及两孔盾构叠落隧道近接影响分区情况,得出盾构法开挖能够较好地控制叠落隧道相互影响程度,减小叠落隧道施工风险。针对叠落隧道近接施工特点,总结提出近接隧道施工对策。(3)采用数值模拟方法分析了小半径曲线条件下盾构施工引起周边地层变形规律,隧道曲线线形导致隧道周边地层变形及塑性区呈不对称分布,曲线半径越小,地层变形及塑性区不对称性越明显；通过在隧道周边设软弱等代层模拟盾构超挖、盾尾空隙以及注浆等,等代层厚度越大,地层变形越大；在曲线段盾构左右不对称推力影响下,两侧不对称推力差值越大地表沉降槽不对称性越明显,千斤顶的总推力越大地表沉降值越小。结合小半径曲线条件下盾构施工特性,总结提出小曲线段盾构施工对策。(4)应用叠落式隧道近接影响分区研究结果对北京地铁六号线南锣鼓巷站-东四站区间叠落隧道工程进行近接影响分区,通过工程实践和现场监测表明,本文所进行的近接施工影响研究以及小曲线盾构隧道施工地层变形规律研究是科学合理的。通过对比暗挖、盾构叠落段与两孔盾构叠落段现场监测数据,得出盾构法施工能有效控制地表变形,减小施工扰动,降低施工风险。更多还原

【Abstract】 This paper has a systematic study on the key construction technology of overlapping tunnel with small radius curve through engineering analogy, numerical calculation and on-site measure, and so on, which takes the Nanluoguxiang Station-East station overlapping tunnel section project of Beijing Metro Line6as background, aiming at adjacent excavation problem of urban uderground, around the adjacent influenced partition, strata deformation control and optimization of construction scheme and other key technologies.The following achievement and outcome was gained:(1) Combined with the basic theory of adjacent influenced partition, the paper puts forward the standard of adjacent construction influenced partition for overlapped tunnel based on the additional deformation. And then with numerical calculation method, the paper analyzes mutual influence degree of excavation-shield overlapping tunnel and two-hole overlapping shield tunnel, from surface additional deformation, tunnel side additional deformation and plastic zone layout, divides adjacent partition into3areas(intensive-effect area, weak-effect area, no-effect area).(2) Contrast to the mutual influence degree of excavation-shield overlapping tunnel and two-hole overlapping shield tunnel, this paper concluded that the shield excavation can better control the mutual influence and the construction risk of overlapping tunnel. And then, the paper puts forward proper construction-safety controlling countermeasures, aiming at the adjacent construction characteristics.(3) Through numerical calculation method, this paper has a study on the surrounding strata deformation law caused by shield at small radius curve condition. The construction of shield tunnel with small radius curve leads to the asymmetric distribution of the strata deformation and plastic zone, the smaller the curve radius, the more obvious the asymmetry of strata deformation and plastic zone. Use the equivalent circle zone simulate the overbreak of the shield, shield tail interspace, grouting, and so on, the thicker the equivalent circle zone, the greater the stratum deformation. About the impact of asymmetric thrust, the greater the difference of left and right, the more obvious the asymmetry of strata deformation, the greater the total jack thrust, the smaller the surface settlement. And then, the paper puts forward proper construction-safety controlling countermeasures, aiming at the tunnel construction with small radius curve. (4) The research result of the overlapping tunnel adjacent partition has been fully applied in Nanluoguxiang Station-East station overlapping tunnel section project of Beijing Metro Line6. The research result of the overlapping tunnel adjacent partition and the surrounding strata deformation law caused by shield at small radius curve condition was considered to be scientific and rational according to the project and field testing result. Contrast to the monitoring results of the excavation-shield overlapping tunnel project and two-hole overlapping shield tunnel project, this paper concluded that the shield excavation can better control the surface settlement, Reduce the construction disturbance and risk.更多还原