【作者】 马可栓；

【导师】 丁烈云； 郑俊杰；

【作者基本信息】 华中科技大学 ， 岩土工程， 2008， 博士

【摘要】 虽然盾构法施工技术有了很大的发展,但仍不可避免会引起地层的扰动,导致隧道周围地层变形及引起地表沉降,引起近邻建筑物的损害,从而引发环境土工问题,这种现象在软土地层中尤为显著。本文以武汉长江隧道工程关键技术研究项目为依托,系统地研究了泥水盾构施工对地基和建筑物的影响以及相应的保护措施。本论文的创新之处体现在以下五个方面:一、以广州地铁二号线越三盾构区间工程、南京地铁一期工程15标盾构区间工程、武汉长江公路隧道盾构区间工程为对象,对于其施工引起地表施工期纵向沉降规律进行研究,揭示其在软弱地层盾构法施工引起地基变位的原因及其产生机理。二、以武汉越江公路隧道为工程背景,针对不同工况下,考虑和不考虑上部建筑物,进行大量二维和三维有限元数值试验,二维分析表明,可以用来预测哪些部位对于建筑物来说是最危险的部位;隧道埋深小于1.0D情况下,影响范围不大,但是影响程度却在增加,对于泥水盾构来说,埋深越小,意味着施工参数调整幅度小,施工更为不利,地面更容易冒浆。三维数值试验表明,上部建筑物的存在对隧道周围塑性区的大小影响不大,后续隧道对其先行隧道周围的塑性区影响较大,表明后行隧道开挖对两隧道之间附近的土体具有一定的影响;考虑建筑物的存在,横向沉降槽的形状明显不同,沉降槽形状由连续光滑变得有锯齿状的突变;建筑物纵向来看,出现的危险时刻是在隧道开挖面通过前后的4D范围内。针对三维分析模型,通过有关参数调整,数值实验结果和现场试验结果比较接近。三、建立了系统的建筑物保护体系,为了防止对相邻的既有建筑物产生影响,首先应该做的就是给予影响的盾构一侧采取主动措施,必须从盾构机的泥浆质量、泥水压力、盾构推进压力、掘进速度、同步注浆及姿态控制等各方面加强控制。然而,当即便采取了盾构一侧的措施仍担心对既有建筑物产生不利影响时,就必须对近邻建筑物采取相应的加固措施。以上系统的理论保护体系已应用于古建筑鲁兹故居和武汉理工电教楼,并取得较好的施工效果和社会效益。四、针对武汉长江隧道工程,结合国内外工程经验,提出了武汉长江隧道近邻建筑物保护标准,针对古建筑保护,提出了双控控制标准,建筑物本身变化(裂缝)和建筑物沉降以及地面沉降,并成功应用于工程中。五、对横断面沉降槽进行研究表明,对于武汉地层,Peck公式仍可以使用,对于双线隧道引起的沉降槽,提出超几何方法,解决了其沉降最大值不一定出现在两隧道中心,而且沉降槽经常出现不对称的情况,对于Peck公式是一个改进,并提出了先行沉降和附件沉降引起的沉降槽宽度系数设计建议值分别取0.45和0.5。以上研究成果的获得,为越江盾构隧道的成功贯通,鲁兹故居的成功保护,为后续工程的设计,施工,监测将起到不可忽视的的作用。更多还原

【Abstract】 Although the shield construction technique has developed greatly, it will inevitably cause the stratum perturbation, so as to distort soil and cause the surface subsidence, and distory the close adjacent buildings, thus the initiation environment earthwork problem will appear. This phenomenon is especially remarkable in the soft soil. Taking Wuhan Yangtze River tunneling key technologies research project as the background, the dissertation studies the effect of the slurry shield construction to the ground and buildings and protection measures in the full scales.This dissertation’s innovation including five aspects as follows: First, taking Guangzhou subway two lines Yue San shield sector project, the NanJing subway first phase 15 sign shield sector project and the Wuhan Yangtze River highway tunnel shield project as the object, it studies the lasted subsidence rule during the shield construction period to discover the reason and mechanism of the ground dislodgement in the weak stratum shield law construction. Second, taking the Wuhan Yangtze river highway tunnel as the project background, the two-dimension and the three dimension finite element numerical simulations are conducted with considering or without considering the building in view of the different operating mode. The two-dimension analysis indicates that it may be used to forecast which spots are the most dangerous spots during the whole process. The tunnel burying depth is smaller than in the 1.0D situation, the area of the settlement is less narrow, but the value of peck settlement is larger. Regarding to the slurry shield tunnel, the burying depth is smaller, it means that the construction parameter turning band is small, the construction is more disadvantageous, the ground is easier to brave the thick liquid. The three dimension numerical simulation indicates that building’s existence does not influence badly on the plastic area’s size around the tunnel. It indicates that the next tunnel excavation the nearby soil body has certain influence on two tunnels. Considering that building’s existence, crosswise subsider shape obvious different, the subsider shape smoothly continuously has the zigzag sudden change. The dangerous time of the building longitudinal is around the tunnel excavated surface passes in the AD scope. For the three dimension model, the experimental result and the field test result are quite close with the related parameter adjustment. Third, the building protection system has been established in order to prevent to influence on the neighboring building, first it is for tunnel excavation to take the driving measure. The shield machine mud quality, the slurry pressure, the shield advance the pressure, the tunneling speed, the synchronized slurry and the attitude control and so on in various aspects should be controlled increasingly. However, even if when taking tunnel excavation measure is still to worry that the building was affected adversely, the corresponding reinforcement measure must be taken in the close building. Above The theory protection system applies in the historic building Luci and the Wuhan Institute of Technology electricity and education building, and makes the good construction progress and the social efficiency.Fourth, in view of the Wuhan Yangtze River tunneling, referring to the domestic and foreign project experience, the dissertation proposes protection standard of the Wuhan Yangtze River tunnel normal neighbor buildings, and double controls standard in view of the historic building protection-the building itself changes (crack) and the building subsidence as well as the surface subsidence, applies successfully in the project. Fifth, it conducts the research to the cross section subsider to indicate that the Peck formula still might use for the Wuhan stratum, proposes the superpueition technique for settlement cough of the double tunnel, which solves its subsidence maximum value to vary from two tunnel centers, moreover the subsider had the asymmetrical situation frequently, for the Peck formula, it is an improvement and proposes firstly the subsidence and the appendix subsidence caused the trough width parameter design proposal value are 0.45 and 0.5, separately.Above research results will play an important role in the river shield tunnel’s success penetration, protection of the Luci, the construction and the monitor of the following projects. It also will offer important reference to the similar projects in the design, construction and the measurement.更多还原