【作者】 余佳力；

【导师】 徐礼华；

【作者基本信息】 武汉大学 ， 结构工程， 2012， 博士

【摘要】 随着城市交通事业的发展,地下隧道工程日益增多。由于城市环境的复杂性,隧道施工将会经常出现穿越或邻近密集建筑群的情况,从而影响建筑物的安全和正常使用。因此,研究隧道施工对地表建筑物的影响是非常必要的。本文结合厦门机场路一期工程JC2、JC3标段工程中隧道邻近或穿越地表建筑物的实际,采用理论分析、施工监测和数值模拟相结合的方法,比较系统地研究隧道施工对周边建筑物的影响,主要研究内容和成果如下：(1)通过理论分析,探讨隧道开挖造成的地层移动和变形产生的机理,分析表明,开挖造成的地层移动和变形主要由以下几方面组成：施工引起的地层损失、周围地层孔隙水的变化、受剪破坏的重塑土再固结以及衬砌变形等,其中地层损失和地层疏水引起的地表移动和变形是主要部分；通过随机介质理论分析隧道开挖深度、开挖断面大小和地层条件对隧道施工中地表移动和变形的影响,结果表明,当隧道埋深增大时,地表的位移和变形值也都相应减小；地表位移和变形、沉降槽的宽度均随隧道开挖半径的增大而增大。对于软弱地层,开挖影响范围大；对于较坚硬的地层,开挖影响范围小。(2)对JC2、JC3标段工程中隧道穿越的地表建筑物进行了安全监测,通过分析监测结果,得出不同结构型式、不同高度建筑物的沉降及裂缝的分布及其随施工过程而演化发展的规律：连拱隧道CRD法施工中,掌子面CRD1～4开挖期间对混合结构沉降影响最大,掌子面CRD1～5开挖期间对框架结构影响最大；裂缝多处于纵墙门窗洞口的对角处,沉降较大一侧的上角和沉降较小一侧的下角表现为开裂或者是已有裂缝的开展,沉降较大一侧的下角和沉降较小一侧的上角表现为已有裂缝的闭合；隧道施工穿越建筑物时间较长,建筑物沉降较大,裂缝宽度开展变化也较大；框架结构抵御隧道施工引起环境变化的能力强于混合结构的；低层建筑抵御隧道施工引起环境变化的敏感度高于多层建筑的。(3)基于岩石爆破理论和爆破地震波的特性,针对我国《爆破安全规程》(GB6722-2003)中地表建筑物的爆破振动判据的不足,即因忽略结构物本身的自振特性而不能充分反映爆破振动对建筑物的影响,提出了建筑物爆破振动安全判据的建议：对建筑物进行振动危害评价及确定建筑物的破坏判据时,应考虑爆破地震波的振动主频和建筑物自振频率的影响,并采用相关爆破规程中关于此类建筑物抗爆破振动的质点速度作为安全判据。(4)对地表建筑物在爆破地震波作用下的动力响应进行了理论分析,结果表明：爆破地震波幅值越大,地表建筑物振动的幅值也就越大；在线性反应中,只要爆破地震波卓越频率接近地表建筑物自振频率,线性变形就会加大；在非线性反应中,若爆破地震波的卓越频率接近或大于地表建筑物的自振频率,在结构反应进入非线性阶段后,变形会减小或停止加大。若爆破地震波的卓越频率小于地表建筑物的自振频率,在结构反应进入非线性阶段后,变形可能会进一步加大；爆破振动的持续时间越长,其强迫振动引起的位移幅值出现的次数也就越多。(5)运用数值模拟方法,对爆破地震波作用下建筑物的动力响应进行了模拟分析,提出如下建议：为保证建筑物在爆破地震波作用下的安全及正常使用,减小爆破地震波的最大振速,增加爆破地震波的主频,使其远离结构的自振频率,减小建筑物和爆破地震波之间的共振效应。更多还原

【Abstract】 Nowadays, with urban traffic developing rapidly, the amount of underground tunnel projects has had an augmentation. Tunnel projections are constructed near or even across districts with the high density of buildings frequently due to the complexity of urban environment, increasing the risk of unsafety for their surroundings. On the ground of that, researches on how tunnel constructions affect the buildings on the earth surface are very necessary.Considering the environment of the projection sections (Xiamen JiChangLu project JC2and JC3), including the surface buildings which are nearby or even across the projection sections, the influence of tunnel constructions on the surrounding buildings are compared systematically with the use of three methods(theoretical analysis, construction monitoring and numerical simulation). The main research contents and results are as follows:(1) Through theoretical analysis, the mechanisms of the strata movement and deformation caused by tunnel excavation are discussed in this paper, indicating that the strata movement and deformation mainly result from following aspects:the strata loss caused by construction; the change in the amount of peripheral pore water; the reconsolidation of the remolded soil which are subjected to shear failure; lining deformation and so on, among where strata formation and water loss have play critical roles in the strata movement and deformation. On the basis of the random medium theory, during the tunnel construction process, the effects of excavation depth, the excavation section size and formation condition on the surface movement and deformation are analyzed. It could be concluded that, with the depth of tunnels increasing, the surface displacement and deformation value corresponding decrease; with the excavation radius increasing, the surface displacement and deformation as well as the width of settling tanks have a rise. Soft strata are larger than hard strata, in terms of excavation influence range. (2) The surface buildings which are across the projection sections (JC2JC3) have done safety monitoring. Based on those statistics, the settlement and the distribution of cracks are obtained for different structure types and heights, and the corresponding laws of development are documented:under the multiple arch tunnel construction of CRD method geology and hydrogeology conditions, project CRD1-4have the biggest effect on the settlement of mixed structures while project CRD1-5have the biggest effect on the settlement of frame structures. Cracks emerge in the diagonal sections of the vertical walls involving window or door openings more frequently, in which cracking or the development of existing crack appear near the corner of the upside of the larger settlement side and the downside of the less settlement side while cracking at other place has been closed; during the long period of construction, the settlement of specific buildings and the width of cracking increase. Frame structures with high height are stronger than mixed structures with low height, in terms of the capacity of resisting the changes occurred by tunnel construction.(3) Based on the rock blasting theory and the properties of blasting seismic waves, aimed at the defects in<Blasting Safety Procedures of China>(GB6722-2003) about the blasting vibration criterion for surface buildings, that is not full to reflect the influence of the blasting vibration on buildings due to ignoring structures itself vibration characteristics, the advice about the building safety criterion has been proposed:when the risk assessment and the destroyed criterion of buildings are being determined, the influence of the vibration frequency of the blasting seismic waves and buildings themselves should been taken into consideration; according to related rules, the blasting vibration particle velocities are used as safety criterion.(4) The dynamic responses of surface buildings under blasting seismic waves have been analyzed. The theory analysis deduce results, showing that:amplitude of the surface vibration increase with the rise of blasting seismic waves; in nonlinear reaction, if the value of EDFR close to that of natural frequencies of surface buildings, linear deformation will be on the rise; when it comes into the nonlinear phase, if the value of EDFR close to or even larger than that of natural frequencies of surface buildings, deformation will be in decline or stop to rise, while quite the reverse is true. The longer the blasting vibration last, the more frequently the amplitude of vibration displacement occurred.(5) Dynamic responses of the buildings under blasting seismic waves have been on the simulation analysis with the use of the finite element method; relative suggestions are proposed as follows:to ensure the buildings under blasting seismic waves can be used safely, for the blasting seismic waves, the vibration velocity should be reduce while the natural frequency should increase, making it far away from the natural frequency of the structure itself and reducing the resonance effect between the building and blasting seismic waves.更多还原