【作者】 贾勇；

【导师】 姜忻良；

【作者基本信息】 天津大学 ， 结构工程， 2010， 博士

【摘要】 盾构法是在软土地区修建地下隧道的一种重要手段,但不论采用哪种方法都会对周围土体产生不同程度的影响。本文针对盾构施工对周围土体扰动机理展开论述,分析了盾构法对周围土体扰动的成因,讨论了盾构施工对周围土体应力应变扰动、引起地面沉降的因素。有限元法是计算盾构隧道开挖的重要方法,本文从数学与力学研究方法入手,开展了盾构施工引起土体变形的三维有限元数值计算的研究;本文以天津地铁一号线工程及广州地铁二、八号延长线工程为背景,在两工程中试验区间进行了隧道开挖过程中地层沉降与倾斜的现场试验。在对盾构施工段各层土体在开挖过程中的水平和垂直位移进行了现场实测的基础上,根据工程实际,综合考虑盾构隧道施工过程中的材料非线性、盾尾建筑空隙、盾构密封舱内土压力、土体与衬砌结构的相互作用等因素,利用有限元程序ABAQUS建立三维有限元模型,对盾构隧道动态开挖过程进行模拟。通过与现场实测数据的对比表明,有限元计算结果与实测结果吻合良好。本文采用大型通用非线性有限元分析软件ABAQUS进行数值模拟,综合考虑了土体非线性、土体与衬砌作用、注浆压力、和支护压力等主要因素建立力学模型,利用有限元方法对盾构隧道动态开挖过程进行模拟。本文研究了盾构法施工引起地表和不同土层不同方向上变形的规律,研究盾构施工过程中周围土体变形的不同变化规律,研究了支护压力、注浆压力、以及刚度折减时选择的系数等因素对结果的影响。本文还以等效荷载来模拟建筑物,考虑隧道上方有带浅基础的建筑物时,分析了此时地表的变形,同时还研究了浅基础不同尺寸的影响;当邻近有建筑物时,本文研究了建筑物处于不同位置时的影响;最后本文还研究了平行隧道同向间隔一定距离开挖时土体的变化特点。本文的研究为盾构隧道开挖设计计算的参数选择及施工时有关参数的选择提供了可靠依据,同时也为盾构隧道开挖地层变位预测提供技术支撑。更多还原

【Abstract】 Shield is an important method of the tunnel construction in soft soil, however, itwould certainly cause various degrees of effect on the surrounding soil no matterwhich way be taken. In this paper, the surrounding soil disturbance mechanism andthe causes of it are analyzed, and the surrounding soil stress-strain disturbance and thefactors that cause land subsidence have been discussed.FEM is an important way of tunnel excavation calculation, with the mathematics andmechanics research methods, this paper studies the FE numerical calculation of soildeformation caused by tunnel excavation. With the background of Tianjin No. 1subway project and Guangzhou No. 2/8 extension subway project, the field test ofground settlement and tilted have been processed. Based on the field test on horizontaland vertical displacement of each layer, the 3D dynamic tunnel excavation model hasbeen simulated by ABAQUS program, considering by the material nonlinearity, thegap of shield empennage, earth pressure in shield airtight cabin, the interaction ofsurrounding soil and lining structure. The field measurement data shows that the FEcalculation is given a good match on the measured results.In this paper, large-scale general nonlinear FE analysis program ABAQUS has beenadopted for numerical simulation. The dynamic tunnel excavation model has beenbuilt by a comprehensive consideration on key factors such as soil non-linearity, theinteraction of soil and lining, grouting pressure and the supporting pressure. Thispaper analyses the law of deformation on ground and each layer as well as thesurrounding soil caused by tunnel excavation, and the effects on result caused byvarious factors such as pressure support, pressure grouting, as well as the stiffnessreduction coefficient.This paper employs equivalent load to simulate the building, which possessingshallow foundation upon the tunnel. This paper also analyses the ground deformationas well as the effect of shallow foundation in different sizes and locations. Finally, thevarious characters of soil have been studied in the condition of parallel with the tunnelexcavation to a certain distance interval.The research of this paper offers the reliable basis for the choice of parameters ondesign and construction of tunnel excavation, and also provides the technical supportfor the forecast of ground during tunnel excavation.更多还原