【作者】 雷明锋；

【导师】 彭立敏； 施成华；

【作者基本信息】 中南大学 ， 土木工程， 2013， 博士

【摘要】 摘要：城市轨道交通盾构隧道结构设计寿命为100年,其岩土赋存条件复杂、周边环境敏感、列车运行密度极高,在外界环境长期作用下结构性能不断劣化,一旦损坏不易或不可更换,同时也给结构性能状态评估及预测控制带来了极大的困难。我国城市轨道交通盾构隧道建设正处于飞速发展阶段,面临的健康服役问题日益突出,如何准确评价和预测其结构性能,保证全寿命周期内的良好服役状态,是当前亟需开展系统研究的基础科学问题之一。本文以国家重点基础研究发展计划项目(973：2011CB013802)等课题为依托,针对侵蚀环境下盾构隧道结构性能全寿命计算方法这一科学问题,采用理论推导分析和人工环境模拟试验等手段开展研究,以期为我国城市轨道交通盾构隧道建设的合理设计和科学维护提供理论指导。论文主要完成了以下研究内容：(1)构建了以人工环境模拟试验为基础的环境时间相似理论,从方法上提出了解决人工环境和自然环境混凝土耐久性试验结果相关性的基本思路。建立了盾构隧道结构混凝土耐久性设计和寿命预计方法,并拓展至半概率基础设计领域。(2)设计研发了环境和荷载耦合作用下的盾构隧道结构耐久性试验系统,并进行了人工环境模拟试验。探明了环境离子浓度、侵蚀时间和荷载水平对氯离子入侵及其在混凝土中含量分布的影响规律。(3)基于单轴荷载作用下混凝土微观孔隙的变化,建立和推导了荷载对氯离子入侵影响的分析模型和表征函数。通过数值拟合得到了环境离子浓度和侵蚀时间对扩散系数及表面氯离子浓度的影响规律。建立了环境与荷载耦合作用下的盾构隧道结构混凝土耐久性评价模型及计算方法。(4)根据钢筋锈蚀层分布模式,分别建立了均匀侵蚀和单向均匀侵蚀两种条件下的平面应变力学模型,并基于厚壁圆筒理论,推导出了钢筋锈胀应力场和位移场的计算公式,据此提出了钢筋锈胀压力的计算方法。(5)建立了基于极限分析理论的管片混凝土开裂钢筋锈蚀临界率分析模型和计算方法。引入钢筋锈蚀速率函数,进一步建立了均匀侵蚀和单向均匀侵蚀条件下,混凝土锈胀裂损的全寿命演化方程,形成了基于混凝土钢筋锈胀裂损的盾构隧道结构正常使用寿命预计方法体系。(6)从管片接头的传力性质出发,通过接头局部范围截面力学参数的等效换算,将非连续的管片结构转化为连续的非均质结构,建立了一种新的盾构隧道管片结构计算模型——非均质等效梁模型,推导得到了接头截面等效力学参数的解析解,并给出了迭代计算流程和进行了实例验证。(7)研究提出了盾构隧道管片接头截面和主截面弯矩的联合失效模式及失效准则。建立了基于增量法的管片结构极限承载能力计算方法。进一步引入钢筋锈蚀率时程函数和锈蚀钢筋力学性能时变演化方程,构建了环境和荷载耦合作用下的盾构隧道结构承载能力评估和安全性寿命预计方法。(8)依据试验成果和参考既有研究成果,进行了实例计算和工程应用。验证了本文提出的侵蚀环境盾构隧道结构性能全寿命计算方法是可靠的,且具有较强的可操作性；非均质等效梁模型,能够较好地反映接头的存在对管片结构整体刚度的影响,计算结果可靠,且具有良好的收敛性。更多还原

【Abstract】 Abstract:The designed life of shield tunnel structure in urban rail transit is100a, its occurrence condition and neighbour environements are complex and sensitive, also the train’s transporting density is high, so it is not easy to change of not once it is destroyed because of the structure decayed with the external environments action for long term, meanwhile it brings great difficult to condition acessement and prediction control of structure performance. The shield tunnel construction of urban rail transit in China, the problem of healthy service is increasingly prominent. In that, how to evaluate and predict the structure performance well and turely for ensuring well service state in its life cycle, is one of the basic scientific problems for researching urgingly.In this thesis, the calculation methods for calculating the life cycle structure performance of shield tunnel in aggresive environments were studied by means of theoretical derivation, artificial environment simulation testing and other ways, relying on the subjects supported by the National Basic Research Program of China (973:2011CB013802) and so on. And the results may provide a theory reference for the rational design and scientific maintenance of urban rail transit construction.Thesis completed the following contents:(1) The environment-time similarity theory was established based on indoor artificial environment simulation test, which has solved the correlation problem of indoor environment and field exposure test results. And then, the methods of durability design and life prediction of shield tunnel structure were put forwad, also it was extended to half probabilistic design method further.(2) The shield tunnel segment concrete durability test system coupling with erosion environment and structure load was developed. And then, the influence laws of environments ion concentration, erosion time and loading level against to the chlorine ion intrusion and distribution were discussed and proved according to the test results.(3) Based on the microstructure characteristics of concrete under uniaxial load, an analyzing model of chlorine ion intrusion were established and the calculating expressions were derived out. By using the numerical simulation method, the influence laws of environments ion concentration, corrosion time aginst to surface chloride concentration and diffusion coefficient were obtained. And then, the durability evaluation model and calculation method of sheld tunnel structure under the coupled action of erosion environments and structure loads were put forward.(4) According to the rust modes, two linear elastic plane strain models of uniform erosion and unidirectional uniform erosion were established respectively, and then, based on the thick-walled cylinder analysis theory, the calculating formulas of corroded expansion stress and displacement field were derived out, and the specific calculation method used to determine the pressure of corroded expansion were obtained.(5) The analysis model and calculation methods of rebar corrosion rate when the segment concrete cracking, were put forward by using the limit analysis theory. And then, the life-cycle evolution equation of shield tunnel structure with rebar corrosive crack damage under the uniform and unidirectional uniform corrosion, were put forward further. Finally, the normal service life prediction method and system of shield tunnel structure under rebar erosin and concrete crack were formed.(6) Proceeding from the transmission properties of segment joint, the discontinuous segment structure is transformed into a continuous non-homogeneous structure through mechanical parameters equivalent conversion at the joint local scope section, a new structure calculation model of shield tunnel named non-homogeneous equivalent beam model was established, and the analytical solutions about connector section equivalent mechanical parameters were derived. Finally, the iterative calculation process was given out.(7) A failure modes combaning by joint cross-section and the main bending moment of shield tunnel segment and the failure criterias were proposed respectively, and the calculation method of ultimate bearing capacity of shield tunnel segment structure was established based on the incremental method. Further, the bearing capacity evaluation method and safety lifetime forecasting method of shield tunnel structure coupled by the erosion environment and structure load were constructed, in which the time-varied functions of rebar corrosion rate and its mechanical properties after corroded were introduced. (8) According to the the test results and refer to the experimental data reported in existing documents, a case was calculated and analyzed as an example. The results indicate that the calculation methods of life cycle strcuctre performance of shield tunnel, advanced in this thesis, under coupling action of aggressive environments and structure loads is reliable, and has well maneuverability; the non-homogeneous equivalent beam model can better reflect the impact of the existence of joint aginst to the overall stiffness of segment structure, its calculation results are reliable, and has good convergence.更多还原