【作者】 程熙竣；

【导师】 王志杰；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2012， 硕士

【摘要】 随着近些年来隧道工程的不断发展,以及对于隧道衬砌耐久性问题的深入研究。衬砌结构的耐久度问题逐渐成为了公路隧道工程学科研究的热点与难点。越来越多的学者与工程设计人员将目光投向了对于结构寿命的研究。伴随着规范对于结构使用寿命延长的要求,在设计与建设初期判断公路隧道结构的寿命能否满足要求,由于缺乏足够丰富的统计数据,对其理论的研究有着非常重要的意义。对于公路隧道衬砌结构寿命的评估预测,不仅能对运营阶段的隧道进行安全性评估,确定隧道需要投入安全加固的大概年限,同时能从耐久度的角度对隧道设计理念与标准起到修正的作用,使公路隧道的设计与运营管理更符合经济性。论文以达万高速沙坝湾隧道为背景依托,通过对于衬砌结构损伤机理以及结构寿命影响因素的研究,总结了衬砌结构使用寿命预测方法。1.结合隧道工程的特点,综合考虑隧道结构所承担的复杂荷载条件以及不同于一般大气环境的自然影响因素,明确了公路隧道衬砌结构损伤主要由混凝土碳化及钢筋锈蚀所决定,并深入分析了衬砌混凝土碳化机理以及钢筋锈蚀机理。确定了适合于公路隧道工程的碳化预测模型。2.以承载力极限作为寿命评定的最终状态,总结了公路隧道衬砌结构使用寿命预测方法,将结构寿命分为两个阶段进行计算,分别为钢筋无锈工作时间以及结构破坏工作时间。3.确定了公路隧道寿命预测所需要的现场实测指标。分别研究了二氧化碳浓度检测、环境温度、相对湿度检测、二次衬砌缺陷状况检测的工作原理与操作方法,对于国内外先进的检测仪器作了详细介绍。4.针对公路隧道衬砌结构普遍存在的结构缺陷问题,通过FLAC3D软件对二衬结构混凝土厚度不足、强度不足、存在空洞的缺陷状况区分了十种工况进行数值模拟,经过数据后处理与安全系数的计算,得出了每种缺陷在不同位置与范围存在时对于隧道结构整体安全性的影响。同时,从侧面反映了结构缺陷对于结构原始安全系数的削弱,从而直接缩短了隧道结构的使用寿命。5.运用公路隧道使用寿命预测方法对达万高速沙坝湾隧道进行使用寿命预测。结合现场实测数据与隧道结构缺陷的相关数据,评定结果证明沙坝湾隧道使用寿命不能符合规范要求,需要对于结构缺陷进行修复。论文由于引入了隧道结构缺陷对于衬砌结构使用寿命的影响,使用于公路隧道衬砌寿命预测时更符合实际情况。更多还原

【Abstract】 the booming of tunneling industry in recent years, and the studying on durability of tunnel lining, durability of tunnel lining structures becomes difficulty but popular subject in tunneling research. More and more researchers and engineers have been focusing on expanding the life of tunnels. The government is working on improving normalization of expanding the life of tunnel structures. Because we are lack of the data, which determines if life of the highway tunnel structure satisfies these regulations by government in the very beginning of construction phase, the study on the theory of expansion has significant importance. Predicting the life of highway tunnel lining structures benefits us in many ways. In the operation phase, it evaluates the safety of the tunnel and roughly determines the years for security reinforcement; it revises the design concepts and standards on durability of tunnel and makes operation management more economically effective. My thesis is based on the example of Dawan sandbank tunnel. By the study on damage mechanism of tunnel lining structures and the factors to determine the life of the structures, the evaluation system is built.1. Considering the complicated conditions of the load of the structures of tunnel, special effect of atmospheric environment on it, and combined with the characters of the tunnel itself, it is clear that the damage of tunnel lining structures is mainly caused by concrete carbonization and reinforcing bar corrosion; indeed, we deeply analyze the theory of concrete carbonization and reinforcing bar corrosion. From the analysis, we come up with the model which is good for predicting concrete carbonization on highway tunnel engineering.2. Setting the final evaluation of the life to be ultimate bearing capacity, we build the evaluation of the life of tunnel lining structures system. Moreover, we split the life of the structure into two phases--the duration for reinforcing steel being non-rusty and period which damages appearing on structures.3. We define the worksite measured process parameters to predict the life of highway tunnel. The parameters include concentration of carbon dioxide, environmental temperature, relative humidity, and the working principle and operation of detecting the second lining defects. I also introduce various advanced analytical and test instruments both at home and abroad. 4. Being aimed at the structures of highway tunnel lining defects, by FLAC3D software, we have divided second lining into ten categories based on insufficient thickness and strength, and existing of loose region or cave of concrete cover. We go through numerical simulation for each category. After post data processing and calculation of safety coefficients, we get the effect of each defect with different locations and ranges on safety of the whole tunnel structure. Besides, structural defects weaken the safety coefficients of the original structure; indeed, directly shorten service life of tunnel structure.5. We use the evaluation of the life of tunnel lining structures system to evaluate the life of Dawan sandbank highway tunnel. With combining worksite measured data and data of tunnel structural defects, we conclude that the service life of Dawan sandbank tunnel does not meet the requirement, and the structural defects need to be fixed.Since my thesis states the effect of tunnel structural defects on life of tunnel lining structures, the evaluation of the life of tunnel lining structures is more practical.更多还原