【作者】 张伟；

【导师】 李夕兵；

【作者基本信息】 中南大学 ， 岩土工程， 2008， 博士

【摘要】 随着公路建设大力发展高等级公路和完善中西部公路网交通工程的不断进行,高速公路和高等级公路的建设逐渐从平原、微丘区向山岭重丘区等地延伸,公路隧道的建设越来越不可避免,并且在公路建设中所占的比重越来越高。在这种发展趋势下,由于山区复杂的应力场环境和不同岩体结构条件,隧道开挖施工过程中不可避免的会遇到许多工程灾害问题。本文在湖南省交通科技项目和国家自然科学基金重大项目资助下,对山岭公路隧道在开挖施工、建设过程中所遇到的工程灾害问题进行了系统研究。主要研究内容和成果如下:（1）基于距离判别分析理论,考虑影响隧道围岩类别的定性和定量因素,选用7项指标作为判别因子,利用大量工程实例的数据作为学习样本,建立了隧道围岩类别判定的距离判别分析模型,并利用回代估计法进行检验。研究结果表明,该模型比较稳定,判别能力较强。将该模型运用实际公路隧道工程的围岩类别判定中,判别结果和实际情况一致。（2）基于Bayes判别分析理论,从围岩应力、岩性和能量三个方面出发,选定围岩最大切向应力与岩石单轴抗压强度之比（σ_θ/σ_c）、岩石单轴抗压强度与抗拉强度之比（σ_c/σ₁）和弹性能量指数(W_e1)作为岩爆预测的判别指标,利用国内外大量典型地下工程岩爆实测资料作为学习样本,建立了岩爆发生可能性及其烈度分级预测的Bayes判别分析模型。将该模型运用到国内深埋公路隧道的岩爆预测中,判别结果完全符合现场岩爆情况,为岩爆预测问题提供了一条有效途径。（3）利用有限差分软件FLAC^3D,对富水地段公路隧道进行三维流固耦合分析,考虑了地下水渗流作用对公路隧道的开挖影响,研究了隧道开挖地下水渗流分布规律。研究发现:围岩孔隙水压力场分布随隧道开挖逐步发展成一个以隧道开挖区域为中心的近似于渗水漏斗的分布形状,围岩类别和隧道埋深对渗流场的分布形式影响不大,流动矢量表明连拱隧道开挖后渗漏水多发部位主要集中在拱部和边墙上,在隧道施工中做好地下水的良性排放十分必要。（4）分析了各种工程状况:围岩类别、隧道埋深、地下水水位、施工工法以及偏压对隧道稳定性的影响。研究结果表明:围岩类别对隧道稳定性的影响最大。同一类别围岩在相同的施工工艺情况下,埋深越大,围岩的稳定性越不利,围岩塑性区分布范围随埋深的增大而增加。山体初始地下水位对公路隧道围岩的稳定性存在一定影响,随着地下水位的下降,隧道拱底涌起量基本呈线性减少,且递减幅度较大。围岩塑性区分布范围也随地下水位的下降而减少。通过支护结构受力分析,发现连拱隧道中拱墙和仰拱的接触部位喷射混凝土层的局部受力较大,因此,在初期支护达到一定强度后,应尽早实施二次衬砌,以避免发生局部开裂破坏而导致隧道渗水等不良病害现象。（5）根据理论研究成果,提出了一系列针对性极强的防排水综合控制技术措施,具体包括:富水段超前地质预报、超前环向孔帷幕注浆堵水技术、喷射抗渗混凝土、新型粘贴式集水排水系统、隧道底板涌水的盲沟集排水等技术,并把这些防排水措施与初始防排水设计和地下工程防水技术规范要求紧密结合,通过现场实施证明,取得了良好的防排水效果。首次提出的隧道工程新型粘贴式集排水系统,利用泄水孔与弹性集水槽相结合,围岩的渗水流入集水槽,然后引入环向或纵向排水盲管,该系统的集水率达到85%,使得喷射混凝土和防水布安装在无水或小水条件下进行,提高了其施工质量,增强了隧道防排水效果,具有较大的推广应用前景。（6）利用连拱隧道周边位移监控量测结果对连拱隧道围岩-支护系统的稳定性进行了分析。从量测断面的水平位移收敛历程基本类似,收敛曲线最终全部趋于收敛,最终收敛位移相差相对较小。利用修正的双曲线函数,对隧道左右洞室总体的水平收敛位移进行了回归分析,分析结果完全满足各项设计规范的规定。最后针对位移判别具有不确定性的特点,利用模糊概率方法对隧道的整体稳定程度进行了分析。更多还原

【Abstract】 More and more tunnels were built in the mountain highway with the development of the highway construction and transportation net.Due to the complicated geological stress-field and different rock-mass construct condition,some engineering disasters took place in the process of tunnel excavation.Such as the failure of tunnel surrounding rock,rock-burst in deep tunnel,seepage and leakage,and so on.To remedy such engineering problems,the author studied deeply and systematically on the prevention and control technology of engineering disaster with the support of the Hunan province transportation science & technology project and the key project of the natural science foundation of China.The main contents of the dissertation are summarized as follows:（1） Based on the principle of distance discriminant analysis theory, a classification model of tunnel surrounding rock was established in this paper and seven indexes reflecting the engineering quality of tunnel surrounding rock were considered.The discriminant functions of model were obtained through training a large set of expansive samples.The re-substitution method was introduced to verify the stability of this model and the ratio of mistake-discrimination is zero.A set of data in two tunnel engineering were used to test the discriminant ability of model and the results show that this model has high prediction accuracy.（2） Based on the principle of Bayes discriminant analysis theory,a discriminant analysis model of prediction of possibility and classification of tunnel rock-burst was established in this paper.Three factor indexes including the ratio ofσ_θ/σ_c andσ_c/σ_t,and W_et were regarded as discriminant factor of the discriminant model and a series of underground rock projects at home and abroad were taken as the training and testing samples,and the ratio of mistake-distinguish is zero after this model was trained.Rock-bursts of Tongyu tunnel in Cheng-qian highway and Kuo-cang mountain tunnel in Zhu-yong highway were used to verify this model.The results show that the discriminant model can be used to predict the possibility and classification of rock-burst in deep underground engineering and the prediction accuracy is very high.（3） Based on the coupled fluid-mechanics theorem,FLAC^3D（Fast Lagrangian Analysis of Continua in 3 Dimension） numerical software has been used for the analysis of mountain multi-arch tunnel design in aquiferous stratum.After tunnel excavation,the groundwater will flow through the rock fissures under the different pore pressure in the network and at last the pore pressure of groundwater has a funnel-shaped distribution in excavation regional.The most leaking places around tunnel concentrate on the vault and the side wall.So it is necessary to make the underground water drain actively.（4） The coupled fluid-mechanics numerical analysis had been done by considering the effect of rock classes,covering depths,underground water tables,construction methods and initial supporting systems.The results show that the surrounding rock classes have most important influence on the stability of tunnels,and so does the tunnel covering depths.The research indicated that the settlement of the vault derived from coupling analysis when considering the seepage flow effect were bigger than that of the seepage flow effect was not considered and the underground water tables influent the stability of tunnels to some degree. Therefore,it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.（5） According to the results of theory analysis,the treatment measures which have important pertinence for resolving the problem of tunnel leakage were put forward.The methods include the geology forecast in an aquifer stratum,the technology of grouting and shot concrete with anti-seepage and so on.These treatment measures were adopted to prevent and drain the underground water around the tunnel. The tunnel’s construction proved that these measures had achieved a preferable effect to the original design;especially at the places where the leakage always takes place if none treatment measures were adopted.The new gathering and draining groundwater system can gather about 85% underground water which flew into tunnel along the cracks and joint fissures.（6） The measuring results of surrounding displacement was used to analyze the stability of rock-supporting system in multi-arch tunnel.The convergence course of horizontal convergence curves was similar for every section and the difference of final displacement between those convergence curves was very little.Then the modified hyperbola function had been used to regress the displacement convergence curves of surrounding rock.Furthermore,the stability of tunnel was calculated with the formula of fuzzy probability.The present formula and experience could be referenced in the design,construction and researches of similar tunnels.更多还原