【作者】 张步才；

【导师】 王志强； 梁收运；

【作者基本信息】 兰州大学 ， 建筑与土木工程（专业学位）， 2013， 硕士

【摘要】 随着我国国民经济飞速发展,基础设施建设大力推进,交通(公路、铁路、城市地铁)、水利等设施的建设高峰期已经出现,越来越多的工程修建说明了一个问题：中国已是世界上隧洞及地下工程规模最大、数量最多、地质条件和结构形式最复杂、修建技术发展速度最快的国家之一,技术水平与建设成就已走在世界前列。但由于岩土体物理力学性质的不明确性、隧洞工程的个体差异性等原因,尤其对饱水黄土隧洞而言,设计理论还不够完善。因此研究饱水黄土隧洞支护衬砌结构设计具有理论与实践意义。通过介绍引洮工程15#隧洞的工程概况,明确了该隧洞与周边环境的关系,借助多年来积累的工程地质勘查资料及科研成果,分析了该隧洞洞身围岩的特殊性质。该隧洞洞身围岩主要为第四系饱水土,由可塑～硬塑状的重粉质壤土、粉质粘土和软塑状的粉质壤土、砂壤土组成,整体土层极不均一,围岩性状差异大。其次,总结现有隧洞衬砌结构设计的计算模型,指出每种模型各自的特点以及相关的计算理论,并选择了利用两种模型分别计算的方法。选取类马蹄形及圆形断面两种不同工况,利用ANSYS软件对该隧洞衬砌结构进行力学分析,发现圆形断面的受力比类马蹄形受力好。然而,类马蹄形断面与圆形断面相比具有更大的使用空间和使用宽度。在满足相同净空的要求下,圆形隧洞的开挖量大,衬砌和加固圈的用量也相应增大,施工没有类马蹄形断面方便。总结各方面因素,建议采用类马蹄形断面型式。随后用FLAC软件模拟了隧洞的开挖,经过计算表明,按照原设计文件的支护衬砌结构偏于保守,有较大的优化空间。将原设计文件中的衬砌减薄100mm、锚杆设置减少4根,从支护前、支护后、设置锚杆后三个阶段对整个开挖过程进行分析,得出优化方案是可行的。再对地震作用下隧洞衬砌结构的力学响应进行时程分析,验证优化方案中衬砌结构在地震作用下的稳定性,同时说明支护体系中锚杆的设置在抗震中的重要作用。最后通过对该隧洞施工过程中实际监测数据进行回归分析,指出隧洞的支护参数要随时根据施工过程中围岩的动态信息进行调整,保证施工安全顺利进行。引洮工程15#饱水黄土隧洞断面较大,长度较长,工程地质条件极为复杂、性质恶劣,具有极强典型性,研究该隧洞的支护衬砌结构设计对今后类似工程的建设具有极强的指导意义。更多还原

【Abstract】 With the rapid development of China’s national economy, the infrastructure construction has been promoted, China is stepping into the phase of construction peak on transportation (such as road, rail, urban subway), and water conservancy facilities, the increasing number of engineering construction illustrates a fact: China has became one of the countries which has the largest scale of underground projects all over the world, and the amount of tunnels in china is the largest, with the uttermost complex geological conditions. China has the fastest speed of technological developme-nt with respect to these projects, and our technical level and economic achievements have been walking in the forefront of the world. However, due to the reasons about the unclear properties of the physical and mechanical properties of rock and soil, the tunnel project’s individual differences, the design theory is not perfect especially for water-saturated loess tunnel, it is theoretically and practically significant to study water-saturated loess tunnel the support lining structure design.Through the introduction of the "Yintao" project15#tunnel project overview, we can realize the relationship between the surrounding environment and the tunnel, with the help of engineering geological exploration data and research results accumulated over the years, we analyzed the special nature of the surrounding rock of the tunnel body and came up with a stability evaluation. The tunnel body surrounding rock is the fourth unsaturated soil, constructed by plastic to hard plastic like heavy silt loam, silty clay and soft plastic-like silty loam, sandy loam, the overall soil very uniform, the rock traits very different. Secondly, we summarize the existing tunnel lining structure design calculation model, pointing out the characteristics and computational theory of each model, and select the means of calculated using two methods respectively. Selecting class horseshoe-shaped and circular cross-section of two different conditions by ANSYS mechanical analysis of the lining structure of the tunnel, found that the force of the circular cross-section is better than the class horseshoe force. However, comparing with a circular cross section, the class horseshoe-shaped cross-section has more using space and greater width. To meet the same clearance requirements, the circular tunnel has lager amount of excavation, and using more lining and reinforcement ring, and it is not as convenient as the construction of class horseshoe section. Summarize various factors, it is recommended to use the class horseshoe-shaped sectional form. Then we used FLAC software to simulate the excavation of the tunnel, calculations show that, in accordance with the original design file support lining structure is conservative, we can largely optimize it. Thinning the lining in the original design file about100mm, decrease4bolt set, analyzing the entire excavation process from the perspective of supporting ago、after supporting、 after setting the bolt, we can conclude that optimization scheme is feasible. Tunnel lining structure mechanical response under earthquake time history analysis to verify the stability of the optimization program lining structure under seismic action also indicates the important role of anchor support system set up in the earthquake. Finally, the regression analysis through the tunnel construction process monitoring data, pointed out that the tunnel support parameters should be adjusted at any time based on the dynamic information of surrounding rock in the construction process, so that we can ensure the construction of safe and smooth.Water diverting project15#water-saturated loess tunnel section, with longer length, very complex engineering geological conditions, and poor nature, is a very strong typical of the tunnel support lining structure design for the construction of similar projects in the future with a strong guiding significance.更多还原