【作者】 周博；

【导师】 陈善雄；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2008， 硕士

【摘要】 通透肋式拱梁隧道是一种全新的半明半暗异型隧道结构型式,其受力模式与承载机理尚不清楚,其设计理论有待建立,因此,开展通透肋式拱梁隧道相关问题研究具有重要意义。依托黄(山)塔(岭)桃(林)高速公路龙瀑隧道工程,采取现场勘察、室内试验、理论分析和数值模拟相结合的方法,对肋式拱梁隧道变形规律、结构荷载模式开展了系统的研究,揭示了肋式拱梁隧道的变形特性,提出了肋式拱梁隧道的结构荷载简化模型?本文的主要内容和成果如下:1、开展了龙瀑隧道工程场址地质调查,全面地评价了龙瀑隧道工程场址的工程地质特性,为肋式拱梁隧道修建提供了基础性资料。2、针对黄(山)塔(岭)桃(林)高速公路龙瀑隧道段,进行了道路结构型式比选。方案比选表明:肋式拱梁隧道具有边坡扰动小、环境破坏少、结构简洁轻盈、外形美观、通透性佳的优点。在此基础上,提出了通透肋式拱梁隧道方案。3、简要分析了肋式拱梁隧道的变形特性,并开展了不同开挖方式下隧道及边坡的受力变形数值模拟对比研究。研究表明:开挖方式对隧道应力与变形影响较大,对边坡的应力与变形影响较小。采用后施作肋梁方案时,肋梁内力仅约为先施作肋梁时的50%,隧道边坡的应力在拱顶处也较先施作肋梁时小。开展了黄(山)塔(岭)桃(林)高速公路龙瀑隧道数值模拟分析,并与现场监测数据进行对比,对比表明:两者变形规律基本一致,应力大小、分布基本吻合,数值模拟真实地揭示了隧道的受力状态。4、对肋式拱梁隧道的边坡破坏模式进行了对比分析,研究表明:均质围岩下,围岩强度较低时,隧道的破坏模式为由拱脚附近开始,沿着某一斜直线的楔体滑移;围岩强度较高时,自身承载能力强,不会因岩体内材料的破裂而屈服,隧道边坡内不会发生楔体滑移;非均质围岩下,隧道破坏模式仍为沿着某一斜直线的楔体滑移,且滑移发生在浅层强度较低的岩层中,这表明浅埋隧道的结构荷载主要为浅层围岩的松动荷载。破坏模式分析表明:肋式拱梁隧道的边坡破坏模式符合《公路隧道设计规范》中关于浅埋隧道破坏模式的假定,故肋式拱梁隧道的结构荷载模型可参考《公路隧道设计规范》中浅埋偏压隧道荷载计算方法确定。5、对边坡破裂角计算方法进行了对比分析,对比表明:《公路隧道设计规范》推荐解法引入了围岩内摩擦角、边坡坡角、滑移面摩阻力等影响参数,考虑因素相对全面,能与数值计算结果较好吻合,适合用于肋式拱梁隧道边坡的破裂角计算。6、提出了肋式拱梁隧道结构荷载简化模型。分析了不同的切坡深度、不同围岩条件下结构荷载模型的变化规律,分析表明:结构荷载简化模型能正确地反应切坡深度、围岩性状改变引起的荷载变化规律。定量对比表明:由于边坡坡面临空,开挖引起的偏压荷载更突出,故须对结构荷载简化模型的横向荷载进行修正;围岩性状的改变引起松动破坏区域的改变,而结构荷载简化模型对围岩性状改变不敏感,故对结构荷载简化模型进行了改进。利用实测数据验证了改进结构荷载模型。相关成果已成功应用于黄(山)塔(岭)桃(林)高速公路龙瀑隧道工程,直接指导了工程建设,取得了良好的技术效果和社会效益。更多还原

【Abstract】 Drafty tunnel with ribbed arch beam is a new tunnel structure type which is half-embedded and half-uncovered. Its stress mode and load mechanism is still unknown and the design theory remains to be established. Thus studying on drafty tunnel with ribbed arch beam has a significant meaning.Relying on the Long-Pu tunnel engineering of Huang (shan)-Ta(ling)-Tao(lin) highway, the systemic research is done for the deformation law of tunnel with ribbed arch beam and the structural load mode by combining field investigation, laboratory test, theoretical analysis and numerical simulation. The deformation characters of tunnel with ribbed arch beam have been revealed and its simplified model of structural load has been put forward.The main content and results of this paper are listed as following:The site geological survey of Long-Pu tunnel engineering was completed, its engineering geological characteristic was evaluated comprehensively, and the basic information for construction of drafty tunnel with ribbed arch beam was obtained.According to the Long-Pu tunnel section of Huang(shan)-Ta(ling)-Tao(lin) highway, the structure types of tunnel are compared and selected. Compared with other schemes, tunnel with ribbed arch beam has many advantages such as small disturbance of slope, little environmental disruption, simple and lightness structure, nice shape, good drafty performance. Based on this, the scheme of drafty tunnel with ribbed arch beam is proposed.The deformation characters of tunnel with ribbed arch beam were analyzed briefly; the comparative study of forced deformation of tunnel and slope under different excavation methods was developed by finite element method. It is conclude that the excavation method has an obvious effect on deformation and stress of tunnel and a tiny effect on deformation and stress of slope. Comparing the results of scheme imposing ribbed beam later with those of scheme imposing ribbed beam first, it shows that: the force on ribbed beam of the former is about 50% of that of the latter. The forces on anti-slide pile and inside liner of tunnel have little difference for these two situations, and as well as the stress and the deformation of slope. Thus the effect of different excavation methods on slope can be ignored. Developing the numerical analysis of the Long-Pu tunnel of Huang-Ta-Tao highway and comparing it with the field monitoring data, it shows that: their deformation laws are basically identical with each other; the value and distribution of stress anatomize basically each other; and the simulation results can really reflect the stress states of tunnel.The comparative analysis of slope failure mode of tunnel with ribbed arch beam was developed. The results are listed as follows: for the case of homogeneous surrounding rock, the failure mode of tunnel starts from the area adjacent to skewback and a wedge body along a certain leaning line slips when the strength of surrounding rock is low; the failure mode of tunnel changes and the slip can not be considered as a wedge body slip when the strength of surrounding rock is high. For the case of heterogeneous surrounding rock, failure mode of tunnel is still the wedge body slip along a certain leaning line and the slip happens in the shallow rock stratum with a low strength. It means that structural load of shallow tunnel is mainly the loosening load of shallow rock stratum. According to the analysis of failure mode, it is concluded that: slope failure mode of tunnel with arch beam of costal type coincide with the assumption about failure mode of shallow tunnel in“Code for Design of Road Tunnel”. So structural load model of tunnel with ribbed arch beam can be drawn lessons from the calculating method of load for shallow and bias tunnel in“Code for Design of Road Tunnel”.A comparative analysis of the calculating methods for fracture angle of slope and tunnel was developed, the analysis shows that results using the method recommended in“Code for Design of Road Tunnel”accord with the numerical calculating results, for its considering factors are comprehensive and it introduces many influence parameters such as internal friction angle of surrounding rock, slope angle, frictional resistance of slip plane and so on. Thus this method is fit for calculating the fracture angle of slope of tunnel with ribbed arch beam.A suitable simplified model of structural load for tunnel with ribbed arch beam was proposed and the change laws of structural load model under different slope cutting depth and different surrounding rock were analyzed. Analysis shows that structural load model can basically reflect load change laws caused by the changes of slope cutting depth and surrounding rock properties. Comparing results show that because the slope surface is free surface, the inclined press load caused by excavation is more outstanding. So it is necessary to modify the horizontal load of simplified model of structural load. Change of properties of surrounding rock causes change of loosening failure area, while the simplified model of structural load is not sensitive to change of properties of surrounding rock. Thus the simplified model of structural load is improved. Using the measured data, the improved structural load model is verified. The related achievements have been applied to the Long-Pu tunnel engineering of Huang(shan)-Ta(ling)-Tao(lin) highway and give a direct guidance to the engineering construction. A good technical effect and social benefit has been obtained.更多还原