大断面富水泥岩隧道受力特性及仰拱底鼓机理研究

发布时间：2018-04-09 12:33

本文选题：富水泥岩　切入点：仰拱底鼓　出处：《兰州交通大学》2017年硕士论文

【摘要】：改革开放以来全国的经济发展迅速,同时全国的交通建设也发展非常迅速,而西北黄土地区的交通建设与黄土隧道的建设是息息相关的,而富水泥岩开挖后软化很快,产生的问题较多,与其他类型的隧道相比,富水泥岩隧道受到的松散土压力普遍较大,尤其是大断面富水泥岩隧道,这种松散土压力就更大,因此,大断面富水泥岩隧道更容易出现隧道病害,而最常见的隧道病害则是隧道仰拱底鼓,因此,对大断面富水泥岩隧道受力特性及仰拱底鼓机理研究是非常有必要的。得出的主要研究成果如下:(1)研究国内外关于泥岩隧道的底鼓类型、底鼓机理与底鼓控制措施的研究现状,分析泥岩隧道的受力特点,总结泥岩隧道仰拱底鼓发生机理,基于实际工程特点,针对目前存在的问题,提出本文的研究思路及内容。(2)通过对隧道取回的泥岩试样的地球成分、化学成分以及微观结构的试验数据分析研究,并对隧道泥岩的膨胀性进行判别,从而得出隧道泥岩几乎没有膨胀性,但具有崩解性。(3)通过对隧道现场监测数据的分析,可以得出该隧道受到较大的松散压力,而且该隧道的拱腰与仰拱拱脚处受力最大,是较为危险的部位,该隧道仰拱底鼓原因很可能是两仰拱拱脚受到较大的松散挤压力以及地下水的水理作用共同作用的结果。(4)由模型试验可知,大断面泥岩隧道在施工时,拱腰、拱脚与拱底是最为容易破坏的部位,这与实测结果相似,而且地基承载力不足,隧道会出现整体下沉,通过该模型试验也验证了较大松散围岩压力是导致仰拱底鼓的主要原因之一。(5)基于Midas/GTS三维有限元数值模型和结构力学法,来进一步分析泥岩隧道受到较大的压力荷载时,隧道衬砌的受力特征及变形规律,通过与室内模型试验结果进行对比,进一步验证了较大松散围岩压力可以引起隧道仰拱底鼓开裂。(6)基于全文分析,总结出了该隧道仰拱底鼓开裂的机理主要是围岩岩体性质较差,使得隧道受到较大松散压力,加之地下水的水理作用,又由于一些工程因素的作用,加剧了仰拱底鼓,最终导致了仰拱开裂,同时针对该隧道的特定条件,提出了较为合理的控制措施。为实际工程应用提供参考意见。
[Abstract]:Since the reform and opening up, the national economy has developed rapidly, and the national traffic construction has also developed very rapidly. However, the traffic construction in the northwest loess region is closely related to the construction of loess tunnels, and the cement rich rock softens quickly after excavation.There are more problems. Compared with other types of tunnels, the loose soil pressure of cement-rich tunnel is generally greater than that of other types of tunnels, especially the large-section cement-rich tunnel, and the loose soil pressure is even greater.Tunnel diseases are more likely to occur in large section cement-rich tunnel, and the most common tunnel disease is tunnel inverted arch bottom bulge. Therefore, it is necessary to study the mechanical characteristics and the mechanism of inverted arch bottom of large section cement-rich tunnel.The main research results obtained are as follows: 1) studying the types, mechanism and control measures of bottom drum of mudstone tunnel at home and abroad, analyzing the mechanical characteristics of mudstone tunnel, summarizing the mechanism of bottom bulging in reverse arch of mudstone tunnel,Based on the characteristics of practical engineering and in view of the existing problems, this paper puts forward the research ideas and contents of this paper. Through the analysis of the earth composition, chemical composition and microstructure of the mudstone samples collected from the tunnel, the paper analyzes and studies the experimental data of the earth composition, chemical composition and microstructure of the mudstone samples taken from the tunnel.By discriminating the expansibility of tunnel mudstone, it can be concluded that the tunnel mudstone almost has no expansibility, but it has disintegrating property. (3) by analyzing the monitoring data of tunnel, it can be concluded that the tunnel is subjected to greater loose pressure.Moreover, the arch waist and the arch foot of the inverted arch of the tunnel bear the greatest force and are the more dangerous part.It is very likely that the reason of the bottom drum of the inverted arch of the tunnel is the result of the combined action of the two inverted arch feet subjected to greater loose extrusion pressure and the hydrological action of groundwater. According to the model test, the arch waist of the large section mudstone tunnel is in construction.The arch foot and the bottom of the arch are the most easily damaged parts, which is similar to the measured results, and the bearing capacity of the foundation is insufficient, and the tunnel will sink as a whole.Through the model test, it is also proved that the large loose surrounding rock pressure is one of the main causes of the inverted arch floor bulge. Based on the Midas/GTS three-dimensional finite element numerical model and structural mechanics method, this paper further analyzes the mudstone tunnel subjected to larger pressure load.The stress characteristics and deformation law of tunnel lining are compared with the results of indoor model test. It is further proved that the large loose surrounding rock pressure can cause tunnel arch bottom bulging cracking. (6) based on the full-text analysis,It is concluded that the cracking mechanism of the inverted arch floor of the tunnel is mainly due to the poor rock mass property of surrounding rock, which makes the tunnel under relatively loose pressure, and the hydrological effect of groundwater, and the effect of some engineering factors, which intensifies the inverted arch floor drum.At the same time, the reasonable control measures are put forward in view of the specific conditions of the tunnel.To provide reference for practical engineering application.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451

【参考文献】