【作者】 刘杨；

【导师】 李忠献；

【作者基本信息】 天津大学 ， 结构工程， 2006， 硕士

【摘要】 当前,地下空间的开发已成为国家基础建设的一项重要组成部分。在城市地铁、地下商业空间等各类结构中,为预防各种生产事故或恐怖袭击所造成的意外爆炸,地下结构应有足够的抗爆能力,因而研究地下结构遭受各种内部爆炸冲击下的动力响应,对地下工程的设计、施工及抗爆研究都有着重要的理论意义和工程价值。本文研究单侧隧道内爆炸荷载作用下双线地铁隧道的动力响应及抗爆措施,主要工作包括以下几个方面。(1)在土-结构动力相互作用分析中,采用有限元与无穷元相耦合的方法建立了由双线隧道及其周围有限成层土区、远场半无限土区所组成的整体计算模型,并对巴朗所做的地下隧道爆炸试验进行了数值模拟,验证了本文所建立模型的合理性。(2)依据某实际地铁工程的地质勘探资料建立土体的有限元模型,分析了地铁隧道衬砌及周围土体的位移、速度、加速度、正应力和剪应力等的变化规律与发展趋势,以及地下爆炸波沿有限成层土区传播的行波效应和衰减特征。(3)对于隧道衬砌与周边土体的相互作用问题,使用Goodman单元做为接触单元,研究分析了接触面滑移、张合对隧道及土体应力场的影响规律;同时分析了爆炸超压、隧道埋深和间距以及周围土质条件等对隧道衬砌应力场的影响规律。(4)针对隧道衬砌的破坏情况,选用泡沫铝做为隧道衬砌的抗爆防护材料,分析了其对隧道衬砌的抗爆效果及工程应用的可能性。通过以上工作,得到如下结论:隧道的埋深及其周围的土质条件以及软弱下卧土层,对遭受内部爆炸的隧道及其邻近隧道的动力响应及破坏程度产生显著的影响;相邻隧道的合理间距与其周围的土质条件密切相关,土质越硬,则间距应越大,同时两隧道外壁间的最短距离应不少于一倍的隧道直径;在遭受内部爆炸的隧道内侧贴装泡沫铝材料,可使隧道衬砌的应力及变形明显降低,从而起到防护隧道衬砌的理想效果,对隧道抗爆工程具有广阔的应用前景。更多还原

【Abstract】 At the present time, the exploitation of underground space has been becoming the important component of the basic development of our country. Underground structures, such as subways and underground commercial spaces, should have the sufficient anti-explosion ability to prevent from blast triggered by accidents or terroristic attacks. Therefore, studying the dynamic responses of underground structures to various internal explosions has important theoretic meanings and engineering values in the design, construction and anti-explosion analyses for underground structures. In this paper, the dynamic responses and anti-detonation measure of two-way subway tunnel subjected to explosion loads inside one-sided tunnel are investigated, and the primary works are as follows.(1) A whole numerical model, consisting of two-way subway tunnels, its surrounding finite stratified soil and the far-field semi-infinite soil, is established in consideration of soil-structure interaction using the coupling method of the finite and infinite element. Through the numerical simulation for the experiment held by Baron, the validity of the model proposed in the dissertation is proved.(2) Based on the geological reconnaissance materials of an actual subway engineering, the finite element model of soil is built, and the rules and developing trends for some responses of tunnel linings and the soil around, such as displacements, velocities, accelerations, normal stresses and shear stresses, are analyzed in detail, and meanwhile the traveling-wave effects and the attenuation characteristics of the underground explosion waves propagating along the semi-infinite soil are also testified.(3) As to the interaction between the tunnel linings and the soil around, the Goodman element is introduced as a kind of contacting element to investigate the laws of the slipping and debonding of interfaces. In addition, the effects of the explosion overpressure, the embedded depth and the spacing interval of the two-way subway tunnels, and the properties of soil surrounding the tunnels on the stress fields of the tunnels and soil around are discussed at length.(4) In reference to the breakage of tunnel linings under the blast, the foam aluminum is applied as a type of blast protection material to study its anti-blast effects on tunnel linings as well as its feasibility of engineering application.更多还原