跨断层隧道震害特性的能量分析方法

An Energy Analysis Approach for Seismic Characteristics of Crossing-fault Tunnel

研究目的:跨断层隧道在地震中容易产生破坏,在变形直至破坏的过程中都伴随着能量的吸收和释放。鉴于此,为了解跨断层隧道的震害特性,本文采用基于能量释放率的分析方法对断层影响下的隧道震害进行研究。此外,利用FLAC3D软件对隧道进行数值模拟,以验证该方法的适用性。研究结论:(1)在断层错动与地震耦合作用下,隧道拱肩、拱腰和拱脚的动力响应最大,而拱顶和拱底的动力响应稍弱;(2)在断层错动与地震耦合作用下,应力集中的位置不随断层宽度而改变,随着断层宽度的增加,能量释放和应力集中的范围逐渐扩大,而地震作用在断层处逐渐减弱;(3)依据动力响应曲线,可以确定隧道的塑性屈服区以及核心设防的长度;(4)能量分析方法可用于隧道的震害特性分析,为隧道抗震设防提供可靠依据。

Research purposes ： Crossing - fault tunnel is easy to damage under ground motion. In the process of deformation to destruction for tunnel, energy absorption and release were accompanied. Therefore, in order to understand the seismic damage behavior of the crossing - fault tunnel,an approach of energy release rate was used to study the characteristics of seismic damage of tunnel influenced by crossing - fault. In addition,a numerical simulation of the tunnel was established,and the applicability of energy analysis approach was verified. Research conclusions：（1） Under the action of coupling fault movement and earthquake,the seismic response of the spandrel,haunch,and arch springing of tunnel is bigger than that of the vault and arch bottom of tunnel. （2） Under the action of coupling fault movement and earthquake,the position of stress concentration does not change with the change of fault width. With the increase of the width of the fault,the scope of energy release and stress concentration is gradually enlarged while the seismic action in fault location is gradually weakened. （3 ） Based on the dynamic response curve,the plastic yielded zone and the core seismic fortification length of tunnel can be identified. （4） Energy analysis method can be used to analyze the seismic behavior of tunnel and provide reliable basis for the tunnel seismic fortification.