强震作用下运营隧道裂损衬砌动力响应分析

运营隧道由于地质因素、施工因素与地下水因素造成衬砌结构带裂缝工作。在地震力作用下,带裂缝的衬砌的安全性难以保证。基于隧道衬砌结构裂损的不同位置和裂缝不同深度的考虑,建立了三维数值有限元模型,采用时程分析的方法研究了衬砌的动力响应。研究表明:①在地震力作用下,隧道衬砌受往复拉压作用;在剪切波作用下,最大弯矩、轴力发生在隧道横截面"X"位置;②带裂缝衬砌在地震力作用下,纵向裂缝处混凝土应力集中,主筋拉应力增大,其他位置内力与完好衬砌响应相同;③随着裂缝的位置不同,对隧道安全性的影响不同,影响顺序由大到小依次为225°、315°、270°;④衬砌初始裂缝深度越深,在地震作用下应力集中情况越严重。

Dynamic Response of Operational Tunnel Lining With Cracks under Great Earthquake Exitation

Due to geological factors, construction factors and underground water, operational tunnel might work with lining cracks. When earthquake happens, lining with cracks would damage and influence its safety. Considering lining cracks at different positions and depths, three dimensional finite numerical model is developed, time history method is used to study the dynamic response of tunnel lining. The results show that (1) under earthquake force, cyclic tensile and compressive force are acted on tunnel lining. Under the shear wave, maximum moment and axial force happen at the X position of the tunnel. (2)under earthquake force, lining with cracks will face stress concentration at the crack location. Stress of main steel would increase. Stress at the other positions are the same with the one with no crack. (3) Different positions of cracks would have different influence to tunnel safety. The sequence of the influence is 225 degree, 315 degree, and 270 degree. (4) deeper the initial cracks are, the stress concentration are more severe.