超卸载对内水压盾构衬砌结构力学性能的影响分析

Study on Effect of Overload and Unloading on Mechanical Properties of Lining Structures for Shield Tunnels with Internal Water Pressure

鉴于已有的研究多针对交通领域的盾构隧道,未能揭示承受内水压荷载作用的深埋盾构隧道在受到临近施工扰动时的力学响应,采用三维有限元精细化模型研究了超/卸载对内压盾构隧道力学性能的影响。研究表明:内水压荷载作用下,隧道顶部超/卸载时,隧道的收敛变形、接头张开量及螺栓拉力均随超/卸载值增加而增大。顶部超载时,衬砌环整体呈下沉趋势,位于拱腰上部的接头为其薄弱点;顶部卸载时,衬砌环整体呈上浮趋势,位于拱腰下部的接头为其薄弱点;且内水压盾构隧道衬砌结构抵抗顶部卸载的能力小于抵抗顶部超载时的能力。

In view of the fact that the existing studies mostly focus on shield tunnels in the traffic field and the mechanical response of deep-buried shield tunnels subjected to internal water pressure when disturbed by adjacent construction are not revealed,the effects of overload/unloading on the mechanical properties of shield tunnels with internal water pressure were studied by using a three-dimensional finite element model.The results show that the convergence deformation,joint opening and bolt tension of the tunnel increase with the increase of overload/unloading value.When the tunnel top was overloaded,the lining structure moves downwards,and the joint located at the upper part of the arch waist is its weak point;when the top was unloaded,the lining structure moves upward,and the joint located at the lower part of the arch waist is its weak point;the lining structure with the action of internal water pressure has less ability to resist the unloading effect than that to resist the overload effect.