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衬砌背后空洞的存在严重影响了围岩与衬砌之间的相互作用,极易引起衬砌结构破损并直接影响到运营安全。通过模型试验,系统研究了拱顶与拱肩背后存在双空洞条件下隧道结构裂损演化过程及衬砌结构轴力和弯矩的变化规律。模型试验结果表明:(1)衬砌背后双空洞的存在,严重影响隧道结构的受力状态,易导致衬砌结构承载力不足;(2)拱顶与右拱肩背后存在双空洞条件下衬砌裂缝出现的顺序为:仰拱内表面裂缝→空洞间衬砌内表面裂缝→拱肩空洞右侧衬砌外表面裂缝→拱顶空洞左侧衬砌内表面裂缝→左拱脚衬砌外表面裂缝→右拱腰衬砌外表面裂缝;(3)空洞尺寸变化显著改变了衬砌内力分布,空洞尺寸的增加,引起两空洞间衬砌结构轴力减小而弯矩增大,使两空洞间的衬砌结构破坏程度更严重;(4)衬砌背后空洞的位置及数量对隧道结构裂损过程有较大影响,衬砌背后存在双空洞时衬砌裂缝的传播过程更复杂。研究成果可为衬砌背后多空洞影响下衬砌裂缝病害的防治和修复提供参考。
The existence of the cavity behind the lining has a serious impact on the interaction between the surrounding rock and the lining, which can easily cause the lining structure to be damaged and directly affect the operation safety. Through the model test, the evolution of the tunnel structural failure and the change of the axial force and bending moment of the lining structure are systematically studied under the existence of double cavities behind the vault and spandrel. The results of the model tests show that: (1) The presence of double hollows behind the lining has a serious impact on the stress state of the tunnel structure, which leads to insufficient bearing capacity of the lining structure. (2) The lining cracks occur under the double empty cavities behind the vault and the right shoulder The order is as follows: Inverted inner surface cracks → Cracks in the lining of the lining between the cavities → Cracks on the right side of the shoulder of the arch shoulder Cracks → Cracks in the lining of the left side of the vault cavity → Cracks in the outer surface of the left arch foot lining → Right arch lumbar lining (3) The change of void size significantly changed the distribution of lining internal force and the increase of void size, which caused the decrease of axial force and the increase of bending moment in the lining structure between the two hollows, which made the lining structure destruction worse between the two hollows. ( 4) The location and number of the cavity behind the lining have a great influence on the cracking process of the tunnel structure. The propagation process of the lining cracks is more complicated when there are double hollow behind the lining. The research results can provide references for the prevention and repair of lining cracks under the influence of multiple cavities and cavities in lining.