强降雨条件下管道型隐伏溶洞对隧道衬砌结构影响研究

Effects of Pipe-Type Hidden Caverns on Tunnel Lining Structure Under Strong Rainfall Conditions

为探究管道型隐伏溶洞内水压力急剧增加对隧道衬砌结构力学响应特征的影响规律,通过有限差分软件FLAC3D进行数值模拟,对衬砌的受力变化情况和破坏特征进行分析,并开展室内相似模型试验,验证数值模拟结果的有效性。基于此,建立实际拓展工况的计算模型,进一步研究溶洞位置、尺寸及水压力大小对衬砌结构内力的影响特征。结果表明:1)溶洞位于拱顶时,随着溶洞内水头不断增加,衬砌内力和位移均有所增大,且呈“S”形增加,试验工况条件下衬砌发生渗漏水破坏时水压力为1.35 MPa;2)溶洞位于不同位置对衬砌内力分布有一定影响,溶洞位于拱顶时抗水压力能力相对边墙及拱底降低0.3 MPa,位于拱顶时衬砌结构抗水压力能力最小;3)在相同水压力下,随着溶洞尺寸增大,衬砌内力显著增加,溶洞影响范围有所扩大。

To investigate the mechanical response characteristics of a tunnel lining structure under the condition of a sharp increase in the water pressure in pipe-type hidden caverns,numerical simulations are performed here using the finite difference software FLAC3D to analyze the force changes and damage characteristics of the lining.Additionally,the effectiveness of the numerical method is validated through similar indoor model tests.Furthermore,numerical models for the actual expansion conditions are constructed to examine the effects of the cavity location,cavity dimension,and water pressure on the internal forces of the lining structure.The results reveal the following aspects:(1)When the cavity is located at the crown,the internal force and displacement of the lining increase in an"S-shaped"manner with increasing water head in the cavity.Moreover,the water pressure is 1.35 MPa when the lining is damaged by water leakage under the test working condition.(2)Various cavity locations differently affect the internal force distribution of the lining.Furthermore,when the cavern is located at the crown,the water-pressure resistance decreases by 0.3 MPa compared with those at the sidewall and bottom,indicating the smallest water-pressure resistance of the lining structure.(3)Under the same water-pressure conditions,the internal force of the lining considerably increases with increasing cavity size,and thus the influencing scope of the cavity broadens.