富水管道型岩溶隧道衬砌结构力学响应特征研究

Mechanical response characteristics of lining structure of pipeline karst tunnels in water-rich areas

对于围岩中存在管道型溶腔的岩溶隧道而言,受地表强降雨及地下水的影响,管道型溶腔内极易积聚高水压力,进而引发衬砌开裂、渗漏水及涌水病害。为了探明管道型溶腔中高水压力对衬砌结构的影响,开展了富水管道型岩溶隧道衬砌结构力学响应模型试验,对不同溶腔位置及不同水头高度影响下的衬砌结构内力特征进行了研究。基于此,建立扩展工况的数值计算模型,进一步探究了不同溶腔直径、溶腔位置及溶腔水头高度对衬砌结构内力的影响。结果表明:当隧道周围存在管道型溶腔时,与溶腔接触位置的衬砌内侧承受较大的正弯矩,为衬砌结构的最不利受力位置;随着溶腔直径和溶腔内水头高度的增加,衬砌内力显著增大;溶腔所在位置影响着衬砌内力的分布,当溶腔位于隧道拱顶时,衬砌结构的抗水压能力最小。研究结果可为管道型岩溶隧道的结构设计及安全施工提供借鉴。

For the karst tunnel with pipeline cavity in the surrounding rock, it is very easy to accumulate high water pressure in the pipeline cavity due to the influences of heavy rainfall on the surface and groundwater, which will lead to lining cracking, water leakage and water gushing diseases. To explore the influence of high water pressure on the lining structure, a model test of pipeline karst tunnels under high water pressure was carried out, and the internal force characteristics of tunnel lining under the influence of cavity position and head height were studied. Based on this, the numerical calculation model of extended working conditions was established. The effects of cavity diameter, cavity position and water head height on the lining structure were further explored. The results show that the inner side of the lining in contact with the cavities bears larger positive bending moment, when there are karst cavities around the tunnel, which are the most unfavorable stress positions of the lining. The internal force of the lining increases greatly, with the increase of cavity diameter and water head height in the cavity. The location of the cavity affects the internal force distribution of the lining, and the anti-water pressure capacity of the lining is the smallest, when the cavity is located at the tunnel vault. The research results can provide reference for the structural design and safe construction of pipeline karst tunnels.