京珠高速公路洋碰隧道水害原因分析及安全性评价

针对降雨引发的岩溶地区隧道水害影响隧道运营安全问题,以京珠高速公路洋碰隧道为例,通过地质勘探与水连通试验,探明隧址区不良地质情况与水连通特性,采用数值仿真方法探究雨后高水压下隧道结构应力场、渗流场的特征规律,并结合病害情况提出整治措施。研究结果表明: 1)地表强降雨、地层岩溶发育、灌入式雨水下渗通道是此次水害的主要原因,而这些原因综合导致的隧道外水压力过高是病害发生的直接原因; 2)由于排水能力相对不足,地层高水头下隧道结构(尤其是隧底和拱顶)仍承受较高水压力,大幅削弱了衬砌结构安全性,易引发边墙、隧底的裂损问题; 3)采取“增设泄水廊道+地表封堵及引流+增设边墙泄水孔”的整治措施后,整治效果良好。

Causes Analysis of Water Disease in Yangpeng Tunnel on Beijing-Zhuhai Expressway and Its Safety Evaluation

The water disease of highway tunnel in karst area caused by rainfall often occurs, which seriously affects the safety of tunnel operation. Hence, in order to further clarify the formation mechanism and adverse effects of this kind of water disaster, the geological exploration and water connectivity test are carried out in Yangpeng Tunnel on Beijing- Zhuhai Expressway. And then the characteristic of stress field and seepage field of the tunnel under high water pressure after rain are explored through numerical simulation method, and countermeasures are put forward. The results show that: (1) The main causes of the water disease are heavy rainfall, karst strata and water infiltration channel, and the high external water pressure caused by the above-mentioned reasons is the direct cause of the disease. (2) Due to the lack of drainage capacity, the tunnel structure, especially in the bottom and crown, still bears high water pressure, which greatly weakens the safety of the lining structure and is easy to cause cracks in the sidewall and the bottom of the tunnel. (3) The renovation measures of new discharge chamber + surface plugging and drainage + new discharge hole in sidewall are adopted, and the applicable effect is good.