Abstract: It occurred water and mud bursting in waterrich karst section in the excavation process in Xiangshan tunnel of LongyanXiamen railway line. Surface subsidence happens, surrounding environment and construction safety are faced with serious damage and threats. There are 500 000 m3 sand and mud and water in the tunnel due to the construction of antislope. How to carry out water drainage and mud cleaning, how to deal with the mud and water gushing of highpressure karst section and how to effectively control the construction risk are the most difficult points. "Mud sealing and no water sealing" ground surface deep hole sealing method is adopted after serious technical research and technologies, such as advance grouting, support strengthening and rational excavation are used so as to successfully clean the mud and drain the water. In the end, the safe construction of mud and water gushing in highpressure waterrich complex karst section is guaranteed.

Key words: High-pressure water-rich, Complicated karst, Mud surging collapse, Pressure with water, Safety excavation, Critical technology