Evaluation on operation safety and maintenance condition of tunnel crossing Yellow River

The operation safety of the tunnel crossing Yellow River is absolutely critical to the normal operation of the whole Middle Route Project of South-to-North Water Diversion(MRP-SNWD).The operation requirements and layout of monitoring devices of the tunnel are introduced.We emphasize the risk factors of the tunnel operation,including uneven longitudinal settlement,seismic action,over-running,anti-seepage and drainage of lining,cavitation and abrasion.It is believed that even under all unfavorable conditions,the displacement of tunnel joints can meet anti-seepage demands with high anti-seismic capacity;anti-seepage and drainage measures are dependable and water seepage is not the controlled condition for safety operation;the tunnel is not affected by cavitation and abrasion of high velocity flow and long-term safety operation can be guaranteed.