为解决富水黄土隧道掘进过程中遇到的掌子面渗涌水、洞周土体软弱剥落、初期支护变形坍塌与隧基软弱等技术难题，以银西高铁驿马一号隧道为例，对高铁富水黄土隧道首次采用地表降水开挖与隧底软基注浆加固开展深入研究，并对该措施的降水疏干与软基加固效果进行分析、验证。研究结果表明： 1）在富水黄土隧道地表降水设计时，按经验参数确定的涌水量与实际涌水量常存在较大差异，结合掌子面实际涌水量或参照局部深井疏干试验后的参数进行设计，是确保设计方案与实际吻合的关键。 2）实践表明，对穿越深厚富水软塑黄土层隧道开展地表超前降水疏干是可行的，地表降水能提前疏干洞身周边土体，提高围岩稳定性，便于洞内施工作业，较采用单独的洞内排水方式疏干洞身周边土体，更为有效、时间更短。 3）在富水软塑黄土隧道中采用钢管桩加固隧基，与隧道掘进交叉作业干扰大，在软塑层中成桩困难，加固、堵水效果差；而采用袖阀管注浆加固隧基，对掘进施工干扰小，堵水和加固软塑土体的效果更佳。

Many technical issues are encountered during the construction of the Yima No. 1 tunnel on the Xi′anYinchuan highspeed railway in the waterrich loess stratum, including water seepage on the tunneling face, soft surrounding rock spalling, primary support deformation and collapse, and soft foundation of the tunnel bottom. As a result, an indepth study on surface dewatering excavation and soft foundation reinforcement is conducted, and the dewatering and reinforcement effect is analyzed. The findings are as follows: (1) Because the designed water gushing volume is largely different from the actual one based on experience, a deepwell drainage test should be performed first to provide a reference for water gushing volume parameter design. (2) The practice demonstrates that advanced surface dewatering for the tunnel crossing deep waterrich soft plastic loess soil layer is feasible. Surface dewatering which is superior to intunnel drainage, can improve the stability of the surrounding rock and facilitate tunnel construction. (3) When tunnel foundations are reinforced with steel tube piles in waterrich softplastic loess stratum, many disadvantages occur, including large disturbance to tunnel excavation, complex pile formation, and low water stop and reinforcement effect, whereas Soletanche grouting performs better.