在低黏聚力的软弱地层、大断面隧道开挖中，掌子面稳定是施工中面临的很大问题。采用超前预加固工法，对浏阳河隧道开挖过程进行数值模拟，通过分析超前预加固法对隧道位移、受力的影响，并研究各加固参数的敏感性，得到掌子面的超前锚杆加固长度对掌子面的稳定性影响最大，掌子面外超前预加固对改善超前核心土受力也有较大影响。

The stability of the tunnel face is a big challenge when a tunnel with large crosssection is constructed in soft stratum with low cohesion. Numerical simulation is made for the excavation of Liuyanghe tunnel, which is constructed by prereinforcement method. By analyzing the impact of the prereinforcement on the displacement and forcebearing behavior of the tunnel and by studying the sensitivity of all the reinforcement parameters, the authors conclude that the reinforcement length of the advance anchor bolts has the greatest impact on the stability of the tunnel face and that the prereinforcement outside the perimeter of the tunnel also has great impact on the improvement of the forcebearing behavior of the advance core.