盾构穿越饱和砂土地层中的运营地铁时，在地铁列车振动荷载的作用下开挖面前方土体中会产生超孔隙水压力，影响开挖面稳定，通过动三轴试验对不同类型砂土在地铁列车振动荷载的作用下的超孔隙水压力增长规律进行了研究。研究表明，随着地铁列车振动荷载振幅的增大，超孔隙水压力逐渐增大，当振幅不大于10 kPa时，超孔隙水压力的增加并不明显；开挖面支护力减小，会使振动荷载对超孔隙水压力的影响增强，而且这种影响对土体竖向应力卸荷比土体水平应力卸荷更为敏感；在饱和松散细砂地层中，地铁列车振动荷载对超孔隙水压力的影响最为显著；地铁列车振动荷载引起的开挖面超孔隙水压力绝对数值不大，但能使泥水盾构泥膜承受的压力差至少减小约33%。

The excess pore water pressure, which imposes a negative role on the stability of excavation face, generated in sand due to the train vibration load of a running metro when a slurry shield cross under the metro. This paper presents an investigation on the effect of the train vibration load on the generation of excess pore water pressure in three categories of sand specimens through dynamic triaxial tests. It is concluded that the excess pore water pressure increases with the rise of amplitude of train vibration load; but the increase of excess pore water pressure is not significant when the amplitude of train vibration load is less than 10 kPa; and the influence of train vibration load on the excess pore water pressure is more significant when the excavation face pressure declined; moreover, the decrease of vertical pressure plays a bigger role in the growth of excess pore water pressure than that of horizontal pressure. The vibration load has the most significant influence on the excess pore water pressure in saturated loose fine sand. The excess pore water pressure could reduce the resultant pressure on filter cake at least 33%.