中文摘要：

地铁运营前下卧层土体存在不同程度固结，这会影响到运营期隧道周围土体中孔压的变化，进而产生不均匀沉降。通过GDS循环三轴试验系统对杭州饱和软黏土进行动力测试，研究了固结度、固结应力、循环应力比对孔压发展的影响。在现有研究成果的基础上建立了考虑初始固结程度的孔压模型。研究表明：循环荷载下饱和软黏土的孔压发展形态比应变发展形态更具规律性，固结程度愈高的土体孔压发展愈缓慢，并且随振动次数增加，在较低的孔压水平就可达到稳定。预测地铁长期荷载下土体的孔压和沉降时考虑孔压测试时的滞后现象会达到更好的效果，所得的孔压模型能够较好地模拟地铁运营荷载下孔压的发展。

英文摘要：

The underlying soil possesses the nature of variation in consolidation degree before subway operation, which will result in the change of pore pressure as well as the differential settlement. Hangzhou saturated soft clay is tested by dynamic triaxial test system to find the effect of consolidation degree, consolidated stress and cyclic stress ratio on the development of pore pressure. A new pore water pressure model considering the initial consolidation degree and the threshold cyclic stress ratio is proposed on the basis of existing research findings. The results show that under cyclic loadings, the development of pore pressure undergoes higher regularity than that of shear strain. The higher the consolidation degree is, the slower the pore pressure increases. Furthermore, the pore pressure will be stabilized at a lower level with the increment of cyclic times. Taking pore pressure delaying into consideration will lead to more desirable results while predicting the pore pressure and long-term settlement of the tunnel. The obtained pore pressure model can well simulate the pore pressure development under subway loadings.