郑开下穿越工程非饱和土土-水特征曲线室内试验研究

利用气相法和渗吸法，对郑州至开封下穿越工程降水施工引起的非饱和砂质粉土和粉质黏土的土-水特征曲线进行了室内试验研究。研究结果表明，非饱和砂质粉土和粉质黏土的进气值约为2 kPa和250 kPa，残余饱和度对应的吸力值约为15 MPa和28 MPa，两种非饱和土的减饱和过程都具有明显的阶段特征。通过该工程非饱和土土土-水特征曲线的分段性研究，对于工程降水施工以及掌子面加固等有重要的指导意义。

Laboratory experimental study of soil-water characteristic curves of unsaturated soils of Zhengzhou-Kaifeng underpass project

Based on osmotic method and vapor phase technique, the soil-water characteristic curves of unsaturated soils-the sandy powder soil and the silty clay which produced by dewatering construction of Zhongzhou-Kaifeng underpass project were studied. Results show that the air-enter values for the sandy powder soil and the silty clay are about 2 kPa and 250 kPa; the residual saturation degree values are about 15 MPa and 28 MPa and the desorption process of both unsaturated soils shows clearly in step-phase. The step-phase study of characteristic curves of unsaturated soils has very important meaningful for dewatering construction and the excavation face reinforcement of Zhengzhou-Kaifeng project.