饱和软黄土城市地铁隧道自身和环境风险普遍较高，为了准确辨识、评价和规避可能存在的施工安全风险，在饱和软黄土典型物理力学特性和地层赋存规律研究的基础上，分析风险发生的根本原因，结合工程实践讨论4种典型风险，并提出风险控制措施。研究表明： 1)饱和软黄土在Q3和浅层Q2黄土地层中均有分布，具有欠压密特征、饱水软弱性和失水变形大的特性。2)因大孔隙结构的存在，在水的作用下，土体稳定性变差，是城市地铁隧道工程风险产生的根本原因。3)失水变形是环境风险的根源，制定合理的地下水控制措施是关键；饱水软弱性是自身风险的根源，可采取选择规避、优化竖井位置和开挖方向、评价降水后状态、加强堵头墙刚度及多策并举等控制措施。

The urban metro tunnels in saturated soft loess are generally high in their own and environmental risks. In order to accurately identify, evaluate and avoid the possible construction safety risks, the typical physical and mechanical properties of saturated soft loess and the formation occurrence law are analyzed to explore the root causes of the risks. Combining with engineering practice, four typical risks are discussed and corresponding risk control measures are proposed. The research shows that saturated soft loess is distributed in both Q3 and shallow Q2 loess strata and has the characteristics of under compaction, watersaturated weakness, and large deformation due to water loss. Because of the existence of macropore structure, the soil stability becomes worse under the action of water, which is the fundamental reason for the risk of urban metro tunnel engineering. Deformation due to water loss is the primary cause of environmental risks, and the key is to formulate reasonable groundwater control measures; Watersaturated weakness is the primary cause of its own risk. Control measures such as avoiding saturated soft loess, optimizing the location and excavation direction of the shaft, evaluating the state after dewatering, strengthening the stiffness of plug wall, and taking multiple measures can be employed.