Deformation of the surrounding rock is an anticipated geological hazard when driving tunnels through soft rock. If deformation is not restricted, it can lead to serious engineering safety hazards. Therefore, studying the factors that affect the deformation of soft rock tunnels is highly significant. This study selected twelve main influencing factors involving subjective and objective factors and four actual indexes to establish a deformation risk assessment system for a soft rock tunnel. Data envelopment analysis (DEA) was innovatively utilized to analyze the efficiency of the twelve factors which affect the deformation of soft rock tunnels. The analytical results showed that the water content of the soft rock was the most efficient factor, followed by the tunnel depth, uniaxial compressive strength, excavation method, strength-stress ratio and groundwater seepage condition. A risk assessment model for the deformation of a soft rock tunnel was established using a normal cloud model and verified by the deformation occurred in typical soft rock tunnel cases. Risk assessment results confirmed that the proposed model was consistent with actual deformation risk degree. This model can guidie significance for the assessment of soft rock tunnel engineering.

当隧道穿过软岩时，围岩的变形是一种预期的地质灾害。如果不限制变形，就会导致严重的工程安全隐患。因此，研究影响软岩隧道变形的因素具有十分重要的意义。本研究选取包括主客观因素在内的12个主要影响因素和4个实际指标，建立了软岩隧道变形风险评估体系。创新性地利用数据包络分析（DEA）对影响软岩隧道变形的十二个因素进行效率分析。分析结果表明，软岩含水量是最有效的影响因素，其次是隧道深度、单轴抗压强度、开挖方式、强应力比和地下水渗流情况。使用正态云模型建立软岩隧道变形风险评估模型，并通过典型软岩隧道变形情况进行验证。风险评估结果证实，该模型与实际变形风险程度一致。该模型对软岩隧道工程评价具有指导意义。