This Code was prepared on the basis of the Interim Prouisions on Risk Assessment and Management of Railway Tunnel Engineering （Document TJS [2007] No.200） incorporating relevant research and experience in risk management of railway tunnel in recent years，in line with the Technicarl Specification for Risk Management of Railway Construction Projects （Q/CR 9006-2014），according to Notice of CHINA RAILWAY on Issuing the Preparation Plan for Railway Engineering Project Standards in 2014 （Document TZJS [2014] No.176）.
　　This Code comprises 7 chapters titled General Provisions， Terms， Basic Requirements， Risk Management at Feasibility Study Stage， Risk Management at Preliminary Design Stage and Construction Drawing Preparation Stage， Risk Management at Construction Stage， Risk Management Report respectively，and one appendix.The main contents include：
　　1.In Chapter \"General Provisions\"， the basic principles that shall be followed in risk management are defined，and the stipulations that risk management at each stage shall be carried out in terms of safety， social stability， quality， environment， construction period，investment and third-party risk taking into account the technical characteristics of tunnels are provided.The risk management shall focus on the safety risk and the social stability risk，and great importance shall be attached to the sudden and catastrophic risks.
　　2. In Chapter \"Terms\"， terms such as geological risk9 technical risk， natural risk， social stability risk，critical tunnel，post assessment of risk are added
　　3.In Chapter \"Basic Requirements\"， risk grading， risk acceptance criteria and risk management requirements for all project parties are defined； the grading standards for risks of casualties，environmental impact， economic loss and delay are revised； the grading standards for
　　social stability impact and function defect are added，and the risk grading standard，risk acceptance criteria and risk control principles are revised.
　　4.In Chapter \"Risk Management at Feasibility Study Stage\"，the risk management process is defined，the risk management plan is added， and the key technical points of management of geological risks，natural risks，social stability risks and technical risks are clarified.
　　5.In Chapter 66Risk Management at Preliminary Design Stage and Construction Drawing Preparation Stage\"，the risk management process is defined，the risk management plan is added，the checklist of hazard factors is optimized，and the key technical points of risk management of railway tunnel with different characteristics are defined.