Research On Dynamic Analysis Over Overall Construction Process Of Expressway Tunnels And Feedback Design Methods

As a type of underground works, the expressway tunnel project is featured withconcealment, complexity, uncertainty and huge investment risks. Uncorrectable losses maybe generated due to possible risks during the construction process. With the rapiddevelopment of our expressway, how to control various risks during the tunnel constructionand how to realize safe, economic and highly-efficient management objective has become anurgent problem.The paper, based on analysis over current status of static and dynamic risks of tunnelworks at home and abroad, has firstly analyzed tunnel works and its risk occurrencemechanism, explored risk components of tunnel construction, proposed evaluation flow fordynamic risks of tunnels and analyzed characteristics of four common risk analysis methods,risk levels of tunnels as well as the application of acceptance standards in risk management.Work breakdown structure (WBS) and risk breakdown structure (RBS) are used inanalysis over dynamic risks during tunnel construction. Monitoring items for dynamic risksarising from expressway construction and highway tunnel construction based on WBS-RBSare proposed. Therefore, information collection and forecast necessary for risk managementare being researched. A comprehensive geological forecast system combining TSP remotegeological detection and forecast and close-range detection by geological radar and a meansfor the collection of monitoring and measurement dynamic data indispensable to dynamicmanagement of risks are proposed according to characteristics of tunnels.A flow to incorporate common risk analysis methods into risk analysis of tunnel works isproposed taking into consideration of characteristics and construction complexity of tunnelworks. A risk evaluation model for tunnel construction based on monitoring andmeasurement is established in allusion to widely adopted new Austrian tunneling method andindispensable monitoring and measurement means of new Austrian tunneling method. Thecomprehensive risk indexes of various measurement indicators as well as their impact ontunnel construction can be calculated through the model. Then, control measures can beadopted according to risks.Dynamic feedback design flow, key implementation points and design methods fortunnel construction based on dynamic analysis are proposed by integrating risk analysis oftunnels with feedback design. Necessary modifications and adjustments are carried out forpre-design of tunnels according to analysis results of dynamic risks, which can full exerttheir role in guiding tunnel construction and ensuring construction safety.In allusion to problems existing in the management of dynamic risks of tunnel works, anexpressway dynamic risk management system is formulated in accordance with thedevelopment idea of risk management system of enterprises and some practices during expressway tunnel construction, i.e., three-tier system for management of dynamic riskduring tunnel construction. Meanwhile, feasible measures and methods during practices areproposed.The application of aforementioned theories and methods are verified respectively throughBaoding–Fuping Expressway.