Risk assessment model for tunnel ventilation shaft boring based on improved SPA-EWM theory
To meet the requirement of"forming a deep and large shaft in one time",shaft boring machine(SBM)was made.Taking the engineering application of SBM as the research background,the risk factors of SBM tunnelling is analyzed and identified.The shaft construction risk is divided into five levels.A three-levels shaft tunnelling risk assessment index system is constructed.Considering the problem of taking the same,different and opposite values in the degree of linkages,the assignment method in the set-pair analysis(SPA)method is improved.Based on the entropy weight method(EWM)to calculate the weight vector of each risk factor,a risk assessment model for SBM boring in deep ground shaft was established to improve the SPA method.A trend was fitted to the change relationship between the association degrees.The calculated risk value is to give the basis for risk level assessment.With the help of this risk assessment model,the risk assessment and prediction of the ventilation shaft construction in volcanic tunnels along the river highway is carried out.Different methods of taking the shaft construction risk by engineering managers with different risk preferences are proposed.The applicability of the risk model was further validated in conjunction with the field measurement results.Based on the first application of SBM method in China,this study proposes a risk assessment model for deep ground shaft SBM boring to play a theoretical guiding role for the construction of deep large shafts.It also lays a certain theoretical foundation for future risk assessment research of deep ground shaft boring.
NETL
NSTL
万方数据
