Coupling analysis of tunnel construction risk in complex geology and construction factors

Generally, multiple risk factors are involved in tunnel construction accidents. Therefore, it is of particular importance to evaluate the mechanisms of multifactor risks and measure coupling risks in tunnel construction safety. Tunnel construction risk components under complex geology and construction factors were investigated using 101 tunnel construction accidents as examples. N-K and coupling degree models were introduced for tunnel construction risk analyses to calculate the coupling degrees of each component of single-factor and two-factor risk coupling models, respectively. Meanwhile, the correlation mechanism between tunnel construction risk value and each risk component was analyzed. The obtained results indicated that the coupling risk of complex geology and construction factors was greater than that of two factors independently, and a strong coupling relationship was witnessed between complex geology and construction factors. Strong coupling resulted in a sharp risk increase or sudden coupling change, which caused risk expansion and even generated new risks. This method provided a theoretical basis for the tunnel construction risk coupling mechanism.