Risk Assessment of Water Inrush in Karst Tunnels Based on the Efficacy Coefficient Method

Abstract

With the rapid development of China's economy, more and more long-deep tunnels are under construction, especially in the mountainous area of western China and in karst areas [1][2], which pose a great challenge for tunnel engineering. Long-deep tunnels are always buried in complex geological conditions with high geo-stress, high water pressure, strong karst geology, and construction disturbance [3]. Additionally, it is quite difficult to make a Pol. J. Environ. Stud. Vol. 26, No. 4 (2017) AbstractWater inrush is one of the typical geological hazards of tunnel construction in karst areas. It is necessary to predict water inrush more accurately for karst tunnels. Firstly, we created a model on risk evaluation of water inrush based on the efficacy coefficient method. Then karst hydrologic and engineering geological conditions were considered in detail, and several typical factors were selected as evaluation indexes, including formation lithology, unfavorable geology, groundwater level, and so on. Moreover, the weight coefficients of the selected evaluation indices were calculated using the analytic hierarchy process method. Furthermore, the total efficacy coefficient was presented to specify the risk grade of the evaluation samples. Finally, the risk grade of water inrush for karst tunnels is divided into four levels: severe (red), high (orange), elevated (yellow), and guarded (blue). Additionally, the model of risk assessment of water inrush was applied to Jigongling tunnel along the Fanba Expressway in China. The results show that the present evaluation results agree well with the construction situation, which also agree with the relative analysis results of attribute mathematical theory. The presented work with the efficacy coefficient method is relatively simple with strong operability, which has potential for predicting water inrush in karst tunnels.

Risk Assessment of Water Inrush in Karst Tunnels Based on the Ideal Point Method

“…The obtained results were compared with the results of the relevant methods (Table 8). It was found from Table 8 that the results from the proposed model agreed with results from set pair analysis [26], the efficacy coefficient method [27], and the cloud model [28]. Therefore, the proposed method used to assess the risk level of water inrush in karst tunnels is feasible and effective, and convenient to operate.…”

“…The analytic hierarchy process (AHP) [27,28] was presented to determine the weights of each evaluation index. AHP is mainly performed with mathematics and psychology.…”

“…Meanwhile, a new risk evaluation model based on the fuzzy topsis method was presented with the consideration of both the uncertainties and the new factors [25]. In addition, set pair analysis [26], the efficacy coefficient method [27], and the cloud model [28] were also successfully applied in risk assessment of water inrush in karst tunnels.…”

Study on the risk assessment of water inrush in karst tunnels based on intuitionistic fuzzy theory

“…AHP was presented to determine the objective weights of the evaluation indices. AHP was applied with the following procedure (Saaty 2008;Wang et al 2017c):…”

Numerical Simulation on the Seepage Properties of Soil‐Rock Mixture

“…Many scholars devote themselves to the research of water inrush, and more and more methods are used to evaluate the risk of water inrush in tunnels [5][6][7][8][9][10][11][12]. e causes of water inrush in the tunnel are complicated, being not only affected by the geological conditions but also influenced by construction disturbances [13][14][15][16].…”