Failure prediction method of the anchor cables in the metro stations under unilateral deep excavation

Abstract

To ascertain the anchor cable failure caused by the overturning and slipping of the station structure under unilateral excavation with zero distance from the station, this study takes the balance of the station-cable system under zero-distance unilateral excavation as the research object, and derives the total anti-slip force and anti-overturning moment of the cables based on the Rankine’s earth pressure theory and the force balance of the metro station. In addition, a novel failure prediction method is proposed to judge the failure of the station-cable system under various design conditions by taking the supporting capacity of the multi-layer cables as the evaluation index and multiple main influencing factors as the control indexes, so as to predict the structural risk. This method comprehensively considers multiple independent variables such as excavation depth, groundwater level, interval spacing and anchor cable design angle. Furthermore, based on Pearson correlation analysis, the sensitivity of the cable supporting force to various factors decreases in the following order: excavation depth > groundwater level > interval spacing > station width > cable design angle. Therefore, reducing the excavation depth is the most effective way to reduce the risk of the station-cable system caused by unilateral excavation. If it is necessary to increase the excavation depth, the cover-excavation reverse method can be used to indirectly reduce the effective excavation depth, thereby ensuring the safety of the structural system. This method can predict the risks of similar projects and reduce the occurrence of accidents.