Settlement Prediction Method of Extra-Large Diameter Tunnels in Soft Rock Strata

This research was undertaken to predict the result of vault settlement during excavation super-large-span tunnels in soft rock strata, which are prone deformation and hard aftermaths. Numerical simulation applied tackle with problems such as proneness prediction on settlement. As a result, model for continuous tunnel face keeps advancing proposed, influencing factors span depth taken into consideration, put forward optimization variable-section construction scheme. The results show that becomes fast at beginning because its surrounding rocks characterized by weakness, incompleteness, poor stability. At initial stage excavation, varying had greater impact settlement, indicating primary support has be enhanced weak rocks. pilot proceeds, high-stress zone transfers deep part is capable rapidly predicting locations other than observation points. final amount affected span, depth, basic mechanical parameters key variable cross-section lies parts where stress concentrated, thus requiring reinforcement frequent monitoring. methods analysis may provide data technical means control large-span strata.