Research Trend and Prospect of Reconstruction and Extension Technology of Existing Highway Tunnels

The rapid development of social economy leads to an increasingly obvious contradiction between transport demand and capacity. The reconstruction and expansion of existing highway tunnels have become a long-term and effective means to improve the highway transportation environment in the future. Through the literature retrieval and case statistical analysis of typical reconstruction and expansion of highway tunnels, the development trend and research trends of highway tunnel reconstruction and expansion are clarified. Point out the research status and deficiencies of highway tunnel reconstruction and expansion schemes, and propose reconstruction and expansion schemes based on the comparison and selection of schemes. Combined with four typical reconstruction and expansion construction methods and tunnel expansion coefficients, and construction methods for reconstruction and expansion of existing highway tunnels are put forward. The research dynamics and deficiencies of surrounding rock pressure calculation, surrounding rock mechanical response, blasting vibration control and supporting parameters of the reconstruction and expansion highway tunnel are expounded. The application prospects of BIM technology, artificial intelligence technology, and green carbon neutral concept in the reconstruction and expansion of tunnels are put forward, and it is pointed out that the standardization of construction standards, the intelligentization of expansion plans, the innovation of construction methods and the systematization of theoretical research are the key research directions in the future.