Abstract: A redevelopment scheme for highway tunnels with large cross sections is presented using analog simula? tions and numerical calculations to study the law of surrounding rock deformation and stress variation during in-situ reconstruction of a large cross section tunnel in weak surrounding rock based on the first domestic in-situ reconstruction of a highway tunnel expanded from a twin-tube, four-lane highway tunnel into a four-tube, eight-lane tunnel. A combined construction scheme is set forth in which new construction goes before expansion, providing a reference for highway tunnels and similar underground works.