The Effects of Joint Networks on The Stability of Two Parallel Tunnels

The development of transport infrastructure connecting the regions in Vietnam is increasingly receiving attentions. Highways are being built throughout all the regions of the country. Due to the complex mountainous topography, the process of forming and building highways in Vietnam will be required the construction of tunnels through the mountains. The excavation of mountain traffic tunnels as well as subway tunnels are often involved the use of two parallel tunnels to increase transport capacity and improve operational convenience of tunnels. Currently, analysis of two parallel tunnels are often applied assumptions for tunnels with circular cross - sections in an elastic and isotropic medium, with the ground surface assumed to be flat, and the two tunnels considered in a half - infinite space using numerical analysis models. Two parallel tunnels with different cross - sections for various purposes, under varying ground surface conditions, have also been studied by various complex methods and numerical models. However, research on the excavation of twin parallel tunnels through mountains in complex geological conditions, including stratified rock masses, joint networks, and karst caverns, are still many limitations. Therefore, in - depth research will be conducted to ensure the effective excavation, support, and use of tunnels. The results of the article show that, in this study, the suitable tunnel shape is horse - shoe. As the density of joint networks increases, the stability of the tunnels decreases, and the damage zone around the tunnels increases.