🔵 New Post 🚀 The New Austrian Tunnelling Method (NATM) is based on the principle of mobilising the ground’s inherent strength to ensure stability. The diagram illustrates a double core excavation sequence, where the tunnel is divided into top heading, bench, and invert sections. Sequential excavation and immediate application of shotcrete with lattice girders and rock bolts allow stress redistribution, minimising deformation. The field image shows the practical implementation of this method, h