INTRODUCTION Shotcrete lining forms an integral part of conventional tunneling and is widely applied for underground excavations. Early strength gain of the shotcrete is a crucial aspect for ground support and safety of operatives. Strength requirements are dependent on various factors such as lining thickness, ground type, excavation size and tunnel depth. The early strength gain is typically ...

Since, both the relative position of tunnels and the construction procedure affect the soil movement and internal forces in the lining, it is of major concern to study the influence of these factors on the tunnel design. Construction procedures of tunnels have considerable effects on the magnitude of surface movements and lining stresses. This paper describes numerical analysis of construction ...

The construction of new tunnels above existing has become increasingly common to optimize underground space utilization. However, such may pose potential engineering hazards due cracking in the secondary lining lower tunnel. This study investigates occurrence and evolutionary characteristics longitudinal cracks tunnel during upper adjacent pre-existing Our findings demonstrate that a significan...

In this paper, the fracture zone of Chunxuan Road Tunnel in Jinan, Shandong Province, China was selected for engineering background. With reference to field monitoring data, a finite element model established based on strength reduction method. aid model, influences different initial support parameters (including lining, bolt and steel arch) tunnel deformation were analyzed obtain reasonable pa...