Impact of Construction Method and Ground Composition on Headrace Tunnel Stability in the Neelum–Jhelum Hydroelectric Project: A Case Study Review from Pakistan

During underground construction, the behavior of ground is influenced by characteristics rock mass with situ stresses and water, cross section excavation area, method, rate excavation. These fundamental features are considered to ensure support stability excavations achieve long-term successful operation. However, composition Himalayas hinders tunnel excavation, especially in case mechanized tunneling; this causes time cost overruns. This study has reviewed recently completed Neelum–Jhelum Hydroelectric Project; project complexities, geological environments involving significant overburden tectonic stresses, effects method on were analyzed. The major challenges that encountered during construction discussed herein along their countermeasures. An analysis project-related data reveals latest techniques approaches considering mechanics used complete project; existing methods accordingly verified extended. Apart from composition, play an important role occurrence severe bursts. Thus, findings expected be helpful for future tunneling projects Himalayas.