AUTHOR=Chen Yunjuan , Liu Mengyue , Su Mengzhen , Ding Mingxu , Li Haolin , Jing Yi 

TITLE=Prediction of water inflow and analysis of surrounding rock stability in unfavorable geological mountain tunnel

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2024.1373627

DOI=10.3389/feart.2024.1373627

ISSN=2296-6463

ABSTRACT=During the construction of a mountain tunnel, water inflow and rock instability are common occurrences due to adverse geological conditions, posing serious threats to construction safety. This study focuses on a proposed mountain tunnel and utilizes employs multiple formulas to predict potential water inflow during excavation. Based on the amount of water inflow and deformation of surrounding rocks, comprehensive determinations are made for the thickness of grouting rings and permeability coefficients. The results demonstrate that: (1) Different formulas yield slightly varied outcomes but overall trends remain consistent; considering various calculations, the normal water inflow for this tunnel is approximately 115.5908×10 3 m 3 /d with a maximum at 210.9100×10 3 m 3 /d. (2) Increasing grouting ring thickness or decreasing permeability coefficient can effectively reduce water inflow, although diminishing returns occur as changes become smaller in magnitude. (3) Pre-grouting curtains have an evident effect in enhancing stability; however,, yet their their effectiveness decreases with increased thickness. (4) Taking into account both safety and economic factors, it is recommended that the grouting ring thickness be set at 8m with a permeability coefficient equaling one hundredth that of surrounding rocks for this tunnel project.