Combination of engineering geological data and numerical modeling results to classify the tunnel route based on the groundwater seepage

Abstract

The main objective of this paper is to categorized the unexcavated Zagros tunnel route based on the observed water inflow and seepage hazard. Water inflow and water pressure controls are needed in the design, construction, and exploitation of underground structures. An estimate of the inflow rate is required to size the pumping system, and treatment plant facilities for construction planning and cost assessment. An estimate of the excavation-induced drawdown of the initial groundwater level is required to evaluate potential environmental impacts. In this paper based on the geological investigation, observed, measurement water seepage into tunnel and numerical modeling, The Universal Distinct Element Code (UDEC), the remaining unexcavated Zagros tunnel route has been categorized into three categories including high Risk, moderately risk and low risk. Results show that around 60 m of tunnel (3%) length can conduit the large amount of water into tunnel and categorized into high risk zone and about 45% of tunnel route has moderately risk.