جستجوی مقالات مرتبط با کلیدواژه "جریان آب زیرزمینی" در نشریات گروه "علوم پایه"

High local groundwater flow into rock tunnels is a technical and environmental problem for underground constructions. Geological structures such as faults, open fractures, and dissolution channels could play important roles in conducting ground waters to the tunnels. However, prediction of groundwater inflow from these structures using analytical and empirical method often failed due to given hydrogeological assumptions and simplification such as a homogeneous and isotropic porous medium around the tunnel. The Zagros water tunnel is located in the northwest of Kermanshah province. A huge amount of groundwater flow into the tunnel through fractures occurred during drilling of the second part of tunnel. The second part of tunnel passes through Pabdeh and Gurpi formations. A considerable amount of groundwater flushed into the tunnel when the Ilam Formation was penetrated, causing numerous problems and great damage to the drilling operation. The goal of this study is to identify the factors that influenced water flows into the tunnel. To this purpose, geological features of high flow rate zones have been identified and investigated. The highest input rate (800 l/s) was recorded in the zone Hz23 located in Kurdighaseman anticline. The relationship between geological features and the groundwater inflow into the tunnel indicated that faults play conveying role for ground water into the tunnel. Evaluation of high local groundwater inflow to rock tunnels based on characterization of geological structures is more reliable compared to available analytical and empirical estimation.

Part 4 of Ghomroud tunnel is located in the Sanandaj-Sirjan geological zone. In this area, due to the existence of numerous faults, crushed zones and significant development of major and minor catchments, the tunnel has been encountered with the risk of groundwater influx. On the other hand, due to some limitations such as thick(up to 600 meters in some localities)overburden over the tunnel and the lack of exploratory drilling down to the tunnel level, it has been difficult to forecast and estimate the groundwater flow in the tunnel route. Due to the existence of numerous faults in part 4 of the Ghomroud tunnel ,encountering of the drilling machine (Double Shield TBM) with high-pressure water could cause influx of large amounts of water into the tunnel and collapse of rock masses in the crushed zones. It hence could cause deviation of the machine and drilling stop. In this article, the lack of data from boreholes led us to try investigating the development of groundwater flow in the tunnel based on geomorphological evidence. Analytical modeling and geomorphological field survey in the area show a relative consistency between geomorphology and volume of water flowing in the tunnel excavation. Therefore, according to measurements conducted on the water entering the tunnel, about 80 liters per second of water flowed into the tunnel, which is in agreement with geomorphological studies. Results show that the study of morphology and surface features could provide useful information in order to identify more precisely the hydrogeologic conditions of the area.