Abstract Considering that improper treatment of water inflow during tunnel construction may seriously affect local ecological and social environments, and using a typical water-inflow section of the Mingtangshan tunnel as an example, this paper proposes a conceptual hydrogeological model for water inflow in a fractured zone based on a small-scale test for hydraulic pressure at a water-stopping point on a typical section. It presents three fissure water-distribution models for the fractured zone before and after excavation. The results show that: 1) a perched water saturated zone in the surface weathered fissure rock layer will appear or disappear after water inflows with the coming of the wet season or dry season; 2) the hydraulic pressure of the water-inflow point increases rapidly after water stopping and then slows down, which can be reflected by a logarithmic model; 3) a water-head depression cone is formed near a single water inflow point, and a balance will be reached by connecting to other interlinked points of water inflow after water stopping; and 4) seven-day monitoring indicates that a stable hydraulic pressure can be achieved after 24 hours of water stopping.
Abstract：
Considering that improper treatment of water inflow during tunnel construction may seriously affect local ecological and social environments, and using a typical water-inflow section of the Mingtangshan tunnel as an example, this paper proposes a conceptual hydrogeological model for water inflow in a fractured zone based on a small-scale test for hydraulic pressure at a water-stopping point on a typical section. It presents three fissure water-distribution models for the fractured zone before and after excavation. The results show that: 1) a perched water saturated zone in the surface weathered fissure rock layer will appear or disappear after water inflows with the coming of the wet season or dry season; 2) the hydraulic pressure of the water-inflow point increases rapidly after water stopping and then slows down, which can be reflected by a logarithmic model; 3) a water-head depression cone is formed near a single water inflow point, and a balance will be reached by connecting to other interlinked points of water inflow after water stopping; and 4) seven-day monitoring indicates that a stable hydraulic pressure can be achieved after 24 hours of water stopping.
.A Conceptual Water Inflow Model and Characteristics of the Hydraulic Pressure of Water-Stopping Points in the Mingtangshan Tunnel's Fractured Zone[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(5): 110-116
2015, Vol. 52 