RESEARCH ON VENTILATION SYSTEM FOR LARGE DIAMETER AND LONG DISTANCE SHIELD TUNNEL CONSTRUCTION AT SUTONG GIL UTILITY TUNNEL ENGINEERING

Tunnel construction ventilation is an important factor affecting the efficiency and safety of shield tunnel construction. The paper proposes a new ventilation system for the large diameter and long distance tunnel construction at Sutong GIL utility tunnel engineering. The tunnel is a single line tunnel without shaft and parallel guide hole, which is crossing gas stratum of Yangtze river bed. Moreover, the tunnel internal structure constructs when the tunnel bores, which causes a huge challenge for ventilation. Firstly, it chose the best ventilation-the forced and relay ventilation, according to the relevant specifications and engineering experience of similar projects. Next, it calculated the required air volume and wind pressure in the restriction of the trackless transport and equipment performance. The effects of harmful gases such as stratigraphic gas and automobile exhaust is fully considered in the calculation. At last, it put forward reasonable improvement measures for the field ventilation and the technical parameters of a safe and effective ventilation system. The measures improved the field construction conditions. The 5466m distance and large diameter tunnel successfully uses the single-head forced ventilation, which is of significance of the similar tunnel ventilation.