| Since more and more deeply buried super-long tunnels are constantly emerging with the development of economy, there is a higher demand on design of ventilation in tunnels. Economic basal area and economic wind velocity of ventilation shaft are optimal matched with civil investment, equipment investment and operation energy. Multiple ventilation shafts will be set for segment ventilation in deeply buried super-long tunnels. The changes of position or basal area of each ventilation shaft will have a serious effect on ventilation of whole tunnel. Segment longitudinal ventilation has become the mainstream ventilation mode in long tunnels. As an indispensable part of segment longitudinal ventilation system, ventilator room seems particularly important.The10km project of Daxiang Valley-Niba Mountain Tunnel, two-hole one-way traffic, is a controlling project of expressway from Ya'an to Luzhou. It has several characters such as long, deeply buried, complex topography and geomorphology and significant climate division. In order to build safe, environmental and energy saving tunnel, based on Niba Mountain super-long highway tunnel, combined with the project of key technology research on a deeply buried super-long tunnel--Daxiang Valley-Niba Mountain Tunnel (2006318000104) supported by the Chinese Western Road Construction Scientific and Technological Project, such aspects as optimization technology of ventilation shafts, optimization configuration technology of ventilator and ventilation design method of underground ventilator rooms in tunnels have been analyzed and studied systematically and thoroughly, by different research means such as data investigation, theoretical analysis, in-situ measurement, mode test, programming and numerical simulation.What this paper mainly discusses lies in the following areas:1. According to the study on ventilation shafts of tunnels, multivariate complete integrated intelligent comparison and selection method based on DTM mode and economic basal area of ventilation shafts and wind velocity optimization method for life-cycle economic benefit have been established. Optimization system of ventilation shafts in tunnels has been obtained by programming.2. Based on study on optimization configuration technology of ventilator in tunnels, design method of improving efficiency of more parallel axial flow ventilators has been established. And some design parameters such as ventaliator numbers, power ratio, installation sapce, installation height and setting length are proposed.3. According to design of underground ventilator rooms, such as partition design, determination of environmental standards, pollutants calculation method, measures to control pollutants, in normal operation needs, environmental standards in underground ventilator rooms, including pollutant concentration, noise grade, temperature and humidity, and air change numbers, have been set up with someone or unattended duty in deeply buried super-long tunnels. Calculation method of harmful gas concentration, including air transport and free diffusion, in underground ventilator rooms in normal operation mode has been established in deeply buried super-long tunnels. Pollutant concentration is a function of pollutant concentration, volume flow rate, time and volume of ventilation rooms.4. On the basis of study on calculation method of temperature and smoke flow in fire design of underground ventilation rooms, as well as safety evacuation measures, calculation method of temperature and smoke concentration of underground ventilation rooms under fire mode of in tunnels or in ventilation rooms has been established respectively. And design method of safety evacuation in underground ventilation rooms is also given.5. Considering of design method in normal operation and fire condition comprehensively, ventilation design method of underground ventilator rooms has been established.(1) According to environmental standards and pollutant concentration calculation method in underground ventilator rooms, required air volume in normal operation in condition of continuous ventilation and air change ventilation mode has been obtained. And air volume of the normal ventilation system has been also determined.(2) According to smoke exhaust requirements in fire mode, required air volume of disaster prevention system has been obtained.(3) By comparison of air volume in normal ventilation system and disaster prevention system, required air volume in underground ventilator rooms has been determined ultimately.(4) Through the calculation of residual heat and humidity, setting of air conditioning system or not and its scale has been determined.(5) Condition of equipment of ventilation system has been obtained by calculating resistance of ventilation duct and power of ventilator.(6) Safety evacuation and design safety of ventilation system have been checked by fire performance-based design of underground ventilation rooms and calculation method of temperature and smoke flow in fire mode.(7) Through recheck of foregoing parts, ventilation system of underground ventilation rooms has been established. |
