The Research Of The Impact Of Ventilation System On Underground Cave Dwellings' Structural Performance

The underground cave dwellings locate on the Loess Plateau in western of Henan Province are unique and special. They are warm in winter and cool in summer, and have a series of advantages, such as low cost, aseismic and long service period. They stand for the wisdom and diligent of China's working people for thousands of years. They are a model of man and nature lived in harmony.However, the underground cave dwellings still have some problems, so that the traditional culture houses are slowly disappearing. The lack of Ventilation is one of the main reasons, meanwhile it also produces a series of problems against human habitation, such as moisture, mold, high concentrations of air pollutants and so on. This paper proposed a set of new ventilation system to solve these problems, to improve the comfort and make these green buildings continue to develop forever. This new cave ventilation system improved the effect of ventilation significantly under the prerequisite of the structural safety. With the support of national "11th five-year plan" technology plan (subject number:2006BAJ04A02-01), this paper made the following research:1. According to the concept and working principles of displacement ventilation, formulated the possibility and favorable factors of displacement ventilation with the underground cave dwellings, draw forth the ideas and methods of displacement ventilation in the underground cave dwellings, and proved that this system can get a good ventilation effect using the calculation method.2. This paper structured a reasonable displacement ventilation system in the underground cave dwellings and described the size of it in detail. The ventilation system had several advantages:high efficiency ventilation; prevent dust and rain water fall into; use of safety; maintenance easy and washable; durable and low cost.3. This paper described the installation process of the displacement ventilation systems with the underground cave dwellings specifically. To improve construction efficiency and construction quality, this paper presented a new type small vertical portal construction tool of cave thick layer, which was cylinder shovel. This tool was flexible, easy to use, strong and solid.4. This paper calculated the structure performance of underground cave dwellings using the numerical analysis method. Analyzed and compared the maximum shear stress of several groups programs, and refered to several other stress components according to the Mohr-Coulomb failure theory that the destruction of all the soil was shear failure. In order to advantage the analysis and comparison, this paper proposed a concept of modular cave. The conclusions were as follows:the 160mm hole of the displacement ventilation system for the underground cave dwellings was safe, which couldn't threaten the security of the structure.