Research On Application Of EPS Thermal Insulation Material For Perennial Permaforst Roadbed Project In Qinghai-Tibet Plateau

With the development of west of China being advanced and the basic facilities at the core of traffic project being built, more and more roadbed will be built in frozen earth area. The continual freezing and expanding, melting and submerging and melting and sinking of roadbed are the main problem on the building and maintaining of road in frozen earth area. In view of the problem of roadbed frozen disaster, some engineers have made many studies of the characteristics of the roadbed freezing and expanding, melting and submerging and temperature field. They have raised all kinds of engineering steps on roadbed against frozen disaster, For example, adopting the reasonable height of roadbed , building ventilative embankment, setting up the defense, burying hot metal stick, making use of stone to protect slope and laying thermal insulation and heat insulation material etc, Laying EPS is one of these special steps. These steps make the temperature field of roadbed stable and solve the problems of roadbed frozen disaster to some extent. However, under the different conditions of climate, hydrogeology and engineering geology, all of above-mentioned steps aren't reliable in technology and reasonable in economy. Aiming at the frozen disaster of roadbed at special frozen earth area, it is necessary for us to make deep-going study on the steps about roadbed against frozen disaster.According to the domestic and foreign related to achievement of study, I have studied the application of EPS thermal insulation material on frozen earth roadbed in Qinghai-Tibet plateau. First, I have carried out laboratory text analysis on EPS, roadbed soil layer and embankment packing, combining with present relevant domestic and foreign scientific research achievement, I defined every characteristic parameter. From experimental result, I preliminarily know that EPS is good thermal insulation material because the absorption of water is low and heat insulation is good, It is practicable at preserving temperature field of frozen earth roadbed and bringing frozen disaster under control; Second, according to the analysis of the EPS that is applied into practical project, I have studied the practical effect which EPS preserve roadbed temperature field, and the influence that was made after building field. I have get that EPS can influence moisture content and frozen upper limit, Through practical measuring data, I have studied freezing and expanding quantity and melting and submerging quantity during a completefrozen and melting cycle as well as have expanded and proved the practical application effect of EPS with some reference significance to deep research of some connected problems. Finally, through computer data analysis, setting up the analytical model of finite unit, I have simulated the temperature field of roadbed heat preservation, then expounded and proved that the height of embankment influenced the effect of thermal insulation material. This paper finally reasoned that EPS is practical and effective in the frozen earth roadbed project and raised the disadvantages during research and some problems that should be noticed in order that EPS can be made full use of insulating heat.