Analysis on cooling effect of new hollow concrete brick revetment under gravel pavement in permafrost regions

As a proactive cooling measure for permafrost roadbed, the hollow concrete brick revetment is a new engineering measure to control radiation and convection. The hollow brick revetment engineering test is conducted, which reveals not only the process of its cooling mechanism, but also its cooling performance. The research results suggest that 1) this new structure presents outstanding cooling performance compared with the general embankment, and the annual average temperature of sunny slope drops by about 3 °C and the shady slope by about 1.74 °C. 2) This new structure could effectively eliminate the impact of sunny-shady effect. To be specific, in general embankment sunny slopes are positive in temperature and shady slopes are negative, but the new revetment allows both sunny and shady slopes to have negative temperatures, and thus the temperature difference between sunny slope and shady slope is decreased from 2.22 °C to 0.96 °C. 3) The ground temperature would decrease further as the roadbed heat transfer is in a state of natural thermal equilibrium with the presence of the hollow block revetment. 4) The ground temperature field of the roadbed is stable and symmetrical, the permafrost table is effectively raised, and the temperature in the middle of embankment decreases by 1 °C within a year, so it can be inferred that the temperature drop in embankment is beneficial to its thermal stability in the long run, as proven by the results of the numerical simulation.

► The new hollow concrete brick revetment is suggested for Qinghai-Tibet Railway. ► This new revetment is a new measure to control radiation and convection. ► This new revetment presents outstanding cooling effect. ► This new revetment could effectively eliminate the impact of sunny-shady effect. ► Research shows this new revetment is beneficial to its thermal stability.