Composite ventilating and cold energy gathering roadbed

Abstract

The composite ventilating cold collecting road bed has the embankment structure comprising one tamped grit layer on tamped natural surface, one penetrating horizontal broken stone layer on the grit layer, concrete slab with longitudinal ventilation holes spread on the horizontal broken stone layer with the ventilation holes being perpendicular to the road bed orientation, and tamped soil refilling on the concrete slab. The combination of crushed stone layer and ventilating concrete slab has fast heat exchange of the ventilating holes with outside air natural convection temperature lowering effect of broken stones and thus can disperse heat at most in summer and block the heat transfer to inside the road bed in summer to lower the temperature of frozen earth below road bed and avoid the damage of the road bed caused by repeated freezing and thawing.

Description

technical field [0001] The invention relates to a road structure, in particular to a composite ventilation and cooling roadbed. It can effectively reduce the temperature of the frozen soil at the lower part of the roadbed, raise the upper limit of the frozen soil, and improve the stability of the frozen soil roadbed. Background technique [0002] In the permafrost region of the Qinghai-Tibet Plateau, due to repeated freeze-thaw effects, many special natural geological phenomena have occurred in the permafrost region, such as frost heave, thaw settlement, freeze pull, freeze-thaw sorting, etc., which have a great impact on the project. influences. Statistical research shows that the main engineering diseases in permafrost regions come from thawing and frost heaving. At present, the Qinghai-Tibet Railway (Golmud-Lhasa section) under construction is the plateau railway with the highest altitude and the longest mileage in the world. It traverses about 632 kilometers of permafr...

AI Technical Summary

Problems solved by technology

This measure utilizes the natural convection cooling effect of the porous medium to cool down the lower soil. However, due to the poor integrity of the loose block (broken) stone body, it is difficult to guarantee the mechanical stability, and it is easy to deform under the action of external forces such as locomotives. even collapsed

In the construction of the Qinghai-Tibet Railway, my country has adopted a subgrade structure in which a certain thickness of soil is added to the top of the block (crushed) stone layer. This structure can ensure the overall stability of the subgrade, but the impact of the upper soil layer on the embankment not only reduces The contact area between the block (crushed) stone layer and the air, and the temperature difference between the top and the bottom of the block (crushed) stone layer becomes smaller, which leads to the weakening of the natural convection effect in the block (crushed) stone layer, or even disappears, which cannot effectively dissipate the outside air. The cold energy is transferred to the permafrost below the embankment

Therefore, in high temperature permafrost areas, it is quite difficult to use these existing technologies alone to protect the lower permafrost and ensure the stability of the subgrade.

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