Method for improving frozen stability of highway subgrade in seasonal frozen region

Abstract

The invention discloses a method for improving the frozen stability of a highway subgrade in a seasonal frozen region. According to the method, double subgrade isolating layers (namely an upper isolating layer and a lower isolating layer) of the subgrade is adopted, wherein the lower isolating layer is used for isolating capillary water under the maximal highway frozen depth for many years and reducing ice gathering amount of a subgrade soil body to the utmost extent; meanwhile, the upper isolating layer is used for isolating pavement water seepage at the top of the subgrade and draining water horizontally; the upper isolating layer and the lower isolating layer act together to realize a long-term stability purpose of the subgrade. By the adoption of the double-isolating-layer technology, water stability and the frozen stability of the subgrade can be well effectively ensured, so that deficiencies in the design of highways in cold areas in China can be made up.

Description

Technical field: [0001] The invention relates to a method for improving the freezing stability of road subgrades in seasonally frozen regions. Background technique: [0002] Permafrost is widely distributed in my country. The permafrost area is 2.15 million square kilometers, and the seasonal frozen soil area is 5.137 million square kilometers. The sum of the two accounts for about 75% of the country's land area. Most areas in northern my country are seasonally frozen areas. In winter, as the atmospheric temperature drops, the soil freezes when the soil temperature drops to the crystallization point of the pore water in the ground-air heat exchange process. Ice crystals will appear in soil pore water and migrated water from external water sources. Under the influence of negative temperature difference, moisture moves upward to form ice accumulating layer. Under the condition of water supply, the accumulating ice layer will continue to thicken, causing the volume of the soil...

AI Technical Summary

Problems solved by technology

[0007] 1. Although the setting of the cushion layer can reduce the possibility of groundwater being transported into the pavement structure, there will still be a significant increase in water content in the roadbed, and the maximum freezing depth generally exceeds the depth of the cushion layer. Under the influence of comprehensive freezing and thawing, Causes the softening and unevenness of the pavement foundation, resulting in a large number of diseases

[0008] 2. At present, the cushion is mostly made of granular materials, such as gravel or gravel, which are directly paved on the roadbed. Under the action of the increase in water content and the weight of the vehicle, the roadbed soil will pollute the gravel cushion, and the final result is similar to The structure of mud-bound gravel, which seriously reduces the function of the cushion

That is to say, there may be a possibility that part of the surface water seeps into the subgrade, and the existing gravel cushion cannot prevent this part of the water from seeping into the subgrade

Images