A treatment method for expressway subgrade in permafrost regions

Abstract

The invention discloses a method for treating a subgrade of a highway in a frozen soil region. The method comprises the following steps: a, thawing a frozen soil subgrade in a frost line in advance; b, excavating all thawed soil; c, laying a layer of coarse-grained soil and a reversed filter layer at the bottom of an excavation layer, and laying lime waterproof layers and gravel expansion guide layers on two sides; d, filling activated magnesia carbonized and cured sludge soil layer by layer and performing tamping reinforcement; e, compacting filled embankment filling soil and setting a coarse-grained soil layer containing an XPS insulation board below a pavement structure; f, setting waterproof protecting feet on two sides of an embankment respectively. Subgrade pre-thawing, filling treatment and soft soil carbonization and curing technologies for the frozen soil region are fully combined, the frozen soil subgrade is effectively reinforced, the engineering problems of refreezing and frost heaving of subgrade soil are well solved, non-uniform settling of the subgrade is further reduced, and the problem of secondary damage of the highway in the cold region is reduced greatly. The method has the advantages of being economic, environmentally friendly, safe, efficient, high in controllability, easy to operate and the like.

Description

technical field [0001] The invention relates to the fields of geotechnical engineering and road engineering, in particular to a treatment method for expressway subgrades in permafrost areas. Background technique [0002] China is the third largest frozen country in the world. Its permafrost area accounts for about 22.3% of the country's land area, while the seasonal frozen soil area accounts for about 53.5%. It has had a significant impact on my country's transportation infrastructure. In recent years, with the development of the economy in cold regions, the requirements for transportation and infrastructure construction in permafrost regions have gradually increased, and the railway and ordinary road networks have been unable to carry the existing transportation volume; at the same time, in order to protect precious and Fragile ecosphere, reducing human damage as much as possible, closed highway is the best choice. However, the construction of expressways in permafrost are...

AI Technical Summary

Problems solved by technology

[0004] The replacement and filling method is easy to construct and has a wide range of applications, but it is difficult to eliminate or reasonably control the frost heave deformation of the subgrade, and it needs to be replaced within all or part of the freezing depth, which requires high fillers

Coarse particles are often used as fillers in frozen soil subgrades, but actual engineering shows that they can only reduce frost heaving of subgrade soil, and at the same time, water migration may occur; after repeated freezing and thawing, the water content of coarse particle fillings will increase, thereby inducing frost heaving of subgrades , muddying, cracking, subsidence and other diseases will pose a certain threat to the durability and stability of the road

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