A temperature control structure suitable for subgrade and slope engineering in permafrost regions

Abstract

The invention relates to a temperature control structure suitable for subgrade and slope engineering in permafrost regions. The temperature control structure includes a pebble layer, a diatomite layer, an inner water-repelling layer, a bottom surface layer, an outer water-repelling layer and a drain pipe. The bottom surface layer is arranged on the subgrade in the permafrost region, the bottom surface layer is provided with the inner water-resisting layer and the outer water-resisting layer; In contact with each other; the space formed by connecting the inner water-repelling layer, the bottom surface layer and the outer water-repelling layer is filled with the diatomite layer, and the top surface of the diatomite layer is provided with the pebble layer ; A part of the drain pipe is obliquely inserted into the bottom of the diatomite layer through the outer water-resisting layer, and the other part is placed in the atmospheric environment. The invention has the characteristics of operability and durability for large-scale mechanical construction.

Description

technical field [0001] The invention relates to the field of frozen soil engineering, in particular to a temperature control structure suitable for subgrade and slope engineering in permafrost regions. Background technique [0002] Frozen soil is a soil body whose temperature is equal to or below zero and contains ice. Permafrost is widely distributed in the world, accounting for about 50% of the total land area. Among them, my country's permafrost area accounts for about 22.4% of the country's land area, mainly distributed in the northeastern part, western high mountainous area and Qinghai-Tibet Plateau. Engineering structures such as subgrades constructed in permafrost areas change the heat exchange conditions between the underlying permafrost and the atmosphere and the soil around the structures, causing the permafrost around the subgrades and other engineering structures to melt and sink year by year , seriously affecting the safe use of roadbeds and other engineering ...

AI Technical Summary

Problems solved by technology

[0004] However, the main problems in the current common roadbed temperature control measures are as follows: (1) Heat pipes are installed on both sides of the roadbed in the form of point-shaped heat pipes, and a single heat pipe only cools the soil within a certain range around it. The roadbed of the heat pipe often has through longitudinal cracks on the surface of the asphalt pavement, and the pavement is prone to waves, which seriously reduces the smoothness of the pavement

(2) Ventilation pipe subgrade The ventilation pipe is constructed in the subgrade body. The diameter of the ventilation pipe is often large. Large-scale mechanical compaction is used, which leads to uncontrollable soil engineering quality of the ventilation pipe layer. In the later use process, engineering diseases such as uneven settlement of the road surface and large-scale cracks on the road surface often occur, and the ventilation pipe is prone to dislocation, blockage, Fractures and other problems eventually lead to failure of ventilation pipes, further aggravating engineering diseases of permafrost subgrades

(3) The block stone subgrade has less restrictions on mechanized construction, but the special climate environment of the Qinghai-Tibet Plateau with high radiation and large temperature difference between day and night makes the weathering of rocks very strong. There are different degrees of weathering and fragmentation, and the formed rock debris blocks the pores in the block stone layer of the roadbed, seriously affecting the effective work of the block stone layer, and the weathered block stone layer leads to uneven settlement of the roadbed

(4) Similarly, gravel slope protection is also faced with the failure of the engineering measures due to rock weathering

(5) The water grid proposed in the patent CN 109695188 A can only be used in new roadbed projects, and cannot be used in existing roadbed engineering disease control projects; at the same time, the hard insulation board with water storage grids is not used in the construction process. It is impossible to use large machinery to compact the roadbed soil, leaving a huge hidden danger for the uneven settlement of the roadbed after the construction of the roadbed is completed

(6) The preparation process of the subgrade soil material proposed in the patent CN 110510899 A is complicated, especially the porous materials such as diatomite need to be heated to 90-120°C for drying, and then the porous materials such as diatomite are placed in the phase change agent Stir and mix for 3-4 hours, and finally place it on filter paper and dry it at 40-50°C. In permafrost regions such as the Qinghai-Tibet Plateau, where the environment is harsh, the above-mentioned treatment of diatomite at the level of engineering use is completely unavailable in engineering construction. Feasibility; and although the porous soil material applied in the subgrade body has absorbed a specific phase change agent, as the service life of the project increases, the phase change agent is easily replaced by water, resulting in frost heave of the subgrade in cold seasons. Thawing occurs in the warm season, seriously affecting the stability of the subgrade and causing greater engineering damage

For slopes in permafrost regions, engineering measures such as increasing the amount of excavation to reduce the slope and constructing support structures are often adopted. In the case of landslides, earth and rocks can only be excavated elsewhere for filling. These engineering measures have not fundamentally solved the problems of slope instability, sliding and landslides caused by the degradation of permafrost below the slope surface.

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