A method for reducing the temperature of permafrost and preventing water collection into foundation pits in permafrost regions

Abstract

The invention relates to a method for cooling peripheral frozen earth and preventing water catchment in an excavation pit for a permafrost region. The method is characterized in that a pit slot is excavated at a position which is 0.5-5 m far away from the rim of the designed pit; the slot depth is a depth being 0-100 cm below underground permafrost table; a cooling pipe is paved at the bottom of the pit slot; a waterproof film is paved on the cooling pipe, the bottom of the slot, and the wall of the pit to a ground surface, and refilled and punned with filled earth; and the cooling pipe injected with circular freezing liquid is connected with a refrigerator on the ground surface through a hose. Shown by practices, with the adoption of the method provided by the invention, the problems of melting and stability loss of the frozen earth and the frozen earth in the excavation pit in a warms-season construction process and water leakage and water collection of underground water can be solved through the effective combination of refrigeration and water insulation, so that the permafrost stability can be effectively protected, and the normal construction and the long-term stability of the Qinghai-Tibet direct-current networking engineering in the permafrost region can be ensured.

Description

technical field [0001] The invention relates to a method for excavating foundation pits of frozen soil and preventing groundwater during the excavation process of engineering building foundation pits in warm seasons in permafrost regions. Background technique [0002] my country's permafrost covers an area of ​​about 2.15 million square kilometers, accounting for about 22% of the country's land area, ranking third in the world. It is mainly distributed in the Qinghai-Tibet Plateau, Northeast China, Xiaoxing'an Mountains, Tianshan Mountains, and Altai Mountains. With the continuous acceleration of national economic construction, the construction of major national projects such as Qinghai-Tibet Highway, Qinghai-Tibet Railway, Qinghai-Tibet Power Transmission Line, Northeast Harbin-Dalian Expressway, and Sino-Russian Oil Pipeline are constantly being carried out in these special areas. During the construction of these projects, especially the construction of major transmission ...

AI Technical Summary

Problems solved by technology

After the excavation of the foundation pit, it is very easy to cause a large amount of water gushing, the melting of permafrost, and the collapse of the foundation pit

Therefore, construction in warm seasons is not only more difficult to isolate groundwater, but also causes more serious consequences due to water gushing.

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