Cofferdam construction method with grooves milled through limited hole forming of percussion drill combined with steel sheet piles

Abstract

The invention discloses a cofferdam construction method with grooves milled through limited hole forming of a percussion drill combined with steel sheet piles. The cofferdam construction method is characterized in that a steel trestle platform and main bridge steel pile casings are used as supports, limited hole forming is performed through the percussion drill according to the plane position of a cofferdam, through two times of limited hole forming in staggered positions, milled grooves used for fixing the steel sheet piles are formed in a river bed with a rock face according to the plane position of the cofferdam, and the steel sheet piles are driven to be inserted in the milled grooves one by one to form the steel sheet cofferdam; the milled grooves are compactly filled with bagged clay on the outer side of the steel sheet pile cofferdam; finally, bottom sealing concrete is poured to the inner side of the steel sheet pile cofferdam for sealing the bottom and stopping water. According to the method, under the construction conditions of swift water flow, constructors do not need to block gaps between the cofferdam and the rock face of the river bed through underwater operation, potential safety hazards caused by the situation that the operators perform underwater blasting on river bed rock are avoided, and construction safety is improved.

Description

technical field [0001] The invention relates to a construction method of a cofferdam, more specifically a cofferdam construction under the conditions of rapid water flow, no coverage of the river bed, large rock surface fluctuations, and underwater pier caps below the river bed rock surface method. Background technique [0002] In engineering construction, when the cap is located below the river bed of the rock surface, the conventional method is to use casings, double-wall steel cofferdams, and concrete caissons to form a closed cofferdam in the construction area, and pour concrete at the bottom of the river inside the cofferdam. After condensation, drain the water to ensure that the cofferdam area is basically dry, so as to ensure the normal construction of the cap. [0003] The Yanguoxia Yellow River Bridge in Yongjing County, Gansu Province is located 700m downstream of the dam of the Yanguoxia Hydropower Station. Since the construction period was in summer, the flood d...

AI Technical Summary

Problems solved by technology

[0003] The Yanguoxia Yellow River Bridge in Yongjing County, Gansu Province is located 700m downstream of the dam of the Yanguoxia Hydropower Station. Since the construction period was in summer, the flood discharge flow of the hydropower station reached 6.5m / s rapidly. Years of erosion caused the riverbed at the 4# and 5# water piers of the bridge There is no covering layer on the surface, the strength of medium weathered sandstone is up to 800Kpa, and the bedrock surface has large undulations. It is difficult to seal the bottom of the concrete with the traditional cofferdam construction method, and the overall cofferdam is difficult to locate under the impact of torrent water. Regardless of the blasting technology or the vibration caused by the mechanical excavation of the breaking hammer, the bottom cover concrete will crack. In addition to the erosion of the torrent water, the conventional cofferdam method cannot achieve the effect of water sealing, and the safety of the workers cannot be guaranteed, so it cannot be satisfied. construction needs

[0004] Under the environmental conditions of rapid water flow, no cover layer on the river bed, large rock surface fluctuations, and caps buried below the river bed surface, there is no public report on the use of traditional cofferdam construction.

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