Composite foundation with karst landform and construction method thereof

Abstract

The invention provides a composite foundation with karst landform and a construction method thereof. The method comprises the following steps: (1) placing positioning plates in the bottom of a foundation pit with the karst landform; (2) drilling and digging down to form anchor holes in the positioning plates; (3) fixing anchor rods in the anchor holes; and (4) placing reinforcement cages in the foundation pit and pouring concrete. According to the technical scheme, through the change of the structural style of the upper foundation, the composite foundation with short piles and rock anchor rodsand the construction method, the composite foundation can be used in special geological conditions with thick covering layers and high-relief underlying bedrock surfaces, is free of influence of underground water level and hole wall stability, and is capable of effectively solving the technical problems in model selection, design and construction of power transmission line pole tower foundationsin mountainous areas in the west of Guangdong.

Description

technical field [0001] The invention relates to a composite foundation suitable for karst landforms, in particular to a composite foundation for karst landforms and a construction method. Background technique [0002] The tower foundation of the transmission line mainly bears the uplift load. The anchor foundation is a foundation type that uses the reinforcement anchored into the bedrock surface to bear the uplift load. It has small openings, low concrete consumption, strong environmental protection, and pullout resistance. It has excellent bearing performance and other characteristics, so it is widely used in transmission line projects in mountainous areas of our country. The transmission line corridors in mountainous areas in the western part of Guangdong generally have special geological conditions where the overlying 5-7 thick overburden layer has a large undulation of bedrock. In order to achieve the designed pile depth, it is necessary to excavate or blast the bedrock...

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Problems solved by technology

However, the karst landforms in western Guangdong often have uneven bedrock surfaces and large fluctuations. If the construction process of drilling first and then excavating is adopted, the accurate positioning of the anchor holes on the bedrock surface cannot be guaranteed; at the same time, the upper part of the technology mentioned in this patent The structure is a bottom expansion foundation with an expansion head at the bottom. This structure type is suitable for geological conditions where there is no groundwater and the shallow soil is relatively stable. For the western Guangdong area, the annual rainfall is large, the groundwater level is high, and the covering layer is thick (5- 7m) geological conditions, if the superstructure adopts the expanded foundation with expanding head at the bottom, it will often lead to the tower of the foundation pit, which will affect the construction quality and personnel safety

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