UHPC-NC COMPOSITE PILE FOUNDATION AND CONSTRUCTION METHOD THEREFOR FOR POWER TRANSMISSION TOWER IN SALINE-ALKALI AREA

摘要

The present invention relates to the field of power transmission line tower foundations. Disclosed are an ultra-high performance reactive powder concrete (UHPC)-normal concrete (NC) composite pile foundation and a pile forming method therefor, which are applicable to strongly corrosive salinized soil areas or geological condition areas with obvious dry-wet and freeze-thaw alternate action. The foundation comprises: a foundation main pile penetrating through a soil layer to a supporting layer, and a prefabricated UHPC outer sleeve, wherein the portion, below the bottom of the UHPC outer sleeve, of the foundation main pile is of a columnar structure, and the outer side surface of a section in contact with the sleeve changes along with the shape of the inner wall of the sleeve. Compared with the conventional anti-corrosion measures, under the same geological conditions and the same external load effect and on the basis of excellent material performance of UHPC, the UHPC-NC composite pile foundation has the advantages that the corrosion resistance of the power transmission tower foundation in a saline-alkali area is greatly improved, and the initial construction cost and the whole-life maintenance cost are greatly reduced. The prefabricated sleeve is combined with a dry operation method of bored (digged) cast-in-place pile construction method, so as to ensure that the quality of a pile body is good, residents are not disturbed during construction, and environmental hazards are small.