Construction method for large-diameter ultra-deep rock borehole bottom-expanding filling pile

Abstract

The invention discloses a construction method for a large-diameter ultra-deep rock borehole bottom expansion grouting pile, which comprises the following steps: (a) first preparing a plurality of steel plates; (b) forming and expanding holes for piles; (c) preparing a steel skeleton; (d) hoisting of the steel frame; (e) secondary cleaning of the hole by air lift reverse circulation; (f) acceptance of the hole depth, hole diameter, and sediment at the bottom of the hole, if unqualified, continue to clean the hole until it is qualified; (g) carry out initial irrigation After the initial pouring is completed, remove the funnel and insert the discharge port of the pump truck directly into the conduit for pouring until the predetermined elevation is reached. During the concrete pouring process, it must always be ensured that the depth of the lower opening of the conduit is 2-6m in the concrete. Adopting the method of the invention ensures the verticality of the pile body and the pore-forming efficiency of the pile body in the weak soil layer during construction, and in addition, reuses the construction wall mud to ensure the project quality and obtain good energy-saving and environmental protection benefits.

Description

technical field [0001] The invention relates to a construction method of cast-in-situ piles, in particular to a construction method of large-diameter ultra-deep rock boreholes and bottom-expanding cast-in-place piles. Background technique [0002] At present, the pile diameter of ordinary bored piles is 600-1200mm, and the pile length is 20-50m. It is mainly suitable for general clay, sandy soil, gravel soil and other soil layers. widely used in. [0003] If the construction of large-diameter ultra-deep rock drilling bottom expansion grouting piles adopts conventional construction methods: bury steel casings, the depth is not less than 1 to 1.5 meters, and use positive circulation (pile depth below 30 meters) or reverse circulation (pile depth 30~ 50 meters) to form a hole, clear the hole, put in a steel cage, and pour concrete. This conventional construction method cannot solve the problem of difficult drilling into the complex bottom layer through the pebble layer (maxim...

AI Technical Summary

Problems solved by technology

This conventional construction method cannot solve the problem of difficult drilling into the complex bottom layer through the pebble layer (maximum thickness 14m), boulder layer (maximum thickness 1.8m), moderately weathered and slightly weathered granite, etc. The problem of secondary crushing, especially the major problem of verticality control of the granite joint surface with large slope (maximum slope 73.2°), and the production of ultra-deep cast-in-situ pile steel casing, the docking and correction problems in sinking, and It will not be able to guarantee the requirements of project quality, construction period, safety, civilized construction and environmental protection. According to the latest search, there are only 5 domestic documents related to this type of pile foundation. There is no relevant literature report on the construction technology of bored expansion and controlled cast-in-situ piles