The project is located in Shanwei City, Guangdong Province, entrusted by Lufeng Baolihua New Energy Power Co., Ltd., our company undertook the pile foundation construction of the project including 80 bored piles with a diameter of 1000 mm and 80 high-pressure rotary piles with a diameter of 700 mm. The pouring pile is a rock-embedded pile, the concrete strength grade is C30, the design requires embedding in the moderately weathered rock layer, and the depth is not less than 1D, and the pile length is not less than 15 m. The effective diameter of the high-pressure rotary piles is 700 mm, the effective pile length is not less than 9 m, and the pile bottom elevation is satisfied to reach the strongly weathered granite surface.
The work content of this project contract mainly includes the surveying and setting out of the bored piles, the burial of the casing, the preparation of slurry, drilling, the production and placement of the steel cage, the clearing of the holes, the pouring of concrete, the surveying and setting out of the high-pressure rotary spray piles, the positioning of the drilling rig, the high-pressure rotary spraying operation, the cleaning of the appliances, and the collection of the pile foundation completion data. Construction started on October 29, 2021 and completed on January 10, 2022, taking 74 calendar days, meeting the requirement of 80 calendar days of the contract.
For this project due to the upper layer of backfill contains construction waste and stones, causing some of the rotary pile construction difficulties, before construction, we leveled the site ground, removed the obstacles on the surface of the location of the pile, before the construction of high-pressure rotary pile, the use of pilot hole machine in the original pile location for pilot hole, pilot hole depth of not less than 9m, while ensuring that the bottom of the hole into the strongly weathered granite surface. For the problem that the pile cannot be formed due to the loss of the sprayed cement slurry before the initial setting caused by the tidal phenomenon of seawater, the slurry is prepared strictly according to the designed water-cement ratio, which is 1:1. The prepared slurry is filtered and the specific gravity of the cement slurry is 1.51kg/m³, which is randomly checked at any time to ensure the cement slurry ratio. Meanwhile, the sodium silicate mixture is injected during the grouting process to shorten the initial setting time of the cement slurry.
This project adopted punching drilling and high-pressure rotary pile construction, the construction encountered a lot of technical and construction difficulties, under the attention and strong support of the company's leadership, overcoming all difficulties, the project department staff unity, careful organization, careful construction, the successful completion of the construction task, and accumulated valuable experience.
