How to handle center deviation of bored piles?
1. Quality problem and phenomenon: After breaking off the pile head, a deviation between the center of the bored pile and the design requirement is found through survey setting-out inspection.
2. Cause analysis
1) There is an error in pile position setting-out.
2) The shape of the casing does not meet requirements or deviation occurs during embedding.
3) The positioning of the reinforcement cage is inaccurate.
3. Preventive measures
1) Carefully recheck during pile position setting-out, set up straddle-type control stakes and take certain protective measures so as to accurately determine the drill bit center and accurately position the reinforcement cage.
2) The shape of the casing shall meet requirements, and the backfill around it during embedding shall be compacted to prevent movement during drilling.
3) The reinforcement cage shall be positioned accurately and fixed firmly, and concrete may be poured only after rechecking confirms no error.