What is the speed requirement when pouring concrete into underwater cast-in-place piles? Who can tell us why?

Continuous perfusion is ideal, and now it is ideal to take at least time to remove the catheter and stop for a few minutes.

Reasons: ① It is difficult for the conduit to be completely waterproof in mixed water, but if the concrete is continuous, it will make up for a small amount of water leakage; ② If the concrete stays in the hole for too long, it will reach the initial setting, which will cause irreparable loss to the quality of concrete members; (3) When pouring concrete underwater, it can be poured smoothly by relying on the fresh concrete in the conduit to top the concrete buried above the depth of the conduit. If the time is too long, the concrete buried above the pipe depth will become hard and difficult to top, resulting in pipe sticking.