How To Prevent And Solve The Collapse Hole Accident

The construction of bored pile is mostly carried out in quaternary loose strata, so collapse is the most common accident in the construction of bored pile

1. Signs before an accident

Slump hole and shrinkage hole occur in drilling construction, generally speaking, it does not happen suddenly. There were some signs before it happened.

If the water level in the protection cylinder drops abruptly: there is mud at the protection cylinder; In the process of drilling, the rotary resistance of drilling tool increases. The proportion of mud increases (it is not easy to detect when rotary drilling).

2. Preventive measures:

(1) In addition to the clay layer, other strata should be drilled with mud wall protection.

(2) The protective cylinder should be buried in the stratum suitable for the placement of the protective cylinder, and the surrounding area should be tamped with viscose, and the buried position should be concentric with the hole position.

(3) When drilling loose silt layer, the footage speed should be properly controlled, if the "fast through" is bound to backfire.

(4) After the final hole, when preparing for the injection of concrete, sufficient water supply should still be ensured.

(5) The outer diameter of the drill is not less than the design pile diameter, and the drill diameter should be regularly checked to prevent shrinkage.

(6) Once the slump hole is found, the drilling should be immediately temporarily stopped, and the location of the slump hole section should be timely processed to ensure the safety of personnel and machinery.

3. Conclusion: In the construction process of rotary drilling rig, no matter what problems encountered, the first time to find out the cause, in the case of ensuring safety to solve.