Buried Drilling Bucket Phenomenon

Buried drilling bucket phenomenon: the drill bucket is buried by rocks or sediments falling from the collapsed hole and cannot be lifted or rotated.

1. Analysis of the reasons for buried drilling bucket

Construction process issues

For high groundwater level and loose geology such as sand layer, gravel layer, sand egg layer, backfill soil, etc., mud static pressure or casing hole forming technology should be used; if dry hole forming technology is used, the loose ground will collapse instantly bury.

Poor mud quality

If the mud is not prepared according to the hydrological and rock-soil conditions, the insufficient retaining wall will cause the hole to collapse, and the drill bucket will be buried in the hole by the rock and soil falling from the collapsed hole.

Insufficient mud level

If the mud level is low, the support of the mud pressure on the hole wall will be lost or reduced, especially if the position around the casing is prone to collapse.

Clearing sediment buried drilling bucket

The mud quality is poor, the sand content is high, and the hole has been parked for a long time, resulting in a large amount of sediment at the bottom of the hole, and the sediment needs to be cleaned.

Equipment failure

The drilling rig fails, causing the drill bucket to stay in the hole for too long, the quality of the mud is poor, the hole is partially collapsed, or the sand-containing settlement in the mud will bury the drill bucket at the bottom of the hole.

2. Measures to prevent buried drilling bucket

Construction technology

There are four major technologies of rotary excavation construction: dry hole forming, mud static pressure, casing, and concrete wall protection technology, four technologies can be selected according to hydrology and rock and soil conditions which can be used singly or in combination. As long as the purpose of ensuring construction safety, construction quality, improving efficiency, energy savings, and environmental protection is achieved.

Mud quality

Adjusting the corresponding mud specific gravity and viscosity according to hydrology and rock and soil conditions can greatly reduce the probability of collapsed holes and buried drilling buckets.

Mud liquid level

Maintaining the highest mud level can maintain the mud pressure, support the hole wall, and reduce the probability of hole collapse and buried drilling bucket.

Clear sediment

When clearing a thick sediment layer, monitor the drilling depth of the single bucket through the display, and drill down to the bottom of the hole (the main coil wire rope is loose) with a footage of 1 m to prevent buried drilling bucket due to the light sediment load and excessive footage in a single bucket.

Equipment maintenance

Daily inspection, weekly inspection, monthly inspection, manual inspection, visual inspection, regular inspection of equipment on time.

Maintenance: Regular maintenance of equipment on time can reduce equipment failure.

Drilling tool selection

According to the hydrology and geotechnical conditions, the drill bit is selected to reduce the drilling load, ensure the quality of the hole, and protect the components.

3. Buried drilling bucket solution

Clean up the sediment

To clean up the buried drill bucket caused by the sediment, first understand the type of sediment. If the sediment is sand or soil with small particles, you can use the mud positive circulation punching method or gas lift reverse circulation to remove the sediment and use the mud specific gravity and viscosity. Suspend the sediment and bring it out of the hole, remove the buried drill sediment, and lift the drill bucket out of the hole; if the sediment particles are large, reverse circulation drilling rigs can also be used to pump the sediment.

Diver impact drill

No sediment or clear the sediment to the top of the drill bucket. The top plate of the drill bucket can also be detected by using the measuring rope and pendant, but the drill bucket still cannot be lifted and rotated. The diver can remove the drill pipe pin. Then use the impact hammer to wash away the bottom hole bucket.

Manual digging

The muck buried in the collapsed hole contains large boulders, pebbles, and even large stones.