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How to solve the failure in the construction of rotary drilling rig
Release time:
2018-10-26
Author:
Source:
Rotary drilling rig is an indispensable construction equipment for building engineering into a hole, which can be used for sand, clay, silty soil and other soil construction, and is widely used in continuous, foundation reinforcement and multiple foundation construction. However, any product will be abnormal in use. Today, Xiao Bian is talking about the failure of machinery in construction. Common faults in the construction of rotary drilling rig: 1. During the perfusion process, if it is found that the mud level in the borehole casing suddenly rises and overflows the casing, then drops suddenly and bubbles appear, it should be suspected that it is a sign of hole collapse and can be detected by a sounding hammer. If the sounding hammer was originally suspended on the concrete surface and has not been taken out, it is buried and cannot be lifted up, or the sounding hammer is used for sounding
Rotary drilling rig is an indispensable construction equipment for building engineering into a hole, which can be used for sand, clay, silty soil and other soil construction, and is widely used in continuous, foundation reinforcement and multiple foundation construction. However, any product will be abnormal in use. Today, Xiao Bian is talking about the failure of machinery in construction.
Common faults in the construction of rotary drilling rig:
1. Hole collapse
During the injection process, if the mud level in the borehole casing suddenly rises and overflows the casing, then drops suddenly and bubbles appear, it should be suspected to be the sign of hole collapse, which can be detected by sounding hammer. If the sounding hammer was originally suspended on the concrete surface and is now buried and cannot be lifted up, or the sounding hammer cannot reach the original depth when detecting the concrete surface, with many differences, it can be confirmed that it is indeed a collapsed hole.
The reasons for hole collapse may be leakage around the bottom of the casing, the water level in the hole is lowered or in the tidal river, when the water level difference in the hole decreases during high tide, the original hydrostatic pressure cannot be maintained, and the hole collapse may be caused by stacking heavy objects around the casing or machine vibration.
After the collapse of the hole, the cause should be found out, and corresponding measures should be taken, such as maintaining or increasing the water head, removing heavy objects, eliminating vibration, etc., to prevent the hole from continuing to collapse, and then suck out the soil collapsed into the hole with a mud suction machine. If the hole does not continue to collapse, normal perfusion can be restored. If the hole collapse is not serious, it can be backfilled to the position above the hole collapse, and measures such as improving the mud performance, increasing the water head and burying the casing in depth can be taken to continue drilling. In case of serious hole collapse, the drilled hole shall be immediately backfilled with sand or small gravel with clay. After a period of suspension, the cause of hole collapse shall be found out and corresponding measures shall be taken to re-drill. When the hole collapse is not deep, the method of deep burying the casing can be adopted, and the soil around the casing can be tamped and re-drilled.
2. Deflection of hole body
In case of hole body deflection and bending, the reason shall be analyzed and treated. Generally, the drill cone can be hung at the deviation position to sweep the hole repeatedly to make the hole upright; if the deviation is serious, backfill the cohesive soil to the deviation position, and then drill in after the deposition is dense.
3. Reaming and shrinkage
In case of reaming and shrinkage, measures shall be taken to prevent hole collapse and excessive swing of drill cone. Shrinkage is caused by excessive wear of drill cone, untimely welding and repair, or soft soil and clay mudstone swelled by water in the stratum. For the former, timely welding and repair drill cone should be paid attention to, while for the latter, high-quality mud with low water loss rate should be used to protect the wall. When shrinkage has occurred, it is advisable to use a drill cone to repeatedly sweep the hole up and down to enlarge the hole diameter.
4. Paste drilling and buried drilling
Paste drilling and buried drilling often occur in rotary drilling and percussion drilling in the positive cycle (including submersible drilling rig). In this case, the mud consistency, the inlet and outlet of drilling slag, the inner diameter of drill pipe and the slag discharge equipment shall be checked and calculated, and the appropriate footage shall be controlled; if the drilling has been seriously burnt, the drilling shall be stopped to raise the drilling cone and remove the drilling slag.
5. Shim
Staking often occurs in percussive drilling. After sticking, it should not be forced to lift, but only lightly. When it is not moving, it can be impacted by a small impact drill cone or the drilling slag around the drill cone can be loosened by punching and suction before lifting.
6. Falling objects
When drilling and falling objects, they should be fished quickly with fishing forks, hooks, rope slings and other tools. If the falling objects have been buried by sediment, the sediment should be removed according to the above-mentioned items, so that the fishing tools can contact the falling objects before fishing.
In any case, it is strictly prohibited for construction personnel to enter the borehole without casing or other protective facilities to deal with the fault. When it is necessary to drill the casing or other protective facilities, check that there is no harmful gas in the hole, and prepare safety facilities such as anti-virus, anti-drowning, anti-collapse and burial before action.
For the new technology of rotary drilling rig construction, we also need to accumulate more experience, especially for the various problems encountered in the construction, we need to seriously summarize and analyze, to ensure that the same situation will not be at a loss. I believe that with the in-depth promotion of rotary drilling rig, we will learn more and more, deal with the problem will be more and more simple, the work will be more and more smooth.
Common faults in the construction of rotary drilling rig:
1. Hole collapse
During the injection process, if the mud level in the borehole casing suddenly rises and overflows the casing, then drops suddenly and bubbles appear, it should be suspected to be the sign of hole collapse, which can be detected by sounding hammer. If the sounding hammer was originally suspended on the concrete surface and is now buried and cannot be lifted up, or the sounding hammer cannot reach the original depth when detecting the concrete surface, with many differences, it can be confirmed that it is indeed a collapsed hole.
The reasons for hole collapse may be leakage around the bottom of the casing, the water level in the hole is lowered or in the tidal river, when the water level difference in the hole decreases during high tide, the original hydrostatic pressure cannot be maintained, and the hole collapse may be caused by stacking heavy objects around the casing or machine vibration.
After the collapse of the hole, the cause should be found out, and corresponding measures should be taken, such as maintaining or increasing the water head, removing heavy objects, eliminating vibration, etc., to prevent the hole from continuing to collapse, and then suck out the soil collapsed into the hole with a mud suction machine. If the hole does not continue to collapse, normal perfusion can be restored. If the hole collapse is not serious, it can be backfilled to the position above the hole collapse, and measures such as improving the mud performance, increasing the water head and burying the casing in depth can be taken to continue drilling. In case of serious hole collapse, the drilled hole shall be immediately backfilled with sand or small gravel with clay. After a period of suspension, the cause of hole collapse shall be found out and corresponding measures shall be taken to re-drill. When the hole collapse is not deep, the method of deep burying the casing can be adopted, and the soil around the casing can be tamped and re-drilled.
2. Deflection of hole body
In case of hole body deflection and bending, the reason shall be analyzed and treated. Generally, the drill cone can be hung at the deviation position to sweep the hole repeatedly to make the hole upright; if the deviation is serious, backfill the cohesive soil to the deviation position, and then drill in after the deposition is dense.
3. Reaming and shrinkage
In case of reaming and shrinkage, measures shall be taken to prevent hole collapse and excessive swing of drill cone. Shrinkage is caused by excessive wear of drill cone, untimely welding and repair, or soft soil and clay mudstone swelled by water in the stratum. For the former, timely welding and repair drill cone should be paid attention to, while for the latter, high-quality mud with low water loss rate should be used to protect the wall. When shrinkage has occurred, it is advisable to use a drill cone to repeatedly sweep the hole up and down to enlarge the hole diameter.
4. Paste drilling and buried drilling
Paste drilling and buried drilling often occur in rotary drilling and percussion drilling in the positive cycle (including submersible drilling rig). In this case, the mud consistency, the inlet and outlet of drilling slag, the inner diameter of drill pipe and the slag discharge equipment shall be checked and calculated, and the appropriate footage shall be controlled; if the drilling has been seriously burnt, the drilling shall be stopped to raise the drilling cone and remove the drilling slag.
5. Shim
Staking often occurs in percussive drilling. After sticking, it should not be forced to lift, but only lightly. When it is not moving, it can be impacted by a small impact drill cone or the drilling slag around the drill cone can be loosened by punching and suction before lifting.
6. Falling objects
When drilling and falling objects, they should be fished quickly with fishing forks, hooks, rope slings and other tools. If the falling objects have been buried by sediment, the sediment should be removed according to the above-mentioned items, so that the fishing tools can contact the falling objects before fishing.
In any case, it is strictly prohibited for construction personnel to enter the borehole without casing or other protective facilities to deal with the fault. When it is necessary to drill the casing or other protective facilities, check that there is no harmful gas in the hole, and prepare safety facilities such as anti-virus, anti-drowning, anti-collapse and burial before action.
For the new technology of rotary drilling rig construction, we also need to accumulate more experience, especially for the various problems encountered in the construction, we need to seriously summarize and analyze, to ensure that the same situation will not be at a loss. I believe that with the in-depth promotion of rotary drilling rig, we will learn more and more, deal with the problem will be more and more simple, the work will be more and more smooth.
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