Views: 0 Author: Site Editor Publish Time: 2026-02-03 Origin: Site
In pile foundation construction, the drilling process of rotary drilling rigs is susceptible to geological conditions, operational standards, and other factors, often leading to issues such as jamming and deviation. If not addressed promptly or improperly, these problems can affect construction efficiency, pile foundation quality, and even damage equipment. This article outlines the emergency handling procedures and precautions for two common issues, providing reference for on-site construction.
Drilling jamming refers to the sudden halt of the drill string during the drilling process, where normal feeding or lifting cannot be achieved. It is often caused by geological obstructions, drill string malfunctions, or improper operation. The steps to address this issue include "identifying the cause—precise intervention—resuming operations.".
First, immediately stop drilling and cut off the power supply to the equipment to prevent bending of the drill rod or motor overload caused by forced start-stop operations. Then, investigate the cause of the jam: - If due to geological factors, such as encountering boulders, hard soil layers, or underground pipelines, preliminarily assess based on resistance feedback from the drill rod and on-site geological survey data. Blind impact is strictly prohibited. - If due to drill tool failure, inspect for worn drill teeth, stuck material in the drill bit, or loose drill rod connections. Promptly remove accumulated soil and debris from the drill bit and replace damaged drill teeth. - If due to improper operation, such as excessive drilling speed or inappropriate mud slurry ratios leading to borehole collapse and drill burial, prioritize addressing the borehole stability issue.
During disposal, for hard objects such as isolated rocks, low-speed and small-feed trial drilling or replacement with alloy drill bits for crushing can be employed. Manual cleaning methods should be used to remove foreign objects when necessary. For stuck drills, adjust the mud density, inject high-quality mud to reinforce the borehole wall, then slowly lift the drill rod while gradually clearing collapsed soil inside the borehole. Violent lifting is strictly prohibited. For drill tool jamming, reverse the drill rod in conjunction with minimal feed to loosen and remove the obstructed material.
Before resuming operations, inspect the integrity of the drilling tools and the stability of the borehole wall, adjust the drilling parameters, and ensure the equipment is functioning properly before gradually restoring drilling according to the specifications.
Drill deviation refers to the condition where the borehole axis deviates from the designed axis, exceeding the permissible tolerance specified in the standards. This is often caused by uneven geological conditions, tilted drill rods, uneven force distribution on the drill bit, or borehole wall collapse. Timely correction is necessary to prevent further deviation from affecting the bearing capacity of the pile foundation.
Upon detecting a deviation in the borehole, immediately halt drilling. Measure the position and deviation value of the offset, and determine the extent and range of the deviation. If the deviation is minor (within the specified limit), corrective drilling can be employed: adjust the drill rig's level to ensure the drill rod is vertical, use low rotational speed and small feed rates, repeatedly sweep the deviated section to gradually correct the borehole axis; simultaneously adjust the mud mix ratio to enhance wall protection and prevent borehole wall collapse during the sweeping process.
If the deviation is significant, the backfill correction method should be employed: fill the hole with a mixture of clay and crushed stone, backfilling up to 1-2 meters above the offset section, compact the mixture, and then resume drilling. During the drilling process, continuously monitor the verticality of the drill rod and adjust parameters in real time. If the deviation is caused by borehole wall collapse, first reinforce the borehole wall, circulate and replace with mud, and then proceed with the correction operation after the borehole wall stabilizes.
After the deviation correction is completed, the borehole axis must be measured again. Normal drilling can only resume after confirming that the deviation meets the specified requirements. If the deviation remains uncorrected despite multiple attempts, the accuracy of the drilling rig equipment and the verticality of the drilling tools must be checked, and the machine should be stopped for maintenance if necessary.
1.During the emergency response process, an alert zone must be established at the scene, with professional personnel directing operations. Unauthorized personnel are strictly prohibited from entering to prevent safety incidents.
2. It is strictly prohibited to forcibly address stuck or deviated hole issues to avoid secondary failures such as drill pipe breakage, bit damage, and large-scale hole wall collapse.
3. Conduct geological surveys before work, familiarize with the geological conditions of the construction area, and develop emergency plans in advance. Regularly inspect drill tools and equipment accuracy, standardize operational procedures, and reduce the occurrence of two types of issues.
4. After emergency handling, records must be properly maintained, the causes of issues analyzed, subsequent construction parameters and operational standards optimized, and measures taken to prevent recurrence of similar problems.
