Pile-driving slurry sedimentation agents are particularly effective for treating high-concentration drilling and pile-driving mud wastewater. There are generally two main approaches for using sedimentation agents during the drilling process: one is to enhance lubricity, and the other is to treat the mud wastewater itself. To gain a comprehensive understanding of the use of polyacrylamide flocculants in drilling operations, let’s first examine the drilling process: As soon as drilling begins, the drilling mud must be prepared. During drilling, the circulation is positive—mud is pumped into the borehole through the drill pipe, carrying along with it the cuttings and sand from the borehole. The mud then flows out through the mud outlet in the casing into the mud pit, where it undergoes sedimentation before being pumped back into the drill pipe and re-circulated into the borehole. The primary function of the drilling mud is to form a protective mud film on the borehole wall during drilling, thereby safeguarding the wall and preventing its collapse. Therefore, the treatment of drilling mud is of paramount importance.

1. If the mud weight is too high, it can lead to mud inclusion in the pile body—especially in strata with abundant clay. When drilling progresses too rapidly or when the hole isn't thoroughly cleaned in one pass, sizable mud chunks of varying sizes tend to accumulate inside the borehole. When the mud weight is excessively high, these mud chunks may cling to the reinforcing cage or remain suspended in the mud slurry. Once concrete pouring begins, some of these mud chunks get trapped within the pile body (in severe cases, small-strain testing may reveal integrity defects in the pile). Other chunks become lodged around the reinforcing cage, causing the cage to float upward and drawing the attention of the supervisor or the owner due to quality concerns. In the most serious scenario, the entire reinforcing cage can be deformed and even jammed against the casing pipe, resulting in failure of the pile’s concrete placement. In such instances, the only options are either to re-drill the hole or discard the pile entirely! Therefore, whether a pile has been properly constructed becomes immediately apparent once the foundation excavation is completed: poorly executed piles will exhibit mud inclusion around the pile body, concrete segregation, and dry mud clumps adhering to the reinforcement bars.

2. The specific gravity of the slurry affects the initial grouting volume—higher specific gravity means a larger initial grouting volume. However, given the widespread use of ready-mixed concrete today, the initial grouting volume is no longer considered particularly important.

3. If the mud weight is too low, the borehole is prone to collapse. Therefore, before pouring, it’s generally advisable to keep the mud weight between 1.1 and 1.15. When the mud weight approaches 1.1, better sealing performance of the casing is required; otherwise, if the pouring process takes a long time, the concrete in the pile body may be adversely affected.

4. Bored piles are highly variable, and geological conditions differ from place to place. Construction management personnel must thoroughly understand the local geological soil stratigraphy in order to manage the project effectively. All parameters of the drilling mud serve merely as guidelines; specific details should be determined on-site.

Pile-driving slurry wastewater is continuously generated during the piling process. If not treated promptly, the turbid water in the recycling system will interfere with ongoing drilling operations. Simply allowing the slurry to settle on its own is too slow and cannot keep pace with the piling schedule. Only by using a rapid slurry-settling agent to accelerate the sedimentation of the slurry wastewater and promptly filtering and transporting it off-site can the issue of pile-driving wastewater treatment be effectively resolved.