帷幕灌浆是抽水蓄能工程防渗加固的常用手段,注入率是帷幕灌浆的重要监测参数,直接影响灌浆的质量。注入率的波动段是灌浆施工过程中的关键阶段。目前对注入率过程监测数据的挖掘研究较少,灌浆中的合理注入率缺乏科学判据,也难以指导灌浆压力的调节。为此,提出一套帷幕灌浆波动段注入率区间分析和计算方法,对帷幕灌浆的历史注入率过程线形进行分类,选取出注浆过程的正常灌段,通过分析各灌浆参数与波动段单位平均注入率的相关性,选取灌浆强度数(GIN)、波动段浆液平均密度和灌浆孔序分别作为能量、裂隙和灌序指标;对注浆过程正常灌段进行聚类,计算各类的波动段注入率区间,最后判断各历史灌段的波动段单位平均注入率所处的具体波动段注入率区间,根据判断结果给予灌后评价。将提出的方法运用于五岳抽水蓄能电站上水库库盆坝趾帷幕灌浆工程实践中,结果表明:该方法的可行性及灌浆相似性假设得到了验证;评价等级处在Ⅰ级至Ⅳ级的灌段占93.5%,Ⅴ级到Ⅶ级的低评价灌段仅占一小部分。研究成果可供从事帷幕灌浆的工程技术人员参考。

[Objective] Curtain grouting is a commonly used method for anti-seepage reinforcement in pumped storage projects, and injection rate is an important monitoring parameter that directly affects grouting quality. The fluctuation section of injection rate is a critical stage in the grouting process. At present, research on the analysis of injection rate monitoring data is scarce, scientifically sound criteria for reasonable injection rate are lacking, and it is difficult to guide the adjustment of grouting pressure. This paper proposes a method for analysing and calculating the injection-rate interval of the fluctuation section, providing scientifically sound intervals for different grouting scenarios. [Methods] By analysing the temporal evolution of injection rate during curtain grouting, the rate-time curve was divided into three stages—fluctuation, sharp-decline, and termination—and its patterns classified into four types: normal, sharp-decline, low-level injection, and non-convergent. Normal-pattern sections were selected as standard grouting segments, and two key parameters of the fluctuation section—unit-average injection rate and average slurry density—were calculated to indirectly represent the average geological conditions of the treated strata. Owing to the large scale of the grouting area and inherent geological variability of the treated strata, the unit-average injection rate exhibited high dispersion. Therefore, based on the intrinsic correlation between resource allocation decisions and geological information, the concept of “grouting similarity” and a dynamic geological-zoning approach were proposed. Correlation analysis between grouting parameters and unit-average injection rate selected GIN value, average slurry density, and hole sequence as energy, fracture, and sequence indices, respectively. Clustering was applied to standard grouting segments based on these indices to reduce dispersion. After de-noising the target parameters within each category using DBSCAN, based on the 3σ control principle in risk management, if the data followed a normal distribution, points falling outside the ±3σ range could, under the principle of controlling type Ⅰ and type Ⅱ errors, be identified as extreme outliers. The Shapiro-Wilk method was used to test the normality of each cluster, and for those that passed, the ±3σ interval was calculated as the injection rate interval for the fluctuation section. Based on the degree to which each segment's parameters deviated from the interval center, the specific interval of the fluctuation-section unit-average injection rate of completed segments was determined, and a preliminary post-grouting geological assessment was provided, thereby achieving data-driven quality management of curtain grouting. [Results] This method was applied to the curtain-grouting project of Wuyue Pumped-Storage Power Station for clustering analysis of completed grouting sections. Results showed that parameter distributions within most clusters satisfy the normality assumption. The calculated fluctuation-section injection rate intervals for each grouting-similarity pattern conformed to the similarity hypothesis and provided an effective control tool for injection rate process control and management. Based on these intervals, preliminary relative geological assessments precisely identified outlier sections with significant deviations from a large number of grouting segments and the proportion of outliers met quality-risk-management standards. [Conclusions] In summary, the proposed method for determining the injection rate interval of the fluctuation section is logically rigorous and reliable, significantly improving the scientific management of curtain-grouting construction in large-scale pumped-storage projects.