高密度电法在水库坝基无损检测中的应用

某坝基为砂卵石基础,其下为强风化基岩,坝基渗漏和左右岸绕坝渗漏是该水库坝基存在的主要地质问题。为此,采取了塑性混凝土防渗墙与双排帷幕灌浆相结合的综合防渗措施。为了检测水库坝基及塑性混凝土防渗墙施工质量,防止水库正常蓄水后发生渗漏,选用了高密度电法进行无损检测。工程采用温纳施伦贝尔法观测,分别采用5m和10m电极间距,电极数60个,剖面数16。依据5m和10m道距实测视电阻率剖面与反演结果的解释,对水库坝基和防渗墙的工程质量进行了评价,认为-25m桩号塑性混凝土防渗墙可能存在渗漏问题,-80m桩号对应一低阻异常,坝体可能存在渗漏通道;其余部位未发现明显异常。

Application of High-density Electric Survey in Reservoir Dam Foundation Nondestructive Testing

Beneath the dam foundation of sand and gravel is strongly weathered bedrock; seepages of dam foundation and both left and right dam abutments are the main geological problems existed. Therefore, integrated seepage prevention measures of plastic concrete impervious wall and double row curtain grouting were used. For detection of dam foundation and plastic concrete impervious wall construction quality, to prevent seepage after reservoir normal impoundment, the high-density electric survey nondestructive testing was used. The Wenner and Schlumberger methods were used in observation, 5m and lOm electrode spacing, 60 electrodes, 16 sections have used. Based on 5m and lOm group intervals observed apparent resistivity sections and inversion results interpreted, assessed reservoir dam foundation and impervious wall construction quality. Finally considered that plastic concrete impervious wall near the -25m peg, the seepage is probable, near -80m peg is corresponding to a low-resistivity anomaly, and thus may have seepage channels in the dam body, no obvious anomalies in other parts.