填埋场渗漏条件下的自然电位响应特征及影响机制

为探索自然电位法监测填埋场渗漏的可行性及适用条件，需在中试尺度揭示渗滤液渗漏条件下的自然电位异常特征和关键影响因素. 通过构建试验场地来模拟填埋场的渗漏场景，模拟填埋场代表性渗漏速率下的自然电位异常，分析自然电位信号对渗漏速率敏感性和响应关系，同时分析不同采样电极条件对检测信号的影响. 结果表明:①渗漏条件下，渗漏区域的自然电位发生明显变化，因此自然电位可以作为渗漏的响应指标；另外，渗漏条件下，自然电位时序方差的峰值位置与渗漏通道区域重叠，表明时序方差可以作为漏点精准定位的指标. ②自然电位与渗漏速率成正比，当渗漏速率为200 mL/s时，不极化电极检测到的自然电位异常高达16.1%；当渗漏速率分别减至166.67和102.04 mL/s时，自然电位异常相应减至9.3%和3.7%；当渗漏速率降至43.48 mL/s时，已不能观测到自然电位异常. ③相比于极化电极，不极化电极对渗漏条件下自然电位异常变化的响应更为敏感，能够更及时响应并精准定位渗漏的位置. 研究显示，通过检测自然电位可实现对渗漏点的精准定位；渗漏速率与自然电位异常呈显著正相关趋势；相较极化电极，不极化电极具有更高的稳定性能和检测精度. 

Response Characteristics and Influence Mechanism of Self-Potential under Landfills Leakage

In order to explore the feasibility and applicable conditions of self-potential monitoring for landfill leakage, it is necessary to reveal the abnormal characteristics and key influencing factors of the self-potential under leakage conditions at a pilot scale. Through the construction of a test site to simulate the landfill leakage scenario, the self-potential anomalies under the representative landfill leakage rate were simulated, the sensitivity and response relationship of the self-potential signal to the leakage rate were analyzed, and the influence of different sampling electrode conditions on the detection signal was also analyzed. The results show that: (1) The self-potential in the leakage area changes obviously under the leakage condition, so the self-potential can be used as the response index of leakage. In addition, the peak position of the self-potential time-series variance overlays with the area of the leakage channel under the leakage condition, indicating that the time-series variation can be used as an indicator for the accurate location of the leakage point. (2) The self-potential is positively proportional to the leakage rate, when the leakage rate is 200 mL/s, the self-potential anomaly detected by the non-polarized electrode is as high as 16.1%. When the leakage rate decreases to 166.67 and 102.04 mL/s, the self-potential anomaly decreases to 9.3% and 3.7%, respectively. However, when the leakage rate decreased to 43.48 mL/s, no self-potential anomaly could be observed. (3) Compared with the polarized electrode, the non-polarized electrode is more sensitive to the abnormal changes of self-potential under the leakage condition, and can respond timely and more accurately locate the location of leakage. The study shows that the leakage point can be accurately located by detecting the self-potential, and by the quantitative analysis. The leakage rate is positively correlated with the anomaly of self-potential, and the non-polarized electrode has higher stability and detection accuracy than the polarized electrode. The application of the self-potential method in the field of landfill leakage detection has a great development prospect.