An increasing economic interest leads to construction on old landfills and waste deposits, raising questions about potential contamination of groundwater due to installation of piles through clay barriers. The current consensus in the geotechnical practice, that penetration of clayey hydraulic barriers by driven steel piles with closed conical tips should not cause pollution of the underlying aquifers, is challenged in this paper. Consolidometer and flow-column tests on clays with iron-rich pore fluid were performed for the assessment of pile corrosion effects on hydraulic barriers. Based on the results of these tests, a constitutive model for the coupled chemomechanical behaviour was modified to account for different pore-fluid chemistry and incorporated into a finite-element code to solve the problem of iron diffusion originating from a corroding source in a case study on groundwater pollution. The combined action of diffusion, corrosion and increased convection resulted in an overall increased transport rate and therefore a significantly earlier arrival of critical concentrations of the pollutant in the aquifer that was initially protected by a hydraulic barrier. Once this barrier is perforated by foundation piles subjected to corrosion, small concentrations can arrive in the aquifer up to four times earlier than implied by the initially low hydraulic conductivity.

中文翻译：

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钢桩腐蚀对水力屏障渗透性的影响

日益增长的经济利益导致对旧的垃圾填埋场和废物堆积场的建设，对由于通过粘土屏障安装桩而引起的地下水潜在污染提出了质疑。在岩土工程实践中，目前的共识是，具有封闭的圆锥形尖端的打入式钢桩穿透粘土质水力屏障不应引起对下层含水层的污染。对富含铁的孔隙流体的粘土进行固结仪和流柱试验，以评估桩对水力屏障的腐蚀作用。根据这些测试的结果，修改了一个耦合化学力学行为的本构模型，以解决不同的孔隙流体化学问题，并将其纳入有限元代码中，以解决在地下水污染案例中源自腐蚀源的铁扩散问题。扩散，腐蚀和对流增加的综合作用导致总体传输速率提高，因此临界浓度的污染物明显早于最初由水力屏障保护的含水层。一旦该屏障被受到腐蚀的基础桩打穿，小浓度的水可以比最初的低水力传导率所暗示的时间早四倍到达含水层。腐蚀和对流增加导致运输速度整体提高，因此污染物临界浓度明显提前到达含水层中，而该污染物最初是由水力屏障保护的。一旦该屏障被受到腐蚀的基础桩打穿，小浓度的水可以比最初的低水力传导率所暗示的时间早四倍到达含水层。腐蚀和对流增加导致运输速度整体提高，因此污染物临界浓度明显提前到达含水层中，而该污染物最初是由水力屏障保护的。一旦该屏障被受到腐蚀的基础桩打穿，小浓度的水可以比最初的低水力传导率所暗示的时间早四倍到达含水层。