Department of Environmental Engineering Sciences, University of Florida, PO BOX 116450, Gainesville, FL 32611, USA.
Int J Environ Res Public Health. 2011 May;8(5):1692-706. doi: 10.3390/ijerph8051692. Epub 2011 May 24.
Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth.
向填埋场废物中添加液体可能会导致孔隙水压力增加，这反过来可能会增加对填埋废物体的岩土稳定性的担忧。虽然垂直井渗滤液再循环对填埋场孔隙水压力的影响已经进行了数学建模，但在运行中的填埋场中尚未报告这些系统的测量结果。在佛罗里达州一个全规模运行的填埋场中，在一个液体添加井周围的废物中放置的振弦式压力计记录了 2 年的数据。在添加液体之前，测量到的孔隙压力随填埋场深度的增加而增加，这表明气体压力增加和废物渗透性随深度降低。当开始添加液体时，相对于远离井和位于较深位置的测压计，靠近渗滤液注入井或填埋场表面的测压计对渗滤液添加的响应更快。液体添加停止后，测量到的孔隙压力并没有立即下降，而是随着时间的推移缓慢下降。尽管在液体添加井的底部存在很大的压力，但在周围的废物中测量到的压力要小得多。本研究中记录的压力的空间变化表明，废物渗透性是各向异性的，并随深度降低。
