填埋场渗滤液水位的形成及增长规律分析

On the leachate level formation and growth of solid waste landfill

过高的渗滤液水位是造成垃圾填埋场发生失稳破坏的主要原因,也是加剧填埋场污染负荷、降低填埋场单位面积填埋量的重要因素。根据饱和-非饱和渗流理论,考虑填埋场堆填过程中渗透系数沿深度的变化规律,采用数值方法研究填埋场水位的一维和二维形成及增长规律,提出了填埋场中孔压的分布模式。分析了不同因素对填埋场渗滤液水位的影响规律。结果表明,降雨强度、垃圾饱和渗透系数等对渗滤液水位的形成和增长影响显著,分析结果与实测水位较符合。

The present papdr is aimed at reporting an analysis method of the one and two dimensional leachate level formation and growth of the solid waste landfill based on the saturated and non-saturated seep- age theory, while considering the seepage coefficient variable with the landfill depth. The present study comes from the need that landfilling serves as the main solid waste disposal method in most of the Chinese cities and their surrounding rural areas in our country. Therefore, in our paper, we have proposed a pore water pressure distribution model of landfill and offered the interrelated terms for deep sliding analysis of the landfill. Since the leachate of such landfill is the main byprod- uct, it would become a much more serious problem for the environ- mental protection. As we know, the leachate of such landfill comesmainly from the rainfall of the corresponding landfill area, it has nat- urally brought about the groundwater penetration and permeation. High leachate level of the solid waste landfill has thus not only be- come the main mason for solid waste landfill failure, but also con- tributes to the environmental pollution load, inevitably reducing the solid waste erosion capability per area unit of the solid waste landfill. It is just for this reason that we have carefully investigated the impact of the leachate level caused by the above-mentioned factors and con- cluded that the rainfall intensity and the waste saturated seepage coef- ficient tend to impact the formation and growth of leachate level strongly, which is likely to be distinctly varied with the different rain- fall intensities. What is more, it can also be concluded that the greater the rainfall intensity, the higher leachate level will be. The leachate level tends to get stabilized when the outllowing rate equals to the rainfall intensity saturation. If the maximal waste saturated seepage coefficient by criterion is used, the leachate level would be very low. However, if the minimal waste saturated seepage coefficient is used, the leachate level would be very high for a long time when the landfill had been fulfilled. Such a kind of leachate level is usually underestimated by other softwares such as FILL, for the softwares of- ten ignore the pore ratio with the seepage coefficient of the waste varying with the landfill depth. Therefore, when the above said soft- wares are used, the analysis method proposed by us in this paper will be much more convenient and suitable for the high water content and high compressible landfill to be used for analysis in China＇ s case. That is to say, the result of our test proves to be persuasive in accord with the results of the field tests.