| Leachate water level in the landfills of southern China are generally high, giving rise to serious slope stability and contamination problems. Therefore, it is of practical and theoretical significance to control the leachate level in municipal silid waste landfill.Focused on that problem, the writer completed laboratory tests, field monitoring, and numerical analysis. The main contents and conclusions are as follows.(1) This article introduced the seepage theory of pumping vertical well,as well as its applying condition.(2) Saturated hydraulic conductivity-depth curve of MSW was measured by laboratory tests on borehole samples from Suzhou Qizishan Landfill. While the effective stress increased from 10kPa to 250kPa, the hydraulic conductivity decreased from 10-3cm/s to nearly 10-6cm/s. The laboratory tests also indicated that degradation plays a minor rule in the decrease of hydraulic conductivity with depth.(3) The writer completed the in situ pumping test in Suzhou Qizishan Landfill, and the infiltration ponds test in Chengdu Chang'an Landfill. Then compared the conductivity-depth curve of laboratory tests and in situ tests. It is found that the results of in situ tests are of an order of magnitude higher than those of laboratory tests.(4) The in situ pumping test in Suzhou Qizishan Landfill demonstrated that the discharge rate dropped with the lengthening of pumping time, and it arrived at equilibrium at about 15m3/d-25 m3/d. The radius of influence of the vertical well is about 40m-50m.(5) The numerical analysis of SEEP/W indicateds that the most important parameters in vertical well design are:the hydraulic conductivity, the distance of wells, and the inside mid-cover.(6) Based on the Expand Project of Qizishan Landfill in Suzhou, and the Emergency Reinforcement Project of Xia-ping Landfill in Shenzhen, the writer bring forword two engineering methods that can be used in controlling short-time leachate level and long-time leachate level.
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