Stability Study On Harzardous Waste Landfill

With the rapid development of China’s industrial, the total amount of industrialsolid waste increased year by year, especially hazardous waste. Landfill have beingwidely used in actual hazardous waste treatment and disposal engineering, for whichcan be able to minimize the impact on human healthy and ecological environment byseparating the waste from the environment. However, landfill safety incidents haveoccurred frequently, a huge security risk exists in the vast majority of our hazardouswaste landfill engineering. Therefor, the study on the stability of hazardous wastelandfill. is of great practical significance.On the basis of previously experience about the stability of landfill, firstly, thisresearch has determined basic physical and geotechnical engineering properties ofseveral categories of typical sludge hazardous waste indoor, such as Hangzhou oxygenplant sludge, contaminated soil, zinc/chrome sludge, oil sludge, fly ash/slag mixture,filter filling materials, based on ‘Soil test method standards’（GB/T50123-1999）, andanalyzed the possible influence on the. landfill slope stability. Secondly, establishphysical and mechanical model outdoors, using the Hangzhou hazardous waste landfillas the prototype object, and monitor the stress and displacement of the mechanicalmodel, meanwhile, do the stability numerical simulation analysis of the mechanicalmodel, using Geo-Studio numerical simulation series software, compared with theactual monitoring results and adjust the relatively parameter, to establish a evaluationmethord using Geo-Studio numerical simulation software.,which can apply inhazardous waste landfill stability.Finally, combining with the engineering mechanicalparameters of different hazardous waste and a variety of landfill scene, used theestablished numerical simulation method to judge thelandfill stability situation andanalyze the impact factor and sensitivity, and summerized up the hazardous wastelandfill stability assessment method to applied to the actual landfill engineering.The soil test results show that, for the three sludge hazardous waste, oxygen plantsludge, zinc/chrome sludge and oil sludge, whose moisture content （up to70%） andorganic matter content are much higher than the non-sludge waste, grading uneven, theeffective diameter is in the range of0.075⁰.25mm, their penetration coefficientare respectively0.413×10^-3,0.760×10^-3and1.366×10^-3cm/s, which is an order ofmagnitude smaller than that of contaminated soil(6.499×10^-3cm/s) and fly ash/slagmixture(8.365×10^-3cm/s), and two orders of magnitude smaller than that of filter filling materials(33.822×10^-3cm/s). Unconfined compressive strength and cohesionvalue lists for different hazardous wastes are: fly ash/slag mixture>filter fillingmaterials> contaminated soil> Hangzhou oxygen plant sludge>zinc/chrome sludge>oil sludge. Factors of hazardous waste landfill stability and their impact sensitivity ofnumerical simulation results show that, compared with landfill height, the slope hasmore important impact. Shear strength properties （c, φ） of harzardous waste have moresignificant effect on the langfill stability than their bulk density, and the internalfriction angle have more sensitive to the landfill stability, than the cohesion.ApplyGeo-Studio numerical simulation method to the actual hazardous waste landfillengineering—Hangzhou hazardous waste landfill, the simulation results show that:when the shear strength of hazardous waste are belong to the range of （c≥2kpa,φ≥30°）、（c≥10kpa, φ≥24°）、（c≥30kpa, φ≥18°）、（c≥60kpa, φ≥12°）, they are stablewaste, which are satisfied the requirements of the hazardous waste landfill on thestability and can be admission directly; when belong to the range of（c≤50kpa, φ≤6°）、（c≤30kpa, φ≤12°）、（c≤2kpa, φ≤18°）, they are unstable, then need for curingstabilizing treatment before entering the hazardous waste landfill; except all that,which are relatively stable, the stability of such hazardous waste landfill is limited bythe landfill height and slope conditions in the landfill operation, we needs to considerother factors, to prevent the pile from the formation of an unstable state.