垃圾土降解-渗透特性与填埋场液-气耦合轴对称流体运移理论研究

The objectives of the proposed research are to investigate the peak gas generation during degradation of the organic constitutes in municipal solid waste, find seepage testing method for unsaturated solid waste, establish the axial symmetrical moisture transport theory with considering hydraulic-gaseous coupling effect in landfill and find its solutions, approach the characteristics of moisture transport and hydraulic-gaseous pressure distribution in waste mass, and develop the calculation and design methods for leachate reinjection and gas extraction for bioreactor landfills. The proposed research activities include:According to the gas generation characteristic during organic degradation and Darcy's and Fick's laws, use hydraulic-gaseous coupling constitutive equation for unsaturated waste to develop the axial symmetrical moisture transport equation set with considering hydraulic-gaseous coupling effect. Conduct degradation tests for organic constitutes of the solid waste to measure peak gas generation values in various conditions and conduct seepage tests for unsaturated solid waste to investigate the effects of void ratio, moisture content, constitutes and amount of organic materials on the values of the parameters in the axial symmetrical moisture transport equation set with considering hydraulic-gaseous coupling effect. According to influence characteristic between pore water pressure and pore gas pressure, propose the recursion method to solve the equation set of pore water and gas pressures, and develop the axial symmetrical moisture transport theory with considering hydraulic-gaseous coupling effect in landfill and find its theoretical solution or numerical solution for various conditions. Based on the results of axial symmetrical lab bioreactor model tests and in-situ gas extraction tests under various conditions, confirm the theoretical or numerical solution of the axial symmetrical moisture transport theory with considering hydraulic-gaseous coupling effect, and develop the calculation and design methods for leachate reinjection and gas extraction for bioreactor landfills.

进行垃圾土有机物降解产气峰值规律调查、非饱和垃圾土流体渗透试验方法发展、垃圾填埋场液-气耦合轴对称流体运移理论及求解方法建立、填埋场流体运移与液-气压力分布规律揭示、垃圾填埋场淋滤液回灌井与抽气井计算理论研究。考虑有机物降解产气特征，依据Darcy定律和Fick定律等，利用非饱和垃圾土液、气耦合本构方程，建立轴对称液-气耦合流体运移理论控制方程组；进行有机物降解产气速率峰值规律、非饱和垃圾土流体渗透特性试验，揭示孔隙比、含水量、有机物成分与含量等对垃圾土液-气耦合流体运移理论计算参数的影响规律；根据孔隙液压与孔隙气压相互影响特性，提出孔隙气压和孔隙液压控制方程组递推解法，发展不同条件下液-气耦合轴对称流体运移理论的理论解或数值解方法；通过不同条件下轴对称生物反应器模型试验和现场抽气井集气试验，对液-气耦合轴对称流体运移理论解进行验证，发展垃圾填埋场淋滤液回灌井与垃圾气抽气井设计计算方法。

进行了垃圾土有机物降解产气峰值规律调查、非饱和垃圾土流体渗透试验方法发展、垃圾填埋场液-气耦合轴对称流体运移理论建立及求解、填埋场流体运移与液-气耦合作用机理揭示。（1）考虑有机物降解特征，依据Darcy定律和Fick定律等，利用非饱和垃圾土液、气耦合本构方程，建立轴对称液-气耦合流体运移理论控制方程组；（2）研究了垃圾土有机物含量、含水量、孔隙比和温度对垃圾土降解产气特性的影响，得到垃圾土降解产气双峰值规律；（3）利用张力计和简易蒸发法测得垃圾土土水特征曲线，得到有机物含量和孔隙比对垃圾土土水特征曲线的影响。利用自行研制的垃圾土气体渗透试验装置得到垃圾土全含水率气体渗透系数，得到气体渗透系数随饱和度的三阶段规律；（4）得到轴对称液-气耦合模型的简化解析解并采用DQM法获得模型的数值解，基于模型解答分析了填埋场液-气压耦合运移规律；（5）开展了考虑气-液耦合的垃圾土边坡稳定分析研究。发表论文11篇，其中SCI检索论文4篇，EI检索论文4篇；主持完成的研究成果获得部级科技进步二等奖。达到并部分超过申报时的预期目标。