摘要
生活垃圾中有机物降解会产生大量的垃圾填埋气体,如CO_(2)、CH_(4)。填埋气体在不能有效收集和排放的情况下,可能会导致填埋场覆盖层的失效或是发生气爆事故。为探究填埋覆盖层气体的突破压力与排放,采用逐步加压法对不同干密度、饱和度和围压条件下的压实黄土进行气体突破压力试验,通过压汞(MIP)试验对气体突破压力进行预测。结果表明:压实黄土在饱和状态下,气压较低时的气体排出速率很小可以忽略不计,当气压达到阈值时,气体排出速率急剧增加;气体突破压力随干密度和围压的增大而增大,与围压相比干密度对其影响更为显著。另一方面,压实黄土的气体突破压力与固有渗透率在对数坐标下具有较好的线性关系;MIP试验表明,可采用汞饱和度与入汞压力曲线出现拐点时的入汞压力对气体突破压力值进行预测。研究结果为西北黄土地区垃圾填埋场覆盖系统的优化设计提供有益见解。
Biodegradation of organic matter in municipal wastes can produce a large amount of landfill gas,including CO_(2)and CH_(4).If the landfill gas is not collected and discharged ef-fectively,the failure of the landfill cover or an airburst accident will be led to.In order to investigate the gas breakthrough pressure and emission of landfill overburden,the gas breakthrough pressure test of compacted loess under different dry density,saturation,and confining pressure was carried out by stepwise pressurization method,and the gas break-through pressure was predicted by mercury intrusion porosimetry(MIP)test.The results show that in the saturated state of compacted loess,the gas emission rate of the compacted loess is minimal or negligible when the gas pressure is low.There is a dramatic increase in the gas emission rate when gas pressure reaches the threshold value.The gas breakthrough pressure increases with the incdry density and confining pressure.Further,the dry density has a more significant effect on the gas breakthrough pressure compared to the confining pressure.On the other hand,the gas breakthrough pressure and intrinsic permeability of compacted loess have a good linear relation in logarithmic coordinate.As indicated by the MIP test,mercury intake pressure at the inflection point of the mercury saturation and mercury intake pressure relationship curve is used to predict the gas breakthrough pressure.The findings deliver some design guideposts to landfill cover systems of North-West China.
作者
文少杰
郑文杰
李东风
胡文乐
Wen Shaojie;Cheng Wenchieh;Li Dongfeng;Hu Wenle(School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2024年第2期68-76,共9页
China Civil Engineering Journal
基金
创新人才推进计划-科技创新团队(2020TD-005)
中共中组部“国家海外高层次人才引进计划”青年项目(2019)。
关键词
黄土
覆盖层
气体突破压力
气体排放速率
渗透率
loess
landfill cover
gas breakthrough pressure
gas emission rate
permeability
