岩土力学 ›› 2024, Vol. 45 ›› Issue (S1): 471-476.doi: 10.16285/j.rsm.2023.0739

• 基础理论与实验研究 • 上一篇    下一篇

黄土覆盖层气体突破和循环气体渗透特性试验研究

文少杰1, 2,郑文杰1, 2,胡文乐1, 2   

  1. 1. 西安建筑科技大学 土木工程学院,陕西 西安 710055;2. 西安建筑科技大学 陕西省岩土与地下空间工程重点实验室,陕西 西安 710055
  • 收稿日期:2023-06-06 接受日期:2023-08-09 出版日期:2024-09-18 发布日期:2024-09-21
  • 通讯作者: 郑文杰,男,1980年生,博士,教授,主要从事特殊土力学与工程防灾方面的研究。E-mail: w-c.cheng@xauat.edu.cn
  • 作者简介:文少杰,男,1992年生,博士研究生,主要从事环境岩土工程方面的研究。E-mail: wenshaojie@xauat.edu.cn
  • 基金资助:
    中共中组部“国家海外高层次人才引进计划”青年项目(2019)

Experimental study on gas breakthrough pressure and cyclic gas permeability characteristics of loess cover layer

WEN Shao-jie1, 2, CHENG Wen-chieh1, 2, HU Wen-le1, 2   

  1. 1. School of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055, China; 2. Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055, China
  • Received:2023-06-06 Accepted:2023-08-09 Online:2024-09-18 Published:2024-09-21
  • Supported by:
    This work was supported by the Organization Department of the Central Committee’s ‘Overseas High-Level Youth Talents Recruitment Program’ (2019).

摘要: 垃圾填埋场中未处置的垃圾会持续排放大量有毒气体,布置覆盖系统是减少有毒气体排放到大气中的有效方法。然而有毒气体积累可能导致填埋场覆盖系统失效或空爆事故。我国西北地区黄土常作为覆盖材料,为避免上述问题发生,对压实黄土试样进行了气体突破压力和渗气特性试验。结果表明,压实黄土在饱和状态下,当气体压力较低时,气体的排出率很小或可忽略不计;当气体压力达到阈值时,气体的排出率开始急剧增加;压实黄土的气体突破压力随有效压力的增加而增加,当有效压力从10 kPa增加到20、30 kPa时,气体突破压力值分别从28.95 kPa增加到30.97、37.27 kPa;在循环渗气试验中压实黄土试样渗气特性表现出滞后现象;此外,气压引起的试样体积变化与有效应力之间存在指数关系,可将气压升高引起有效应力降低导致试样体积出现急剧膨胀视为垃圾填埋场黄土覆盖层整体破坏的前兆。

关键词: 压实黄土, 垃圾填埋场, 覆盖系统, 气体突破压力, 渗气率

Abstract: Unprocessed landfill waste continues to produce large amounts of hazardous gases, and the building of a cover system is an effective method to reduce the emission of landfill gas. However, the accumulation of hazardous gases may result in landfill cover breakdown or airburst accidents. This study investigates gas breakthrough pressure and emission from landfill covers by conducting tests on compacted loess specimens, commonly used as cover material in northwest China. Results indicate that at low gas pressures, gas emission from saturated compacted loess is minimal. As gas pressure reaches a threshold, emission rates rise sharply. The gas breakthrough pressure of compacted loess increases with increasing effective stress. With effective pressure increasing from 10 kPa to 20 kPa and 30 kPa, gas breakthrough pressures increase from 28.95 kPa to 30.97 kPa and 37.27 kPa, respectively. In the cyclic gas permeability test, the gas permeability characteristics of compacted loess specimens show hysteresis. In addition, An exponential relationship exists between specimen volume change and effective stress induced by gas pressure. A significant specimen volume expansion due to reduced effective stress from increased gas pressure can signal impending destruction of landfill cover systems.

Key words: compacted loess, landfill, cover system, gas breakthrough pressure, gas permeability

中图分类号: TU431
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