温度变化对高塑料含量垃圾土变形和强度特性影响机理研究

Due to the high content of the plastic, the deformation and strength behavior of municipal solid waste (MSW) is readily influenced by the elevated temperature during the operation of the landfill, leading to a significant decrease of the soil strength. It is usually difficult to fully study the deformation and strength properties of MSW and propose corresponding deformation and failure criteria as a result of its complex components and influence factors. Up to now, few studies have been performed to study the effect of temperature on the deformation and strength properties of the MSW, which however has become increasingly emergent. To address this issue, temperature controlled laboratory Triaxial test would be performed in the reconstituted MSW samples, incorporating the effect of the stress paths and temperatures. A corresponding constitutive model for the MSW is then proposed based on the critical state theory and associated flow rule. This project is supposed to provide a theoretical guide on predicting the strength parameters of MSW and evaluating the deformation behavior and slope stability of the landfill.

高塑料含量垃圾土的变形和强度在填埋场运行过程中容易受温度影响，温度增加时垃圾土的强度会显著降低。由于垃圾土成分复杂，敏感影响因素多，目前要全面研究垃圾土的变形强度特性，并提出合理的变形特性模型和垃圾土剪切破坏准则尚需要做很多工作；但对于高塑料含量垃圾土受温度升高影响的强度变形特性和变化规律研究比较迫切，目前的研究工作鲜有涉及。申请项目将利用人工配制垃圾土和改造的可调恒温应力路径控制三轴仪，进行垃圾土在恒温应力路径控制条件下的室内三轴剪切试验，研究不同恒定温度条件下高塑料含量垃圾土的变形和强度特性变化规律。在此基础上采用临界状态土力学理论和相关联流动法则，建立考虑温度影响的高塑料含量垃圾土的本构模型，揭示填埋场升温过程中塑料成分影响垃圾土变形强度机理。项目预期成果为合理确定实际填埋场垃圾土变形强度参数、预测填埋场的变形和库容、保证填埋场边坡稳定提供理论支持。

高塑料含量垃圾土的变形和强度在填埋场运行过程中容易受温度影响，温度增加时垃圾土的强度会显著降低。本项目对GDS应力路径三轴仪进行了温度控制系统的改造，开展了高塑料含量垃圾土人工配制和可调恒温应力路径控制三轴固结排水剪切试验，研究了垃圾土在恒温应力路径控制条件下的三轴剪切试验的变形和强度特性，得到了温度影响下高塑料含量垃圾土的变形和强度变化规律，发展了考虑温度作用的高塑料含量垃圾土弹塑性本构模型，揭示了温度对高塑料含量垃圾土变形和强度影响的机理。通过与室内三轴试验结果比较，初步验证了所建立本构模型的合理性和准确性。最后，开展了考虑温度影响的典型垃圾土边坡稳定分析研究以及无锡填埋场失稳破坏案例分析，验证了考虑温度影响的垃圾土强度方程的合理性。本项目所取得的研究成果为生活垃圾填埋场提供了考虑温度影响的变形强度参数，为填埋场库容计算和安全稳定性分析提供了理论支持。