城市固体废弃物应变硬化机制与强度参数确定方法

发布时间：2018-03-22 12:50

本文选题：土力学　切入点：城市固体废弃物　出处：《岩石力学与工程学报》2014年04期 　论文类型：期刊论文

【摘要】：通过对常规三轴仪进行改装,开展最大竖向应变达50%的城市固体废弃物(MSW)三轴剪切试验。试验表明:大应变条件下MSW试样发生破坏且其破坏应变随填埋深度增大而减小。通过组分分离得到MSW的基本相和加筋相,并对其分别进行三轴固结排水剪切(CD)试验,发现其应力应变曲线均呈应变硬化型。在此基础上,对基本相进行筛分,并结合不同粒径粒组的微观结构阐述基本相中有机纤维体的存在形式及其加筋作用机制。进一步对各粒组进行CD试验,发现除粒径小于0.075 mm的粒组外其余粒组的应力应变关系均表现为应变硬化。通过基本相灼烧前后的CD试验比较,发现有机纤维体在应变达到一定程度后才开始发挥加筋作用,且剪切过程中伴随着纤维体断裂以及纤维体与颗粒间滑移。最后,基于MSW的三轴剪切试验结果,分别对三轴固结不排水剪切(CU)试验和CD试验抗剪强度参数的确定方法进行探讨。
[Abstract]:By modifying the conventional triaxial apparatus, The triaxial shear test of MSW with the maximum vertical strain of 50% was carried out. The results showed that the failure of MSW specimen occurred under the condition of large strain and the failure strain decreased with the increase of landfill depth. The MSW was obtained by component separation. Basic and stiffened phases, The results of triaxial consolidation and drainage shear test show that the stress-strain curves are of strain hardening type. On this basis, the basic phases are screened. Combined with the microstructure of different particle groups, the forms of organic fibers in the basic phase and the mechanism of reinforcement were expounded. It was found that the stress-strain relationship of the other granular groups except those with particle size less than 0.075 mm showed strain hardening. The CD tests before and after the basic phase burning were compared. It is found that the organic fiber body does not begin to play the role of reinforcement until the strain reaches a certain extent, and the shear process is accompanied by the fracture of the fiber body and the slippage between the fiber body and the particle. Finally, based on the triaxial shear test results of MSW, The determination methods of shear strength parameters of triaxial consolidation undrained shear cuff test and CD test were discussed respectively.
【作者单位】：浙江大学软弱土与环境土工教育部重点实验室;浙江大学岩土工程研究所;
【基金】：国家重点基础研究发展计划(973)项目(2012CB719800) 国家自然科学基金资助项目(51127005)
【分类号】：X705;TU41

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