金盼, 陈波, 胡云世. 2023. 制样含水率影响红黏土强度特性的微观机理研究[J]. 工程地质学报, 31(6): 1811-1819. doi: 10.13544/j.cnki.jeg.2021-0574.
    引用本文: 金盼, 陈波, 胡云世. 2023. 制样含水率影响红黏土强度特性的微观机理研究[J]. 工程地质学报, 31(6): 1811-1819. doi: 10.13544/j.cnki.jeg.2021-0574.
    Jin Pan, Chen Bo, Hu Yunshi. 2023. Mechanism on strength characteristic of lateritic specimens prepared with different water contents[J]. Journal of Engineering Geology, 31(6): 1811-1819. doi: 10.13544/j.cnki.jeg.2021-0574.
    Citation: Jin Pan, Chen Bo, Hu Yunshi. 2023. Mechanism on strength characteristic of lateritic specimens prepared with different water contents[J]. Journal of Engineering Geology, 31(6): 1811-1819. doi: 10.13544/j.cnki.jeg.2021-0574.

    制样含水率影响红黏土强度特性的微观机理研究

    MECHANISM ON STRENGTH CHARACTERISTIC OF LATERITIC SPECIMENS PREPARED WITH DIFFERENT WATER CONTENTS

    • 摘要: 将制样含水率分别小于和大于最优含水率制备得到的红黏土(称为干侧样和湿侧样),通过轴平移技术(ATT)或蒸汽平衡技术(VET)施加吸力后,用非饱和土三轴仪开展同一净应力下的吸力控制三轴剪切试验,分析制样含水率对压实红黏土强度特性的影响。试验结果表明:无论是干侧样还是湿侧样,土体的峰值强度和剪胀量都随着吸力的增大而增大,且高吸力试样表现出明显的剪胀和软化力学特性。此外,相同吸力下,干侧样的峰值强度和剪胀量均大于相应湿侧样的试验结果,证实了制样含水率会对压实红黏土的力学特性产生重要影响。相同吸力和孔隙比的干侧样和湿侧样压汞试验结果表明,干侧样和湿侧样的孔径分布曲线存在明显差异,干侧样为双峰型孔径结构,湿侧样则为典型的单峰型孔径结构。进一步量化分析后确定,干侧样峰值强度大于相应的湿侧样,主要是由于干侧样的大孔径(d>0.2 μm)累计体积量小于相应湿侧样的大孔径累计量引起的。而且,土体的峰值强度随大孔径累积体积量的增大而呈指数减少。

       

      Abstract: The compacted lateritic specimens, prepared at dry side of optimum water content(dry specimens) and wet side of optimum water content(wet specimens) in proctor, were applied suctions by axial transform technique(ATT)or vapor equilibrium technique(VET),respectively. The specimens were firstly carried out suction-controlled shear tests under constant net stress by unsaturated triaxial apparatus, to investigate the effect of specimen prepared water content on the strength characteristic of lateritic clay. The obtained results illustrate that peak strength and dilatancy of specimens increase with an increase in suction, no matter dry specimens or wet specimens. And strain-softening and shear-dilatancy in the stress-strain curves are observed in the specimens with high suctions. In addition, the dry specimen has higher peak strength and more dilatancy than that of wet specimen at the same suction, which verifies that the specimen prepared water content has great influence on the strength characteristics of compacted lateritic specimens. Then, the results obtained from the mercury intrusion porosimetry(MIP)on both dry and wet specimens, indicate that the pore size distributions(PSDs) are different for dry and wet specimens with the same void ratio and suction. The bimodal PSDs exhibits in the dry specimens, while the unimodal PSDs exhibits in the wet specimens. Besides, the dry specimen has higher peak strength than that of wet specimen with the same void ratio, which can be attributed to less cumulative volume of macro-pores(d>0.2 μm). Moreover, the peak strength of clay exponential decreases with an increase in the cumulative volume of macro-pores.

       

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