基于三联隧道凝灰岩地层段大变形问题，利用室内蠕变试验方法，研究凝灰岩的流变特性。采用非线性拟合方法，比较分析 H －K 流变模型拟合值、Burgers 流变模型拟合值与试验数据的关系，研究凝灰岩的蠕变变形特征、长期强度。研究结果表明：凝灰岩蠕变变形随时间趋于稳定，属于稳定蠕变。结合蠕变试验结果，数值模拟三联隧道凝灰岩地层段围岩的流变特性，验证了凝灰岩 H －K 流变模型的适用性。综合以上，H －K 模型能够描述三联隧道凝灰岩的流变特征，且凝灰岩长期强度为瞬时强度的0．61倍。该成果对于三联隧道凝灰岩地层段隧道支护的优化调整，以及隧道结构长期稳定评价具有参考价值。%Based on the large deformation problem in tuff formation of trigeminy tunnels,the rheological charac-teristics of tuff were studied by use of laboratory creep tests.Nonlinear fitting method was applied to compare and analyze the relationships among the fitted values of H -K rheological model,of Burgers rheological model and experimental data,and study the deformation characteristics in creep process of tuff as well as its long -term strength.The results show that the creep deformation of tuff tends to be stable as time goes by,being a kind of steady creep.Combined with the creep test results,numerical analysis for rheological properties of tuff formation in trigeminy tunnels was presented,which in turn verifies the applicability of H -K rheological model for tuff. The research results indicate that H -K rheological model can describe the creep properties of tuff,and the long-term strength of tuff is only 61 percent of its peak strength in triaxial tests.The obtained solutions can be used to optimize and adjust the supporting structures of trigeminy tunnels in tuff stratum,and provide references to long -term stability of tunnel structures for assessment.
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