新岩滑坡膨胀性软岩Duncan-Chang模型及归一化特性研究

Duncan-Chang Model Parameters and Normalized Behavior of the Swelling Soft Rock of Xinyan Landslide

延边地区公路沿线广泛发育一种膨胀性较强的软岩,具有较强膨胀性,致使这一地区公路边坡出现了多处滑坡现象,带来了较大的危害。为了描述该地区岩土介质材料的强度及变形特征,分析吉林省在建汪延高速公路上的新岩滑坡的稳定性并为支护设计提供基本参数,通过现场取样,进行室内固结不排水剪切试验。试验表明:试样的应力-应变关系曲线为典型的双曲线,在低围压下,土体表现出弱应变硬化型,在高围压下,土体呈现明显的应变硬化型。结合Duncan-Chang模型,对实验结果进行分析,得到了D-C模型参数,并在此基础上,研究该地区膨胀土的归一化特性,结果表明,当归一化因子为(σ1-σ3)ult时,归一化程度最好,同时建立了应力-应变关系特性的归一化方程,能较好预测应力-应变关系。

Soft rock with expansion properties is distributed widely along the highway in Yanbian area which gave rise to instability of slopes and brought about great damage in this area.In order to describe the strength and stress-strain characteristics of the geotechnical dielectric material in this area,the stability of Xinyan landslide on the Wangqing-Yanji highway in Jilin Province was analyzed and parameters of the support work were provided.Indoor consolidation-undrained shear test was carried out on the soil samples taken from the construction site.Results revealed that the stress-strain curves of the samples were typical hyperbola： under low confining pressure,the soil exhibited weak strain hardening;while under high confining pressure,the soil displayed obvious strain hardening behavior.In association with Duncan-Chang model,the test results were analyzed to obtain parameters of the model.On the basis of this,the normalized behavior of expansive soil in this area was studied,and the results showed that the normalized degree was highest when the normalization factor was（σ1-σ3）ult.Furthermore,the normalized equation of strain-stress curves was established,which would well predict the variation trend of stress-strain relation.