卵石土蠕变本构模型及其工程应用

卵石土是岩土工程建设中的常用材料,由于针对其流变力学特性的研究较少,导致无法评价该种材料的长期稳定性。采用试验研究、理论分析和数值模拟相结合的研究方法,针对卵石土开展了室内三轴蠕变试验,对卵石土蠕变的有关力学问题进行了探讨,分析了卵石土蠕变与时间、应力状态的关系,并提出了11参数卵石土蠕变的数学表达式及相应的参数指标。将该本构模型嵌入到ABAQUS软件中,计算了某大桥锚碇下覆地基的长期沉降变形。结果表明,提出的本构模型可以很好地描述卵石土的流变特性。与锚碇沉降变形监测结果相比,蠕变加速变形阶段的沉降计算结果偏大,蠕变稳定阶段的沉降计算结果偏小。研究结果可为卵石土的长期变形计算提供相关参考。

Creep Constitutive Model of Cobbly Soil and Its Engineering Application

Cobbly soil is widely applied in geotechnical engineering construction by virtue of its good engineering characteristics. The inadequate research on cobbly soil, especially on its creep characteristics, results in improper ways in evaluating its long-term stability. In the present research, the creep properties of cobbly soil are studied via laboratory triaxial compression test, theoretical analysis and numerical simulation. The relations of creep versus time and stress are analyzed, and a creep model containing eleven parameters is put forward. The creep model is embedded in ABAQUS software to calculate the long-term deformation of the foundation of a bridge as a case study. Results manifest that the constitutive model presented in the paper well describes the rheological properties of cobbly soil. Compared with monitoring results of anchorage deformation, the result of settlement calculation in creep acceleration stage is larger, while in stable creep stage is smaller.