花岗岩残积砂质黏性土的蠕变特性与本构模型

花岗岩残积砂质黏性土越来越多地被选作建(构)筑物天然地基持力层,但目前关于花岗岩残积砂质黏性土的研究主要停留在短期的强度和变形阶段。为探讨花岗岩残积砂质黏性土在长期荷载作用下的变形特性,对潮州市花岗岩残积砂质黏性土进行蠕变试验。结果表明,花岗岩残积砂质黏性土蠕变变形随时间的增加不断增大,但变形速率不断减小,直至变形稳定;随着剪应力及固结压力的增加,蠕变特性更加显著。引入邓肯-张模型对整数阶Poynting-Thomson流变模型进行修正,修正后的P-T模型可以较好地描述花岗岩残积砂质黏性土蠕变特性。研究结果有助于进一步认识花岗岩残积砂质黏性土的蠕变特性,为花岗岩残积砂质黏性土地基处理提供参考。

Creep characteristics and constitutive model of granite residual sandy clay

Granite residue sand viscous soil is more and more selected as the natural foundation holding layer of building(structure),but at present,the research on granite residual sand viscous soil mainly stays in the short-term strength and deformation stage.In order to investigate the deformation characteristics of granite residual sand viscous soil under long-term load,creep test was carried out with Chaozhou granite residual sand viscous soil as the research object.The results show that the creep deformation of granite residual sandy clay increases with the increase of time,but the deformation rate decreases until the deformation is stable;with the increase of shear stress and consolidation pressure,the creep characteristics become more significant.Duncan-Zhang model is introduced to modify the integer Poynting-Thomson rheological model.The modified P-T model can better describe the creep characteristics of residual sandy clay of granite.The results are helpful for scholars to further understand the creep characteristics of granite residual sand viscous soil,and provide a reference for the treatment of residual sandy clay foundation of granite.