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通过对南宁市环线路基堑方膨胀土进行的大量室内直剪蠕变试验,研究了各种竖向应力条件下不同剪应力水平对膨胀土蠕变特性的影响。试验结果表明,膨胀土的蠕变不但与加载时间有关,更与应力水平有关。当竖向应力较大时,蠕变曲线呈衰减蠕变特征;随着水平剪应力的增大和竖向应力的减小,蠕变形式从衰减变为非衰减,即土的蠕变为非线性蠕变。对南宁膨胀土的试验曲线进行了数值分析,得到了剪切蠕变的非线性经验模型,该模型能较好地描述南宁膨胀土的剪切蠕变特性,为膨胀土非线性流变问题的研究提供了参考。
Through a large number of indoor direct shear creep tests on expansive soils along the gantry of Nanning Ring Road, the effects of different shear stress levels on the creep characteristics of expansive soils under various vertical stresses were studied. The test results show that the creep of expansive soil is not only related to the loading time, but also to the stress level. When the vertical stress is larger, the creep curve shows a decay creep characteristic. With the increase of horizontal shear stress and vertical stress, the creep deformation changes from attenuation to non-attenuation, that is, the creep of soil is nonlinear Creep. The experimental curves of Nanning expansive soil are numerically analyzed and a nonlinear empirical model of shear creep is obtained. The model can well describe the creep characteristics of Nanning expansive soils, and provide a theoretical basis for the nonlinear rheological problems of expansive soils Research provides a reference.