红层泥质岩循环干湿风化下变形特性试验研究

泥质岩土石料填筑体因风化引起的工后变形沉降破坏,已成为道路等土建设施成败的关键。基于此,对泥质岩烘干与浸水循环条件下,侧向自由与侧向约束下的膨胀与收缩变形特征进行试验研究,研究结果表明:通过无侧限状态下,自然风干的试样与加热带加速风干的试样变形特征对比可知,加热带加速风干过程不影响试样干湿过程中整体的体积变形趋势,同样可以体现泥质岩试样在自然状态下循环干湿的变化特征;通过加热带风干条件下,无侧限和有侧限约束下的试样对比可知,约束条件不影响试样过程中整体的体积变形趋势;泥质岩在循环干湿风化过程的单次浸水和单次风干过程的体积变形特征与岩石受荷蠕变特征相似,并提出类Kelvin膨胀及收缩模型,与试验数据拟合效果良好;自然风干泥质岩试样在循环干湿风化过程中随干湿次数的增加,体积变形量逐渐增大,循环干湿过程中试样变形稳定所需时间主要取决于试样内部裂隙的扩展情况。

Experimental study on deformation characteristics of red-bed mudstone under cyclic dry-wet weathering

The post-construction deformation and settlement failure caused by weathering of mudstone earth rockfill has become crucial to the success of road and other civil engineering facilities. Therefore, swelling and shrinkage deformation characteristics of mudstone under the condition of lateral restraint and lateral freedom by means of dry-wet cycle were studied. Accelerated drying of heating belt, under lateral freedom condition, through a comparative analysis of deformation characteristics between natural air-drying specimens and accelerated drying specimens, does not affect the overall volume deformation trend in the process of dry-wet cycle. It can also reflect repeatedly dry-wet variation characteristics of mudstone specimens under natural state. The overall volume deformation trend, in the case of heating belt weathering, according to a comparison of the specimens under the condition of lateral freedom and lateral restraint, does not have a correlation with constraint condition. In the process of dry-wet weathering cycle, the volume deformation characteristic of mudstone under single soaking and single drying being similar to that of rock creep under load, similar Kelvin swelling-shrinkage model fitted well with the test data is proposed. In the process of dry-wet weathering cycle, the volume deformation of natural air-dried mudstone specimens increases with the increase of dry-wet times, and the required time for the deformation stability mainly depends on the expansion of internal cracks of the specimens.