【摘要】 为寻求改性膨胀土干燥开裂的调控机制，预防膨胀土工程灾害，在干湿循环条件下，针对不同煤矸石粉掺量的膨胀土进行收缩试验，确定煤矸石粉的最佳掺量及体缩率，通过土样表面的裂隙图像，计算土样外表面的裂隙率，借助压汞试验获得土样内部孔隙率和平均孔径参数，对体缩率、裂隙率、孔隙率等收缩性指标进行分析，揭示煤矸石抑制膨胀土收缩裂隙发育发展的机制。结果表明，在干湿循环下，煤矸石粉掺量为9%时，土样的收缩性得到较好的抑制；掺入煤矸石可降低膨胀土孔隙率，使土体内部结构更加稳定；素膨胀土和改性膨胀土的体缩率、面裂隙率和孔隙率与干湿循环次数的关系均符合三元二次方程。更多还原

【Abstract】 To seek the regulatory mechanism of improved expansive soil dry crack, and prevent the expansive soil engineering disasters, under the condition of dry-wet circulation, according to the shrinkage test of expansive soil with different coal gangue powder content, we determine the optimum content of coal gangue powder and the volume shrinkage of the expansive soil. The soil sample crack area ratio is calculated through the crack on the surface of the soil sample image, the surface crack rate is obtained with the help of mercury injection test for soil samples internal porosity and average aperture. The correlation analysis of volume shrinkage, fracture rate, porosity and average pore diameter is carried out to reveal the mechanism of coal gangue inhibiting the development of shrinkage cracks in expansive soil. The results show that the shrinkage of soil samples is well inhibited when the coal gangue powder content is 9% in the dry-wet cycle. Adding coal gangue can reduce the porosity of expansive soil and make the soil structure more stable. The relationship between the volume shrinkage, cracking area rate and porosity of pure or modified expansive soil and the number of dry and wet cycles accords with the ternary quadratic equation.更多还原