干湿循环条件下秸秆灰渣改良膨胀土试验研究

膨胀土是遇水较为敏感的特殊土,所以研究膨胀土在干湿循环条件下的抗剪强度特征非常重要,尤其是对改良膨胀土的研究更有实际的工程意义。通过室内直接剪切试验,研究了膨胀土及秸秆灰渣改良土的抗剪强度特征。试验证明,膨胀土的抗剪强度随着灰渣含量的增加而增加,在灰渣含量为17%时强度及黏聚力达到最大值;而改良土的内摩擦角随着灰渣含量的增加而增加,同时改良土强度随着竖向力及养护龄期的增加而线性提高;干湿循环试验证明,膨胀土随着秸秆灰渣含量的增加抗剪强度衰减程度逐渐减小,试样的抗剪强度在第1次干湿循环时衰减较大;4次干湿循环后膨胀土黏聚力从37.0kpa,衰减到4.0 k Pa,内摩擦角衰减范围是28.3~11.64,17%秸秆灰渣改良土黏聚力衰减范围是74.16~57.43,内摩擦角衰减范围是46.05~42.25;直接剪切试验表明17%秸秆灰渣改良土为最佳配比。

Research on Improved Expansive Soil with Straw Ash under Dry and Wet Cycling Conditions

Expansive soil is a special soil that is sensitive to water. Therefore, it is very important to study the shear strength characteristics of expansive soil under dry-wet cycle circulation conditions, it has practical engineering significance especially for the study of improved expansive soil. Through indoor direct shear test,the shear strength characteristics of expansive soil and improved soil with straw ash were studied. The test proves that the shear strength of expansive soil increases with the increase of ash content. When the ash content is 17%, the strength and cohesion force reach the maximum value, while the internal friction angle of the improved soil increases with the ash content. The increase, while the strength of the improved soil increases linearly with the increase of vertical force and curing age; the dry-wet cycle test proves that the degree of shear strength attenuation is gradually reduced with the increase of straw ash content, and The shear strength of the straw ashmple is greatly attenuated during the first dry and wet cycle; after 4 dry and wet cycles, the cohesive force of the expansive soil is reduced from 37.0 kPa to 4.0 kPa, and the internal friction angle is in the range of 28.3 to 11.64. 17% straw ash is used to improve soil cohesion. The force attenuation range is 74.16~57.43, and the internal friction angle attenuation range is 46.05.3~42.25.Direct shear test showed that 17% straw ash improved soil was the best ratio.