干湿循环下膨胀土基质吸力测定及其对抗剪强度影响试验研究

发布时间：2018-05-21 10:09

本文选题：膨胀土 + 干湿循环　；参考：《岩土力学》2017年03期

【摘要】：采用常规直剪仪对干湿循环作用下的非饱和膨胀土进行了不排水剪切试验,获得了不同含水率试样的总应力抗剪强度指标,可采用总黏聚力和总内摩擦角来反映土体的不排水抗剪性能;采用滤纸法测定了剪切完成后试样固定剪切面的基质吸力,结合直剪试验结果建立了全吸力范围内非饱和膨胀土的抗剪强度模型,通过试验对比验证了模型的合理性。干湿循环会显著降低膨胀土的不排水抗剪强度,其中对土体总黏聚力的削弱程度远大于对总内摩擦角的削弱程度。总应力抗剪强度指标与基质吸力的对数值近似为线性关系,土体抗剪强度随着基质吸力的增加而非线性增大,增大速率逐渐减小。试验结果表明,采用常规直剪仪和滤纸法开展干湿循环条件下非饱和膨胀土的抗剪强度研究是可行的。
[Abstract]:The undrained shear test of unsaturated expansive soil under dry and wet cycle was carried out by using a conventional direct shear apparatus. The total stress shear strength index of samples with different moisture content was obtained. The total cohesive force and the total internal friction angle can be used to reflect the undrained shear properties of the soil, and the matrix suction of the fixed shear surface of the sample after shearing is measured by the filter paper method. The shear strength model of unsaturated expansive soil in the range of full suction is established based on the results of direct shear test. The rationality of the model is verified by experiments. The undrained shear strength of expansive soil can be significantly reduced by dry-wet cycle, and the degree of weakening the total cohesive force of soil is much greater than that of the total angle of internal friction. The logarithmic relationship between the total stress shear strength index and the matrix suction is approximately linear. The shear strength of the soil increases nonlinearly with the increase of the matrix suction, and the increasing rate decreases gradually. The experimental results show that it is feasible to study the shear strength of unsaturated expansive soil under dry and wet circulation by using conventional direct shear apparatus and filter paper method.
【作者单位】：南昌航空大学无损检测技术教育部重点实验室;南昌航空大学土木建筑学院;云南农业大学水利学院;
【基金】：国家自然科学基金（No.51408291，No.41662021) 南昌航空大学无损检测技术教育部重点实验室开放基金（No.ZD201529002）江西省交通运输厅重点科技项目（No.2013C0006） This work was supported by the National Natural Science Foundation of China (51408291, 41662021), the Open Fund of Key Laboratory of Nondestructive Testing of the Ministry of Education (ZD201529002) and the Key Technology Program of the Communications Department of Jiangxi Province (2013C0006)
【分类号】：TU443

【参考文献】