论文部分内容阅读
为研究湿热多雨气候条件诱发的干湿循环过程对红黏土长期性能的影响规律,对制样过程中干湿循环含水率变化幅度控制技术进行改进,制备不同干湿循环次数以及含水率变化幅度试样。利用固结排水三轴剪切与压缩试验,研究了干湿循环次数与干湿循环含水率变化幅度对压实红黏土工程性状的影响规律。结果表明,压实红黏土的黏聚力c与内摩擦角φ均随干湿循环次数N的增加而衰减,首次干湿循环之后衰减效应最显著,其后较弱并趋于稳定,φ的衰减程度小于c,且在低围压下的抗剪强度随干湿循环衰减更加显著;压缩模量E_(1-2)随N的总体衰减规律与强度参数类似,但衰减幅度小于c而大于φ;随着干湿循环含水率变化幅度增大,压实红黏土c与E_(1-2)略有减小,φ基本不变,压实红黏土含水率在ω_(opt)±4%变化范围内,具有相对稳定的力学特性。该研究表明,红黏土不宜直接用于填筑路床与边坡表层的填料,可以作为上下路堤堤心的填料,但必须采取防排水工程措施与边坡防护措施。
In order to study the influence of the wetting and drying process on the long-term performance of red clay induced by hot and rainy climatic conditions, this paper improves the control technology of the rate of change of moisture content during the process of sample preparation, and prepares different wetting and drying cycles and the variation range of water content kind. Three-axis shear and compression tests of consolidated drainage were carried out to study the effect of the number of wet-dry cycles and the variation of moisture content in wet-dry cycles on the engineering properties of compacted red clay. The results show that both the cohesion c and the internal friction angle φ of compacted red clay decrease with the increase of the number of dry-wet cycles N, the decay effect is the most significant after the first wet-dry cycle, and then weak and tends to be stable. Φ The decay degree is less than c, and the shear strength under low confining pressure decays more significantly with the wet-dry cycle. The general attenuation law of elastic modulus E_ (1-2) with N is similar to that of strength, but the attenuation amplitude is smaller than c and larger than c φ; with the increase of the moisture content in the wet and dry cycles, the compacted red clay c and E_ (1-2) slightly decreased, φ remained unchanged, the compacted red clay moisture content was within ± 4% Within the range of variation, it has relatively stable mechanical properties. The study shows that red clay should not be directly used to fill the road bed and the surface of the slope padding can be used as the upper and lower embankment embankment filling, but must take measures to prevent drainage and slope protection measures.