冻融循环对阳曲隧道黄土强度影响对比试验研究

Study of Influence of Freezing-thawing Cycle on Loess Strength of Yangqu Loess Tunnel

为了研究冻融环境对黄土强度的影响,以山西阳曲1号公路隧道不同含水量的黄土为研究对象,设计冻融循环次数和含水量变化的对比试验,通过进行冻融前后的直接剪切试验,获得含水量不同的黄土经过不同次数冻融循环后的强度变动规律。结果表明:原状土样和重塑土样在含水量变大的过程中,抗剪强度与黏聚力均在减小,内摩擦角基本保持稳定,但原状土样的抗剪强度与黏聚力始终高于同含水量的重塑土样。在含水量较高的情况下进行冻融试验,发现黄土干密度变化非常明显,此现象表明影响黄土冻胀劣化的主要因素是含水率的大小,黄土中水分含量越大劣化征象越显著。

The comparative tests are made on influence of freezing-thawing cycle and water content on loess strength of Yangqu Highway Tunnel No. 1 in Shanxi. The testing results show that： 1） The shear strength and cohesion of intact and remolded soil samples reduce with the water content increases; the internal friction angles of both samples remain stable; the shear strength and cohesion of intact soil samples are larger than those of remolded soil samples under same water content. 2） The obvious variation of dry density of loess under high water content and freezing-thawing test shows that the larger the water content is,the more significant the loess degradation is.