不同冻融循环次数对膨胀土三轴剪切强度的影响  

The Effect of Different Freezing-thawing Cycles on the Triaxial Shear Strength of Expansive Soil

作　　者：张逯见[1] ZHANG Lu-jian(Anyang Vocational and Technical College,Anyang 455000,China)

机构地区：[1]安阳职业技术学院,河南安阳455000

出　　处：《山东农业大学学报（自然科学版）》2020年第2期360-364,共5页Journal of Shandong Agricultural University：Natural Science Edition

摘　　要：冻融循环损伤作用是影响膨胀土边坡的安全建设与运营的重要影响因素。为了研究冻融循环引起膨胀土力学特性的衰减规律,本文对南水北调中线的渠道边坡膨胀土试样进行0~8次的冻融循环处理,然后对土样开展围压为100、200、和300 k Pa的三轴固结排水剪切试验,并对土体强度指标的冻融劣化效应进行了定量评价。结果表明:不同冻融循环次数下膨胀土的三轴剪切强度与围压保持线性正相关的关系;同一循环次数下,三轴剪切强度在0~6次冻融循环次数增加有明显下降趋势,6~8次冻融后几乎保持稳定;根据摩尔库伦准则计算了土体的强度指标-内聚力c和有效内摩擦角φ,对数函数可以对强度指标和循环次数的关系进行有效拟合;根据试验结果提出一个考虑冻融循环次数的强度表达式,由此预测了膨胀土在多次冻融循环后的强度指标。Freezing-thawing cycle damage is an important factor affecting the safety construction and operation of expansive soil slope. In order to study the freeze-thaw cycle caused attenuation law of expansive soil mechanical properties, of the middle route of south-to-north water transfer canal slope of expansive soil specimen processing, 0 ~ 8 times of freeze-thaw cycles of soil sample and confining pressure is 100, 200, and 300 k Pa triaxial consolidation drained shear tests, and the intensity of freezing and thawing soil degradation effect has carried on the quantitative evaluation. The results show that the triaxial shear strength of expansive soil has a linear positive correlation with confining pressure under different freezing-thawing cycles. Under the same cycle number, triaxial shear strength showed a significant decrease trend when the number of freezing-thawing cycles from 0 to 6 increased, and almost remained stable after 6 freezing-thawing cycles.According to the Mohr-Coulomb criterion, the strength index of soil mass--cohesion c and effective internal friction angle are calculated, and the logarithm function can effectively fit the relationship between the strength index and the number of cycles. A strength expression considering the number of freezing-thawing cycles is proposed, and the strength index of expansive soil after multiple freezing-thawing cycles is predicted.

关 键 词：冻融循环 膨胀土 剪切强度 

分 类 号：TU475.5[建筑科学—结构工程]