Deterioration Characteristics of High-fill Loess Shear Strength under Freeze-thaw
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摘要: 以延安新区高填方黄土为研究对象，开展了冻融作用下高填方黄土抗剪强度试验研究，分析了冻融作用对高填方黄土抗剪强度指标影响规律及其劣化特性。结果表明，冻融作用下高填方黄土黏聚力随冻融循环次数增加而逐渐减小，第4次冻融后黏聚力损伤增量达到最大，之后随着冻融继续进行，黏聚力损伤增量逐渐减小；干密度相同时，含水率越小黏聚力越大，且在冻融作用下含水率越小，黏聚力劣化幅值和速率越大，冻融作用下内摩擦角没有明显规律性变化。给出了冻融作用下高填方黄土黏聚力损伤劣化模型，并利用独立试验数据进行了验证，结果表明该模型能较好地描述冻融作用下高填方黄土黏聚力劣化特征。Abstract: Taking the high-fill loess in Yan'an New Area as an example, the experimental study on the shear strength of high-fill loess under freeze-thaw action was carried out, and the influence of freeze-thaw action on shear strength index of high-fill loess and its deterioration characteristics were analyzed. The results show that the cohesive force of high-fill loess decreases gradually with the increase of freeze-thaw cycles under the action of freeze-thaw, after the fourth freeze-thaw cycle the cohesive force damage increases to the maximum, and then decreases gradually with the continuation of freeze-thaw. When the dry density is the same, the smaller the water content, the greater the cohesion, and the smaller the moisture content under freeze-thaw, the greater the amplitude and rate of cohesion deterioration. The internal friction angle has no obvious regular change under the action of freeze-thaw. The cohesive damage degradation model of high-fill loess under freeze-thaw action is given and verified by independent test data. The results show that the model can effectively describe the cohesive force degradation characteristics of high-fill loess under freeze-thaw.
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Key words:
- freeze-thaw /
- high fill /
- loess /
- shear strength /
- deterioration characteristics
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表 1 拟合参数1
含水率/% a b d f R2 14 0.5025 −4.5237 2.0777 66.602 0.9884 12 0.5558 −5.0918 3.2835 69.862 0.9860 9 1.1013 −9.3090 7.0197 123.17 0.9839 7 1.3814 −12.655 11.807 153.40 0.9819 
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表 2 拟合参数2
a1 a2 R2 −1.3684 −2.2462 0.9705 b1 b2 R2 12.298 20.247 0.9787 d1 d2 R2 66.606 −24.899 0.9994 f1 f2 R2 −135.24 −206.23 0.9673
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