發(fā)布時間：2018-03-28 23:18

  本文選題：節(jié)理裂隙　切入點：增濕-減濕　出處：《工程地質學報》2017年02期

【摘要】：黃土內部存在各種裂隙,增濕-減濕作用導致原狀黃土內部裂隙不斷發(fā)展演化,因此研究在增濕-減濕作用下黃土裂隙發(fā)育演化規(guī)律具有非常重要的意義。以陜北延安地區(qū)某邊坡黃土為研究對象,通過CT掃描技術獲得了增濕-減濕作用下土樣細觀結構變化圖,得到了土樣CT數(shù)ME及SD值隨土樣增濕-減濕作用的變化曲線。研究結果表明:隨著土體濕度的增加,土體內部損傷速率緩慢增加,當含水率超過土樣塑限后,土體內部損傷速率加快,含水率超過一定值時,速度又減緩,CT數(shù)的均值和方差隨含水率變化皆呈反"S"曲線;隨著干濕循環(huán)次數(shù)的增加,土樣微裂紋逐漸發(fā)育,表現(xiàn)為伸長變寬,呈不規(guī)則的分叉、甚至貫通;4次干濕循環(huán)后,土樣裂隙裂縫基本成了網狀,土樣較破碎,此時CT數(shù)的均值和方差變化不大;干濕循環(huán)幅度越大,土樣內部損傷程度也越大,土樣內部節(jié)理裂隙發(fā)展也就越快。
[Abstract]:There are all kinds of cracks in loess. The effect of humidification and desiccating causes the internal cracks of undisturbed loess to develop and evolve continuously. Therefore, it is of great significance to study the development and evolution of loess fissures under the action of humidification and dehumidification. The microstructure changes of soil samples under the action of humidification and dehumidification were obtained by CT scanning technique, and the curves of soil CT number ME and SD value with soil sample humidification and moisture desiccation were obtained. The results showed that: with the increase of soil moisture, The internal damage rate of soil increases slowly. When the moisture content exceeds the plastic limit of soil sample, the damage rate of soil is accelerated, and when the moisture content exceeds a certain value, the mean value and variance of CT number slow down with the change of water content are all in inverse "S" curve. With the increase of dry-wet cycle times, the microcracks of soil samples develop gradually, showing that the microcracks of soil samples grow wider and become irregular bifurcations. Even after four dry-wet cycles, the cracks of soil samples are basically reticulated, and the soil samples are relatively broken. At this time, the mean and variance of CT number change little; the larger the range of dry and wet circulation, the greater the damage degree of soil sample, and the faster the development of joints and fractures in soil sample.
【作者單位】： 西安科技大學建筑與土木工程學院;四川省眉山市彭山區(qū)住房和城鄉(xiāng)規(guī)劃建設局;
【基金】：國家自然科學基金項目(41672305,41172262) 陜西省重點科技創(chuàng)新團隊計劃(2014KCT-30)資助
【分類號】：P642.131

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本文編號：1678511