酸性环境下黄土湿陷性试验与湿陷敏感性研究

发布时间：2018-07-20 15:06

【摘要】：黄土的胶结连接是黄土湿陷的重要内在因素,对其湿陷敏感性有着直接影响。为了对胶结连接在黄土湿陷敏感性中的作用有更清楚的认识并提出一个能科学的判定黄土湿陷敏感性的评价方法,在黄土湿陷性试验的浸入水溶液里添加不同浓度的硝酸,测试在酸性环境中,不同压力下黄土的湿陷系数、稳定时间、湿陷速率等湿陷敏感性指标。同时用扫描电镜观察试验前后土样的孔隙、结构变化情况。试验结果表明:在酸性溶液中,湿陷性黄土在低压状态下的湿陷系数增大较多,在各级压力下的湿陷稳定时间均有所延长;在水溶液和酸性溶液中,黄土有着不同的湿陷敏感压力区间;湿陷性黄土的结构强度对湿陷性黄土的深度有着重要影响等。在此试验基础上,吸取前人的经验,提出用完成90%湿陷量的用时和湿陷系数这2个指标对黄土及其场地进行湿陷敏感性评价,并以发生过湿陷的场地——抽黄渠为实例对此方法进行验证。验证结果表明,该方法能准确地反映湿陷场地的湿陷敏感性,对湿陷场地上的工程建设具有一定的指导意义。此外,该方法简单、科学,又能与现行规范相结合,因此,易于被业界接受并推广,是对现有少数关于黄土湿陷敏感性研究的有益补充。
[Abstract]:The cementation connection of loess is an important internal factor of loess collapsibility and has a direct influence on its collapsibility. In order to have a clearer understanding of the role of cemented joints in the sensitivity of loess collapsibility and to put forward a scientific evaluation method of loess collapsibility sensitivity, different concentrations of nitric acid were added to the soaking water solution of loess collapsibility test. The collapsibility indexes of loess under different pressures, such as coefficient of collapsibility, time of stabilization and rate of collapsibility, were tested in acidic environment. At the same time, the pore and structure of soil samples before and after the test were observed by SEM. The results show that in acid solution, the collapsibility coefficient of collapsible loess increases more at low pressure, and the stable time of collapsibility is prolonged at various pressures, and in aqueous solution and acid solution, the collapsibility coefficient of collapsible loess increases at low pressure. Loess has different sensitive pressure zones and the structural strength of collapsible loess has an important influence on the depth of collapsible loess. On the basis of this experiment and drawing on the previous experience, it is put forward that the sensitivity of loess and its site should be evaluated by using the two indexes of time and coefficient of collapsibility to complete 90% of the volume of collapsibility. The method is verified by an example of the site of over-subsidence-the drainage channel of the Yellow River. The results show that the method can accurately reflect the sensitivity of the collapsing site and has certain guiding significance for the engineering construction of the collapsible site. In addition, the method is simple, scientific, and can be combined with the current norms. Therefore, it is easy to be accepted and popularized by the industry, which is a useful supplement to a few existing researches on loess collapsibility sensitivity.
【作者单位】：西安理工大学土建学院;西安理工大学陕西省黄土力学与工程重点实验室;陕西煤田地质勘查研究院有限公司;陕西环保产业集团有限责任公司;
【基金】：陕西省科技统筹创新工程重点实验室项目(2014SZS15 Z02)~~
【分类号】：TU444

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