排灌水条件下砂黏土层变形响应模型箱试验
发布时间：2019-05-07 11:46
【摘要】：地面沉降区野外钻孔土层应变监测数据表明,含水砂层上方的黏土层存在着明显的压应变。为研究这一现象,建立了砂黏互层小型模型箱,沿土层竖直方向埋设分布式应变监测光纤,水位管和沉降标。开展了3次排灌水循环试验,并监测土层在竖直方向上的应变,水位高度和沉降量的变化。试验结果表明:在3次排灌水循环中,土体渗透率减小,土体被压密;黏土层存在水压变化的滞后现象;排水过程中,黏土层中的孔隙水出现负压,相应区域也出现显著的压应变。结合前人研究,分析讨论了钻孔应变数据与模型箱试验结果,得出结论:砂层排水后,黏土层释水和补给不平衡,导致负压的出现,并在黏土层中产生额外的有效应力和压缩变形。在地下水位波动时,这种效应可能会导致砂层上方的黏土层被持续缓慢压缩。
[Abstract]:The monitoring data of the field borehole soil layer in the land subsidence area shows that the clay layer above the water-bearing sand layer has obvious compressive strain. In order to study the phenomenon, a small-scale model box for sand-adhesion is established, and distributed strain monitoring optical fiber, water level tube and settlement mark are embedded in the vertical direction of the soil layer. Three water cycle tests were carried out, and the strain, water level and settlement of the soil layer in the vertical direction were monitored. The results of the test show that the permeability of the soil is reduced and the soil mass is compacted in the three drainage and irrigation water circulation. In the process of drainage, the pore water in the clay layer has negative pressure, and the corresponding region also has significant compressive strain. The results of the experimental results of the borehole strain data and the model box are discussed in this paper. The results of the experiment are as follows: after the sand layer is drained, the water release and the make-up of the clay layer are not balanced, resulting in the occurrence of the negative pressure, and the additional effective stress and compression deformation are generated in the clay soil layer. This effect may result in a sustained and slow compression of the clay layer above the sand layer when the groundwater level fluctuates.
【作者单位】： 南京大学地球科学与工程学院;南京大学(苏州)高新技术研究院;地质灾害防治与地质环境保护国家重点实验室(成都理工大学);
【基金】：国家自然科学基金项目(41230636,41372265,41302216) 地质灾害防治与地质环境保护国家重点实验室开放基金项目(SKLGP2015K018)
【分类号】：TU433
本文编号：2471051
[Abstract]:The monitoring data of the field borehole soil layer in the land subsidence area shows that the clay layer above the water-bearing sand layer has obvious compressive strain. In order to study the phenomenon, a small-scale model box for sand-adhesion is established, and distributed strain monitoring optical fiber, water level tube and settlement mark are embedded in the vertical direction of the soil layer. Three water cycle tests were carried out, and the strain, water level and settlement of the soil layer in the vertical direction were monitored. The results of the test show that the permeability of the soil is reduced and the soil mass is compacted in the three drainage and irrigation water circulation. In the process of drainage, the pore water in the clay layer has negative pressure, and the corresponding region also has significant compressive strain. The results of the experimental results of the borehole strain data and the model box are discussed in this paper. The results of the experiment are as follows: after the sand layer is drained, the water release and the make-up of the clay layer are not balanced, resulting in the occurrence of the negative pressure, and the additional effective stress and compression deformation are generated in the clay soil layer. This effect may result in a sustained and slow compression of the clay layer above the sand layer when the groundwater level fluctuates.
【作者单位】： 南京大学地球科学与工程学院;南京大学(苏州)高新技术研究院;地质灾害防治与地质环境保护国家重点实验室(成都理工大学);
【基金】：国家自然科学基金项目(41230636,41372265,41302216) 地质灾害防治与地质环境保护国家重点实验室开放基金项目(SKLGP2015K018)
【分类号】：TU433
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