基于DFOS的排灌水条件下土体变形响应模型试验研究

发布时间：2018-07-31 07:58

【摘要】：黏土层和砂土层交替变化的多层土体在强烈开采地下水作用下极易产生压密固结而引发地面沉降灾害。本文针对含水层释水引起地面沉降问题,研制了地面沉降试验装置,进行了排灌水条件下含水层系统的沉降及回弹试验。采用分布式光纤感测技术对土体内部应变分布及含水率变化进行耦合监测,并分析了各分层对水位变化的响应特征。结果表明:黏土层和砂土层均表现出了排水压缩和灌水回弹特点,黏土层变形较砂土层明显。各层变形与含水率变化具有良好的对应关系,表现为砂土层变形和含水率变化基本同步,而黏土层变形略微滞后于含水率变化。黏性土压缩曲线具有明显的分段特征,排水时当含水率低于液限后迅速减小,黏土层压缩速率明显加快;回灌时当含水率高于液限后,回弹速率明显加快。试验结果对研究地面沉降机理、评价地面沉降潜力及地下水利用具有重要意义。
[Abstract]:The clay layer and the sand layer alternately change the multi-layer soil body under the strong mining groundwater action easily produces the compaction consolidation and causes the ground subsidence disaster. In order to solve the problem of land subsidence caused by aquifer water release, a land subsidence test device was developed, and the settlement and springback tests of aquifer system were carried out under the condition of drainage irrigation. The distributed optical fiber sensing technique is used to monitor the strain distribution and water content change in soil and the response characteristics of each layer to water level change are analyzed. The results show that both clay layer and sand layer have the characteristics of drainage compression and irrigation resilience, and the deformation of clay layer is more obvious than that of sand layer. There is a good corresponding relationship between the deformation of each layer and the change of water content, which shows that the deformation of sand layer and the change of water content are basically synchronized, while the deformation of clay layer lags behind the change of water content slightly. The compression curve of clay soil has obvious segmental characteristics. When the water content is below the liquid limit, the compression rate of clay layer decreases rapidly, and when the water content is higher than the liquid limit, the springback rate is obviously accelerated when the water content is higher than the liquid limit. The experimental results are of great significance for studying the mechanism of land subsidence, evaluating the potential of land subsidence and the utilization of groundwater.
【作者单位】：南京大学地球科学与工程学院;南京大学地理与海洋科学学院;
【基金】：国家自然科学基金项目(41372265);国家自然科学基金重点项目(41230636)资助
【分类号】：P641.8

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