In this study, a model test was carried out to investigate the hydro-mechanical properties of calcareous sand, and distributed fiber optic sensing technologies were utilized to monitor the entire process. The test procedure had three stages: one-way water supply, one-way drainage, and two-way drainage. The actively heated fiber optic (AHFO) method was used to monitor the soil moisture profiles, and soil deformation was captured using the high-accuracy optical frequency domain reflectometry technique. The Pearson correlation function was used to describe the relationship between soil compression and moisture content. The results indicated that the AHFO method allowed soil moisture measurement in saturated and unsaturated zones with a bias of 0.027 m³/m³. Water infiltration in calcareous sand can lead to uneven settlement, toppling, and horizontal deformation, with most settlements occurring during the watering stage. The ground settlement was mainly caused by particle sliding and rotation during the watering and drainage processes. The results show that settlement occurred earlier when the soil was closer to the water supply chamber. Moreover, tension cracks can easily appear between the calcareous sand and fine-grained soil interlayers. The Pearson correlation coefficients were larger than 0.8, indicating that the soil layer was compressed owing to particle sliding and rotation, and the moisture contents had a linear correlation with compressive strains.

本研究通过模型试验研究钙质砂的水力学特性，并利用分布式光纤传感技术对整个过程进行监测。试验过程分为三个阶段：单向供水、单向排水和双向排水。主动加热光纤（AHFO）方法用于监测土壤水分剖面，并使用高精度光频域反射计技术捕获土壤变形。Pearson 相关函数用于描述土壤压缩与含水量之间的关系。结果表明，AHFO方法允许在饱和和非饱和区测量土壤水分，偏差为0.027 m ³ /m ³. 钙质砂的渗水会导致不均匀沉降、倾覆和水平变形，大部分沉降发生在浇水阶段。地面沉降主要是由于浇水和排水过程中颗粒滑动和旋转引起的。结果表明，当土壤靠近供水室时，沉降发生得更早。此外，钙质砂与细粒土夹层之间很容易出现张裂。Pearson 相关系数大于 0.8，表明土层因颗粒滑动和旋转而受到压缩，含水量与压缩应变呈线性相关。