The field monitoring of the climatic-induced behaviour of the expansive soil has always been difficult, expensive and time consuming. The uncontrollability of the field boundary conditions and the difficulty in accurately measuring them have worsened the problem. As an alternative, the instrumented model set-ups are ideal for long-term monitoring of expansive soils since the laboratory compacted expansive soils become environmentally stabilised after few wet–dry cycles. There had been a very limited laboratory-based column set-ups for the observation of expansive soils under unsaturated conditions with an appropriate set of sensors embedded at known depths. The major difficulties associated with model tests are considerable boundary effect and sensor-to-soil area ratio due to the insufficient physical model dimensions. In this study, the research need for a laboratory model set-up with minimised boundary effects has been addressed by a large instrumented soil column, which could more closely represent environmentally stabilised soil. The current results depict the expected pattern for the variations of soil suction, volumetric water content and soil displacement under wetting and drying phenomenon, which accentuates the applicability of instrumented soil column for the investigation of climatic-induced expansive soil behaviour.

中文翻译：

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用于调查气候地面相互作用的仪器化大型土柱

对膨胀土的气候诱发行为进行现场监测一直是困难、昂贵和耗时的。场边界条件的不可控性和准确测量它们的困难使问题更加严重。作为替代方案，仪器模型设置非常适合膨胀土的长期监测，因为实验室压实的膨胀土在经过几次干湿循环后变得环境稳定。用于观察非饱和条件下膨胀土壤的基于实验室的柱子设置非常有限，并且在已知深度嵌入了一组合适的传感器。由于物理模型尺寸不足，与模型测试相关的主要困难是相当大的边界效应和传感器与土壤的面积比。在这项研究中，大型仪器化土柱解决了对边界效应最小化的实验室模型设置的研究需求，该土柱可以更接近地代表环境稳定的土壤。目前的结果描述了在干湿现象下土壤吸力、体积含水量和土壤位移变化的预期模式，这强调了仪器化土柱在研究气候引起的膨胀土行为方面的适用性。