Field Instrumentation for Real-time Monitoring of Periglacial Solifluction

摘要

Here we describe new field instrumentation recently installed on a non-permafrost solifluction slope in Dovrefjell, Norway, and a continuous permafrost solifluction slope in Svalbard. The equipment is designed to provide continuous data on soil thermal status, hydraulic condition, phase change, soil volume strain and soil shear strain. Supporting frames were constructed from steel scaffolding tubes and provide a stable mounting for two LVDT displacement transducers. These are arranged in an inverted triangular configuration with the triangle apex linked to a small steel footplate embedded in the ground surface, allowing continuous monitoring of frost heave, thaw settlement and downslope surface displacements. In addition, thermistors and Druck PDCR 81 miniature pore pressure transducers were installed to a depth of 0.8 m in Dovrefjell and 1.2 m (approximately 20 cm below the permafrost table) in Svalbard. Thermistors were also mounted above the ground surface to 2 m to measure air temperature. All instrumentation was logged at 1 h intervals using a Campbell CR23X logger and multiplexer. In Svalbard an automatic digital camera recording one image per day was installed adjacent to the site in order to monitor snow depth. Simple Rudberg columns will be excavated after several years to observe the profiles of soil movement.