Measuring the long-term deformation of in-situ ice-rich permafrost using a plate loading test

Abstract

In order to determine the long-term deformation behavior of in-situ ice-rich permafrost under natural conditions, three deformation setups utilizing a plate loading method were built in a permafrost region on the Qinghai–Tibetan Plateau. The loading plates were installed just below the permafrost table, and loads were applied via platforms that were held constant throughout. Variations in permafrost deformation and ground temperatures were recorded over a period of five years. Test results show that ground temperature at the loading plate depth fluctuated seasonally within a warm range between −3.0 °C and −0.2 °C, while the frozen ground settled over a considerable range, between 60 mm and 230 mm. Deformation was observed to be step-like in behavior, given an external load of 0.25 MPa. The amount of settlement observed during deformation was significantly influenced by ground temperature and ice content.