Thermal pressuremeter- Novel tool for study the thermomechanical behaviour of soils

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To analyze the thermo-mechanical behavior of soils, this paper proposes a device that introduces thermal effects into the pressuremeter apparatus, referred to as the thermal pressuremeter. The technique involves heating the liquid contained within the hydraulic system's reservoir, which is connected to the measuring cell. Glycol water is used as the liquid due to its favorable thermal properties. At various temperatures, the liquid is heated and then circulated through the tubing to the probe. As a result, the proposed device can measure the limit pressure of soil subjected to both internal pressure and temperature variations.

Before manufacturing the device, both analytical and numerical models are developed and discussed. Specifically, the pressuremeter test under thermal variations is numerically modeled by simulating the expansion of a cylindrical cavity, where the probe is represented as a cavity undergoing radial expansion. A finite difference analysis, accounting for large strains and thermal effects, is performed using FLAC V 7.00 (Itasca Consulting Group). The model assumes that the soil behaves as a homogeneous, elastic, perfectly plastic material following the Mohr-Coulomb yield criterion. The numerical simulation results, including stresses, displacements, and limit pressure, are compared with a published analytical solution. According to the numerical results, soil temperature has a significant impact on the limit pressure.

The major contribution of this work is the incorporation of thermal variations into a numerical 2D model of cylindrical cavity expansion, validating the effectiveness of the proposed device. These findings are particularly relevant for interpreting pressuremeter test results and designing geothermal piles.

8th International Symposium on Pressuremeters (ISP2025)

Data Interpretation and Analysis