In geotechnical engineering, geostructures with thermo-active functions establish direct thermal exchange between the ground and buildings. They can transfer energy from or into the ground to heat or cool a building. However, adapting foundation piles, completely or in part, to produce energy piles results in heat exchange with the soil, which changes the temperature of the soil and could thereby and affects the geotechnical properties and load bearing capacity of the geostructure. Most calculations of the bearing capacities of deep foundations conducted in France are currently based on in-situ testing results using a pressuremeter. Using finite element method to model the pressuremetric behaviour of a compacted soil subjected to thermo-mechanical variations is the main motivation for this work. In this study, several pressuremeter tests were conducted on a compacted illitic soil in a laboratory tank at temperatures between 1 and 40 C. The impact of temperature variation on the limit pressure (Pl), the creep pressure (Pf) and the Menard pressuremeter modulus (EM) were determined. The results showed a significant decrease for both limit pressure (Pl) and creep pressure (Pf) with the increase of temperature. Numerical simulations of these tests were used to calibrate a bilinear constitutive model, taking into account temperature effects on soil compressibility within a coupled thermo-mechanical framework. Thereafter, a case study of a heat exchanger pile was simulated using the proposed approach.

• Temperature effects on the design parameters of a geothermal pile
  • 1. Introduction
  • 2. Methods
    • 2.1. Material and experimental device
    • 2.2. Sample preparation and compaction in the small-scale model
    • 2.3. Mini-pressuremeter tests
    • 2.4. Pressuremeter parameters of the soil submitted to thermal variations
    • 2.5. Numerical simulation
  • 3. Results and Discussions
    • 3.1. Pressuremeter parameters of the soil submitted to thermal variations
    • 3.2. Simulation of the energy pile behaviour using simplified model
  • 4. Conclusions

Magazine of Civil Engineering / Санкт-Петербургский политехнический университет Петра Великого. — Санкт-Петербург: СПбПУ, 2020-. — Периодичность: 8 раз в год. — Выходит с 2020 г. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Электрон. журнал. — Текст: электронный

Magazine of Civil Engineering / Санкт-Петербургский политехнический университет Петра Великого. — Санкт-Петербург: СПбПУ, 2020-. № 8 (116), 2022. — 1 файл (17,4 Мб). — Свободный доступ из сети Интернет (чтение, печать, копирование). — Электрон. журнал. — <URL:http://elib.spbstu.ru/dl/2/j23-99.pdf>.