This research project focuses on the study of techniques to mitigate the physical deterioration of soil undergoing drying processes. The most important benefit of the project is the development of technologies to reduce or mitigate the impact of soil deterioration on infrastructure, agriculture and natural heritage. This problem is relatively frequent in geotechnical infrastructures (embankments, dykes, dams, landfill covers, etc.) and in agriculture, due to the impact of extreme meteorology on the integrity of the soil. In previous projects, the bases were established for the identification of the mechanisms and parameters that control soil cracking by desiccation. In addition to theoretical and numerical advances, facilities were set up in the laboratory (environmental chamber) and in the field (3x3x0.5 m container) that will be used for this project, whose main objective is to establish techniques for control and mitigation of such deterioration using geosynthetics (permeable geotextiles, waterproof geomembranes and reinforcing geogrids). Such materials are commonly used in engineering, but their application to design is often based on empirical criteria. In this project, the numerical tools and existing experimental facilities will be used to approach the use of geosynthetics as ground improvement elements against deterioration by cracking, with a scientific basis. The project includes two lines of action, one experimental and another theoretical-numerical. In both, the study of compacted soils, instead of the soil with excess water from previous projects, is proposed. This is intended to better reproduce applications in engineering, which are always with compacted soils. In the experimental line, it is proposed to carry out advanced characterization tests of geotextiles, not provided by the manufacturers, but which are fundamental for the analysis (for example, retention curve). Environmental chamber tests with controlled boundary conditions and wetting and drying cycles are also considered, with soil and geosynthetics. Field tests will also be carried out in the existing large container with compacted soil and geotextile (3 types: permeable, waterproof and geogrid). The instrumentation will allow measurements of changes in humidity, temperature, heat flow and suction over time and at different depths, above and below the geosynthetic layer. In addition, meteorological data from the area will also be available. In the numerical line of work, the existing available finite element codes will be used, which solve the coupled Thermo-Hydro-Mechanical problem in unsaturated conditions (liquid water flow and water vapour and air flow). The objective is to reproduce the physical processes involved and simulate the evolution of the variables measured in the tests. An important element for this is the atmospheric boundary condition, including solar radiation and wind velocity, in the heat and water vapour (evaporation) flows on the ground surface. Experience has shown that soil shrinkage and subsequent cracking are highly dependent on evaporation rate, soil type and boundary conditions. The incorporation of geosynthetics in the soil mass clearly conditions these aspects.
Demagistri, A.; Ledesma, A.; Cordero, J.A.; Moreno, R.; Prat, P.; Jacinto, A. International Conference on Unsaturated Soils p. 1273-1278 Presentation's date: 2018-08-04 Presentation of work at congresses