Integrated Geoenvironmental Models for Performance Assessment of Tunnels in Soft Soils

abstract

Geoenvironmental effects on strategic on-ground or underground infrastructure, such as ground subsidence, and earthquakes, along with flooding and material deterioration due to water infiltration and weathering, can significantly affect its short, medium, and long-term performance. Furthermore, these effects are critical in densely populated cities, where the overall safety of a particular structure can be jeopardized if those effects are ignored, and poor geotechnical conditions prevail. This paper presents a case study evaluation based on integrated geoenvironmental models (IGM) for the short and long-term performance of a tunnel built in soft soils in order to establish mitigation measures to avoid irreversible damage or even structure collapse. The method integrates real-time field monitoring with advanced numerical analyses. Based on surrogate models derived from numerical models of several scenarios, it enables the establishment of an optimum range for the expected performance, which is achieved by the development of efficiency curves as a function of the measured environmental parameters (i.e., pore pressure distribution and peak ground acceleration). The proposed methodology is applied to a 10 m diameter, 9.1 km long tunnel, which is part of a metro line, constructed in the high plasticity clays of Mexico City, where the underground infrastructure is exposed to regional subsidence and strong ground motions due to high seismic activity. From the results gathered here, it was possible to assess the behavior of a tunnel under sustained and seismic loading for both short to long-term conditions, establishing a holistic IGM which allows risk reduction, and to develop proper mitigation measures to enhance its resilience during its economic life. © 2025 American Society of Civil Engineers.