1.School of Civil and Hydraulic Engineering,Lanzhou University of Technology,Lanzhou,Gansu 730050,China
2.Engineering Research Center of Western Civil Engineering Disaster Prevention and Mitigation,Ministry of Education,Lanzhou University of Technology,Lanzhou,Gansu 730050,China
Engineering disasters in loess regions are fundamentally macroscopic manifestations of soil structural destabilization induced by the coupled Mechanical-Hydrological-Gas-Chemical (MHGC) interactions. This paper provides a critical review of the state-of-the-art research concerning loess disaster mechanisms under MHGC coupling, identifies current theoretical bottlenecks, and delineates future research trajectories. It is revealed that the nonlinear interplay among distinct physicochemical fields—mediated by mechanisms including suction-effective stress conversion, dissolution-damage coupling, and gas pressure-seepage feedback—constitutes the primary driving force behind multi-scale catastrophic evolution. However, existing constitutive models remain predominantly confined to Hydrological-Mechanical (HM) or simplified three-field coupling scenarios, failing to adequately characterize the unified effects of chemical damage and dynamic gas-liquid-solid phase interactions. Consequently, future research endeavors should align with the imperative for precision disaster control. By integrating typical engineering case studies, it is crucial to conduct in-depth investigations into the MHGC coupling characteristics of unsaturated loess and establish comprehensive constitutive relationships. Such advancements are essential to facilitate a paradigm shift in loess engineering from “passive prevention” to “active regulation,” and ultimately, towards “precision control.”
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