Abstract:To study the mechanical characteristics of the inverted arch structure of highway loess tunnel, taking the Fengshuiling highway loess tunnel as the engineering background, two tunnel sections with different embedded depths were selected. By embedding pressure boxes, concrete strain gauges, rebar gauges, surface strain gauges and other sensors, the evolution laws of surrounding rock pressure, shotcrete stress, steel frame stress, contact pressure between primary support and secondary lining, se-condary lining concrete stress, and reinforcement stress of the highway loess tunnel invert were studied, and the mechanical characteristics of the loess tunnel invert structure were analyzed. The experimental results show that the stress characteristics of the inverted arch structure of the loess tunnel are significantly different under different embedded depths. The pressure of the inverted arch surrounding rock in the section with a larger embedded depth is obviously greater than that in the section with a smaller embedded depth. Under different embedded depths, the stress characteristics of the inverted arch structure of the loess tunnel with the same cross section form and the same surrounding rock condition are diffe-rent, but the position of the arch foot is prone to the tensile stress. The tunnel invert structure with a large embedded depth is easy to show the states of upper compression and lower tension. The bearing capacity of the foundation of the loess tunnel invert has a significant effect on the mechanical characte-ristics of the invert.