Abstract：With regard to the issue of transverse stability mechanism of shallow tunnel constructions in clayey grounds with local loads, an upper bound limit analysis theory and a continuous soil movement model based on Peck’s formula and undrained incompressible condition are employed to computationally study the effects of soil physical-mechanical parameters, shallow foundation loads, and pile foundation loads on the infimums of the necessary tunnel support pressures. It is found that, while keeping other parameters constant, the infimum support pressure decreases linearly with the increase of the shear strength of soil, and increases linearly with the increase of the unit weight of soil; increases linearly with the increase of the magnitude of shallow foundation loads, decreases nonlinearly with the increase of the transverse distance of shallow foundation loads and approaches asymptotically to a constant, and increases nonlinearly with the increase of the lateral range of shallow foundation loads and approaches asymptotically to a constant; increases linearly with the magnitudes of the shear load on pile shaft and the pressure load at the pile end, decreases nonlinearly with the transverse distance of the pile foundation loads and approaches asymptotically to constant, and for end-bearing piles, increases (or decreases) with the length of pile when the latter is smaller (or larger) than the depth where the largest settlement in the vertical distribution occurs.
