Abstract:Reasonably designing the active failure limit support force of the tunnel face is the key to maintaining the stability of the shield tunnel. At present, most limit support force calculation methods are not suitable for complex shield tunnel engineering design. Based on the traditional wedge-shaped calculation model and considering the lateral pressure coefficient under the influence of soil arch effect, a calculation model for the active failure limit support force of tunnel face in layered soil was established by introducing the excavation inclination angle and seepage effect. Combined with a practical engineering case, the soil and design parameters that affect the limit support force were analyzed. The results show that the limit support force of tunnel face increases significantly with the increase of construction depth, groundwater level height, soil weight, and excavation inclination angle, while decreases nonlinearly with the increase of internal friction angle and cohesion; When considering the lateral pressure coefficient under the influence of soil arching effect, the calculated value of limit support force is reduced; The limit support force significantly increases after considering the effect of seepage; The parameter changes of different soil layers have a significant impact on the limit support force.