Analysis of the influence of uneven settlement on the existing shield tunnel lining

The transverse deformation of the tunnel under various loads is unavoidable with the long-term operation of the subway, and the problem of uneven settlement is gradually highlighted. A three-dimensional of tunnel lining model is established in ABAQUS to simulate the uneven settlement and transverse deformation on the safety performance, in which the deformation, internal force, and damage are further analyzed. Based on the simulation, safe settlement values for the shield tunnel with different level of existing transverse deformations (L) are suggested. Because the internal force and damage are not only related to the settlement value (∆) but also to the length of the tunnel where the settlement occurs, the ratio of the settlement value (∆) to the corresponding length (L) of the shield tunnel ∆/L which is called the uneven settlement coefficient is proposed as an index. The uneven settlement coefficient ∆/L is given for different transverse deformations to extend the applicability of the safe settlement values, which provides theoretical support for on-site monitoring and tunnel maintenance to some extent.