Interpretation method for laser-scanning point clouds of segmental tunnel linings based on hybrid analysis

Abstract

Owing to its convenience and precision, laser scanning has been applied in inspecting segmental tunnel linings. The point clouds generated by laser scanning provide valuable geometric information regarding the lining profile. Numerous studies have identified defects including cracks, leaks, and concrete spalling from these point clouds. However, they primarily relied on computer vision and neglected the mechanical information inherent in point clouds. This paper proposes a method for interpreting laser-scanning point clouds related to segmental tunnel linings based on analytical back analysis, known as hybrid analysis. The objective involves interpreting the mechanical behavior of segmental tunnel linings derived from point clouds. Through hybrid analysis, the deformation of the segmental tunnel linings was broken down into deflection and rigid-body motion. This process revealed the contribution of joints to the overall deformation of the linings. The strain of the segmental tunnel linings can be further quantified using the elastic theory of an arch slender. To validate the hybrid analysis, results were compared with experimental monitoring results. Further, potential application scenarios for the proposed method were explored. This method holds promise in engineering practice because it requires limited knowledge of the external loads, rendering it suitable for in-operation tunnels buried in uncertain strata.