Speaker
Description
Cosmic-ray muography has emerged as a powerful non-invasive technique for probing the internal structure and overburden conditions of large-scale infrastructures in complex urban environments. In this work, we report recent progress on studies of two representative underground tunnel systems in Shanghai, China.
First, a portable dual-layer muon flux detector based on plastic scintillators was deployed in the Shanghai Outer Ring Tunnel, an immersed tunnel beneath the Huangpu River, to investigate sediment accumulation above the tunnel crown and to validate the influence of tidal variations on muon flux. By combining in situ measurements with Geant4 simulations that include sediment, water, and concrete layers, we established a quantitative correlation between muon attenuation and overburden thickness. The measured muon flux exhibits a strong anti-correlation with nearby tide-gauge water-level data, demonstrating the sensitivity of muography to both sediment distribution and tidal fluctuations in submerged infrastructure environments.
Second, we are carrying out an ongoing muon radiography campaign in the Caobao Road Tunnel using two transmission-imaging detectors to probe the overburden region above the tunnel. This study aims to reconstruct the three-dimensional density distribution of the overlying soil and structural environment from transmission measurements. Preliminary progress indicates the feasibility of resolving large-scale underground heterogeneities in a dense urban setting and highlights the potential of multi-detector observation for 3D muon radiography of urban infrastructure.
Together, these studies demonstrate the applicability of cosmic-ray muons to long-term monitoring and three-dimensional imaging of urban underground infrastructure. The results support the growing role of muon radiography in civil engineering, geotechnical assessment, and resilience-oriented infrastructure management.