Thermal-Environmental Coupling Wear Mechanism of H13 Steel Disk Cutters in Tunnel Boring Machine Excavation of Composite Strata.

This study addresses abnormal cutter wear in H13 steel disc cutters during tunnel boring machine excavation of composite strata, where transient frictional shearing temperatures interact with environmental degradation. Taking the Xiangshan Tunnel at 160 m overburden depth as the engineering background, a coupled FLAC3D-PFC3D model was developed to resolve the coupled thermo-mechanical process, and a relative wear model based on the Holm method was formulated to incorporate sub-microscopic microstructural damage and quantify wear evolution. Numerical simulations elucidated the coupled thermal evolution mechanism at the cutter-rock interface. Systematic analyses were performed on single-cutter wear under coupled cutting temperature-chemical corrosion and cutting temperature-freeze-thaw cycling, together with the total wear for single-, double-, and triple-cutter configurations. Under temperature-chemical corrosion coupling, the peak wear coefficient of H13 steel reached 1.45 at 600 °C and pH 6. Under temperature-freeze-thaw cycling coupling, H13 steel peaked at 1.75 at 600 °C with 14 freeze-thaw cycles. Under triple-factor coupling, single-cutter wear was primarily influenced by freeze-thaw damage, double-cutter wear by penetration depth and chemical corrosion, and triple-cutter wear by cutter spacing and chemical corrosion. The chemical corrosion proportion in the double-cutter interface reached 89.4%. At 600 °C, thermal softening drastically amplified environmental degradation abrasion in the primary rock material. Chemical-thermal coupling exhibited greater influence than freeze-thaw cycling, and preferential chemical dissolution in the interface zone compressed the cutter parameter regulation space to its limit. The wear coefficient quantification and factor influence ranking reflect the multi-factor-coupled wear evolution in transportation tunnel composite strata. The parameter sensitivity data provides quantitative references for cutter replacement cycles, advanced parameter selection, and per-kilometer cost variations in tunnel construction management.