Liuliu Li, Jinyi Zhao, Chengshuai Qin, Yu Zhang, Feng Shi, Sheng Sun
Silicate-based cliff sculptures constitute an important category of stone cultural heritage, yet their long-term preservation is severely challenged by weathering-induced deterioration and fracture-controlled instability. To elucidate the weathering mechanisms and assess the fracture stability of such heritage rock masses, this study investigates the Kongwangshan cliff sculptures in Lianyungang, China, one of the earliest extant cliff sculpture sites in the country. An integrated, non-contact, and high-precision research framework was established by combining field investigation, petrographic microscopy, X-ray diffraction, pore structure characterization, and high-resolution terrestrial laser scanning. The mineralogical and microstructural analyses reveal that the silicate host rock is dominated by quartz and feldspar, with evident sericitization of feldspars and the development of microcracks, indicating the coupled action of physical weathering and chemical alteration. Pore structure analysis shows overall low porosity and poor pore connectivity, suggesting that fractures, rather than primary pores, serve as the main pathways for moisture migration and weathering reactions. Based on 3D point cloud reconstruction, fracture structural planes were quantitatively extracted, and their geometric parameters were statistically analyzed. The results indicate that the dominant fracture planes dip inward toward the mountain with moderate dip angles (∼26°), which is unfavorable for large-scale sliding and contributes to the current macroscopic stability of the cliff. Fracture extension trend prediction suggests that, at present, key areas of the cliff do not exhibit conditions conducive to the formation of hazardous rock blocks. This study provides a robust scientific basis for stability assessment, preventive conservation, and long-term monitoring of silicate-based cliff cultural heritage sites.