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| Degradation characteristics of pore structure and disturbance state model of gypsum breccia under the combined effect of water erosion and wet-dry |
| ZHU Aihong
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| Fuzhou Ganghou Railway Co., Ltd., Fuzhou 350019, Fujian, China |
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Abstract To reveal the coupled deterioration mechanism of water erosion and wet-dry cycling in gypsum breccia within underground engineering, gypsum breccia from a tunnel project in Shanxi Province was selected as the research object. The samples were subjected to ten wet-dry cycles, and the apparent deterioration characteristics as well as the water absorption-dissolution evolution behavior of the gypsum breccia under cyclic wet-dry conditions were systematically analyzed. Using nuclear magnetic resonance(NMR)technology, the pore structure deterioration characteristics of gypsum breccia during the wet-dry process were characterized. By comparing the deterioration morphology of samples under static water and flowing water conditions(with a flow rate of 10 L/h), the additional deterioration effect of water flow on the wet-dry deterioration process of gypsum breccia was further investigated. On this basis, a wet-dry deterioration model of gypsum breccia was developed based on the disturbed state concept(DSC)theory, combined with P-wave velocity and porosity test results. The results showed that the interfacial bonding strength between different material zones of the gypsum breccia was weakened by wet-dry cycles, while water flow was found to accelerate gypsum dissolution and deteriorate the shallow pore structure of the samples. The deterioration of gypsum breccia was jointly accelerated by the combined actions of wet-dry cycles and hydraulic erosion. A significant correlation was observed between the attenuation of P-wave velocity and the development of the pore structure in the gypsum breccia. The DSC-based wet-dry deterioration model was shown to accurately describe the mechanical deterioration behavior of gypsum breccia under different hydraulic conditions during cyclic wet-dry processes. The findings provide valuable reference data for the engineering design of tunnels in gypsum breccia strata.
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Published: 29 December 2025
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