Han L, Xue S R, Yin D W, et al. Study on the fabric evolution characteristics and damage degradation mechanism of paste filling body samples under the erosion of well water in chloride salt mine under pressure［J］. Journal of Henan Polytechnic University（Natural Science），doi: 10.16186/j.cnki.1673-9787.2026010018

doi: 10.16186/j.cnki.1673-9787. 2026010018

Received：2026-01-12

Revised：2026-08-27

Online：2026-09-30

Study on the fabric evolution characteristics and damage degradation mechanism of paste filling body samples under the erosion of well water in chloride salt mine under pressure

Han Lei¹, Xue Shirui²,Yin Dawei², Li Zongxu³, Ma Shibo⁴,Zhang Zhiwei⁴

（1.Shanxi Coal International Energy Group Co., Ltd., Taiyuan 030000, Shanxi, China；2.State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, Shandong, China；3.School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, China；4.Shanxi Huoerxinhe Coal Industry Co., Ltd., Changzhi 046000, Shanxi China ）

Abstract: [Objectives] Aiming at the problem that paste backfill in goaf of closed mines is subjected to long-term immersion of pressured chloride mine water, this study investigates the fabric evolution law and damage degradation mechanism of paste backfill under chloride ion erosion.[Methods]Using the combination of indoor erosion test and mechanism analysis, macroscopic test and microscopic analysis, the test of paste filling body samples soaked in chloride mine water (soaking age of 150 days) under different water pressures (0,0.5,1.5,3.0 MPa) was carried out. The microscopic morphology characteristics, chloride ion penetration law, hydration products and mechanical properties of paste filling body were studied, and the deterioration mechanism of mechanical properties of paste filling body was analyzed.[Results] The results show that :(1) The uniaxial compressive strength of the paste backfill samples was found to decrease with the increase of soaking pressure. At the same sampling depth, the chloride ion content in the samples immersed under high water pressure was higher than that under low water pressure. (2) The porosity of the paste filling body, the micro-cracks of the sample and the salt corrosion products increase with the increase of the soaking pressure. The internal structure of the paste filling body sample is more loose, the salt corrosion products increase, and the cement hydration products decrease. The diffraction peaks of sodium chloride (NaCl) and Friedel’s salt (Friedel’s salt) were decreased and gradually disappeared with the increase of sampling depth, and the diffraction peak intensity was increased with the increase of soaking pressure. (3) With the increase of soaking pressure, the microcracks and pores inside the filling body were accelerated. At the same time, the generated Friedel’s salt and the chloride ions adsorbed by the pore wall of the sample or the hydrated calcium silicate (C-S-H) gel were accumulated and expanded, which promoted the development of micropores in the sample. The synergistic effect of the two was found to reduce the mechanical strength of the paste filling sample. [Conclusions] This research was of great significance for the long-term stability of paste backfill under water erosion in pressurized chloride salt mines.

Key words: cemented paste backfill; water pressure-chloride salt; mechanical properties; structural evolution; degradation mechanism

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