Study of the spatiotemporal evolution of the stress, deformation and creep characteristics of pillars in solid potash mines
Abstract The stress evolution and creep characteristics of pillars are highly important for safe mining. To study the spatiotemporal evolution of the stress, deformation and creep characteristics of pillars in solid potash mines, the evolution of the stress field and displacement field in the contin...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Springer
2025-08-01
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| Series: | Geomechanics and Geophysics for Geo-Energy and Geo-Resources |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s40948-025-01001-w |
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| Summary: | Abstract The stress evolution and creep characteristics of pillars are highly important for safe mining. To study the spatiotemporal evolution of the stress, deformation and creep characteristics of pillars in solid potash mines, the evolution of the stress field and displacement field in the continuous mining of solid potash mines is monitored by a fibre grating sensing system. The evolution of the surface displacement field during the creep of the pillar was subsequently obtained by digital image correlation technology. Furthermore, on the basis of conventional mechanics theory and the generalized Voigt–Kelvin model, a creep model was established to characterize the degree of deformation of the pillar, and its applicability was verified by experimental data and literature-related data. The results revealed that the deposition velocity of the roof increases linearly during the excavation of the first room in the panel and that the deposition velocity of the roof decreases exponentially during the excavation of the following rooms. After the first layer of the room was exposed, the deposition velocity suddenly increased, and the roof displacement increased significantly. The evolution of mining stress presents a stage of steady increase, a stage of rapid increase and a stage of slow increase. Compared with the stress during first-step mining, the stress during second-step mining is greater. Moreover, the distribution of the mining stresses in the second step depends largely on the nature of the filling body and is significantly enhanced in the stage of steady increase of mining and significantly reduced in the slow increase phase. In the process of pillar creep, the pillar shows an obvious radial and axial displacement gradient with time, and the displacement gradient gradually tends to be stable. The exponential function can also effectively characterize the variation in the radial displacement and axial displacement. With increasing creep time, the axial (radial) deformation first decreases (increases) rapidly and then decreases (increases) slowly. When the creep is stable, the axial displacement decreases linearly in the height direction of the pillar, indicating a symmetrical deformation mode. In contrast, the radial displacement tends to increase and then decrease, and the radial displacement on the left wall of the column is smaller than that on the right wall, indicating an asymmetric deformation mode. The ore layer is composed of carnallite and sodium chloride, and there are staggered structural planes in the ore layer, resulting in an asymmetric deformation mode of radial displacement. The improved Voigt–Kelvin creep model can accurately quantify the degree of creep deformation of a pillar. This model accurately reflects the axial symmetric deformation mode and radial asymmetric deformation mode. The deformation coefficient and displacement cloud diagram of the monitoring points exhibit a high degree of consistency. The research results can provide theoretical guidance for safe mining and tailings filling of solid potash mines. |
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| ISSN: | 2363-8419 2363-8427 |