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Optimization analysis on the support performance of composed anchor rod components in gob-side roadway

Yu Jiang, Jin Linlin, Ma Hongfa, Zhang Jun, Wang Feng, He Xin, Yin Dawei

Mining Science

2025

Vol. 32

65--85

In response to the failure problem of the roadway support structure for the deep buried mine, the mechanical calculation model was established based on the stress state and the boundary conditions of the composed anchor rod under the large surrounding rock deformation, and the failure discrimination criterion was obtained. Then a structural analysis unit for rock-composed anchor was established using ANSYS simulation software, which intensively researched the single-point and local failure characteristics of anchor rods in gob-side entries, and the optimization measures of the com-posed anchor rods were proposed. The findings reveal that the higher preload could restrain the axial displacement of the anchor rod, leading to stress concentration, fracture, or loosening of anchor bolts or nuts by the insufficient rock deformation. In addition, the stress concentration and plastic deformation of pallet orifice are significant as the main pressure-bearing part. The increase in the surrounding rock deformation leads to an enhanced combined action of pressure and shear force between the steel strip and the pallet edge, which makes the steel strip prone to failure. Consequently, the optimization measures of reducing prestress and increasing the size of pallet and strip are proposed, which can effectively control the deformation of surrounding rock and reduce the stress concentration, plastic deformation and failure rate of composed anchor rod.

Analysis of the effect of seasonal changes on sensitive parameters of LAI based Penman–Monteith evapotranspiration model based on particle swarm algorithm

Duan Hao, He Xin, Zhao Hongli, Jin Xiaohui, Xu Haowei, Wang Rong

Acta Geophysica

2023

Vol. 71, no. 2

1033--1043

The existing researches for leaf area index (LAI)-based Penman–Monteith evapotranspiration (ET) model (PML) are mostly carried out at yearly scale and the analysis of effects of seasonal change and different underlying surface conditions on model parameters is scarce. This study emphasizes on the influences of seasonal change and diverse land surface conditions on ET by optimizing the sensitive parameters, namely soil evaporation coefficient f and maximum stomatal conductance gsx, with particle swarm algorithm. This analysis is based on the observations of eight flux stations in China. The model performance is reasonable with a best Pearson r of 0.87. The seasonal calibration results indicate parameters change evidently in different seasons and have obvious spatial heterogeneity. The seasonal calibration method has an obvious effect on improving the ET accuracy in spring, which is mostly influenced by regional temperature and relative humidity. This study further demonstrates the need to dynamically adjust model parameters over time with PML model for evapotranspiration simulations, rather than simply setting these parameters to constants depended on subsurface conditions such as land use type.

4D gas geological research on coal seam with gas hazard potential in mining panel

Cui Hongqing, He Xin, Wang Zehua

Journal of Sustainable Mining

2022

Vol. 21, iss. 2

112--119

According to regulations of the mining industry in China, it is necessary to carry out gas hazard prevention projects in advance when mining coal seams with gas hazard potential, and gas geological research should be taken as the basic work for optimal design and effective construction of gas hazard prevention projects. Research on coal seam with gas hazard potential have shown that anomalous geological area could be the gas hazard potential area as well, where superimposed tectonic and mining stress field usually results in tectonically disturbed coal and pressured gas. A 4D gas geological research method is used to find out the anomalous geological area and assess its gas hazard potential. The method covers two ranges of gas geological research: fine geological survey and 4D analysis. The former includes a comprehensive prospect of concealed small geological anomalies (such as small fault, small fold and coal thickness variation) by use of gas extraction projects; The latter includes a dynamic forecast of gas hazard potential from space-time perspective based on numerical simulation analysis on additional stress fields around small geological structures beyond coal mining face. Its research benefit the optimal design and effective implementation of gas hazard prevention measures in coal mining panel with high coal and gas outburst potential.