Research on prediction of residual deformation in goaf of steeply inclined extra–thick coal seam

Abstract

The residual deformation of a goaf is studied to improve the foundation stability assessment for metro lines passing through the subsidence area of steeply inclined extra-thick coal seams. The variable mining influence propagation angle is introduced to describe the special form of the rock movement. Based on the modified parameters in the traditional probability integral model, a subsidence prediction model is established. Then, based on the idea of an equivalent mining thickness, Kelvin model is introduced to analyze the creep characteristics of the old goaf, and the dynamic prediction function of the residual subsidence is constructed to realize the dynamic analysis of the residual deformation. Moreover, a case study is used to evaluate the predictive effectiveness of the prediction model, and the results are compared with the monitoring data and numerical simulation results. The results show that the values with a relative error between the predicted value and measured value are in the range of ±7%, indicating that the prediction model based on the mining influence propagation angle is feasible. Thus, the residual deformation prediction model based on the mining influence propagation angle is considered to be suitable for predicting the subsidence of engineering projects crossing a goaf.

Semi-real time systems for subsidence monitoring in areas affected by underground mining: the example of the Nuraxi-Figus coal district (Sardinia, Italy)

“…Several coal mining districts located in different countries, characterized by variable geological settings, show temporal delays in the occurrence of maximum surface deformations. This particular subsidence phenomenon, which is called residual subsidence (Alheib et al 2005), continues after the extraction and in some cases can occur some months or years after the end of the underground mining activity (Huang et al 2020;Cui et al 2020;Modeste et al 2021). Sometimes the residual surface deformation could be also characterized by uplift phenomena (Vervoort 2020).…”

Cumulative Deformation Analysis of Foundation of Mined-Out Areas under Dynamic Loading - a Case Study of Taijiao High-Speed Railway

“…Strzalkowski et al used the resistivity tomography to evaluate the possibility of surface collapse in selected areas of shallow mining [7]. Based on the probability integral model, Huang et al conducted the dynamic analysis of the residual deformation in goaf [8]. Wang et al analyzed the deformation response characteristics of the subgrade of the high-speed railway in the mined-out areas [8].…”

Experiment on Space-Time Evolution Characteristics of Deformation and Failure of Overlying strata in Longwall Mining of Steeply Dipping Coal Seam

“…Affected by seam angle, there are significant differences in strata behavior, strata migration law and support-surrounding rock relationship between steeply dipping coal seam and horizontal coal seam. Over the past three decades, a large number of scholars have studied from different aspects of longwall fully mechanized mining in steeply dipping medium thick coal seam, longwall fully mechanized caving mining in thick coal seam, and coal seam group mining under different mining methods of strata behavior(e.g., Luo et al, 2021;Sun et al, 2019;Wang et al, 2020;Yang et al, 2021), bearing capacity of gangue(e.g., Ding et al, 2022;Lv et al, 2022;Wei et al, 2021), space-time evolution characteristics of mining transfer paths(e.g., Chi et al, 2020;Luo et al, 2022aLuo et al, , 2022bLuo et al, , 2022c, disaster-causing mechanism of irregular random separation in stope space(e.g., Hu et al, 2020;Wu et al, 2021), surface subsidence(e.g., Huang et al, 2020;Yin et al, 2018), coupling mechanism and stability control of support-surrounding rock system under interaction of roof and floor(e.g., Liu, 2021;Shen et al, 2021;Wang and Jiao, 2016;Wang et al, 2018;Xie et al, 2021), mechanism of support and equipment downturn and surrounding rock disaster(e.g., Luo et al, 2018Luo et al, , 2022aLuo et al, , 2022bLuo et al, , 2022c. The existing research has solved the basic problems of safe and efficient mining of steeply dipping coal seam to a certain extent.…”