Improvement to the calculating model of the pressure arch’s height considering the confining pressure in the excavation of shallow tunnels

Fan, Hongyun; Li, Liping; Liu, Hongliang; Hu, Jie; Zhang, Mingguang; Zhou, Shen Jie; Yang, Guangyu Robert

doi:10.1007/s12517-021-07507-3

Cited by 9 publications

(2 citation statements)

References 12 publications

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“…A copper mine in Jiangxi was taken as a case study in this research to examine this issue. Using Bieniawski's ultimate pillar strength theory [26], Pu's arch equilibrium theory [27], and the Kastner equation [28], a formula was derived for the critical stable height of goaf. A sensitivity analysis of the factors affecting the critical safe height of goaf was conducted using the orthogonal range analysis method.…”

Section: Introductionmentioning

confidence: 99%

Study of the Critical Safe Height of Goaf in Underground Metal Mines

Zhang,

Chen

et al. 2024

Minerals

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The empty-space subsequent filling mining method is the main mining scheme for underground metal mines to achieve large-scale mechanized mining. The stage height, one of the main parameters of this method, affects the various production process aspects of the mine and influences the stability of the goaf. In order to determine the stage height scientifically and rationally in the empty-space subsequent filling mining method, a formula for the stabilized critical safe height of a high goaf in an underground metal mine was derived based on Pu’s arch equilibrium theory, Bieniawski’s pillar strength limit theory, and the Kastner equation and combined with the results of an orthogonal analysis to rank the importance of the main factors in the formula. A copper mine in Jiangxi Province was used as a case study, with the reliability of the formula verified by numerical simulation and industrial testing. The factors in the formula influencing the critical stabilized safe height of the goaf were, in descending order, the compressive strength of the rock body, the width of the two-step mining pillar, the width of the one-step mining room, the mining height, and the depth of mining. Based on the calculation results, the recommended stage heights are 30 m (−378 m middle section) and 25 m (−478 m middle section) in the area of poor rock body stability and 50 m in the area of better rock body stability. The simulation results show that the goaf is significantly affected by the compressive stress under the condition of a certain rock body stability and that the compressive stress increases with increasing goaf height. The minimum recommended values of the sidewall safety coefficients in areas of poor and better rock stability are 1.04 and 1.06, respectively. The volume deviation coefficients of the three industrial test mines were all controlled within 3%, indicating that no obvious collapse and destabilization phenomenon occurred in the goaf. This paper provides some theoretical and applied guidance for the stage height design of similar underground metal mines using the empty-space subsequent filling mining method.

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Section: Introductionmentioning

confidence: 99%

Study of the Critical Safe Height of Goaf in Underground Metal Mines

Zhang,

Chen

et al. 2024

Minerals

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“…The evolution process of soil arch in shield excavation is investigated, which in turn reveals the three-dimensional force transfer mechanism in the soil arch area [14]. A stratum arch stress model applicable to shallow burial conditions was established based on Pratt's theory, and the calculation results were verified by numerical simulation [15]. The presence of the stratigraphic arch allows the surrounding rock to share most of the overlying load [10], thus reducing the support cost to a certain extent.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Arch Forming Factors of Shallow Buried Hard Rock Tunnel under Overlying Load

Cao,

Cui,

Qin

et al. 2023

Buildings

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To investigate the arching effect of shallow buried hard rock tunnels under overlying load, the engineering scenario of a subway station on Qingdao Metro Line 6 is utilized. A large-scale tunnel loading model test is conducted, in conjunction with finite element numerical simulations, to analyze the impact of various overburden ratios on strata arching. The results show that: when the tunnel excavation span is certain, with an increase in the overlying rock mass, the stress diffusion process of the surrounding rock can be better accomplished to form the arch effect. This means that the thickness of the overburden of the tunnel determines whether or not the surrounding rock appears to have a stratified arch effect. When the tunnel overlying rock thickness is certain, the span of the tunnel determines the shape of the formation into an arch, that is, the curvature of the arch. The joint surface is an important factor in tunnel stability. When the overlying load increases to a certain value, the rock mass at the joint plane slips relatively, leading to the displacement phenomenon of the surrounding rock, which then affects the formation and shape of the formation arch.

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