Abstract
Tunnel Boring Machines (TBMs) are a cutting-edge excavating equipment, but are barely applied in underground coal mines. For TBM excavation projects involving the Zhangji coal mine, the surrounding rock properties, stress field, cross section geometry, as well as the excavation-induced stress path of TBM-excavated coal mine roadways are different from those of traditional tunnels or roadways. Consequently, traditional roadway supporting technologies and experiences cannot be relied on for this project. In order to research an appropriate supporting pattern for a TBM-excavated coal mine roadway, first of all, the constitutive model of roadway surrounding rocks was derived, and a rock failure criterion was proposed based on rock mechanical tests. Secondly, a three-dimension finite element model was established and computer simulations under three different supporting patterns were conducted. Stress redistribution, roadway convergence, and excavation damage zone ranges of surrounding rocks under three different support patterns were analyzed and an optimal support design of the TBM-excavated roadway was made based on simulation results. During roadway excavation, convergence gauge and rock bolt dynamometers were installed for monitoring roadway convergence and the axial forces of rock bolts. The in-situ monitoring results verified the validity of roadway supporting designs.
Highlights
In China, coal is the major energy source and it accounts for about 68% of the total primary energy consumption
This paper presents a case study on optimization of the support design of a Tunnel Boring Machines (TBMs)-excavated
This paper presents a case study on optimization of the support design of a TBM-excavated roadway
Summary
In China, coal is the major energy source and it accounts for about 68% of the total primary energy consumption. As the coal resources within shallow grounds are depleting, mining operation have been moving to increasing deep grounds in recent years [1]. In China, the average depth of coal mining operations has reached up to 556 m and it is increasing at a rate of 8 to 12 m per year. Zhangji coal scale underground colliery located at Huainan, AnhuiAnhui province, China. Zhangji coalmine mineisisa large a large scale underground colliery located at Huainan, province, 1a) with an annual output capacity of million tons of raw coal. China (shown in Figure 1a) with an annual output capacity of 13 million tons of raw coal. Zhangji minecoal covers seven mining areas which are working horizontal extends m m. Zhangji mine covers seven mining areas the Zhangji minecoal covers seven mining areas which are working horizontal extends m m. to −1000 m.coal
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