Abstract
The purpose of this paper is to solve the problem that deep and close-distance cavern and roadway group were easily affected by the adjacent chamber or roadway excavation disturbance and low stability and significant deformation of surrounding rock occurred. The stability and control technology of surrounding rock in the main shaft and auxiliary shaft system has been analyzed by the adjacent chamber and roadway group of −850 m level in Qujiang Mine, China, as an engineering background. Firstly, the numerical calculation of the excavation chamber was, respectively, carried out in different ways with the propagation theory of the excavation disturbance wave. The results show that the interaction of adjacent chamber excavation was more intense. When excavated at the same time, there is a large increase in the movement of the sides and the roof-floor of the chamber and roadway. Then, the mechanism of interaction between low-high stress and excavation disturbance was considered, the corresponding control principles were provided, and a set of critical technologies and equipment were designed according to the deformation characteristics of the large deformation soft surrounding rock. Finally, the comprehensive control method was put forward with the water pump house as an example, that is, anchor, metal net, grouting, combined anchor cable and large-diameter anchor cable. And the related support parameters were determined by the internal damage of the surrounding rock chamber. The numerical simulation results show that the surrounding rock deformation of the chamber and roadway reduced with the revised support program, which the expansion of the rock mass loose circle prevented effectively. The site test shows that the convergence rate of surrounding rock with the improved support was less than 0.2 mm/d, and the rock deformation of chamber and roadway suppressed significantly.
Highlights
Many chambers and roadways are arranged tightly in the mine construction and form a denser chamber group. e influence between the dense chambers is intense, and the stability of a chamber or roadway is mainly affected by the excavation disturbance and the superposition of stress, during an excavation of the chamber or roadway [1,2,3]
In order to eliminate the acceleration discontinuity caused by the numerical integration method, the load waveform was taken as harmonic in the computation at the excavation of blasting vibration and other dynamic disturbances of rock mass. e mathematical expression was usually expressed as follows: P(t)
Main haulageway, and water pump house are excavated at the same time, the displacement of the roof-floor or sides was more massive than all in the absence of the bolting and anchoring support. erefore, the deformation of the water pump house was severe significantly, and the left horizontal displacement of the chamber was substantially higher than the right. e extensive range stress concentration of vertical stress between the water pump house and main haulageway and a sizeable horizontal displacement of surrounding rock near the stress concentration area were formed (Figure 7(a)). e damage range of the surrounding rock chamber and roadway was more extensive, and the loosening circle was larger under the influence of high stress (Figure 7(b))
Summary
Many chambers and roadways are arranged tightly in the mine construction and form a denser chamber group. e influence between the dense chambers is intense, and the stability of a chamber or roadway is mainly affected by the excavation disturbance and the superposition of stress, during an excavation of the chamber or roadway [1,2,3]. E technology of cooperating support and anchor net cable control was put forward [15] He et al used FLAC3D to study the mechanical response and deformation characteristics of different displacement deformation and stress states, which are caused by different excavation sequences of grade separation chamber rock in the deep soft rock roadway [16]. Kang et al researched the stress distribution and comprehensive reinforcement technology of the loose and fractured chamber group surrounding rock in the shaft station of Lu’an Tunliu Mine, Shanxi, China. Erefore, this paper is aimed at the close-distance cavern and roadway group at −850 m level in Qujiang Coal Mine; the stability analysis of surrounding rock of the main and auxiliary shaft system was carried out, and the corresponding control technology was put forward.
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