Abstract
To solve the technical problem of supporting a water-dripping roadway below contiguous seams at the Tuanbai coal mine, the deformation law of surrounding rocks for the roadway was studied using Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D) numerical simulation. Then, a mechanical model of water-dripping rock using a bolt support was established, and further, technical countermeasures to control the deformation of the roadway with a bolt and cable support are proposed. The results show that the erosion of the water dripping on the roadway was substantial and showed notable changes over time during roadway excavation and mining work. These effects caused the road to heave slightly, but it tended to be stable during roadway excavation. Moreover, the erosion of the roof and two ribs increased exponentially, and the floor heave increased with significant displacement oscillation during mining. The anchoring length of bolts and the rock weakening from water dripping had noticeable effects on the surrounding rocks of the roadway. The logical parameters of the bolt spacing and tightening force (the bolt line spacing was 0.7–0.9 m and the tightening force exceeded 40 kN) of the bolt supports were studied and optimized. Finally, a support scheme for water dripping on the roadway at the Tuanbai coal mine is proposed. The observation data regarding the deformation of the surrounding rocks, monitoring of bolt and cable stress, endoscopy results of roof failure, and roof bed separation monitoring were used to verify the reasonableness of the scheme and ensure the requirements for support were met. The study results can serve as a reference regarding the support for water dripping on a roadway under similar conditions.
Highlights
Mining activities can change the structure and stress-state of coal and rocks, resulting in their deformation and destruction
Many studies have been conducted regarding the evolution of mining-induced stress and deformation failure of the surrounding rocks for a roadway below a contiguous seam
The roadway deformation showed a noteworthy effect during the roadway excavation and the mining phases
Summary
Mining activities can change the structure and stress-state of coal and rocks, resulting in their deformation and destruction. Many studies have been conducted regarding the evolution of mining-induced stress and deformation failure of the surrounding rocks for a roadway below a contiguous seam. Yang et al [15] studied the evolution laws of deformation failure and mining-induced stress of the surrounding rocks for roadways, with or without water immersion during roadway excavation, by surrounding rocks for roadways, with or without water immersion during roadway excavation, by numerical simulation. Ren showed that the support of a composite structure with pre-stressed steel bolts and rocks can a better active securing effect. In seam surrounding rocks with boltbolt support is established here.here In this this paper, the effect of bolt anchorage length and water-dripping erosion on rock strength is studied.
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