Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

Abstract

The floor heave is one of the key factors that can restrict high-efficiency and safety mining, especially in the deep roadways with soft rock. Considering the influences of rock fracturing over time on rock mass properties, a case study of the floor heave evolution and rock bolts reinforcement technology was performed in this paper. A numerical simulation was used to study the stress-strain state and displacement of surrounding rocks. It was found that significant floor heave caused by nonlinear deformation of laminated immediate floor under an increase in rock fracturing. The post-peak strain regions appear in the bottom corners of the roadway, after which strata in the immediate floor are destroyed one by one. The joint spacing of 0.45 m on the immediate floor is critical. At this step, post-peak strain regions merge in the central part of the roadway floor, which is the cause of uncontrolled floor heave. Rock bolts reinforcement was proposed to control the floor heave. Three floor support schemes with two types of support elements, different bolt orientations, and lengths of reinforcement were studied. The numerical simulation demonstrated that after reinforcement, post-peak plastic strain in the floor strata was reduced effectively. The optimal floor support scheme and depth of reinforcement were determined by the allowable floor heave. Ideally, the floor heaves could be reduced by rock bolts with a steel belt installed according to the support scheme III and reinforcement length of 2.0 m for outer bolts and 3.0 m for central bolts.

Numerical Study on Failure Mechanisms of Deep Roadway Sidewalls with Different Height-Width Ratios and Lateral Pressures

“…Wei et al [22] simulated the stress of rock around coal roadways using a PFC two-dimensional numerical method. Ivan Sakhno and Svitlana Sakhno [23] suggested that rock failure begins at the corners of the bottom, progressively extending toward the bottom and sidewalls, ultimately leading to uncontrolled floor heaving in the roadway. With the transfer of concentrated stresses in the sidewalls to greater depths, the roof and floor are relatively stable and the sidewalls are gradually destroyed [24].…”

Collaborative optimization of driving support technology in the W3233 working face return airway

“…They analyzed the principle of top and bottom slab deformation and revealed the principle of overburden damage under the influence of mining. Sakhno and Sakhno (2023), aiming at the problem of floor heave in soft rock roadway, studied the use of anchor rod to strengthen strata and control the degree of surrounding rock fracture through numerical simulation. Ma et al (2018) studied the fracture evolution law of the surrounding rock in the support of a deeply buried soft rock roadway.…”