Numerical Modeling of Controlling a Floor Heave of Coal Mine Roadways with a Method of Reinforcing in Wet Soft Rock

Abstract

A floor heave is usually a serious failure phenomenon in mine roadways, especially in the conditions of a wet soft rock. There are bright prospects for using a method of reinforcing for controlling a floor heave in mine roadways under a dramatic heave. In the current research, a floor heave mechanism in the wet soft rock of mine roadways was investigated while the moisture content of the rocks was increasing. That was done by performing numerical simulations in a finite element analysis software system Ansys and by reinforcing the floor in the shape of inverted arch. It was found that a decrease in the modulus of elasticity of rocks caused by saturation leads to a nonlinear increase in a floor heave. This can be explained by the fact that rocks of the floor become plastic strains. A stable correlation was established between water content and a floor heave of a wet rock. It was found that when the floor is reinforced, the proportion of plastic strains in the soil is significantly reduced. The growth of the modulus of elasticity of rocks in the reinforced zone, caused by reinforcing of the floor in the form of inverted arch, leads to a nonlinear decrease of a floor heave. The effective range of floor reinforcing was established. A reliable relation was established between the ratio of the modulus of elasticity of rocks of the reinforced zone to the modulus of elasticity of the surrounding rock and heaving of reinforced rocks. The obtained results can be used to predict the magnitude of heaving of rocks at their saturation, as well as after they are reinforced.

Numerical simulation of the surface subsidence evolution caused by the flooding of the longwall goaf during excavation of thin coal seams

“…Obviously, this influence depends on many factors, first of all, on the type of rocks and the degree of water saturation. Sakhno et al [35] showed that the deformation modulus for wet rock (E w ) can be expressed as:…”

Experimental Study on Dynamic and Static Combined Dynamics of Temperature–Water-Coupled Sandstone and Energy Consumption Analysis

“…Małkowski et al [12] investigated the influence of water immersion time on the mechanical properties of carboniferous mudstone and found that the Young's modulus and compressive strength increased to a certain extent with increasing water immersion time. Sakhno et al [13,14] investigated the mechanism of bottom drumming of the water-bearing soft rock roadway and analyzed the evolution law of it using numerical simulation. Zhou et al [15] analyzed the influence of water content on rock properties and concluded that the tensile strength and compressive strength of rocks with different saturations would be reduced under both static and dynamic conditions.…”