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Wang and Yin numerically simulated the stress-strain characteristics of the surrounding rocks of a mining field under the influence of collapse columns by using FLAC3D with the finite difference method. Finite difference, finite element, and other numerical simulation methods have been applied in recent years to investigate water inrush in coal seams. explained the burst of water inrush from the floor based on cusp catastrophe theory by using mathematical mechanics. analyzed the mechanism and criterion of the collapse column’s activation and water conduction under weak runoff conditions to improve the accuracy of water inrush forecasts. summarized the law of floor water inrush and proposed the preferred plane theory of water inrush. Many scholars have studied the stress distributions of collapse columns and their surrounding rocks and the related failure depth of floors.
#How to change elastic modulus every time step in flac3d full#
Prior to the full mechanization of a mining face that passes a collapse column, the influence of this collapse column on mining stress and the influence of mining stress on the collapse column and floor failure of the working face both need to be established. Collapse columns can directly affect the safe and efficient operations of coal mines. When the compaction and cementation of the fillings in the collapse columns are poor, the columns may be activated and transformed into Ordovician limestone water inrush channels under the action of mining and other external factors, which can lead to water disasters. In northern China, collapse columns are widely distributed in the Permian–Carboniferous coalfields. The three derived values agree well with one another. According to the water injection test, the maximum failure depth of the floor is 18 m. With the collapse column, the failure depth of the floor is 16.8–17.8 m.
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The calculated depth failure of the floor of the working face without structural defects is 14.6–14.7 m based on the Hoek–Brown criterion. The following results were obtained: the failure depth of the full floor is stabilized at 14.6 m the maximum failure depth of the floor near the collapse column is 18.2 m and the stress concentration coefficient is 1.27 times greater than that of normal mining. The floor failure is numerically simulated to assess the damage. The 10–115 working faces that pass the collapse column at a coal mine in Tuanbai are identified as the research object. Here, we present the constructed program in FISH language, render the damage variable in FLAC3D to establish the numerical model, and complete the numerical calculation. The paper not only can provide valuable hints for the research relating to the stability analysis of slopes, but also are instructive for the treatment of sliding accidents in the soft soil embankments in the area of heavy rainfall.The stress change law of a collapse column and the failure depth of a coal seam floor before and after mining when the fully mechanized coal mining face passes through the collapse column are investigated. The grouting process was realized in the numerical model through extensive programming, and the diffusion range of the cement slurry with the duration of grouting can be monitored in the numerical model, whereby the effect of the grouting was evaluated.
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A scheme for the time-dependent slurry diffusion was proposed. The applicability of the reinforcements and the stability of the reinforced embankment were analyzed through numerical simulation. Measures were taken to reinforce the embankment including loading berm, steel pipe grouting and steel sheet pile. The cause of the failure was investigated based on the geological data, construction conditions and numerical results. A sliding accident occurred in the embankment slope of a highway in the south of China.