综放沿空留巷围岩控制机理

采用适于分析岩层断裂和垮落的数值分析软件UDEC建立相应的数值分析模型,分析了留巷前巷道支护形式、充填体宽度、充填方式、充填体强度和端头不放顶煤长度等对综放沿空留巷的作用和效果.研究结果表明:留巷顶板下沉是老顶回转运动与围岩变形的综合反映;充填体上方顶煤位移由老顶岩层运动引起,由浮煤和充填体压缩变形以及充填体承载前预留变形量3部分组成;留巷前巷道支护形式无法控制老顶回转量,但锚网支护巷道留巷效果比架棚巷道好;端头留设一定长度的顶煤不放,有利于老顶回转触矸后形成具有自稳能力的承栽结构.当采用综放沿空留巷时,在保证顶煤及项板稳定前提下,合理利用围岩移动规律,确定合理充填方式和充填体强度,就能保证充填体稳定,达到很好的留巷效果.

Mechanism of controlling surrounding rock around gob-side entry retaining in top-coal caving mining face

By using numerical analyses software UDEC which is suitable for analyzing rock stratum rupture and collapse, the numerical models were set up to study the effect of support way, filling belt width, filling way, filling belt strength and top-coal length uncaved on the gob-side entry retained in top-coal caving mining face. The results indicate that the roof displacement of retained roadway is an integral effect of the rock deformation and the rotating movement of main roof. The displacement of top coal over the filling is caused by the main roof movement and consists of compression deformation of float coal and filling and residual deformation before bearing of filling. Before retaining the roadway, the roadway support is unable to control the rotating amount of main roof, but the better result of retained roadway can be obtained by using bolt-beam-mesh support. The top coals of a certain length retained in face end, which are uncaved, are favorable for formation of a bearing structure with self-stablitity capacity after rotating and contacting waste rock of main roof. On the premise of the stability of roof and top coal, the displacement regularity of surrounding rock must be rationally used to determine the reasonable filling pattern and filling strength in order to ensure the filling stability and a good result of retaining roadway.