复采条带煤柱沿空掘巷稳定性研究

Research on Stability of Roadways Driving along Next Goaf in Repeated Mining of Strip Pillar

详细分析了条带煤柱复采时沿空掘巷的支护特点。顶板锚杆对沿空掘巷的总体稳定性无法起到有效的控制作用,只有提高围岩的强度,发挥围岩的自承能力才能对巷道起到有效的支护作用。针对岱庄煤矿矿2351工作面的具体地质条件确定了具体的支护方式。通过对巷道的支护效果监测分析在该支护方式下,巷道两帮及顶板在巷道开挖初期变形明显,两帮变形尤其是非生产帮变形明显大于顶板变形;由于采空区上方顶板跨落倾斜作用于非生产帮外侧,非生产帮2.2 m处所受压力大于1.0 m处所受压力;巷道掘进完成以后变形和压力仍然有所增加,但最终趋于稳定。研究表明采用高强度左旋连续螺纹锚杆加低松弛预应力锚索的联合支护方式能够保证巷道两帮及顶板围岩的稳定性。

The supporting characteristics of roadways driving along next goal in repeated mining of strip pillar were analyzed. There is no effective action for roof bolt to control general stability of roadways driving along next goal, and the only way to promote the supporting effect for roadways is to improve the strength of surrounding rock and develop its self-bearing ability. The specific support pattern of No. 2351 Coalface was determined according to the actual geological conditions. The monitoring results of roadway supporting showed that there were obvious deformations at roadway sides and roof in the early period of roadway excavation, and the deformation in roadway sides, especially the non-working side of the roadway was greater than that in roof; the pressure at the zone 2. 2 m away from the coalface in non-working side of the roadway was greater than that at the zone 1.0 m away from the coalface because the roof above goal caved and inclined to press on the outside of non-working side of the roadway, The deformation and pressure still slightly increased after roadway excavation completely, but it tended to be stable finally. Analysis results indicate that the combined support pattern adopting the high strength bolt with left lateral continuous thread combined with the bolt cable with low relaxed pre-stress can ensure the stability of roadway sides and roof.