深部沿空切顶巷道底鼓破坏机制及强化控制技术研究

Mechanism of floor heave and reinforced support techniques for gob-side roof cutting entry in deep mine

为解决深部沿空切顶巷道的底鼓大变形破坏及频繁翻修维护问题,分析了深部沿空切顶巷道围岩应力环境的转变特征,基于滑移线场理论建立了不同应力扰动阶段下沿空切顶巷道的底鼓破坏力学模型,研究了不同应力扰动阶段巷道底鼓破坏机制,并开展了底板强化控制试验。结果表明:深部沿空切顶巷道的围岩应力环境转变可分为掘进后切顶前、切顶后一次采动及沿空留巷三阶段;在巷道两侧滑移线场的对称及非对称作用下,三阶段巷道底板分别呈小变形对称底鼓、采场侧高于实体煤侧的非对称底鼓变形及实体煤侧高于采空区侧的非对称大变形底鼓破坏;随采深增加,沿空切顶巷道底板支护荷载增加;底板限制性强化支护底鼓速率下降约33.3%,底鼓量可降低804mm,最适于控制深部沿空切顶巷道底鼓破坏。

In order to solve floor heave and frequent maintenance problems of roof cutting gob-side entry retaining in deep coal mine,the stress environment changes of gob-side entry retaining were analyzed combining with the abutment pressure of mining-induced surrounding rock.Based on the slip-line field theory,the mechanics models of floor heave in gob-side entry retaining under different stress stages were established,and the failure mechanism of floor heave under different stress stages were studied.At last,the strengthened floor control test were carried out.The results show that the stress environment changes of gob-side entry retaining can be divided into three stages:tunneling-roof cutting stage,roof cutting-initial mining stage and the gob-side entry retaining stage.The floor in three stages present symmetrical floor heave with small deformation,asymmetric deformation with floor heave higher in longwall face side than that in solid coal side,and asymmetric large deformation and failure with floor heave higher in solid coal side than that in goaf side.With the increase of mining depth,the minimum support loads of floor in gob-side entry retaining increases.And the floor heave rate of the restricting reinforced support at floor area decreases about 33.3%,the floor heave can reduce 804 mm,and it is most suitable for controlling the deformation and failure of floor in the gob-side entry retaining under cutting roof in deep coal mine.