沿空留巷顶板下沉规律及其影响因素分析

Roof Subsidence Rule of Gob-side Entry Retaining and Its Analysis of Influencing Factors

针对沿空留巷顶板下沉量大、控制十分困难的问题,在分析沿空留巷顶板下沉规律的基础上,利用能量守恒原理,建立了沿空留巷顶板下沉力学模型,推导出顶板下沉量的计算公式,并对顶板下沉的影响因素进行了定量分析和灰色关联度敏感性分析。结果表明:某矿沿空留巷顶板下沉量计算值为371.45 mm,较好地吻合现场测量值,理论计算公式是准确的。顶板下沉随巷道宽度、采高的增加而增大,随直接顶厚度、巷内支护阻力、煤帮侧向支护阻力、巷旁充填体宽度和充填体弹性模量的增加而减小;对沿空留巷顶板下沉的敏感度大小的影响因素依次为采高、充填体弹性模量、充填体宽度、直接顶厚度、巷内支护阻力、巷道宽度、煤帮侧向支护阻力,其关联度分别为0.96、0.73、0.68、0.52、0.28、0.13、0.04。研究结果可为有效控制沿空留巷围岩变形提供依据。

Aimed at the large roof subsidence and difficulty in controlling gob-side entry retaining, roof subsidence me- chanics model was established on the basis of the energy conservation principle after analyzing the surrounding rock deforma- tion law. A calculation formula of roof subsidence was also worked out, and influencing factors of roof subsidence were analyzed by quantitative analysis and grey relational analysis methods. Results showed that the calculated roof subsidence is 371.45 mm which matches with the field measurements. So the roof subsidence calculation formula is accurate. Roof subsidence was in- creased with the lane width and mining depth increase, and decreased with increase of roof thickness, in-lane support resist- ance, coal wall lateral support resistance, filling body width and its elastic modulus. Influencing factors for the roof subsidence of gob-side entry retaining were gradually becoming lower from mining height to elastic modulus ,filling body width, immediate roof thickness, in-lane support resistance,lane width and coal wall lateral support resistance. Its incidence degrees were 0.96, 0. 73 ,0. 68 ,0. 52,0. 28,0. 13 and 0.04 respectively. These resuhs provide a theoretical foundation for effectively controlling surrounding rock deformation of gob-side entry retaining.