摘要
针对大采高沿空留巷的顶板运动特征,提出了巷旁复合承载结构的概念,通过力学分析,揭示了巷旁结构的稳定机理。研究表明:顶板压力由顶板、墙体和底板共同承担,从而形成"顶—墙—底"复合承载结构;区分不同阶段墙体强度与顶板运动的作用关系,认为初期强度应大于顶板载荷,后期应能适应顶板变形,使墙体强度与顶板运动保持动态协调;大采高时顶板向墙体施加更大的水平力,要确保墙体水平滑移因子小于接触面摩擦系数以实现抗滑自稳;墙体内侧应力不能高于顶底板强度,以免顶底板被切断,外侧应力不能高于墙体强度,以免墙体被压裂,降低墙宽和巷宽可减小墙体载荷,据此得出了墙体和巷道宽度的确定方法。结合4.2 m大采高沿空留巷案例给出了工程验证,采用膏体混凝土充填时,满足巷旁结构稳定条件的巷道宽度为3 m,墙体宽度为4 m,实测结果表明了结论的合理性。
The concept of roadside compound structure is proposed through the analysis of roof movement of gob-side entry retaining under large mining height, and the stability mechanism is revealed by mechanical calculation. The results indicate that the roof load is born by a compound bearing structure composed of “roof-wall-floor”. The action relations of staged wall strength and roof movement are distinguished, the initial strength should be larger than the roof load, and the final strength should adapt to the roof deformation, so that the wall strength and roof movement can maintain a dynamic coordination. The roofs impose higher horizontal force on the wall under large mining height, thus the horizontal sliding factor should be less than the friction coefficient on the contact surface of wall and rock to realize self-stabilization. The inboard stress cannot be higher than the strength of roof and floor in order to avoid the strata being cut off, and the outboard stress cannot be higher than the strength of wall in order to avoid the wall being broken. Decreasing the widths of entry and wall can reduce the stress of wall, based on which the determination methods for the widths of entry and backfill body are proposed. A field test with 4.2 m mining height, whose entry and backfill width is designed to be 3 m and 4 m respectively, is conducted to demonstrate the effectiveness of the proposed method. The results verify the reasonableness of the conclusions.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2014年第5期969-976,共8页
Chinese Journal of Geotechnical Engineering
基金
"长江学者和创新团队发展计划"创新团队项目(IRT1084)
高等学校博士学科点专项科研基金项目(20110095110013)
江苏省普通高校研究生科研创新计划项目(CX10B_147Z)
关键词
大采高
沿空留巷
复合承载结构
水平滑移因子
稳定机理
large mining height
gob-side entry retaining
compound bearing structure
horizontal sliding factor
stability mechanism
