摘要
针对深井高应力条件下沿空留巷过程中现有充填体材料不能适应顶板活动的问题,在C40基准混凝土的基础上使用不同掺量聚合物(EVA)和钢纤维进行正交试验,得到了应变系数为2%~10%的改性混凝土。以麦地掌煤矿21213工作面回风顺槽留巷为研究对象,运用理论分析与数值模拟相结合的方法,研究不同应变系数的改性混凝土充填体的支护效果。研究表明:(1)基于弹性地基基础理论和砌体梁理论,得到在该地质条件下应变系数为5.6%的改性混凝土可以使关键块回转触矸达到稳定状态,充填体所需的最大支撑力为20.46 MPa;(2)数值分析结果表明,随着充填体的应变系数逐渐增大,充填体侧与实体煤侧最大垂直应力比由1.26减小到0.33,应力集中位置逐渐从充填体侧转移至实体煤侧,充填体起到让压承载的作用。但应变系数过大的充填体支撑力不足,顶板下沉速度过大,不利于留巷围岩控制。综合分析得出:在21213工作面回风顺槽留巷时应采用应变系数为6%的混凝土为充填墙体,在适应顶板给定变形的同时,有足够高的强度使基本顶平稳回转下沉。
In order to solve the problem that existing filling material can not adapt to roof movement in gob-side entry under high stress condition in deep mine,based on the C40 control concrete,EVA polymer and steel fiber were used to carry out orthogonal tests.Then,the modified concrete with strain coefficient of 2%~10%was obtained.Taking the 21213 working face of ventilation entry of Maidizhang Coal Mine as the engineering research object,the supporting effect of modified concrete filling body with different strain coefficients is studied by combining theoretical analysis and numerical simulation.The conclusions are obtained as follows.Firstly,based on the elastic foundation theory and masonry beam theory,under this geological condition,the modified concrete with strain coefficient of 5.6%can make the key block turn to contact gangue to a stable state,and the maximum supporting force required by the filling body is 20.46 MPa.Secondly,numerical analysis results show that with the increase of strain coefficient of filling body,the maximum vertical stress ratio between filling body side and solid coal side decreases from 1.26 to 0.33,the stress concentration position gradually shifts from filling body side to solid coal side,and filling body plays a supporting-yielding role.However,if the strain coefficient is too large,the supporting force of the filling body is insufficient,and the roof subsidence speed is too large,which is not conducive to the control of the surrounding rock of the retaining roadway.The comprehensive analysis shows that the concrete with the strain coefficient of 6%should be used as the filling wall in the 21213 working face of ventilation entry,which adapts to the given deformation of the roof,and has enough high strength to make the basic roof rotating and sinking smoothly.
作者
张钰凯
张小强
张泽瑞
ZHANG Yukai;ZHANG Xiaoqiang;ZHANG Zerui(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)
出处
《矿业研究与开发》
CAS
北大核心
2022年第5期108-113,共6页
Mining Research and Development
基金
国家自然科学基金面上项目(51974194)
国家自然科学基金青年科学基金项目(51704204)。
关键词
沿空留巷
改性混凝土
数值模拟
让压承载
Gob-side entry
Modified concrete
Numerical simulation
Supporting-yielding
