接触带巷道围岩剪应力分布的接触角效应

接触带巷道围岩剪应力大小及其分布特征是影响巷道安全稳定的关键因素之一,揭示不同接触角的巷道围岩剪应力变化规律是接触带巷道稳定性研究的重要内容。利用三维光弹应力冻结试验,根据光弹材料性质,采用3 000kN的荷载对光弹模型加载,定量表征15°、30°、45°、60°和75°接触角的巷道围岩的剪应力分布状况。以铁矿和石灰岩接触带为工程背景,进行试验研究,结果表明,接触角越大剪应力集中位置越靠近顶底板中央;当接触角在15°～75°范围内变化时,随着接触角的增大巷道顶底部的剪应力总体变化趋势是先减小后增大,在接触角为30°时取到最小值。研究得到的不同接触角巷道围岩应力分布规律对接触带巷道的稳定性控制具有指导意义。

Contact Angle Effect of Shear Stress Distribution in Surrounding Rock of Contact Roadway

The value and distribution of shear stress of roadway surrounding rock in contact zone is one of the key factors for deformation and failure of roadway surrounding rock. Studying the distribution characteristics of shear stress in surrounding rock of roadway with different contact angles is an important basis for the stability of roadway. According to the properties of photoelastic materials, loading the photoelastic model with 3000KN, a three-dimensional photoelastic stress freezing test was carried out to quantitatively characterize the shear stress distribution of surrounding rocks at the contact angles of 15°, 30°, 45°, 60° and 75°. Taking iron ore and limestone contact zone as engineering background, the test showed that: 1) Larger the contact angle is, closer the shear stress concentration position is to the center of the roadway roof and floor. 2) When the contact angle varies in the range of 15° to 75°, the shear stress at the top and bottom of the roadway decreases first then increases, and reaches the minimum when the contact angle is 30°. Three-dimensional photoelastic test can effectively characterize the shear stress distribution of surrounding rock of roadway with different contact angles. The obtained stress distribution law has certain guiding significance for the stability control of engineering roadway.