基于巴西劈裂试验的顺层板岩边坡“滑移-拉裂”破坏研究

怀通高速公路沿线边坡以板岩边坡为主,为揭示板岩边坡的破坏模式与板岩层理角度之间的关系以及获得板岩边坡的稳定性判据,进行针对性的试验研究和理论分析。选取沿线边坡岩样并按照不同层理角θ进行分组,开展巴西圆盘劈裂试验。试验发现：随着层理角度的变化,试样发生5种破坏模式,0°〈θ〈30°时为拉伸破坏,30°〈θ〈45时为拉裂-滑移破坏,45°〈θ〈75°时为滑移-拉裂破坏,75°〈θ〈90°时为滑移破坏,θ=90°时为压张型破坏；其次,对顺层板岩边坡整体滑移破坏和局部滑移-拉裂破坏判据进行推导,得出发生整体滑移破坏的临界坡高公式以及发生局部滑移-拉裂破坏的临界坡长方程。最后,结合怀通高速公路沿线板岩边坡进行实际应用,与沿线板岩边坡实际稳定性情况相吻合。

Research on the bedding slate slope slip-crack destruction based on Brazilian disk splitting tests

The slope along Huaitong highway is mainly slate slope. In order to reveal the connection between the failure model and the bedding angle of the slate slope and get the criterion of slate slope stability,the specific experimental research and theoretical analysis were performed in this paper. First of all,after selecting rock samples along the slope and grouping them in accordance with different bedding angles,the Brazilian disk splitting tests were conducted. The tests show that there are 5 failure modes with the bedding angles changing as follows：tensile failure with 0°〈 θ 〈30°,rip-slip failure with 30°〈 θ 〈 45°,slip-tensile failure with 45°〈 θ 〈75°,sliding failure with 75° 〈 θ 90°,pressure tension destruction with θ = 90°. Secondly,the criterion of the overall sliding failure and partial slip-tensile failure of slate slopes was deduced and the critical slope height and the critical slope length equation were derived when failure occurs. Finally,combining slate slopes along the Huaitong highway,those conclusions were applied into the actual projects and it can be found that the stability condition is made coincident with the actual stability condition of the slate slopes along the highway.