内六线砂泥岩互层危岩体病害特征及加固技术

Characteristics and Reinforcement Techniques of Dangerous Rock Mass Diseases in Sandstone⁃Mudstone Interlayer of Neijiang-Liupanshui Railway

内六线分布着高位危岩体,在2020—2023年间发生了多次崩塌落石事件,冲毁了铁路设施设备,严重威胁铁路运营安全。文章通过现场调查、无人机倾斜摄影、数值模拟等方法,对砂泥岩互层危岩体病害特征及其动力致灾过程进行了研究。结果表明:由于泥岩与砂岩的差异性风化,泥岩遇水软化,失水后崩解,导致砂岩底部悬空。厚层状的砂岩带受到两组陡倾节理切割,大多被切割成柱状或板状,容易发生悬空坠落或滑移式崩塌。危岩体在失稳过程中经历崩落、撞击破碎、回弹和下落,危岩体I-3崩塌后会对线路产生1.6×10^(6) kJ的冲击能量。通过对危岩体采用双锚固段预应力锚索进行加固,取得良好效果,解决了高位高陡危岩体原位整治中锚固的耐久性及预应力损失的技术问题。

The Neijiang-Liupanshui Railway is distributed with high-position dangerous rock masses.During 2020—2023,several rockfall events occurred,which destroyed railway facilities and equipment and seriously threatened the safety of railway operation.Through field investigations,Unmanned Aerial Vehicle(UAV)oblique photography,numerical simulations and other methods,a study was conducted on the characteristics and dynamic processes leading to disasters caused by the dangerous rock masses in the sandstone-mudstone interbedded formation.The results show that due to the differential weathering of mudstone and sandstone,the mudstone softens when it encounters water and disintegrates after losing water,resulting in the bottom of the sandstone to be suspended in the air.The thick-bedded sandstone zones are cut by two sets of steeply dipping joints,most of which are cut into columns or slabs,making them prone to suspended falling or sliding collapses.The dangerous rock masses experience falling,fragmentation due to impact,rebound,and subsequent falling during the instability process.The collapse of Dangerous Rock Mass I-3 will generate an impact energy of 1.6×10^(6)kJ along the railway line.By using double-anchorage section prestressed anchor cables to reinforce the dangerous rock masses,good remediation effects have been achieved,solving the technical problems of anchorage durability and prestress loss in the in-situ remediation of high-position,steep dangerous rock masses.