路堑边坡开挖对邻近既有铁路隧道影响分析

Analysis on Influence of Cut Slope Excavation on Nearby Existing Railway Tunnel

结合工程实际,运用ANSYS有限元数值模拟方法,建立了路堑边坡施工中岩土体开挖和爆破振动对邻近既有铁路隧道结构影响的三维模型,分析并得出了路堑边坡开挖对既有隧道结构应力应变和爆破振动的影响规律。模拟分析表明:1)路堑边坡开挖产生的剪应力是对既有隧道结构影响的最不利因素,既有隧道衬砌结构受到剪应力破坏区域影响时,路堑边坡开挖对既有隧道衬砌产生的应力应变数值影响存在较为明显的突变;2)模型模拟最大段装药量耦合装药结构爆破产生的质点振动数值相对实测数值偏大;3)邻近既有铁路隧道不同间距下最大段药量值可由萨道夫斯基公式和LS-DYNA软件模拟预测数值的平均值确定。

Based on engineering practice, using ANSYS finite element numerical software simulation method, three-dimen- sional model of the cut slope excavation and blasting vibration effect on nearby existing railway tunnel structure is estab- lished, the relationship laws of existing railway tunnel structural stress-strain and blasting vibration influence under the cut slope excavation is analyzed and obtained. Simulation analysis show that： 1 ） Shear stress is the most disadvantage factor and the values of stress-strain exist obvious abrupt changes when existing tunnel lining structure influenced by the shear stress area damage. 2） The model value of particle vibration is bigger than the measured value under the maximum blasting charge with coupling charging structure. 3） The value of the maximum explosive charge under different distance nearby existing railway tunnel may be determined by the average value of Sadov＇s formula and LS-DYNA software simulation predict values.