基于点云数据的围岩力学参数反演方法研究

Study on Country Rock Mechanical Parameter Inversion Method Based on Point Cloud Data

依托南昌地铁1号线盾构工程,探讨基于三维扫描检测技术的围岩力学参数反演方法应用在隧道施工过程中的可行性。具体流程如下:三维扫描获取测点的点云数据并分析计算出管片的位移场,选取周边收敛作为反演的目标值;建立有限元模型,选取敏感性参数弹性模量、内摩擦角、黏聚力建立多个工况并进行反演计算。结果表明:基于三维扫描技术的监测方式较传统监测方式更高效且精确;同时,当围岩弹性模量取值8GPa、黏聚力为700kPa、内摩擦角为28°时,隧道周边收敛值与检测值最为吻合。反演得到的围岩参数值较勘察设计参数值偏低,因此将围岩参数反演方法应用在隧道施工过程参数动态调整中,可以降低隧道施工成本。

Depended on shield engineering in subway Line 1,Nanchang City has discussed country rock mechanical parameter inversion method feasibility based on 3D scanning detection technology.Specific procedures as the follows:through 3D scanning acquired survey station point cloud data and analyzed,computed segment displacement field,selected periphery convergence as the target value for inversion;then established finite element model,selected sensitive parameters of elastic modulus,internal friction angle,and cohesion established multiple working conditions and carried out inversion computation.The result has shown that based on 3D scanning technological monitoring mode is more efficient and accurate comparing to traditional monitoring mode;moreover,when country rock elastic modulus value is 8GPa,cohesion 700kPa and internal friction angle 28°,tunnel periphery convergence value and detected value is most consistent.Inversion acquired country rock parameters are on the low side comparing to exploration designed parameters.Thus to apply country rock parameter inversion method on parameter dynamic adjustment during tunnel operation process can lower down tunnel operation cost.