基于离散裂隙网络与离散元耦合方法的礼让隧道岩体力学参数确定  

Determination of Mechanical Parameters on Rock Mass of Lirang Tunnel Based on Discrete Fracture Network-discrete Element Method Coupling Technology

作　　者：刘波 杨亚刚 LIU Bo;YANG Ya-gang(City College,Dongguan University of Technology,Dongguan 523419,China;China Water Conservancy and Hydropower Fourteenth Engineering Bureau Co.,Ltd.,Kunming 650041,China)

机构地区：[1]东莞理工学院城市学院,东莞523419 [2]中国水利水电第十四工程局有限公司,昆明650041

出　　处：《科学技术与工程》2020年第23期9567-9573,共7页Science Technology and Engineering

基　　金：东莞理工学院城市学院青年基金(2018QJZ001Z);东莞市社会科技发展项目(20185071511503)。

摘　　要：为了准确地确定礼让隧道节理岩体力学参数,采用3DEC程序中离散裂隙网络(discrete fracture network, DFN)技术,建立了能反映节理裂隙分布特征的离散裂隙网络模型。在此基础上,结合室内岩石、节理力学试验,运用等效岩体技术及3DEC程序,建立基于离散裂隙网络-离散元(discrete fracture network-discrete element method,DFN-DEM)耦合方法的等效岩体模型,并构建反映工程岩体节理分布特征的多尺度等效节理岩体计算模型;通过对多尺度等效节理岩体计算模型进行单轴压缩试验,获取岩体峰前及峰后的力学性质,分析节理岩体的尺寸效应、各向异性、表征单元体及等效岩体力学参数。结果表明:DFN-DEM耦合技术解决了非贯通节理的建模问题;随着等效岩体尺度增大,节理岩体峰值强度、弹性模量逐渐减小,各向异性特性逐渐减弱,且尺度达到5 m×5 m×10 m趋于稳定得到表征单元体;表征单元体尺度下等效岩体力学参数为弹性模量9 GPa、单轴抗压强度0.7 MPa、内摩擦角25°、黏聚力0.3 MPa、抗拉强度0.12 MPa,与Hoek-Brown强度准则所得力学参数对比,两者较为接近。该法为研究工程岩体的稳定性提供了数据基础。In order to accurately determine the mechanical parameters of jointed rock mass in Lirang tunnel, the discrete fracture network(DFN) technology in 3 DEC program was used. A discrete fracture network model was established to reflect the characteristics of the joint fracture distribution. On this basis, combined with the laboratory rock and joint mechanics test, the equivalent rock mass model based on the discrete fracture network-discrete element method(DFN-DEM) coupling method was established by using the equivalent rock mass technology and 3 DEC program, and a multi scale equivalent jointed rock mass calculation model reflecting the characteristics of the jointed rock mass distribution was constructed. Then, by means of uniaxial compression test on the calculation model of multi-scale equivalent jointed rock mass, the mechanical properties of rock mass before and after peak were obtained, and the size effect, anisotropy, characterization unit and equivalent rock mass mechanical parameters of jointed rock mass were analyzed. The results show that the DFN-DEM coupling technology solves the modeling problem of non-consecutive joints. With the increase of equivalent rock mass scale, the peak strength and elastic modulus of jointed rock gradually decrease. The anisotropy gradually decreases, and the scale reaches 5 m×5 m×10 m to stabilize the characterization unit. The modulus of elasticity of the mechanical parameters of equivalent rock mass at the unit body scale is 9 GPa, the uniaxial compression strength of which is 0.7 MPa, the internal friction angle is 25°, the cohesive force is 0.3 MPa, and the tensile strength is 0.12 MPa. Compared with the mechanical parameters obtained by the Hoek-Brown strength criterion, the two parameters are relatively close. This method provides a basis for further research on stability of engineering rock mass.

关 键 词：礼让隧道 离散裂隙网络与离散元耦合方法 等效岩体 表征单元体 节理岩体力学参数 

分 类 号：TU452[建筑科学—岩土工程]