基于岩石拉压宏观力学响应的平板模型微观参数匹配分析

Analysis of micro-parameter calibration of Flat-Joint model based on tensile and compressive macromechanical response of rock

为获取颗粒离散元模拟中精确的接触参数,基于岩石单轴压缩模拟试验和拉伸模拟试验,利用离散元“Flat-joint”接触模型,构建完整岩石的黏结颗粒模型。以校正宏观力学响应为目标,基于流程控制法和试验设计法对颗粒接触参数进行标定。通过敏感性分析得到对泊松比、弹性模量、抗拉强度和单轴压缩强度影响显著的微观参数,确定其校正顺序,证明“Flat-Joint”颗粒模型模拟完整岩石的可行性;基于Box-Behnken设计试验的最终结果,提出通用性高的微观参数算法方程;最后以4种不同硬岩为例,确定相应的平板黏结颗粒模型微观参数并进行单轴模拟试验,模拟结果和试验结果在变形性和强度特性方面都取得了很好的一致性,验证了方程的适用性。

In order to obtain accurate contact parameters in particle discrete element simulation,based on rock uniaxial compression and tensile simulation tests,the discrete element“Flat-joint”contact model was used to construct a complete rock bond particle model.With the goal of correcting the macro-mechanical response,the particle contact parameters were calibrated based on the process control method and the design of experiments.Firstly,by means of sensitivity analysis,the microscopic parameters that had significant effects on Poisson’s ratio,elastic modulus,tensile strength and uniaxial compression strength were obtained.The correction sequence was determined to prove the feasibility of the“Flat-Joint”particle model to simulate a complete rock.Based on the results of the Box-Behnken design tests,a highly versatile micro-parameter algorithm equation was proposed.Finally,taking four different hard rocks as examples,the micro-parameters of the corresponding flat-joint bonded particle model were determined and uniaxial numerical simulation were carried out.The simulation results and the experiment results have achieved good agreement in terms of deformability and strength characteristics,verifying the applicability of the equation.