修正RHT模型在岩体爆破响应数值模拟中的应用

岩体爆破是一个极其复杂的物理过程，应用数值模型研究岩体爆破响应的关键在于能否准确地描述岩体在不同应力状态下的力学行为。基于应用标准RHT模型模拟岩体爆破破碎过程存在的缺陷，对RHT模型进行改进，提出了双线性拉伸软化模型，在残余强度面方程中引入罗德角因子，修正了应变率增强因子和拉-压子午比的计算公式。将修正后的RHT模型植入SHALE程序中，并通过不同应力路径下的数值试验检验了修正RHT模型性能。应用修正RHT模型和标准RHT模型分别对爆破漏斗试验进行数值模拟。计算结果表明，修正RHT模型在自由面处形成的爆破漏斗半径更接近于现场试验的实测结果，验证了修正RHT模型的合理性和准确性，说明该模型在岩体爆破响应数值模拟中具有一定的参考价值。

Modified RHT model for numerical simulation of dynamic response of rock mass under blasting load

Rock blasting is an extremely complex physical process.It is essential that the numerical models are capable of describing the material behavior subjected to different stress state.Based on the defects of standard RHT model for describing the blasting process,this paper proposes some modifications to the model formulation,which include a bilinear tensile softening model,a Lode angle dependent residual strength surface,and modified defini tion of the tensile to compressive meridian ratio.The improvement of the performance of the modified RHT model as implemented in SHALE is demonstrated using numerical sample tests.Further,the simulations of blasting crater test are carried out via using the modified RHT model and the standard RHT model respectively.The results show that the radius of the blasting crater simulated by the modified RHT model is more consistent with the field test result,which verifies the rationality and accuracy of the modified RHT model.It demonstrates that the modified RHT model can be of certain value in the numerical simulation of dynamic response of rock mass under blasting load.