动载作用下节理岩体破坏过程非连续数值分析方法研究

Study on the failure process of jointed rock under dynamic load is very significant for guiding the orientational breaking rock in blasting engineering and evaluating the dynamic safety of rock engineering. In this study, we will research the features of dynamic responses of joined rock, and accordingly propose a numerical method for modeling the dynamic failure process of jointed rock based on the DDARF method. Firstly, aiming to the discontinuity and heterogeneity of jointed rock, some indoor tests on the deformation of joint with different connectivity and filling and the strength of intact rock with different heterogeneity under high strain rate will be carried out, and based on the test results, the dynamic nonlinear contact model of joint and the failure criterion of intact rock will be established. Then, the dynamic contact algorithm, cohesive-fracture algorithm and efficient opening-sliding algorithm of joint will be derived. The initiation and growth of joint will be presented by the failure of artificial joint representing the intact rock, thus the numerical method for modeling the dynamic failure process of jointed rock will be established, and the corresponding calculation program will be developed. Finally, several Hopkinson bar tests on cracked specimens will be carried out and simulated by the proposed method for verification, and the failure process and mechanism of jointed rock and the influence of primary joints will be studied.

研究动载作用下节理岩体破坏过程对于指导爆破工程定向破岩及评价岩体工程动力安全性具有十分重要的现实意义。本项目拟在准静力条件下节理岩体非连续变形破坏分析方法—DDARF的研究基础上，针对节理岩体的动力响应特征，研究节理岩体动力破坏分析方法。首先，针对节理岩体的非连续性及非均质性特点，通过高应变率下不同贯通度和充填性结构面的闭合变形特性和滑移摩擦特性试验，以及不同均质度完整岩石类材料的动强度试验，分别建立节理非线性动力接触-摩擦模型及非均质材料动态破坏准则；然后，据此推导节理动态接触算法、虚拟节理动态粘结-破坏算法及高效的开闭迭代算法，通过表征完整岩石的虚拟节理的破坏来模拟裂纹萌生及扩展过程，建立节理岩体动力破坏分析方法，并编制相应的计算程序；最后，进行含裂纹试件的霍普金森杆冲击试验，并采用所提出的方法对试验过程进行模拟，研究动载下裂纹萌生-扩展过程、贯通机理及原生节理的影响。

在准静力条件下节理岩体非连续变形破坏分析方法—DDARF的基础上，针对节理岩体的动力响应特征，研究节理岩体动力破坏分析方法。首先，通过对不同应变率下、不同连通率的节理岩体开展室内直剪试验，一方面，根据不同应变率、节理连通率对节理岩体的变形和强度特征的影响，推导出非贯通节理岩体的基于应变率和连通率的动态破坏强度准则，建立节理岩体动破裂模型；另一方面，研究连通率及剪切速率对节理岩体破坏路径及破坏模式的影响，分析不同条件下节理的衍生、扩展直至贯通全过程的破坏机理。然后，依据建立的动态破坏强度准则，建立节理岩体动力破坏分析方法，并编制相应的计算程序，并通过模拟Hopkinson压杆试验来验证算法在考虑应变率方面的正确性和有效性，最后进行了工程应用，对爆破或地震荷载下大型岩土工程（边坡、隧道）的破坏过程进行了数值模拟，研究动态荷载作用下节理岩体中应力波的传播、岩体动力响应及破坏特征。