DDARF成功实现了模拟岩体裂纹萌生、扩展、贯通、破碎的全过程,但缺乏有效的锚杆失效判据和程序计算收敛判据。针对锚杆体的拉断破坏,采用最大拉应力准则,并在VC++平台下程序实现;针对锚杆体的滑脱失效,采用莫尔–库仑准则对灌浆体强度进行判断,并程序实现;针对程序计算的收敛判据,采用前后两步位移差与当前步位移比值小于某个极小值的方法,并程序实现,同时考虑了松弛因子对收敛的影响。将DDARF中锚杆的失效判据及程序计算收敛判据与室内试验进行对比,并应用到工程算例中。结果表明,DDARF中锚杆的失效判据和程序计算的收敛判据是有效的,能提高计算的效率和精度,为工程中特殊部位的支护提供参考;合理的松弛因子有助于程序计算的收敛,作者建议DDARF中松弛因子取值1.4~1.8较为合理。
The simulation of the whole process of initiation,propagation,penetration and breaking of rock cracks has been successfully realized by DDARF,while the effective failure and convergence criteria of bolts are scarce.For the tensile failure of the bolts,the maximum tensile stress criterion is adopted and the program is realized on VC++ platform.For the slippage failure of the bolts,grouting body's strength is judged by Moore-coulomb criterion,and the program is realized.For the convergence criterion of the program,a method for the ratio of the displacement difference of two adjacent steps to the displacement of the current step which is less than a certain minimum value is adopted,and the program is realized.At the same time,the effect of the relaxation factor on the convergence is studied.The failure and program convergence criteria for the bolts in DDARF are compared with those of the laboratory tests and applied in engineering examples.The results show that the failure and program convergence criteria of DDARF are effective,and can improve the efficiency and precision of the calculation,which may provide reference for engineering support of special positions.Reasonable relaxation factor is benificial to the convergence calculation.It is suggested that the relatively reasonable relaxation factor should be 1.4 ~ 1.8.