基于Info-gap理论的支护围岩稳健可靠性分析

Robust reliability analysis of support surrounding rock based on Info-gap theory

围岩支护结构稳定性是地下结构设计的关键。针对深部隧道围岩参数信息统计不足,引入Information-gap理论,建立支护围岩结构非概率可靠性分析方法。给出了无量纲不确定水平参数的Info-gap模型,根据系统模型和性能要求得到可靠度分析的稳健函数,并将结构发生失效前能够容许的不确定参量的最大波动幅值作为稳健可靠度指标。结合剪切滑移线场理论,推导了均质弹塑性围岩最优支护阻力,建立围岩支护结构稳定分析的响应函数。实例工程展示了稳健可靠度分析的具体操作程序。参数分析表明,支护阻力越大,结构越稳健性;同时,提高巷道围岩的内摩擦角和黏聚力是增加支护结构稳健性的关键。该方法在参数信息少、样本数据有限情况下,是处理不确定问题的一种合理有效方法。

The stability of surrounding rock support structure is the key to the design of underground structure. To overcome the insufficiency of statistical information on surrounding rock parameters of deep tunnels, the information-gap theory is introduced to develop a non-probabilistic reliability analysis method for surrounding rock. The info-gap model of dimensionless parameters is given based on the uncertainty level, and the robust function of reliability analysis is obtained according to the system model and performance requirements. The maximum fluctuation amplitude of uncertainty parameter which can be tolerated before structural failure is taken as a robust reliability index. An optimal support resistance of homogeneous elastoplastic surrounding rock is obtained based on the slip-line field theory. Then a response function of stability analysis of surrounding rock support structure is established. The engineering example illustrates the specific operation procedures of robust reliability analysis. The parameter analysis shows that the greater the support resistance is, the more stable the structure is. In the meanwhile, it is shown that increasing the internal friction angle and cohesion of the surrounding rock is the key to improve the stability of the support structure. The proposed procedure is a reasonable and effective method to deal with the uncertain problem when the parameter information and sample data are limited.