基于Info-Gap理论的地下结构稳健性分析方法

Robust reliability analysis for underground structures based on Info-Gap theory

围绕基于Information-Gap(I-G)理论的地下结构稳健性方法展开研究。首先,根据地下结构输出响应模型中不确定参量可能的取值范围及不同波动幅度对结构安全性能的影响,采用I-G模型量化处理不确定参量;其次,通过地下结构失效准则确立输出模型响应值与临界值之间的关系,由此构建稳健函数,并将结构发生失效前能够容许的不确定参量之最大波动幅度值定义为稳健可靠性指标来度量地下结构的可靠程度,从而形成了基于I-G理论的地下结构稳健性分析方法。最后,以某隧道衬砌稳健性分析为例,详细展示了地下结构稳健性分析的具体实施流程。工程算例表明,稳健可靠性指标反映了结构性能主动抵抗不确定性参量变化的能力。稳健性方法为不易得到不确定性因素足够信息的地下结构可靠性分析开辟了一条新途径。

The central focus is devoted to exploring the robust reliability methodology for underground structures based on the Information-Gap（I-G） theory.Firstly,according to the influences of the possible ranges and the various fluctuations of uncertain variables involved in the output model on the safety performance of underground structures,the I-G model is used to handle the uncertain variables quantitatively.Secondly,the correlation between the response value and the critical value for the output model is developed by use of the failure criterion utilized for underground structures,and the robustness function is then established.On this basis,the greatest horizon of the fluctuation of uncertain variables that the structural performance can suffer is further defined as the robust reliability index which will be consistent with no-failure to measure the structural reliability.Hence,a robust reliability methodology for underground structures by means of the I-G theory is presented.Finally,a scheme to demonstrate the robust reliability evaluation for an example of the tunnel lining is particularly implemented by the proposed approach.The illustrative practical example reveals that the current robust index for structural performance has the capacity to be actively immune to unanticipated variations of uncertainty parameters.The proposed methodology affords a novel route for the reliability assessment of underground structures when the uncertain information is unavailable or scarce.