深基坑稳定性的模糊随机分析

Fuzzy-random stability analysis of deep foundation pit

基坑稳定性分析中的不确定性主要表现为随机性和模糊性,随机性体现为将各种设计参数作为随机变量, 而模糊性主要体现在其失稳的判断标准上,这与深基坑失稳破坏的模糊特征相吻合。重点阐述了深基坑稳定性分析中的模糊性, 并采用模糊随机方法,推导出基坑稳定性的广义模糊随机计算模型, 该模型可以考虑分析中所涉及到的计算力学参数的随机性和失稳判断标准的模糊性。同时还对基坑失稳概率的标准进行了讨论。最后实例分析了坑底隆起失稳的模糊概率。计算结果说明,模糊随机方法能够更全面、合理地反映基坑的实际稳定性。

Fuzziness and randomness are two main uncertainties in the study of stability of deep foundation pit, randomness implies kinds of design parameters being random variables, and fuzziness means that the judgement criterion of stability should be regarded as a vague criterion, which has inexplicit outline, it is in accord with the fact of failure process. This paper emphasizes to study the fuzziness of stability analysis of deep foundation pit, by adopting fuzzy sets and probability theory, a generalized model of fuzzy-random has been put forward to evaluate the stability degree, in this model, the random character of mechanical parameters and the fuzziness of failure criterion, are considered. And it also discusses the failure probability standard of deep foundation pit. Finally, an example is given to calculate the fuzzy failure probability of soil uplift in the bottom of pit, the result indicates that the fuzzy-random method can reflect the actual stability of the foundation pit roundly and rationally.