Fuzzy probability analysis on foundation pit´s base against heave stability

In view of the randomness and fuzziness of the problem of foundation pit´s base against heave stability, the defect of the tradional safety factor method is existent objectively although it is very simple, therefore in combination with structural reliability and fuzzy mathematics theory to solve this problem is of practical significance. The calculating method of the fuzzy instable probability is studied on according to the fuzzy random variable´s probable distribution and membership function. Through an engineering example´s calculating results, the influence of variable´s different probable distribution and limits of the fuzzy transition area on the fuzzy instable probability is analised. The analysis indicates that the influence of the variable´s probable distribution on the results is extremely trivial for the small probability event, in addition, the fuzzy instable probability would be increased along with the increasing of the fuzzy transition area. Therefore, as compared with the safety factor, the fuzzy probability could reflect the essence of the problem objectively and comprehensively.