劲性水泥土搅拌桩地下连续墙贝叶斯网络分析

Bayesian Networks Analysis on Soil cement Mixing Wall

摘要:

分别分析了事件树、故障树和贝叶斯网络的优点和缺点，总结了三者联合应用的必要性，进而改善了贝叶斯网络的构造方法.方法是先将事件树的输出事件和序列事件分别作为故障树的顶事件和中间事件建造系统的故障树，再将故障树转化为系统的贝叶斯网络，然后利用贝叶斯网络的计算优势进行分析；建议贝叶斯网络中的任一非根节点事件出现失效时应按后验概率从大到小的次序对相应根节点事件进行控制.采用文中方法分析了SMW（soil cement mixing wall)深基坑工程的基坑事故发生概率和造成事故的主要基本事件，证明了该方法的实用性.

Abstract:

Based on an analysis of the advantages and the disadvantages of event trees (ET), fault trees (FT) and Bayesian networks (BN) respectively, a conclusion is drawn that the three methods should be applied jointly, and the way to construct a BN is improved. This way consists of three steps. First, the FT whose top event and middle events are the output event and the event sequence of the ET respectively is built. Then, the constructed FT is transformed into a BN directly. Finally, with the advantages of the calculation and analysis, the BN is used to make predictions as well as diagnostics. When there is any failure in the non root node event in BN, the corresponding root node events should be controlled by the descending order of their posterior probability values. By applying the proposed method to the soil cement mixing wall in a deep excavation, the failure probability of the top event and the main cause are figured out easily and the practicability of this method is proved.