公路桥梁施工专项风险等级估测的改进方法

Improved Method of the Evaluation for Special Risk Level in Highway Bridge Construction

桥梁工程施工风险评估对于桥梁工程的安全建设具有重要的意义。《公路桥梁和隧道工程施工安全风险评估指南》推荐采用基于事故严重程度等级(C)和事故可能性等级(P)的风险矩阵来估测风险等级,该方法计算简单、操作方便,但评估结果稳定性较差。基于C等级和P等级对风险等级的贡献量相同,以《指南》中的风险矩阵为基础,根据分形几何学的自相似原理,通过细化C等级和P等级,利用更高阶数的风险矩阵估测风险等级。通过线性插值实现严重程度等级和可能性等级的细化过程,将这两个等级由1标度细化到0.1标度。细化风险等级方法提高了公路桥梁施工专项风险等级估测结果的稳定性和可靠性。

Risk assessment is essential to the safety of bridge construction.Ministry of Transport issued″highway bridge and tunnel construction safety risk assessment guidelines″（Trial）（hereafter referred to as″Guide″）in 2011.The″Guide″requires experts to use risk matrix based on cost level（C）and probability level（P）to estimate the level of risk.This method is easy to operate but has a low stability.Stability is defined as the fluctuating sensitivity of risk level with the change of assessment conditions.Risk assessment is a very subjective activity,fluctuations of C and Plevels will inevitably occur in the process of assessment,which leads to corresponding fluctuations of risk level.The improved method is based on the risk matrix in the″Guide″with a hypothesis that Cand Plevels have the same contribution to risk level.According to the principle of self-similar fractal geometry,a higher order risk assessment matrix is transformed from the basic one by refining the Cand Plevels.The refining process from 1to 0.1scale is realized by linear interpolation.The stability of risk assessment has enhanced observably through this improved method.