Risk analysis of open-cut tunnel under-crossing bridges within right-of-way of highways

With the development of transportation infrastructure, the structures and utilities within right-of-way of highways of open-cut tunnel under-crossing the bridges are increasing. However, these projects face complex construction conditions and high accident risk, and their engineering risks are not yet clear. This paper utilised the work breakdown structure–risk breakdown structure to construct a risk identification matrix and propose a risk sources list. Furthermore, this paper takes an engineering project as a case study. Risk levels for various risk factors were calculated using the entropy weight method and risk matrix, and nine risk factors were identified as high risk. In addition, a three-dimensional numerical simulation model was established to analyse the influence of foundation pit excavation on existing bridge, based on which safety countermeasures for the primary risk factors were proposed. The results indicated that the deformation of the bridge piers was primarily characterised by horizontal displacement and the maximum horizontal displacement reduced from 5.29 to 2.95 mm after the addition of isolation piles and reinforcement piles. The results can provide references for risk identification and analysis in such engineering projects. In the future, it is necessary to further study the safety countermeasures of high-risk sources and improve the risk list.