Abstract:In order to study the accident risk of horizontal directional drilling construction,considering the shortcomings of fault tree qualitative analysis and N-K model quantitative analysis method, a comprehensive model of construction risk analysis combining N-K and fault tree is constructed from four risk factors of human, equipment, environment and management. By establishing the mapping relationship between the bottom event of fault tree construction and the coupling risk factor set of N-K model, the single-factor, double-factor and multi-factor coupling risk probabilities are calculated respectively, the risk coupling value is solved. The results show that the risk probability of horizontal directional drilling construction accidents increases with the increase of risk coupling factors; when the three factors are coupled, the maximum value of equipment-environment-management coupling is 0.2608, followed by man-equipment-management is 0.2034; when the two factors are coupled, the maximum value of the environment-management coupling effect is 0.1554; there are 50 possible ways to cause accidents in horizontal directional drilling construction accidents and the overall accident risk can be prevented in stages according to the preparation stage, the guide hole drilling stage, the reaming stage, the pipeline pullback stage and the planning management stage. On the one hand, the research results can provide a new comprehensive model for risk research, on the other hand, it can also provide an important reference for the safe construction of horizontal directional drilling.The research results can provide an important reference for the safe construction of horizontal directional drilling.