Construction method for penetrating through gas pipeline with pressure downwards at ultra-close distance by using shield tunneling machine

The invention discloses a construction method for penetrating through a gas pipeline with pressure downwards at an ultra-close distance by using a shield tunneling machine, and relates to the technical field of shield tunneling machine construction methods. The construction method comprises the following steps of stopping the shield tunneling machine; accurately positioning the gas pipeline; performing three-dimensional modeling; adjusting the slope of the line, and calculating the nearest distance between the shield tunneling machine and the gas pipeline; replacing fuel gas; re-pushing the shield tunneling machine; grouting for the second time; and recovering the fuel gas. According to the construction method, nitrogen is adopted for replacing fuel gas for pressure maintaining, and the risk when the shield tunneling machine passes is reduced; the soil settlement at a shield body is guaranteed by adopting an anti-mud-effect construction method, and the soil pressure balance in the crossing process is guarante