Construction technology for tunneling first and then well in riverside water-rich sand layer

A construction technology for tunneling first and then well construction of a riverside water-rich sand layer is characterized in that the construction step sequence is adjusted so that a shield can quickly pass through a middle station; excavating a middle well after the station is passed, and meanwhile, dismantling well section pipe pieces; excavating to a designed elevation and then constructing a main body structure; the overall construction step of the first-tunnel and second-well station-crossing section comprises the steps of working well enclosure structure construction, working well foundation pit bottom full reinforcement and working well end reinforcement, crown beam construction, normal shield tunneling station-crossing, working well excavation, inner supporting system construction, well section inner segment dismantling, excavation to the designed elevation and main body structure construction. The working well excavation step and the inner supporting system construction step are carried out at t