A pre-removed segment is a new structure segment applicable to enlarging shield tunnel technology. It can facilitate the removal of the excess partitioned segment, for an enlarged station, by shield tunnel, however, it may cause certain risk of enlarged excavation construction, when a certain construction control limit is exceeded. To study the risk control problem for the removed segment, applicable to the shielded-tunnel-enlarged station, a risk control method, based on the load critical curve of the pre-removed segment is proposed. In this paper, a three-dimensional stratum structure model of the shielded-tunnel-enlarged station is established and variations of forces on the interface of the pre-removed segment are analyzed, under the influences of buried depth and staggered distance, for different enlarged excavation construction stages, as well as different soil properties (elasticity modulus). Combined with the load critical curve of the contact surface concerning the pre-removed segment obtained from the test, the critical construction control surface of buried depth and staggered distance, was obtained to ensure the bearing capacity of the pre-removed segment in different soil properties and in all of the involved enlarged excavation stages. It provides the technical guidance and reference for the construction risk control of the application of pre-removed segment in the shielded-tunnel-enlarged station.