Abstract: Aiming at the problem of complex calculation formula for active soil pressure resultant force of limited soil, based on the newly built foundation pits in the vicinity of subway stations, multiple limited soil failure modes are proposed based on the positional relationship between existing subway stations and foundation pits. The thin layer microelement method is used to consider the frictional effect between the soil and structural interface, and a calculation method for the combined force of active soil pressure is established. By adjusting the spatial position relationship between the newly built and existing structures, a active soil pressure contour map was obtained, and parameter analysis was conducted on it. Furthermore, a simple calculation method for active soil pressure was put forward. The research results indicate that: 1) Five finite soil failure modes have been proposed, and corresponding formulas for calculating the active soil pressure have been established; 2) As the proximity distance increases, the active soil pressure gradually increases; As the thickness of the existing subway station cover increases, the active soil pressure gradually increases when approaching the foundation pit, and the active soil pressure on the side far from the foundation pit first increases, then decreases, and finally increases; 3) The depth of the foundation pit has a significant impact on the active soil pressure, the internal friction angle has an impact on the active soil pressure, and the wall soil friction angle has basically no effect on the active soil pressure; 4) The value of the spatial position relationship coefficient of the combined force of active soil pressure is given. Through the above research, a simple calculation method for the combined force of limited soil active pressure has been proposed, which can provide reference for the design and construction of adjacent engineering.