###### Abstract  
From the aspect of calculation theory, the beam-spring model method and modified routine method of shield tunnel segment structure calculation were improved, and an efficient integrated software system for segment structure calculation of shield tunnel was developed. The beam-spring method is generally calculated according to the assumption of continuous displacement between beams and joints, and the existing modified routine method assumes that the lateral pressure gradient is constant generally, which does not consider the variation in lateral pressure gradient caused by the difference in the lateral pressure coefficient of soil layers or the water level height, which has a certain deviation from the actual situation. The existing beam-spring method and modified  
pressure with gradient variation from the existing modified routine method and studied the influence of the water level change on the internal force of the segments under different geological conditions. [PERSON] et al. [3] used a modified routine method to analyze the internal forces of circular shield tunnel lining segments. [PERSON] and [PERSON] et al. [4] calculated the bending moment of the segments with joint bolts under fully elastic conditions in combination with a modified routine method to study the influence of the transverse deformation of the tunnel on the safety of the tunnel structure and proposed effective value of bending stiffness from the perspective of numerical simulation and theoretical derivation. Regarding the problem that the current beam-spring model cannot simulate the deformation discontinuity of the shield segment joints precisely, many scholars worldwide [5; 6; 7; 8; 9] researched the applicability of the beam-spring method in a segment structure design. The mechanical properties adopted during the calculation of the segment joint have significant impacts on the force and deformation of segment structures, and the calculation accuracy of the beam-spring method depends on the selection of input parameters. Scholars proposed the method for parameter determination of the rotational stiffness of segment joints with corresponding mechanical models based on theoretical analysis, numerical simulation, joint tests, etc. In the aspect of field model test for studying mechanical properties of segments, the test model [10] of the segment lining structure is designed by using a shield tunnel-ground simulation facility and a rotary water pressure device to control the water pressure and the earth pressure separately, based on the ground-structure model; the photoelastic model test is given in reference [11], which promoted the development of shield tunnel segment structure design.  
[PERSON] et al. [12] summarized the mechanical models describing the rotational stiffness value of the joints based on test results, including linear, bilinear, and nonlinear models, as well as the beam-spring continuous model, which uses a continuous spring to simulate the segment joint, assuming joint displacements of adjacent segments at the joint position are consistent. However, there is a significant mismatch between the calculation and measurements of force and deformation of the shield segment lining on the beam-spring continuous model. The beam-joint model [13] ought to have the same stiffness matrix of the joint node force and displacement as the beam-spring discontinuous model, which is more in line with the actual situation in the calculation results.  
Therefore, on the basis of previous studies, this article improved the existing beam-spring method and modified the routine method theory, taking into account the discontinuity of the beam-joint deformation in the beam-spring model and the lateral pressure gradient change in the modified routine method. The calculation software system developed by C# and the python programming language are proposed to improve the accuracy and efficiency of segment structure calculation.