The Coupling Mechanism between Railway Alignment Design and Resource Environment in the Southwestern Mountainous Areas of China

Faced with the characteristics of multifactor coupling and interweaving along the railway lines in the southwestern mountainous areas of China, researching the coupling mechanism and optimizing the collaborative development path between alignment designs and the resource environment is conducive to promoting the green and sustainable development of railways in these southwestern mountainous areas. In this study, first, regarding the environmental characteristics of engineering along the railway lines in the southwestern mountainous area, the key elements of the interaction and coercion between the alignment design (internal system) and the resource environment (external system) are identified, and the interactive impact mechanism of the “alignment design–resource environment” complex is revealed. Accordingly, a nonlinear coupling mechanism between the alignment design system and the resource environment system is established using the deviation coefficient coupling degree model. Second, from a methodological perspective, following a technical path of “analyzing the coercive effects of internal and external factors–identifying coupling relationships–discovering coupling laws–screening driving factors–proposing optimization plans–achieving collaborative development goals”, we propose an overall optimization plan to solve the problem. Finally, the Chengdu Changdu section of the X railway, which is located in a southwestern mountainous area, is taken as an example for this study. The results indicate that if the state of the external system of the KL scheme is continuously improved through the regulation of the u 22 (crossing the ecological protection red line length), u 23 (biodiversity impact), and u 24 (ecosystem impact) indicators and that the internal structure of the line design is improved by optimizing the l 12 (total length of bridges and tunnels) and l 13 (number of stations) indicators, effectively driving the improvement in the u 31 (land resource occupation) and u 43 (land development intensity) indicators, the alignment design and resource environment will exhibit a mutually reinforcing coupling evolution trend and ultimately achieve an “alignment design–resource environment” composite system with higher quality coupling.