The ‌influence of shallow tunnel construction on typical plant-soil ecological hydrological processes

Large-scale water diversion and regulation projects have long transmission lines and large water diversion scales. The groundwater along the project routes is complex. Tunnel construction inevitably affects the groundwater system in the construction area and may influence the ecological hydrological processes of plants and soil along the route. The paper took the a large-scale water diversion project in Southwest China as an example, two research points were selected near a long tunnel in the Kunming section. By monitoring the dynamic changes of surface and deep soil moisture and plant fluid flow, and using the LGR liquid water isotope analyzer to determine the δ2H and δ18O values, the differences in water utilization of typical plants at the two monitoring points are analyzed. This further reveals the influence of long tunnel construction on typical plant-soil eco-hydrological processes. The results show that under the combined influence of human activities such as climate change and engineering construction, and against the background of groundwater level changes in tunnel construction, the soil moisture in both the surface and deep soil at the affected points has decreased, and the plant fluid flow has also significantly decreased. However, the impact on the source of plant water utilization is limited. The research results can provide a basis for the protection of the ecosystem and ecological restoration during the construction of long tunnels.