In the middle section of the Jiangxinzhou wind shaft project within the Nanjing Metro Line 4 Phase II project, spanning from Binjiang Station to the Longjiang interval, a geological composition is encountered consisting of silty clay and a substantial layer of high-pressure water-saturated sands. Below this, there exists a high-strength gravel layer. In the context of ground connection wall construction, failure to select appropriate mud parameters may result in a compromised wall protection effect, leading to potential wall collapse or hole shrinkage. The most direct approach to enhance wall stability is by increasing the mud weight, albeit at a significant escalation in project cost. To ascertain the optimal mud parameters for trenching operations beneath the high-pressure water-saturated sand layer overlain by silt and to conduct an analysis and evaluation of trenching quality under these geological conditions, a parabolic column method three-dimensional model of the mud wall protection system was employed in this study. This model facilitates the calculation of mud parameters, with the subsequent validation of results through trial trenching tests and ultrasonic testing. Ultimately, a suitable mud ratio was chosen based on the research findings. The research outcomes substantiate that a mud viscosity of 60 s and a specific gravity of 1.07 g/cm³ can ensure a stability factor of 1.5. These findings provide valuable reference points for similar projects and hold potential significance for future research in this domain.