Abstract: Objective: The proximity of existing pipelines often weakens the local support capacity of the retaining structures during construction, potentially leading to foundation pit instability. To minimize the impact of existing pipelines on foundation pit retaining structures during construction, it is necessary to conduct an indepth research on the application effect of local reinforcement using freezing technology. Method: Based on the ancillary structure project of Jinan Metro Line R1 Dayangzhuang Station, focusing on the construction problems caused by the presence of highvoltage cable pipelines near the foundation pit retaining structure, a combined retaining structure of ′underground diaphragm wall + bored insitu pile′ is proposed, which adopts the freezing technology for local reinforcement. A simplified numerical simulation model of the foundation pit is established, and the stability of the foundation pit before and after freezing reinforcement is compared and analyzed. Furthermore, reasonable values for the width and thickness of the freezing layer are determined.Result & Conclusion: Before freezing reinforcement, the significant difference in stiffness between the underground diaphragm wall and bored insitu piles made it difficult to coordinate the deformation of the surrounding soil. The support area of bored insitu piles experiences significant internal extrusion, accompanied by substantial land subsidence and severe groundwater seepage. After freezing reinforcement, a frozen cutoff wall is formed, significantly increasing the support stiffness of the bored insitu pile area and reducing the horizontal deformation and land subsidence of the surrounding soil around. Extending the freezing reinforcement range can effectively suppress deformation of the support piles, land subsidence, and ground water seepage. However, when the width and thickness of the freezing layer exceed a certain range, the postfreezing effect becomes less significant. A freezing reinforcement range of 1.5 m in thickness and 9.0 m in width is found to be reasonable.