Leakage Analysis and Control During Large-diameter Shield Tunnel Construction
In response to the frequent leakage issue during tunnel construction despite a large margin of design indicators for tunnel waterproofing,numerical calculations and indoor experiments were conducted to study the waterproofing capacity of large-diameter shield tunnel joint.The main factors affecting the waterproofing of sealing gasket were analyzed,and the leakage patterns and reasons during construction period were sorted out.The leakage control measures and suggestions were proposed.The result indicates that the opening amount has a significant influence on the waterproofing capacity of sealing gasket.As the opening amount increases,the waterproof ability of sealing gasket decreases sharply.The influence of misalignment on waterproof ability of sealing gasket is relatively small.When the misalignment amount increases,the effective waterproof path of sealing gasket decreases.However,the non-misaligned part of sealing gasket can still maintain a certain stress level and maintain a certain waterproof ability.Corner leakage is the main way for pipe joint leakage.Due to the factors ( e.g.,assembly gaps and sealing gasket adhesion),the sealing gasket is prone to accumulate during the assembly process,making it difficult to compress the corner sealing gasket in place and reducing its waterproof ability,resulting in leakage.The on-site measurement of joint opening misalignment of pipe segments meets the design requirements,but the leakage may still occur at the joints.The main reason is that the sealing gasket is subjected to complex and variable forces during the pipe segment assembly process,which cannot be compressed like the design conditions in the laboratory.In addition,the measurement position of the joint is difficult to reflect the actual compression state of sealing gasket,making it difficult to control the quality of sealing gasket assembly.The compression state of sealing gasket after assembly determines the waterproof ability of tunnel.Therefore,during the shield tunneling construction process,the entire process of optimizing waterproof materials,constructing waterproof materials,assembling pipe segments,and grouting behind the wall should be controlled to improve the waterproof ability of sealing gasket at the pipe segment joints.
tunnel engineeringleakage analysis and controlexperimental modelingwaterproofing constructionleakage pattern
NETL
NSTL
万方数据
