Study on Field Test of Joint Waterproofing of Long-segment Heavy-tonnage Prefabricated Assembled Utility Tunnel
In order to demonstrate the waterproof performance of the long-segment heavy-tonnage prefabricated assem-bled utility tunnel in the startup zone of Xiong'an New Area,the field test of joint waterproofing of long-segment heavy-tonnage utility tunnel has been conducted,and the waterproof performance of two types of waterstops after wa-ter injection and pressurization in different cases has been analyzed.As the results indicate:both types of waterstops can meet the waterproofing requirements for the tunnel in normal operation.In the case of tensioning force induced failure of the two types of waterstops,Class Ⅰ waterstop has 2 leakage points and Class Ⅱ waterstop has no leakage point.The reason is that Class Ⅰ waterstop is spliced when kept still and the nonuniform splice width at element joint will result in tensioning force induced failure and thus water leakage.In the case of element dislocation of the two types of waterstops,Class Ⅰ waterstop has no leakage and Class Ⅱ waterstop has 3 leakage points.The reason is that Class Ⅱ waterstop is spliced when suspended and its tensioning force is less than that of Class Ⅰ waterstop,so leakage is more likely to occur in the case of dislocation.For this project,it is recommended to use Class Ⅱ water-stop for waterproofing of element joint.
Urban utility tunnelLong segmentHeavy tonnageJoint waterproofingWater injection and pressuriza-tionField test
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