Experimental Research On The Joint Bending Stiffness And The Compression Performance Of The Gasket Of The Block-type Prefabricated Comprehensive Pipe Gallery

The comprehensive pipe gallery is a kind of underground space structure which contains a variety of municipal pipelines such as water supply,communication,electricity,gas and so on.Due to the high degree of standardization of the comprehensive pipe gallery,prefabrication and assembly technology has become a new trend and research hotspot in the construction of the comprehensive pipe gallery.For the comprehensive pipe gallery adopting block prefabrication and assembly technology,the joint is the weak part,which is very sensitive to deformation and prone to water leakage.However,there is little research on the mechanical and waterproof performance of the joint of the block prefabrication integrated pipe gallery at home and abroad.Therefore,based on the comprehensive pipe gallery project of Wujiu line in Wuhan,this paper has carried out the experimental research on the joint bending stiffness and the compression performance of the gasket of the blocktype prefabricated comprehensive pipe gallery.The main contents are as follows:(1)An experimental research on the bending stiffness of the joint of the block-type prefabricated comprehensive pipe gallery was carried out.The full-scale concrete slab including the transverse joint of the pipe gallery is selected as the test piece.The test pieces are divided into two groups,and the difference lies in the size of the reserved hole and the hand hole of the arc bolt.The bending moment-rotation data curve of the joint is obtained through the laboratory loading test,and then the test data is analyzed to obtain the bending stiffness value of the joint.(2)An experimental research on the compression performance of the joint gasket of the prefabricated comprehensive pipe gallery was carried out.A porous comb type rubber gasket made of EPDM was designed,and its compression test was carried out after it was manufactured.The pressure-opening curve of the joint gasket was obtained through experiments,and the compression performance of the gasket was analyzed.The results of this study show that the bending moment-rotation curve of the joints of the two groups of specimens in the bending stiffness test showed a certain nonlinear characteristic,and the bending stiffness value of the joints gradually decreased as the load increased.Under the design bearing capacity,the bending stiffness values of the two groups of specimens are respectively 12057 k N·M/rad and 4990 k N·M/rad,which shows that the size of bolt reserved hole and hand hole are the important factors affecting the bending stiffness values of the joint.Due to the discontinuity of stiffness and weakening of holes,the stress on the joint of pipe gallery is relatively complex,and stress concentration is easy to occur.According to the pressure-opening test curve of the gasket,the smaller the opening,the greater the pressure required for each stage of loading;when the opening is 4 mm,the closing pressure required for each meter of rubber gasket is 47.50 k N.The designed gasket can not be compressed to an opening of 0mm,and the gasket will produce plastic deformation after unloading.Therefore,the structural form of the designed gasket is optimized in this paper.