Study On The Quasi-static Test Of The Joint Of Precast Reinforced Concrete Underground Comprehensive Pipe Gallery

The underground utility tunnel is one of the important symbols of the modernization of urban municipal infrastructure in the 21 st century.It plays an important role in optimizing the spatial structure and pattern of contemporary cities,building livable cities,and improving the comprehensive loading capacity and functionality of cities.At present,the utility tunnel construction which is commonly used generally exists the problems of difficulty in transportation and installation,heavy wet-bored workload on the construction site,and long construction period.Focusing on these disadvantages,this article uses the method of segmented precast to build the utility tunnel,which has the advantages that the components are completed at the factory with the help of industrial production,and the sleeve grouting connection technology in the prefabricated houses is used to complete the installation of the utility tunnel at the construction site,which avoids large-scale wet-bored on site.In terms of this connection method,this article has done the following works:Three test nodes for the lower and edge part of the utility tunnel were designed.XJ-1 is a cast-in-place comparative test piece;YZ-1 is the first concrete slab type assembled utility tunnel,with the precast bottom plate and precast wall plate connected by flat-type sleeve grouting;YZ-2 is the second concrete slab type assembled utility tunnel,with the precast bottom plate and precast wall plate connected by socket type grouting;A pseudo-static test was carried out on the three designed specimens with controlled displacement loading,the force-deformation curve was obtained,which is the hysteresis curve,and the skeleton curve of the specimen was then to gained.Through the analysis of the test phenomena and test data,the shape of the hysteresis curve of the two of prefabricated test piece and the cast-in-place test piece was roughly shuttle-shaped,and the total energy consumption of the cast-in-place test piece was greater than that of the prefabricated test piece,the energy dissipated of YZ-2 specimen was higher than that of the YZ-1 specimen;the bearing capacity of the YZ-2 specimen was higher than that of the YZ-1 specimen,but both prefabricated specimens had a smaller bearing capacity than the cast-in-place specimen;the trend of the stiffness degradation curves of the three specimens was basically the same,the initial stiffness of the YZ-2 specimen was not much different from the cast-in-place specimen,but it was higher than the YZ-1 specimen;under the same level of cyclic load,the strength degradation performance of the YZ-2 specimen was better than YZ-1 test piece,and it was more obvious when loaded in the negative direction,indicating that the socket connection method used by the YZ-2 specimen had a greater safety reserve than the YZ-1 specimen.In general,the seismic performance of the twoprecast specimens was not much different from the cast-in-place specimens,among them,the seismic performance of the YZ-2 specimen was closer to the cast-in-place test piece;The tunnel structure designed in this article has adopted the industrial production method of being manufactured at the factory and installed at the construction site,which were able to effectively reduce the restrictions on the lifting capacity of the lifting equipment during transportation and installation,cutting down the workload of wet-bored on the construction site,as well as to take into account both the precast utility tunnel construction technology and the excellent performance of both of the tube connection joints,it improved the shortcomings in the current tunnel construction process,which was conducive to the completion of the project quality and quantity on time.