Taking the assembled pipeline as research object,the deformation of sealing rubber ring in the connector under the water hammer pressure was analyzed.Based on the water hammer model with fluid-structure interaction for thick-walled pipe,a new method for calculating coupled water hammer pressure wave velocity in assembled pipeline was proposed.The proposed calculation method was verified by a water hammer experiment,and the influences of sealing rubber ring and thickness-diameter ratio of pipeline on coupled water hammer wave velocity in assembled pipeline were analyzed in detail.The results show that the calculated values obtained by the proposed method are in good agreement with the experimental data,which indicates that the proposed method is correct and reliable.The attenuation rate of the sealing rubber ring to the water hammer wave velocity enhances with the increase of its number,and the greater bulk modulus of the conveying medium in the pipe are,the better attenuation effect of the sealing rubber ring on water hammer wave velocity can be reflected.When the thickness-diameter ratio is less than 0.05,the deviation of calculation results between the proposed method and the thin-walled pipe model is very small,indicating that the proposed method is applicable to both thin-walled and thick-walled pipes.The annular cavities at the joints between pipe sections of the assembled pipeline act as “water hammer pressure buffer rings”.With the increase of the thickness-diameter ratio of the pipe,the attenuation effect of the annular cavities on the water hammer response gradually enhances,which makes the coupled water hammer wave velocity in the pipe increase briefly at first,and then decrease continuously until the limit value.