Study On The Monitoring And Numerical Simulation Of The Vibration And Stress Of Concrete Pumping Pipe

With the development of the modern construction industry,the concrete pumping technology has been greatly improved.The favorable operation of the concrete pumping system is the basis for ensuring the concrete conveying quality and the efficiency of pouring can meet the construction requirements.However,during the concrete pumping process,the pipe may be blocked and leaked due to factors such as the performance of the concrete,the layout of the pipe,and the setting of pumping parameters,which will cause much obstacles to the construction process.Therefore,the study on the variation law of characteristic indexes during the pumping process will have important theoretical and practical engineering value for guarantee the regular process of concrete pumping.In the experiment,the strain gauges and sensors are arranged on the concrete pumping pipeline and the strain and acceleration data of the characteristic section are obtained by dynamic acquisition system.The law of the pipe stress and strain and the acceleration and vibrate displacement of the pumping process is analyzed by reasonable denoising and analyzing process.The experiment results show that:(1)The acceleration value near the pump outlet is larger than that of other parts,and the remaining sections acceleration values are decreased along with the pipeline.In addition,the result show that under different pumping pressures,the greater the pumping pressure,the greater the acceleration value.(2)The vibration displacement of the pipe in the horizontal direction decreases with the extension of the pipe,and the greater the pumping pressure,the greater the displacement of the pipe.In addition,the displacement characteristic coefficients?_x and?_y in the horizontal and vertical directions of different pipe segments,which shows the changes of?_x and?_y can be used to monitor the change of the pipe operating state during pumping process of the specific pipe segments.(3)The hoop strain value is about 2-4 times of the longitudinal strain value of the same section of the pipe,and with the extinction of the pipeline,the hoop strain keep a decreasing trend,but there is a sudden increase at the elbow.However,the longitudinal strain of the pipe will increase in the vertical pipe section due to the pipe and concrete weight.(4)The pressure loss caused by unit length elbow is larger than straight pipe.Furthermore,the pressure loss caused by the 1m elbow is about 6m straight pipe,and the elbow part shows a stress concentration which the stress value is larger than the adjacent straight pipeline.In this thesis,the discrete element model of concrete pumping process is also established.By simulating different pumping conditions,the velocity distribution of concrete particles in the vertical elbow of pipe and the variation of the pressure value of the inner wall of the pipe are obtained,and the results matched well with the stress variation of the vertical elbow section obtained by the experiment result.The research results of the thesis have a good theoretical significance and engineering value for the optimization of concrete pumping process and pipeline monitoring during concrete pumping construction.