Experimental Investigation On Discharge Pressure Of Silo

In the process of emptying, the dynamic lateral pressure is greater than the static lateral pressure has been widely accepted, but how to calculate the dynamic pressure is still an issue that not solved. This paper is based on the project of National Science Fund:Study on the mechanism of dynamic overpressure based on the energy conversion during filling and emptying(1578216) to modify the lateral pressure coefficient in the Janssen formula for calculating the static pressure and study the overpressure coefficient by experiments. The main research contents are as follows:(1) The diameter of the organic glass silo is 1.5m and the height is 5.5m. According to the purpose, put forward the reasonable test plan.Using the earth pressure sensor to measure the static pressure and dynamic pressure during emptying.Three groups of soil pressure sensors are arranged at the same height to ensure the stability and reliability of the data and explore the symmetry of the lateral pressure. According to the test results, calculating the overpressure coefficient of each measuring point, analyzing the position where the maximum overpressure coefficient happens and comparing the overpressure coefficient of each measuring point with the correction coefficient of the horizontal pressure in the standard and observing the flow of the stored material during emptying.(2) It is the first time that use the thin film pressure test system to measure the lateral pressure of the silo.Compare the film pressure test value with standard value and the soil pressure sensor test value, check the accuracy of the test results and explore the application of the thin film pressure test system in measuring the lateral pressure of the silo.(3) According to the characteristics of the storage material,contrast the "soil arching effect" in the field of geotechnical engineering, revise the lateral pressure coefficient in the Janssen formula.By the experiment and theoretical analysis, the conclusions are as follows:(1) the film sensor can measure the silo’s static and dynamic lateral pressure accurately, but must be protected properly in case of dropping from the wall. During emptying, the maximum overpressure coefficient is 2.107,occurred in the lower part about 1/3 of the material accumulation height. (2) The overpressure coefficient of each measuring point is smaller than the horizontal pressure correction coefficient, the calculation of the flow pressure at the bottom of the silo in standard is conservative. (3) Based on the soil arching effect, revising the correction coefficient. The formula calculation results are slightly larger than the experiment results and can ensure the safety of the silo.