| Lateral pressure of silo wall is the foundation load for structural design,so the study of silo side wall pressure is always the most basic and important research in the silo field.There exists the aggregate of grains at the bottom of the silo grain,the aggregate of grains is arched and called vertical arch,which will support the upper grains to some extent.The vertical arch leads to the redistribution of internal stress in silo grain,and then affects the distribution of silo side wall pressure.The horizontal arch is the aggregate of arched grains on the horizontal surface of silo bulk materials.Similar to the vertical arch,the horizontal arch can support the external grains to a certain extent and affect the distribution of the silo side wall pressure.In this paper,the model which considers the horizontal arch effect is established,the calculation method of silo wall side pressure is given,and the influence of horizontal arch on silo wall side pressure is studied.If there is no special explanation in the following text,"arch" refers to the horizontal arch,"arch effect" refers to the horizontal arch effect.The main research contents of this paper are as follows:(1)Put forward the calculation method of the silo side wall pressure which considers the horizontal arch effect.Explore the applicability of the calculation method in this paper.Based on the calculation model which considers arch effect,this paper puts forward three calculation methods of silo wall side pressure.Method 1 takes model A as the research object,which is divided into situation 1 and situation 2 according to the different directions of friction on balanced arch surface and sliding crack surface.Method 2 and Method 3 take model B and model C as the research objects respectively,and both of them are obtained by changing the direction of equilibrium arch from model A.The lateral pressure calculated by this paper is not linear distribution along the depth in deep silo,showing a trend of increasing first and then decreasing.In the large diameter squat silo,the lateral pressure is approximately linear distribution along the depth.Compare silo wall lateral pressure which is calculated by each method with existing experimental results.The comparison results show that the calculation results of situation 1 in method 1 are in good agreement with the test results of deep silo,the calculation results of situation 2 in method 1are close to the test results of the large diameter squat silo.(2)A method for calculating the spatial pressure of bulk material near the wall of the silo was proposed.The calculation method of spatial pressure of storage takes the model A as the research object,selects the unit microelement which has unit length and height.Carries on the static equilibrium analysis to the microelement,obtains the calculation method of storage spatial pressure.Origin was used to draw the three-dimensional surface diagram of vertical pressure distribution of bulk materials in the model A.The results show that the selection of microelement has great influence on the vertical pressure calculation results,and the horizontal arch makes the distribution of pressure uneven on the same horizontal plane.(3)Analyze the influence of the friction direction in the balance arch surface and the sliding surface on the silo wall side pressure.Analyze the concave and convex direction of the balance arch on the calculation results of the lateral pressure of the silo wall.The comparison between different situations in method 1 can reflect the influence of the friction direction to the lateral pressure.The comparison between Method 2,Method 3 and Method 1 can reflect the influence of the concave and convex direction of the balance arch on the lateral pressure of the silo wall.The results show that changing the friction direction and the direction of balance arch will make the lateral pressure increase to a certain extent.(4)Analyze the influence of lateral pressure coefficient,the angle between sliding surface and silo wall,the friction coefficient on the results of lateral pressure in this paper.When the value of lateral pressure coefficients closer to the Rankine active earth pressure coefficient,the angle between sliding surface and silo wall close to 45+φ/2,the result calculated by the method from this study is more consistent with the experimental results.The effective friction coefficient has little influence on the calculated result of the silo wall.The calculated results which adapted by effective friction coefficient is slightly smaller than that of the maximum static friction coefficient.all pressure. |
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