基于直剪试验的稻谷粮堆力学性质研究

为揭示粮仓建设和粮食运输途中粮堆的强度与剪胀特性,开展了在垂直压力为25~200kPa、含水率分别为8.41%、10.59%、13.88%和16.25%条件下的稻谷直剪试验。结果表明:稻谷粮堆剪切变形可分为弹性变形、塑性变形和籽粒压缩3个阶段;不同含水率下,稻谷粮堆强度特性基本符合莫尔-库伦强度准则,随着含水率增加,稻谷粮堆粘聚力逐渐减少,内摩擦角逐渐增大;含水率对稻谷粮堆的剪胀特性影响不明显,但随着垂直压力的增大,其剪缩性越明显;在垂直压力较小的条件下,含水率对稻谷粮堆的抗剪强度影响较大,随着垂直压力的增大,含水率对抗剪强度的影响逐渐减小。研究结果可为粮食仓储和运输、装载粮食机械的设计、粮堆数值仿真建模提供参考。

Study on Mechanical Properties of Rice Grain Stack Based on Direct Shear Test

In order to reveal the strength and dilation characteristics of grain stacks during granary construction and grain transportation,direct shear tests were carried out on rice with moisture content of 8.41%,10.59%,13.88%and 16.25%,respectively,in the range of 25~200 kPa.The results showed that the shear deformation of rice grain pile could be divided into three stages:elastic deformation,plastic deformation and grain compression.The strength characteristics of the rice grain pile basically conform to the Mohr-coulomb strength criterion.The effect of moisture content on the dilatancy of rice grain pile was not obvious,but with the increase of vertical pressure,the dilatancy was more obvious.Under the condition of low vertical pressure,moisture content has a great influence on the shear strength of the rice grain pile.With the increase of vertical pressure,the influence of moisture content on shear strength decreases gradually.The results can be used as reference for the design of grain storage and transportation,grain loading machinery and grain pile numerical simulation.