玉米堆压缩特性的实验研究

STUDY ON COMPRESSION PROPERTIES OF CORN HEAP

利用LHT-1型粮食回弹模量仪对玉米堆(东北产)(含水率为12.56%、14.72%、15.78%、17.09%w.b.)的压缩密度和无侧向膨胀体变模量进行实验测定。选定样品顶部的压应力分别为:0、50kPa、100kPa、150kPa、200kPa、250kPa、300kPa,通过理论推导并计算得到样品所受的平均围压,其值约占所对应的顶部压应力的36.2%。实验结果表明:在同一含水率下,随着平均围压的增大,玉米堆的压缩密度也增大;玉米堆压缩密度与平均围压的关系可用二次方程表示:ρ=-Aσ2+Bσ+C,其中A、B、C分别为方程的系数,并随样品含水率的不同而变化。在同一含水率下,随着平均围压的增大,玉米堆的体变模量也增大;在同一平均围压作用下,随样品含水率的增加,玉米堆的体变模量减小。玉米堆的体变模量与平均围压的关系可拟合出二次方程为K=-aσ2+bσ+c,其中系数a、b、c随含水率的不同而变化。

In this paper, the density and bulk strain modulus of corn heap under compression without lateral expansion were measured by using the LHT-1 rebound modulus tester at four moisture content levels （12. 56%, 14.72%, 15.78% and 17.09% w. b. ）. The compression stresses at the top of corn heap were set as 0, 50, 100, 150, 200, 250 and 300 kPa respectively and the average confining pressure of corn heap was calculated by theoretical equation. The results showed that with the increase of the average confining pressure, the compression density of corn heap also increased in the same moisture content. The relationship between the compression density and the average confining pressure of corn heap can be expressed by a quadratic equation as ρ=-Aρ^2＋Bρ＋C, where A, B and C were respectively the coefficients of the equation varying with moisture content. In the same moisture content, the bulk strain modulus of corn heap increased with the increase of the average confining pressure; in the same average confining pressure, the bulk strain modulus of corn heap decreased with the increase of the moisture content. The relationship of the bulk strain modulus and the average confining pressure of corn heap can be described as a quadratic equation：K=-aρ^2＋bρ＋c, where a, b and c were respectively the coefficients of the equation varying with moisture content.