Authors

Abstract

Well cellar seedling transplanting can effectively avoid series of problems such as long recovery time and poor uniformity of seedlings caused by the server climate conditions outside. Well cellar making is quite difficult in the upland with low moisture content. An opener with large socket was newly designed for the well cellar making. The well cellar making process was simulated by means of discrete element method (DEM), and its verification was qualified by soil bin test, with a relative error 7.46%. Taking arc radius of the opener socket, rotation speed and penetration speed as control factors, and collapse rate of the cellar hole as evaluation index, the influence of control factors on the collapse rate and their significance were obtained by Box-Behnken Design (BBD) test and analysis of variance (ANOVA). A quadratic regression equation of collapse rate with control factors was established, and the optimal parameters of the control factors were obtained as arc radius 128 mm, rotation speed 380 r/min and penetration speed 0.15 m/s, with the minimum collapse rate 22.70%. The collapse rate of the newly designed well cellar opener decreased much compared to the traditional one.

Abstract in Chinese

井窖式移栽可有效避免气候条件引起的还苗期长、秧苗均匀性差等一系列问题，为改善土壤墒情较差时井窖成穴难的现状，本文提出了一种大窝套小孔成穴器。采用离散元法对井窖制作过程进行数值模拟并通过土槽试验验证，相对误差为7.46%。以成穴器的圆弧半径、转速和入土速度为试验因素，以孔穴垮塌率为评价指标，通过Box-Behnken试验和方差分析得出各因素对孔穴塌陷率的影响及其显著性。建立各因素与孔穴垮塌率的二次回归模型，得到的最优参数为圆弧半径128 mm、转速380 r/min、入土速度0.15 m/s，最小垮塌率为22.70%。与传统的井窖式成穴器相比，其垮塌率明显降低。