气压深松特性及技术的试验研究

发布时间：2018-06-25 16:34

本文选题：气压深松 + 深松特性　；参考：《东北农业大学》2016年博士论文

【摘要】：我国是一个严重缺少水资源的国家,研究合理的农田耕作技术,提高土壤的蓄水保墒能力,减少水土流失,避免耕地的继续减少,对实现农业的可持续发展具有重要的现实意义。为解决由于不合理的耕作方式而造成的水土流失,我国实施了“保护性耕作”的耕作方式。深松是保护性耕作的重要组成部分,通过疏松土壤,打破耕地犁底层和加深耕作层,能改善土壤的透水、透气性能和团粒结构,使雨水更容易渗入到土壤中,从而有利于作物根系的发育,提高蓄水保墒能力。但传统的深松方式,存在深松作用范围小、深松深度浅、程度不均匀等问题。因此,对新的耕地深松方式的研究十分必要。论文提出了一种新的耕地深松方式—气压深松:通过向耕地土壤中注入高压气体,使土壤在高压气体的作用下产生裂隙,实现对耕地的深松。为了探寻气压深松效果,探索气压深松特性,解明气压深松参数对气压深松效果评价指标的影响。为此,论文从以下七个方面展开研究,主要的研究内容为:对气压深松裂隙生成原理进行分析,分析气压深松裂隙扩展模型、裂隙扩展机理及气压深松裂隙起劈压力。对深松效果的评价指标进行选取确定,选取土壤孔隙度、土面抬升量作为深松效果的评价指标。给出了各评价指标的测试方法,对测试原理及测试手段进行说明与分析,对指标测试装置及气压深松试验装置进行研制。为验证气压深松效果,进行气压深松效果试验,结果表明:高压气体在土壤内部主要产生水平裂隙,水平裂隙的发展使犁底层的孔隙度明显增大,可有效打破犁底层,深松后土壤中空气的含量增加,使土壤体积膨胀、土面抬升,可在不扰动或少扰动耕作层的情况下得到良好的深松效果;气压深松对容重1.6、1.8g/cm3的犁底层同样具有较好的深松效果,深松后耕作层和犁底层的孔隙度均有大幅度提升,并且作用范围较广,可以克服传统深松铲对容重较大的犁底层难以实施深松的问题;气压深松的最大深松作用半径为0.7m,是传统深松铲深松最大作用半径的2~2.5倍,而对犁底层深松作用半径至少为传统深松铲深松作用半径的3倍,并且作用范围内的孔隙度提升率较高且变化幅度较小,说明气压深松具有深松作用范围广、深松均匀、深松程度高等特点,为得到气压深松参数对深松效果评价指标(土壤孔隙度及土面抬升量)影响的显著性,利用正交试验对气压深松参数:深松气压、喷气深度、气枪喷气孔角度及犁底层容重对土壤孔隙度增加率及土面抬升量影响的显著性进行了分析。得出:深松气压、注气点深度、气枪喷气孔角度对土壤孔隙度增加率及土面抬升量影响显著,而容重影响不显著。为分析深松气压对深松效果评价指标(土壤孔隙度及土面抬升量)的影响规律,利用全因素试验分析了不同深松气压下的土壤孔隙度增加率及土面抬升量。分析表明:水平距离对土壤孔隙度增加率及土面抬升量影响显著;孔隙度增加率最大值出现在与喷气孔相同深度的犁底层,说明与气枪喷气孔深度相同的犁底层可得到较好的深松效果,实际作业中应根据犁底层的位置合理的设置气枪喷气孔的喷气深度;对于容重较小的犁底层,深松气压在土壤中横向扩散和竖向扩散并存,孔隙度增加率随气压增大无明显变化规律,随水平距离增大而波动减小且波幅较大;而容重较大的犁底层,深松气压横向扩散趋势增强而竖向扩散趋势减弱,孔隙度增加率随气压增大呈增大趋势,随水平距离增大而波动减小且波幅较小;深松气压增大对容重较小犁底层的孔隙度增加率及土面抬升量引起的差异不明显,而对容重较大的犁底层引起的孔隙度增加率及土面抬升量差异显著;对于容重为1.4,1.6和1.8g/cm3的犁底层,深松气压分别为1.4、1.8和2.2MPa时,孔隙度增加率及土壤空气增加量最大,说明,对于容重为1.4、1.6和1.8g/cm3的犁底层,分别选用1.4、1.8和2.2MPa的深松气压可得到较好的深松效果。为了探寻气压深松时,高压气体扩散规律,利用CFD软件仿真对不同容重犁底层内高压气体扩散规律进行仿真分析。仿真结果显示:对于容重较低的犁底层,高压气体不易于向水平方向扩散,随着容重的增高,高压气体向水平方向扩散的趋势逐渐增强。对气压深松机进行了总体结构设计、关键部件设计及运动学分析,本机由拖拉机牵引,能在不停车的条件下,通过对耕地内部连续注入高压气体,对耕地实现气压深松作业。论文研究成果可为气压深松技术的研究及气压深松机具的研发提供参考依据。
[Abstract]:China is a country with serious lack of water resources. It is of great practical significance for the sustainable development of agriculture to study rational farming techniques, improve soil water storage and soil moisture conservation, reduce soil erosion and reduce the continuous reduction of cultivated land. As an important part of conservation tillage, deep loosening is an important part of conservation tillage. Through loosening soil, breaking ground ploughs and adding deep tillage layer, it can improve the water permeability, air permeability and pellet structure of the soil, so that the rain can easily infiltrate into the soil, thus it is beneficial to the development of crop roots and improve the ability of storing water and preserving soil moisture. However, the traditional way of deep loosening is small, shallow and uneven in depth. Therefore, it is necessary to study the new way of deep loosening of cultivated land. A new method of deep loosening of cultivated land is put forward in this paper: high pressure gas is injected into the soil of cultivated land to crack the soil under the action of high pressure gas. In order to find the deep loosening of the arable land, in order to find the effect of air pressure deep loosening, explore the characteristics of pressure deep loosening, and clear the influence of the parameters of pressure deep loosening on the evaluation index of the effect of air pressure depth. Therefore, the thesis is carried out from the following seven aspects. The main research contents are as follows: the principle of the formation of air pressure deep loosening gap is analyzed, and the expansion of the air pressure is loose and the crack expansion is analyzed. The evaluation index of the soil porosity and soil surface uplift is selected as the evaluation index of the effect of deep loosening, and the testing methods of each evaluation index are given, the testing principle and test means are explained and analyzed, and the index testing device and the test device are used. In order to verify the effect of pressure deep loosening, the effect of pressure deep loosening is tested. The results show that the high pressure gas produces horizontal cracks in the soil, the development of the horizontal fissure increases the porosity of the plow, which can effectively break the bottom of the plow, and the content of the air in the soil increases after the deep loosening, so that the volume of the soil is increased. The expansion and uplift of the soil can get a good effect of deep loosening in the condition of undisturbed or less disturbed tillage. The deep loosening effect on the bottom of the plough of the bulk density 1.6,1.8g/cm3 is also better, and the porosity of the plough layer and the plow bottom is greatly enhanced after the deep loosening, and the scope of action is wide, and the traditional deep loosening shovel can be overcome. The most heavy plow bottom is difficult to carry out the problem of deep loosening; the maximum release radius of deep loosening is 0.7m, which is 2~2.5 times the maximum radius of the traditional deep loosening shovel, and the deep loosening radius of the plough is at least 3 times that of the traditional deep loosening shovel, and the porosity in the range of action is higher and the change amplitude is more than that of the traditional deep loosening shovel. It shows that deep loosening has a wide range of deep loosening, deep loosening and high depth of loosening. In order to obtain the significance of the influence of the parameters of deep loosening on the evaluation index of deep loosening effect (soil porosity and soil elevation), the parameters of deep loosening air pressure, jet depth, air gun jet hole angle and plow bottom capacity are used in orthogonal test. The effect of soil porosity increasing rate and soil surface uplift was analyzed. The results were as follows: deep loosening pressure, gas injection point depth, air gun jet hole angle on soil porosity increase rate and soil surface uplift are significant, while the effect of bulk density is not significant. The increase rate of soil and the uplift of soil under different depth of pressure are analyzed by the full factor test. The analysis shows that the horizontal distance has a significant influence on the increase rate of soil porosity and the uplift of soil surface; the maximum value of the increase of porosity appears at the bottom of the plow with the same depth as the air blowhole, indicating the air gun jet. The deep loosening effect of the plow with the same hole depth can be obtained. In actual operation, the jet depth of the air gun jet hole should be set reasonably according to the position of the plow bottom; for the low density plow bottom, the deep loosening pressure is both lateral and vertical diffusion in the soil, and the porosity increases with the pressure increasing without obvious change law, with the level of the level. When the distance increases, the wave amplitude is larger, and the horizontal diffusion trend of the deep loosening pressure is enhanced and the vertical diffusion trend is weakened. The increase rate of porosity increases with the increase of air pressure, and the fluctuation decreases with the increase of the horizontal distance and the amplitude is smaller. The increase of the porosity of the smaller plow bottom is increased by the deep pine gas pressure. And the difference in soil surface uplift is not obvious, but the increase rate of porosity and soil surface elevation caused by heavy bulk density is significant. For the plough with 1.4,1.6 and 1.8g/cm3, the increase rate of porosity and the increase of soil air are maximum when the air pressure is 1.4,1.8 and 2.2MPa, respectively, indicating that the bulk density is 1.4,1.6 and the bulk density is 1.4,1.6. In order to explore the law of high pressure gas diffusion, the law of high pressure gas diffusion in the bottom layer of different bulk plows is simulated by CFD software simulation. The simulation results show that the high pressure gas is low in the plow with low bulk density in order to explore the law of high pressure gas diffusion in the bottom layer of different bulk plows by using CFD software simulation. The body is not easy to spread to the horizontal direction. With the increase of the bulk density, the tendency of the high pressure gas to spread to the horizontal direction is gradually increasing. The overall structure design of the air pressure loosen machine, the design of the key components and the kinematic analysis are carried out. The machine is tractive by the tractor, and the high pressure gas can be continuously injected into the cultivated land under the condition of no parking. The research results can provide reference for the research of pneumatic subsoiling technology and the development of pneumatic deep loosening machine.
【学位授予单位】：东北农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S222

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