【作者】 刘磊；

【导师】 刘钦； 张宁；

【作者基本信息】 长安大学 ， 土木工程， 2023， 硕士

【摘要】 在社会经济高速发展的时代背景下,我国面临双碳目标、新旧能源转换的发展趋势,对铁、锰、锌、镍、铬等部分金属资源需求迅速增加。勘探数据表明深海海底蕴藏有丰富的此类多金属结核。为解决我国战略金属资源短缺的问题,国家制定了深海采矿发展战略计划。深海履带式集矿车是目前广为认可的采集方式,其在深海软底质沉积物上能否稳定行驶直接影响海底矿物的开采效率,开展相关研究对促进我国深海矿产资源实现商业开采具有重要战略意义。论文以此为背景,采用理论分析、室内试验和数值模拟方法,深入研究深海集矿车在采集作业过程中履带与土体之间的相互作用。主要工作与结论如下:(1)基于履带土体相互作用理论,简述接地压力与土体沉陷量关系,定性分析集矿车重心偏移的接地压力大小和分布特征,结合土体剪切关系推导接地压力均匀分布和余弦型分布下集矿车牵引力公式,为分析集矿车牵引力影响奠定理论基础。(2)根据软底质沉积物原位力学参数,通过室内试验与DEM模拟直剪试验对比,论证了模拟土体颗粒微观参数的正确性与合理性;建立模拟压陷、剪切及履带土体相互作用土床,并依据“鲲龙500”集矿车结构参数构建相互作用的履带模型。(3)依照Bekker试验原理进行DEM模拟压陷与剪切试验,并与相似工况室内试验定量对比,结果验证了履带土体相互作用土床的可靠性和合理性;通过引入集矿车履带与模拟土体力学参数分析了履带牵引力影响因素,发现增加履齿高度可有效提高集矿车履带在软底质沉积物上的牵引力;同时合理控制接地压力有利于集矿车履带在软底质土体上的通过性与可行驶性。(4)利用Recurdyn与EDEM耦合模拟集矿车在软底质土体上的行驶,研究履带长宽比和支重轮数对接地压力和土体沉陷量及两者关系的影响,分析履齿结构对牵引力的作用。结果表明履带长宽比和支重轮数对接地压力和土体沉陷量产生一定作用效应,但支重轮的影响效应受数目限制;集矿车静止或运动时的均值接地压力—土体沉陷量关系近似符合Bekker压陷理论;实际工程中可通过适当增加履齿高度调整高距比来提高履带净牵引力;合理设计履带板间距进而控制节高比可降低履带反向阻力,从而提高集矿车履带在软底质沉积物上的行驶性。更多还原

【Abstract】 Under the background of the rapid development of social economy,China is facing the development trend of double carbon target and new and old energy conversion,and the demand for some metal resources such as iron,manganese,zinc,nickel and chromium is increasing rapidly.Exploration data show that the deep seabed is rich in such polymetallic nodules.In order to solve the shortage of strategic metal resources in China,the state has formulated a strategic plan for the development of deep-sea mining.Deep-sea tracked mining vehicle is a widely recognized collection method.Whether it can run stably on deep-sea soft sediment directly affects the mining efficiency of seabed minerals.It is of great strategic significance to carry out relevant research to promote the commercial exploitation of deep-sea mineral resources in China.Based on this background,this paper uses theoretical analysis,laboratory test and numerical simulation methods to deeply study the interaction between the track and the soil during the collection operation of the deep-sea mining vehicle.The main work and conclusions are as follows :(1)Based on the theory of tracked soil interaction,the relationship between ground pressure and soil subsidence is briefly described.The ground pressure and distribution characteristics of the center of gravity offset of the mining vehicle are qualitatively analyzed.Combined with the shear relationship of the soil,the traction formula of the mining vehicle under uniform distribution and cosine distribution of ground pressure is derived,which lays a theoretical foundation for analyzing the influence of the traction force of the mining vehicle.(2)According to the in-situ mechanical parameters of soft sediment,the correctness and rationality of the microscopic parameters of the simulated soil particles are demonstrated by comparing the indoor test with the DEM simulated direct shear test.The soil bed is established to simulate the interaction of subsidence,shear and track soil,and the track model of interaction is constructed according to the structural parameters of ’ Kunlong 500 ’ ore collector.(3)According to the principle of Bekker test,the DEM simulation subsidence and shear test are carried out,and compared with the indoor test of similar working conditions.The results verify the reliability and rationality of the soil bed of the tracked soil interaction.The influence factors of the traction force of the track are analyzed by introducing the track and simulating the mechanical parameters of the soil.It is found that increasing the height of the track teeth can effectively improve the traction force of the track on the soft sediment.At the same time,reasonable control of the grounding pressure is conducive to the trafficability and drivability of the mining vehicle crawler on the soft soil.(4)Using Recurdyn and EDEM coupling to simulate the driving of the miner on the soft bottom soil,the influence of the track length-width ratio and the number of supporting wheels on the ground pressure and soil subsidence and the relationship between them are studied,and the effect of the track structure on the traction force is analyzed.The results show that the length-width ratio of the track and the number of supporting wheels have a certain effect on the ground pressure and soil subsidence,but the effect of the supporting wheels is limited by the number.The relationship between the mean ground pressure and the amount of soil subsidence when the mine car is stationary or moving is approximately consistent with the Bekker subsidence theory.In practical engineering,the net traction force of track can be improved by appropriately increasing the height of track teeth and adjusting the height-distance ratio.Reasonable design of track plate spacing and control of pitch height ratio can reduce the reverse resistance of the track,so as to improve the driving performance of the track on soft sediment.更多还原