空间技术对开发太空资源、保卫人类和平、增强综合国力都有重要的战略意义。我国探月工程已经步入正轨，处在国际领先地位，火星探测工程也被提上日程。我国计划在2020年独立进行火星探测，该项目将实现环绕、着陆与巡视工作，而前苏联与美国的火星探测项目均是分多次实现。所以我国亟待对火星探测工程各方面进行细致而全面的研究。火星探测工程中，着陆器、巡视器与取样工具的研究设计都需要在地球进行实验，实验中需要使用用地球材料配制同火星土壤相似的模拟土壤。模拟火星土壤的研制相当程度上制约着相关设备的研究，因此研制我国自己的模拟火星土壤非常迫切与必要。根据用途不同，模拟火星土壤分为化学性质模拟、光学性质模拟、磁学性质模拟、力学性质模拟等多种类型。本文研制的模拟火星土壤以力学相似作为主要研制目标。参考国外模拟火星土壤级配与真实火星土壤颗粒粒径，框定了目标级配范围，在已有模拟火星土壤级配基础上进行了拓宽。汲取国外模拟火星土壤研制经验，选择玄武岩与河砂作为模拟火星土壤的原料。本文对研制过程中四种典型样品进行了一系列的土力学实验，对比实验结果，发现使用河砂粗颗粒替换玄武岩粗颗粒，能有效降低样品中不规则玄武岩颗粒导致的高内摩擦角，并减小可压缩性，增大实验可控制相对密度范围。最终选用由粗颗粒河砂与细颗粒玄武岩粉末按照一定比例配置而成的玄武岩样品C作为模拟火星土壤方案，命名为THU Mars-1模拟火星土壤。该种土很好的模拟了真实火星土壤的级配范围与抗剪性能，可以应用到对抗剪性能要求较高的着陆器着陆与巡视器行走实验，也能应用于对颗粒粒径要求较高的钻进取样实验。本文还参考火星土壤含水量与温度条件，对模拟火星土壤THU Mars-1在低温下的物理力学特性展开实验研究。随温度降低和含水量增加，该土抗剪强度和粘聚力均明显增大，但对内摩擦角的影响较复杂。实验结果给推测真实火星冻土抗剪性能提供了参考。最后本文采用实验测得的参数，使用有限元软件ABAQUS对模拟火星土壤钻进取样过程进行了数值模拟，分析了不同含水量、温度条件对钻取过程的影响。
Space technology has strategic significance for the development of space resources, peace protection, and enhancement of the comprehensive national strength. The lunar exploration project of China is on the right track and is in the leadi in the world. The Mars exploration project has also been put on the agenda. China plans to explore Mars independently for the first time in 2020. We will orbit Mars, make a landing, and deploy a rover at one time, which the Soviet Union and the United States did not implement once for all. Therefore, China needs to carry out meticulous and comprehensive research on various aspects of the Mars exploration project. In the Mars exploration project, the design of the lander, rover, and sampling tools all need to be conducted on the earth. In the experiment, the Martian soil simulants is needed which is made of the earth material. The development of the Martian soil simulant plays an important role in the research of device in the Martian exploration to a considerable extent, so it is very urgent and necessary to develop our own Martian soil simulant.According to different uses, the Martian soil simulant has various simulated target, such as chemical similarity, optical similarity, magnetic similarity, and mechanical similarity. The Martian soil simulant developed in this paper is based on mechanical similarity. Based on the gradation of the Martian soil simulant in other countries and real Martian soil particle size, the target grading range was framed which is wider than before and more similar with the rea condition of Martian soil. Basalt and river sand have been selected as raw materials for the Martian soil simulant.In this paper, some series of soil mechanics experiments were performed on four typical samples during the development process. Comparing the results, it was found that the replacement of basalt coarse particles with river sand can effectively reduce the internal friction angle and compressibility. Finally, a basalt sample C made up of coarse-grained river sand and fine-grained basalt grains in a certain proportion was selected as the Martian soil simulant which is named THU Mars-1. This kind of simulant has the similar gradation range and shear performance with real Martian soil. It can be applied to landing, rover walking , drilling experiment.In this paper, the mechanical properties of the Martian soil simulant, THU Mars-1, at low temperature are studied with reference to the water content and temperature conditions of real Martian soil. The results show that with decreasing temperature and increasing water content, the shear strength and cohesion of the soil increase significantly, but the influence on internal friction angle is complicated. The experimental results provide reference for the shear performance of real Martian frozen soil.Finally, using the parameters measured, the finite element software ABAQUS is used to simulate the drilling process in the Martian soil simulant and the influence of different water content and temperature conditions during the drilling process is analyzed.
