月球低应力梯度环境下月壤异形颗粒相关力学特性及机理研究

A systematic understanding of the mechanical behaviour and engineering response of lunar regolith is of great significance to current lunar exploitation. The low gravity-induced low stress gradient mechanical state is the inborn existent conditions of lunar regolith, while the irregular-shaped particle is its most significant geometric characteristics. The lunar regolith particles exhibit geometric shape related distinctive microscopic behaviour under low stress gradient, which results in a distinctive macroscopic mechanical behaviour that is significantly different from terrestrial granular materials, and reveals the inherent mechanism of low gravity related behaviour of lunar regolith. This project will firstly develop a kind of multiscale mechanical method and related numerical code for lunar regolith. The high-order stress gradient continuum theory will be proposed in this method by considering the stress gradient at microscope scale, meanwhile, a related continuum-discontinuum multiscale numerical method for the high-order theory will be developed in which the irregular-shaped particle will be taken into account at the microscopic scale. Accordingly, related experimental modules for representative volume element testing and physical modelling will be developed under the framework of current geotechnical magnetic-similitude-gravity model testing equipment and CUMT lunar regolith simulant. Further, a series of experimental and numerical studies will be carried out to obtain the irregular particle shape related constitutive strength and deformation behaviour, static bearing capacity, and penetration resistance of lunar regolith under low stress gradient. Finally, the mechanism for the above behaviour and characteristics will be investigated by performing multiscale analysis. The implementation of this project will provide more scientific and reliable theoretical and technical support for the national lunar comprehensive exploration, base construction, and mineral resources exploitation.

系统掌握月壤力学行为及工程响应是月球开发的关键。月球小重力导致的低应力梯度环境是月壤基本赋存条件之一，异形颗粒形状是月壤最显著的特征。低应力梯度环境下月壤颗粒呈现出颗粒形状相关的独特细观行为，导致其宏观力学响应显著不同于地球常规颗粒介质，是小重力影响月壤力学行为最本质的体现。然而，现阶段还鲜有该方面的研究。本项目通过建立月壤应力梯度高阶力学模型在宏观层面纳入应力梯度，建立高阶模型连续-非连续多尺度数值方法在细观尺度纳入异形颗粒形状，进而构建月壤多尺度力学方法并开发相应数值程序；在既有磁拟重力场试验系统和CUMT模拟月壤基础上研制代表性体积单元试验和物理模型试验模块；采用数值和试验手段，研究获得低应力梯度作用下月壤异形颗粒相关的本征强度、变形行为和静承载力、触探阻力特性，并通过多尺度分析揭示其形成机理。本项目的实施将为国家月球综合探测、基地建设和矿产资源开发提供更为科学可靠的理论与技术支撑。

系统掌握月壤力学行为及工程响应是月球开发的关键。月球小重力导致的低应力梯度环境是月壤基本赋存条件之一，异形颗粒形状是月壤最显著的特征。低应力梯度环境下月壤颗粒呈现出颗粒形状相关的独特细观行为，导致其宏观力学响应显著不同于地球常规颗粒介质，是小重力影响月壤力学行为最本质的体现。然而，现阶段还鲜有该方面的研究。本项目通过建立月壤应力梯度高阶力学模型在宏观层面纳入应力梯度，建立高阶模型连续-非连续多尺度数值方法在细观尺度纳入异形颗粒形状，进而构建了月壤多尺度力学方法并开发相应数值程序；在既有磁拟重力场试验系统和CUMT模拟月壤基础上研制了代表性体积单元试验和物理模型试验模块；采用数值和试验手段，研究获得了低应力梯度环境下月壤异形颗粒相关的本征强度、变形行为和静承载力、触探阻力特性，并通过多尺度分析揭示了其形成机理。本项目成果将为国家月球综合探测、基地建设和矿产资源开发提供更为科学可靠的理论与技术支撑。