模拟月壤抗剪强度试验研究及离散元分析

发布时间：2018-03-04 08:28

本文选题：模拟月壤　切入点：抗剪强度　出处：《岩土力学》2017年03期 　论文类型：期刊论文

【摘要】：模拟月壤作为探月工程模型试验的基床材料,其力学特性将直接影响到月球探测器、着陆器等机构的设计,而抗剪强度是其主要力学特性之一。针对软着陆模型试验所用的TJ-1模拟月壤,采用标准应力路径三轴仪对其进行静三轴试验,得到了不同相对密度、剪切速率和围压条件下模拟月壤的应力-应变关系曲线、弹性模量和抗剪强度指标值等,试验结果表明:模拟月壤具有应变软化特征并存在一定大小的表观黏聚力,峰值内摩擦角的值介于43°~51°之间;相对密度越大,应变软化特征越明显,黏聚力和内摩擦角的值都越大:在密实状态时,剪切速率越大,模拟月壤的抗剪强度指标值呈整体下降的趋势。利用PFC~(3D)软件建立三轴试验数值模型,研究了颗粒间摩擦系数、初始孔隙率以及颗粒刚度这3个细观参数对模拟月壤抗剪强度的影响,模拟结果表明:颗粒间摩擦系数是影响抗剪强度指标内摩擦角的主要因素,而初始孔隙率及颗粒刚度的影响则相对不明显;在一定数值范围内,颗粒间摩擦系数越大,内摩擦角的值越大,两者近似呈线性关系。
[Abstract]:As the base bed material for lunar exploration engineering model test, the mechanical properties of simulated lunar soil will directly affect the design of lunar probe, lander and other mechanisms. The shear strength is one of its main mechanical properties. Aiming at the TJ-1 simulation of lunar soil used in the soft landing model test, the static triaxial test was carried out by using the standard stress path triaxial instrument, and the relative density was obtained. Under shear rate and confining pressure, the stress-strain curve, elastic modulus and shear strength index of lunar soil were simulated. The experimental results showed that the simulated lunar soil had the characteristics of strain softening and apparent cohesion. The value of the peak internal friction angle is between 43 掳and 51 掳, the higher the relative density, the more obvious the strain softening characteristic, the greater the cohesion force and the internal friction angle: the higher the shear rate is when the density is dense, The shear strength index value of lunar soil is decreasing as a whole. A numerical model of triaxial test is established by using PFCf3D software, and the friction coefficient between particles is studied. The effects of initial porosity and particle stiffness on the shear strength of lunar soil are studied. The results show that the friction coefficient between particles is the main factor affecting the internal friction angle of the shear strength index. However, the effect of initial porosity and particle stiffness is relatively insignificant, and in a certain range, the larger the friction coefficient between particles, the greater the value of internal friction angle, and the approximate linear relationship between them.
【作者单位】：浙江大学岩土工程研究所;浙江大学软弱土与环境土工教育部重点实验室;
【分类号】：P184.5;TU41

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