颗粒离散元方法中黄土强度参数研究

颗粒离散元方法是离散元方法的一种,其研究对象的强度参数确定过程是非常繁琐的,常规方法必须进行数值计算和室内试验的标定。本文基于PFC软件,编写直接剪切试验程序,通过室内直剪试验和模拟试验对比分析,研究颗粒离散元方法中大孔隙,疏松的黄土强度参数。分析得到重力条件、颗粒密度、刚度和模型尺寸效应对强度曲线的影响,其中尺寸效应影响明显,通过多次计算提出了不同尺寸模型的参数换算公式。研究土体抗剪强度粘聚力c和离散元中接触黏结强度bond之间的线性关系,拟合得到二者的计算公式,通过公式可以快速标定得到颗粒离散元方法中黄土的强度参数,这为黄土地区地质灾害的离散元数值分析提供参数基础。

Study on the Strength Parameters of Loess in Granular Discrete Element Method

Granular discrete element method is a kind of discrete element method. The determination of its strength parameters is very complicated. Conventional methods must be calibrated numerically and calibrated indoors. Conventional methods must be calibrated numerically and laboratory tests results. In this paper, based on the PFC software, the direct shear test program is written. By comparing direct shear tests and simulations, large pores and loose loess strength parameters are researched. By study on the gravity, particle density, stiffness and dimensional effect on the intensity curve, the dimensions effect is significant. By many calculations, different sizes conversion formula is proposed. We found a linear relationship between cohesion and the contact bond strength. By fitting their formulas, it can quickly get the strength parameters in particle discrete element method of loess. This provides a basis for the discrete element numerical parameter geological disasters in loess.