【作者】 李兆明；

【导师】 迟世春；

【作者基本信息】 大连理工大学 ， 防灾减灾工程及防护工程， 2007， 硕士

【摘要】 近年来随着大型机械碾压堆石技术的发展与应用，大粒径的粗粒土可以被碾压成相对紧密的状态。碾压粗粒土具有压缩性小、强度高以及良好的经济性及施工速度快等特点。因此被广泛应用于水利、交通等岩土工程建设中，特别是高土石坝建设中。粗粒土是由粒径大小不等的颗粒彼此充填而呈粒状结构的散粒体，颗粒间常为点接触。试验表明，在压实和剪切等外力作用下，即使施加的能量和周围压力并不很大，也容易发生颗粒破碎。颗粒破碎改变了粗粒土的颗粒粒径、级配曲线及密实程度，影响其后继的应力应变行为，特别是对剪胀有较强的削弱作用。因此建立考虑颗粒破碎的粗粒土弹塑性本构模型，对准确把握粗粒土的工程性质，提高土石坝应力变形分析精度具有现实意义。本文首先全面分析了前人关于土的颗粒破碎的度量方法，分析了各方法的优缺点和适用范围。研究中发现，粗粒土受力变形引起的颗粒破碎与自然风化引起的颗粒破碎有一定关系，可以采用自然风化模型的风化公比来描述粗粒土受力变形的颗粒破碎指数。通过对某工程粗粒土三轴试验中颗粒破碎试验数据的分析整理，提出了度量粗粒土颗粒破碎的计算公式。然后，分析了三轴应力条件下土颗粒的受力情况，根据罗维最小比能原理，推导出考虑颗粒破碎的粗粒土的屈服面。研究了粗粒土的流动法则，硬化规律和弹性规律，构建了考虑颗粒破碎的粗粒土本构关系模型。最后，采用改进的微粒群算法拟合三轴试验曲线，确定了模型参数。再用得到的模型参数计算了其它围压下的三轴试验曲线，与实际的试验曲线比较表明模型有较好的适应性。更多还原

【Abstract】 In recent years, with the development and application of large machinery rolling rocktechnology, large size coarse granular soil can be rolled into a relative close state. Rolledcoarse granular soil has the characteristics of small compressibility, high strength, goodeconomic construction and construction fast. So it is widely used in water conservancy andtraffic earth engineering constructions especially in high embankment dam construction.Coarse granular soil is made of soil granules of different size which fill each other. Testshows that the coarse granular soil is easy to break even though beared not extremely greatenergy and compression force. Particle breakage changed the particle size, size distributioncurve and dense of coarse granular soil, affect its subsequent stress-strain behavior, especiallyhas a strong role of weakening dilatancy. So developing elastoplastic constitutive modelincorporating particle breakage has practical significance of grasping the engineeringproperties of coarse granular soil and improving the analysis precision of stress-deformationfor embankment damThis article first comprehensively analyzes parameters which are used to measureparticle breakage. This article also analyzes advantages, disadvantages and the scope ofapplication of each parameter. Research found that there is some relation between coarsegranular soil breakage caused by stress and deformation and particle breakage caused bynatural weathering, common ratio of natural weathering model can be used to describe brokenindex caused by stress and deformation of coarse granular soil. Through analyzing the testdata of particle breakage of triaxial test, the formula to calculate particle breakage parameteris developed. Then, through analysis of the force of soil particles under triaxial stress, a yieldsurface equation is derived which incorporates particle breakage according to Rowe’sminimum energy ratio principle. After studying plastic flow rule, harden law and elastic lawan elastoplastic constitutive model for coarse granular soil incorporating particle breakage isproposed. Finally the model parameters are determined by using the modified swarmoptimization fitting triaxial test curve. Using these parameters triaxial test stress-strain curveof other confming pressure is calculated. Comparing the results calculated by this model withtest data the valid of this model is verified.更多还原