在水利工程的坝体修建中，以粒状材料作为工程主体的土石坝是主要的形式之一。从而，了解粒状材料的力学特性成为评价坝体工程稳定性的关键点。同时，颗粒形状和颗粒破碎对粒状材料的力学特性影响较大。在此背景下，开展颗粒形状和颗粒破碎对粒状材料变形特性和强度特征的研究显得尤为迫切。针对于此，本文建立了颗粒形状量化参数—球形模数 ，并以此为基础，开展了不同颗粒形状粒状材料试样的常规三轴压缩试验，研究了颗粒形状对变形和强度特性的影响规律，并深入分析了变形过程中的局部颗粒破碎规律，进而基于二元介质理论提出了能够反映此因素的弹塑性本构模型和强度准则，最终合理预测了试验数据。主要研究成果如下：

（1）研究了颗粒形状对压缩变形和强度特性的试验规律。首先，提出了颗粒形状量化参数-球形模数 以及由若干颗粒组成的粒状材料集合体形状量化参数-平均球形模数 ，并给出了计算方法；发展了一种人工制备可破碎粒状材料的制样方法，将人工制备的均质、可破碎颗粒材料（粒状、片状）通过调节片状颗粒掺入比，制备成五种不同 （0.777、0.701、0.668、0.625、0.573）的粒状材料试样，并分别将其在不同围压（200、300、400、500、600kPa）下进行三轴压缩试验。在三轴压缩试验中，可破碎粒状材料表现出硬化、体缩的特性，随着平均球形模数 的减小，粒状材料强度包络线的非线性表现的越明显，且随着 的增大，低围压下的应力莫尔圆呈先增大后减小的趋势，较高应力下表现为逐渐增大，这是由于粒状材料在低围压下发生颗粒转动和滑动，而在高围压下，粒状材料来不及发生颗粒转动和滑动，直接发生颗粒破碎。

（2）研究了粒状材料在变形过程中的颗粒局部破碎规律。通过对三轴试验前后试样进行筛分，确定了其粒径分布曲线的变化情况，从而得到了相对颗粒破损率随着颗粒形状和围压的变化关系，建立了相对颗粒破损率的计算模型；与此同时，通过绘制不同形状粒状材料的 曲线及 曲线，对粒状材料的临界状态进行了分析，建立了考虑颗粒形状和颗粒破碎情况的粒状材料临界孔隙比计算模型。

（3）建立了能够反映颗粒破碎的二元介质弹塑性本构模型。以二元介质理论为基础，将未发生变形及颗粒破碎的粒状材料集合体视为胶结元，而将达到极限破碎状态的粒状材料集合体视为摩擦元，受荷变形中的颗粒破碎过程即为胶结元向摩擦元的转化；同时，为提高模型计算的准确性，提出类摩擦元概念用于描述含有少量胶结元的破碎后重塑试样，并引入摩擦元削弱系数，消除少量胶结元对计算的影响；通过给出考虑颗粒形状和颗粒破碎的体积破损率，建立了可破碎粒状材料的二元介质本构模型，最终成功预测了试验数据，表明该本构模型的合理性。

（4）建立了一个考虑颗粒形状的二元介质强度准则。粒状材料及破碎后重塑试样的强度包络线均表现出明显的非线性，为此本文基于二元介质模型理论，引入了受颗粒形状影响的摩擦元抗剪强度分量削弱系数，建立了一个能考虑颗粒破损和形状二元介质强度准则，并通过对比理论预测和试验结果，表明了该强度准则的合理性。

In the construction of dams in water conservancy projects, earth-rock dams with granular materials as the main body of the project are one of the main forms. Therefore, understanding the mechanical properties of granular materials has become a key point in evaluating the stability of dam engineering. Meanwhile, particle shape and particle breakage have a greater impact on the mechanical properties of granular materials. In this context, it is urgent to carry out research on the deformation and strength characteristics of granular materials on particle shape and particle breakage. In view of this, the particle shape quantification parameter-spherical modulus  is established, then the conventional triaxial compression test (CD) of particle-shaped granular material specimens with different particle shapes is carried out. The influence law of particle shape on deformation and strength characteristics is studied, and the local particle breakage law during deformation process is deeply analyzed. Based on the binary media theory, an elastoplastic constitutive model and strength criterion that can reflect this factor are proposed, and the experimental data is finally reasonably predicted. The main research results are introduced as follows:

(1) The experimental rules of particle shape on compression deformation and strength characteristics were studied. Firstly, the quantitative parameter describing particle shape-spherical modulus  and the quantitative parameter describing the shape of granular material aggregates composed of several particles-average spherical modulus  are established respectively, and the calculation method is given. Secondly, a method for artificially prepared crushable granular materials was developed. The artificially prepared homogeneous and crushable granular materials (Granules and Flakes) were prepared into five different  (0.777、0.701、0.668、0.625、0.573) granular material samples by adjusting the incorporation ratio of flake particles. Lastly, the triaxial compression tests were carried out under different confining pressures (200、300、400、500、600kPa). In the triaxial shear test, the crushable granular material exhibits the hardening and shrinkage deformation characteristics. With the decrease of the average spherical modulus , the nonlinear property of the strength law of the granular material is more obvious; with the increase of , the Mohr circle of stress under low confining pressure first increases and then decreases, and it increases gradually under higher stress. Further analysis, the granular material rotates and slides under low confining pressure, butthe granular material does not have time to rotate and slide under high confining pressure,, and particle breakage occurs directly.

(2) The local crushing law of particles in the deformation process of granular materials was studied. By sieving the samples before and after the triaxial test, the change of the particle size distribution curve was determined, and the relationship between the particle breakage rate and the particle shape and confining pressure was obtained, and the calculation model of the particle breakage rate was established. At the same time, the  curves and  curves of granular materials with different shapes was given, and the critical state of granular materials was analyzed, then a calculation model for the critical void ratio of granular materials was established that considered the particle shape and particle breakage.

(3) A binary medium elastoplastic constitutive model that reflects particle breakage was derived. Based on the binary medium theory, the granular material samples that have not been deformed and particles are crushed are regarded as bonded elements, and the aggregate of granular materials reaching the ultimate crushing state is regarded as a frictional elements. The broken of bonded elements is transformed into frictional elements. Meanwhile, in order to improve the calculation accuracy, the concept of friction-like elements is proposed to describe the remodeling specimen after crushing containing a small amount of cement elements, and the weakening coefficient of frictional elements is introduced to eliminate the influence of a small number of bonded elements on the calculation. By giving the volume breakage ratio considering the particle shape and particle crushing, a binary medium constitutive model was derived, and the experimental data was successfully predicted, which indicatied the rationality of the constitutive model.

(4) A binary medium strength criterion considering particle shape was established. The strength envelope of the granular material and the remodeled specimen after crushing showed obvious nonlinearity. Based on the binary media model theory, the shear strength component weakening coefficient of the friction element affected by the shape of the particle was introduced, and a criterion for considering the strength of the particle damage and shape binary medium was established. By comparing theoretical predictions and experimental results, the rationality of this strength criterion is demonstrated.

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