粗粒土既是一种天然地质体，又能用作建筑材料，在自然界中广泛存在，其力学性质研究对实际工程实践至关重要.在大量关于粗粒土试验与力学性质研究文献的基础上做了以下分析和总结：将粗粒土试验分为三类，包括室内试验、原位试验和数值试验，分别对每种试验的试验原理、仪器、方法和适用范围进行了详细介绍；根据粗粒土力学性质研究现状，重点对粗粒土的剪胀性、颗粒破碎性和软化性这三种特性从形成机制、影响因素和描述方法上进行了深入总结.在此基础上，指出粗粒土力学性质研究方面存在如下不足：现有方法和理论存在一定局限性、宏观特性发生机理假设缺乏客观验证、宏观特性难以用细观力学演绎、多相耦合下的力学性质鲜有研究.最后，从试验、理论和数值仿真试验角度提出关于粗粒土力学性质研究的展望.

Coarse-grained soil, as both geological mass and construction material, is extensively spread in nature. The mechanical properties of coarse-grained soil are of great importance to practical engineering in consequence. In review of related literatures, it was analyzed and summarized on tests and mechanical properties of coarse grained soils as follows: the tests fall into three types including laboratory, in-situ and numerical tests, respectively introduced about the testing principles, apparatus, operations, and applicability; especially, dilatancy, granular breakability and softening behaviors of coarse-grained soil are respectively summarized, from forming mechanism, influences and description methods perspectives. The overview above indicates four insufficiencies of research on coarse-grained soil mechanical properties: existing methods and theories have certain limitations; assumptions on genetic mechanisms of macro properties remain to be verified; it's difficult to deduce macro performances from mesomechanics perspective; multiphase coupling mechanical properties are seldom involved. Finally, the research prospects in mechanical properties of coarse-grained soil were put forward from the views of tests, theories and numerical simulations.

将材料的破坏归结为剪切破坏，每种材料对应于特定的剪切滑动面，抗剪强度为滑动面上正应力的函数，基于不同材料的强度特性将一系列的剪切滑动面统一起来，建立了岩土材料的非线性统一强度模型.非线性统一强度模型的滑动面为β应力空间内的等倾面，在β应力空间内的强度面为圆锥面；在普通应力空间内的强度面为一系列连续光滑、外凸的锥面，在偏平面上强度曲线涵盖了从下限Matsuoka-Nakai曲线到上限Drucker-Prager圆之间的所有区域，子午面上强度线为直线.非线性统一强度模型只有3个材料参数，参数都具有明确的物理意义，通过与国内外学者已取得的岩土类材料真三轴强度试验结果的比较，表明模型可适用于多种类型的材料，并合理描述其非线性强度特性.

<p>The failure of material can be concluded to the shear fracture and each material has a specific shear sliding surface. The shear strength is the function of normal stress on sliding surface. A series of shear sliding surface is unified and nonlinear unified strength model of geo-materials is proposed. Sliding surface of nonlinear unified strength model is isoclinic surface in <em>&beta;</em> stress space. The Strength surface of nonlinear unified strength model is circular conical surface in the <em>&beta;</em> stress space and a series of conical surfaces are continuous smooth and convex in principal stress space. The nonlinear unified strength model can be illustrated as a curve between the Drucker-Prager and SMP in deviatoric plane, and as a straight line in meridian plane. There are only three mechanical parameters in the model which have definite physical meanings. Compared with large numbers of data under true triaxial tests, the applicability of nonlinear unified strength model is verified to different materials. And the proposed model can describe the nonlinear strength property of various materials reasonably.</p>

我国高土石坝数量居世界之首,保证高坝大库建设与长期运行安全是国家经济和公共安全保障的重大需求。系统总结了长江科学院近年来在土石坝工程领域的若干创新与发展。提出了基于“旁压模量当量密度法”的粗粒料级配相似理论试验方法;介绍了研发的系列CT三轴仪,实现了粗粒料组构要素的定量测量;提出了三轴试验中加载板与试样之间由滑动摩擦变为滚动摩擦、整体式接触变为分散式接触的减摩新方法,研发了相关减摩装置;研制了大尺寸、高压力、微摩擦、刚柔复合加载的土工真三轴仪;揭示了粗粒料真实三维应力条件下的强度与变形变化规律、湿化与蠕变变形特性;构建了粗粒料三参量非线性K-K-G剪胀模型、六参数湿化模型、九参数蠕变数学模型及相应的参数确定方法;基于当量密度法的原创思想,提出了利用旁压试验间接确定超百米级深厚覆盖层现场密度的试验方法。上述研究成果可为高土石坝工程建设提供重要科技支撑。

China ranks top in the world in the amount of high earth-rock dam. To ensure the construction and long-term operation safety of high earth and rockfill dams is a major demand posed by national economic and public security. We summarize the major research progresses in the field of earth-rock dam engineering made by the Yangtze River Scientific Research Institute in recent years. Such progresses include: the test method of gradation similarity theory of coarse-grained material based on equalling density with pressuremeter modulus, the series CT triaxial apparatus for quantitatively measuring fabric of coarse-grained material, a novel friction reduction method in which the contact between soil and loading plate is changed from holistic contact to distributed contact and sliding friction to rolling friction, as well as its corresponding friction reduction devices. Moreover, true triaxial apparatus with large scale, high pressure, micro-friction and rigid-flexible composite loading has been developed. The variation law of strength and deformation and the wetting and creep deformation mechanism of coarse-grained materials under real three-dimensional stress have been revealed. The <i>K-K-G</i> nonlinear dilatancy model with three parameters, the wetting model with six parameters, the creep model with nine parameters and the corresponding parameter determination method have been established. In addition, in line with the original idea of equivalent density method, a test method for indirectly determining the field density of deep overburden with over 100 meters by pressuremeter test has been proposed. The above research findings offer crucial scientific and technological supports for the construction of high earth-rock dams.