【作者】 燕全会；

【导师】 杨雪强；

【作者基本信息】 广东工业大学 ， 岩土工程， 2012， 硕士

【摘要】 土体具有复杂的应力应变特性,如剪胀性、各向异性、受应力路径和应力历史影响的特性等。真三轴仪是研究土体在三维应力状态下的重要测试仪器,为探寻土体的应力应变关系十分有效的工具。本文对饱和粗砂进行一系列不同围压、不同中主应力系数、固结排水和不排水剪切的真三轴试验,并在此的基础上,对真三轴系统采集的试验数据进行分析和探讨,其研究工作的主要内容如下：首先介绍真三轴试验仪器的国内外研究现状以及发展回顾并对试验仪器本身所存在的问题进行阐述；从土体应力应变关系的角度出发,介绍了应力应变关系的研究方法与研究进展,同时在此基础上,对砂土的剪胀特性、屈服和强度特性以及砂土在固结排水剪切和不排水剪切下的应力应变特性进行了重点的阐述。其次对砂土真三轴试验准备工作、试验方案以及试验方案的实现进行了阐述,介绍了真三轴试验的试验步骤。之后,在真三轴试验的基础上,对其试验结果进行分析与探讨,得出砂土在不同围压、不同中主应力系数、排水与不排水情况下的剪切特性,并分析造成这种不同的原因。同时,基于大主应力方向与沉积方向不同夹角的试验结果,初步探讨了应力诱发的各向异性以及原始各向异性对砂土变形和强度的影响。最后以Lade-Duncan弹塑性模型理论为基础,分析和探讨饱和粗砂在不同中主应力系数下屈服功与塑性势的关系；不同围压下塑性功与屈服势以及塑性势与屈服势的关系。并进一步结合Matsuokaka-Nakai破坏准则,分析饱和砂土在不同中主应力系数下的强度与变形特性,利用这两种应用比较广泛的破坏准则对土体的破坏强度进行预测。更多还原

【Abstract】 The soil has a complex stress-strain characteristic, such as dilatancy, anisotropy, the stress path and stress history characteristics. As a very effective tool to explore the soil stress-strain relationship, true triaxial apparatus is a very important test equipment to study the soil under the three-dimensional stress state. A series of true triaxial tests were performed on the saturated coarse sand under different confining pressures, different intermediate principal stress coefficient, and under consolidated drained and undrained shear true. Then, on the basis of experimental data collected by the system,this paper analyzes and discusses it. The main content of the research work are as follows.Firstly, this paper introduced the research status of the true triaxial test apparatus, as well as development review and the test instrument itself the problems described and explains stress-strain relationship of the research methods and research progress from the angle of the soil stress-strain relationship, On this basis, this paper focuses on the dilatancy characteristics of sand, yield and strength properties, as well as consolidated drained shear and undrained stress-strain behavior under shear.Then, this paper describes the test preparations, test program and test program to achieve the true triaxial test test steps.While, on the basis of the test results analysis and discussion, this paper deduces and obtaines stress-strain behavior of the sand under different confining pressures, different intermediate principal stress coefficient, drained and undrained and analyze the cause of this different reasons. Results based on the angle of major principal stress direction and deposition in a different direction of the stress-induced anisotropy and the original anisotropy on the deformation and strength of sand.Finally, based on the Lade-Duncan elastic-plastic model theory, this paper analyzes and discusses the relationship between the yield function and plastic potential under different intermediate principal stress; the relationship between the plastic work and the potential yield and plastic potential; the relationship between plastic potential and yield potential under different confining pressures. And further to combine Matsuokaka-Nakai failure criterion, this paper analyzes the strength and deformation characteristics of saturated sand under principal stress coefficient, at the end, this paper predicts the failure strength of the soil by using of more extensive application of these two failure criteria.更多还原