高等土力学考试题复习思考题与参考答案汇总

硕士研究生《高等土力学》复习思考题一(a)、将下面描述“土力学和岩土工程”的英文译成中文Soil MechanicsThis class presents the application of principles of soil mechanics. It considers the following topics: the origin and nature of soils; soil classification; the effective stress principle; hydraulic conductivity and seepage; stress-strain-strength behavior of cohesionless and cohesive soils and application to lateral earth stresses; bearing capacity and slope stability; consolidation theory and settlement analyses; and laboratory and field methods for evaluation of soil properties in design practice.Soil amongst most variable and difficult of all materials to understand and model1. Complex stress-strain (non-linear , irreversible 不可逆的)2. Properties highly variable function of soil types and stress history3. Properties change with time, stress, environment, …4. Every site has different soil conditions - new challenge5. Soil "hidden" underground and data on small fraction of deposit Geotechnical EngineeringThis course describes the application of soil mechanics in the analysis and design of foundations (shallow and deep) and earth retaining structures. The lectures include an overview of geotechnical site investigation methods and in situ tests used to estimate engineering parameters. The course emphasizes the importance of parameter selection in calculations of ultimate and serviceability limit state calculations for both shallow and deep foundations, and discusses methods of soil improvement. The section on earth retaining structures considers systems ranging from gravity walls to composite construction (reinforced earth), from structural support to field monitoring of excavations (bracing, tieback anchors etc.).(1)What is consolidation?Consolidation is a time-related (时间性) process of increasing the density (增加密度) of a saturated soil by draining some of the water out of the voids.(2)The shear strength of a soil [土的抗剪强度] (τf ) at a point on a particular plane was originally expressed by Coulomb as a linear function of the normal stress (σ’f ) on the plane at the same point by'tan ''φστ⋅+=f f cwhere c’ is cohesion [粘聚力] and φ’ is internal angle of friction [内摩擦角].(3) Ultimate bearing capacity (qu) is defined as the pressure which would cause shear failure of the supporting soil immediately below and adjacent to a foundation. (当基底压力增大到极限承载力时,地基出现剪切破坏)(4) Allowable bearing capacity (qa) is defined as the maximum pressure which may be applied to the soil such that the above two requirements are satisfied. From first requirement, qa is defined as: (地基的容许承载力 qa 定义为当上述两个条件满足时的基底最大压力.当条件一满足时qa 定义如下)sua F q q =(5) A foundation must satisfy two fundamental requirements: (设计基础要满足两个要求 ) (a) the factor of safety Fs against shear failure of the supporting soil must be adequate, a value between 2 and 3 normally being specified (地基达到剪切破坏的安全糸数 Fs 要适当,一般在2至3之间 )(b)the settlement of the foundation should be tolerable and, in particular , differential settlement should not cause any unacceptable damage of the structure (基础的沉降和沉降差必须在该建筑物所允许的范围之内)Example 5.5A saturated clay has the following properties:7.2,15.0s ==G λof the soil. Prove that a 1% increase in water content can cause a 20% reduction in the undrained shear strength.SolutionFor undrained triaxial (UU or CU) tests of saturated soils, the volume of the specimen is not allowed to change during axial compression or extension. Therefore, the effective mean stress at failure is given byff 0ln p e e e '-==Γλor⎪⎭⎫⎝⎛-='Γλ0f ex p e e pwhere e0 is the initial void ratio and e' =1. Theundrained shear strength is therefore⎪⎭⎫ ⎝⎛-='==Γλ0f f u ex p 222e e M p M q cvariable is the initial void ratio. This indicates that the undrained shear strength depends onlythe initial void ratio. For saturated soil, we have e=wGs. Therefore, for two initial void ratio, e1 and e2, the corresponding undrained shear strength cu1 and cu2 are related to each other as()⎪⎭⎫ ⎝⎛-=⎪⎭⎫ ⎝⎛-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛-=ΓΓλλλλ12s 1221u2u1ex p ex p ex p ex p w w G e e e e e e c cFor water content increase of 1%, with7.2,15.0s ==G λ, we have()2.115.001.07.2ex p u2u1=⎪⎭⎫⎝⎛=c cTherefore, the undrained shear strength is decreased by 20%.一(b)、《高等土力学》研究的主要内容。

二、与上部结构工程相比，岩土工程的研究和计算分析有什么特点？ 三、归纳和分析土的特性。

四、简述土的结构性与成因，比较原状土与重塑土结构性强弱，并说明原因？ 五/0、叙述土工试验的目的和意义。

五/1、静三轴试验基本原理（即确定土抗剪强度参数的方法）与优点简介五/2、叙述土体原位测试（既岩土工程现场试验）的主要用途，并介绍3种原位测试方法 五/3、粘土和砂土的各向异性是由于什么原因引起的？什么是诱发各向异性？五/4、介绍确定土抗剪强度参数的两种不同方法（包括设备名称），并分析其优缺点？ 五/5、什么叫材料的本构关系？在土的本构关系中，土的强度和应力-应变有什么联系？ 五/6、什么是加工硬化？什么是加工软化？请绘出他们的典型的应力应变关系曲线。