沈阳建筑大学考试评分标准专用纸
2010年 秋 季学期 科目 土力学(B) 适用年级、专业 土木08-9，10 ——————————————————————————————————
一、Choose the right one from the four answers(total 20 points, 2 points per problem)
A C C B B C A D A A
二、Explain the following concepts or definition(total 20 points, 4points per problem) 1. Critical hydraulic gradient
使土开始发生流砂现象时的水力梯度
2. coefficient of curvature Cc
曲率系数定义为（Cc）Cc?状。
d30d10d602,曲率系数Cc描写累积曲线的分布范围，反映曲线的整体形
3. compression modulus
压缩模量：土体在完全侧限的条件下，竖向应力增量与竖向应变增量的比值
4. Ultimate bearing capacity of foundation
地基极限承载力是指地基剪切破坏发展即将失稳时所能承受的极限荷载。
5. Degree of saturation
土中被水充满的孔隙体积与孔隙总体积之比。
三、Answer the following questions simply(total 20 points, 5 points per problem)
1．Give out the meanings of the concepts 草图)?
11?e： 土粒子占总体积的比率 e1?e：孔隙所占总体积的比率
11?e and
e1?e in 3-phase diagram (3 相2. In soil classification，how do we classify the clayey soil and sandy soil？
砂性土根据颗粒级配进行划分 黏性土根据塑性指数进行划分
3. Give out the basic assumptions in Prandtl’s “ultimate subsoil bearing capacity” theory.
假定条形基础置于地基表面、地基土无重量、且基础底面光滑无摩擦力的条件下，基础下形成连续塑性区而处于极限平衡状态时，地基的极限平衡区可分为三个区：在基底下的朗肯主动状态区（Ⅰ区）、基础外侧的朗肯被动状态区（Ⅲ区）以及Ⅰ区与Ⅲ区之间的过渡区（Ⅱ区）。
4. Find the difference between the contact pressure and the net contact pressure of the foundation
基底压力为作用在基础底面的压力。是由上部构造物及基础自重而引起的。
基底附加压力为：作用在基础底面的压力与基底处建前土中自重应力之差，是引起地基附加应力和变形的主要原因。
p0?p??mh
四、There is a sample which is got from a certain natural sand column. The water content measured by experiment is 11%, bulk density ??1.70g/cm3, the minimum dry density is??1.41g/cm3, the maximum dry density is??1.75g/cm3. Please determine the sandy soil’s dense degree (6 points)
?d??1?w?1.701?0.11?1.53g/cm3 2 points
?0.4Dr???d??dmin??dmax??dmax??d??d 2 point
在1/3 至2/3 之间 ，中密 2 point
五、 A 100mm diameter sample of fine sand was tested in a falling head permeameter. The length of the sample was 150mm. Water in the standpipe fell from 1000 to 400mm in 44 seconds. If the diameter of the standpipe was 10mm, determine the coefficient of permeability of the soil. (8 points)
2 2
六、Prove the Relationship E0?(1?2?24
1??)Esbetween the deformation modulus E0and the
compression modulusEs. Where u is Poisson’s ratio. (5 points)
?x??y?K0?z 1 points
?x??y?0 ?x?K0??xE0???yE0???zE0?0 1 points
???zzx??/?1???
???z??yE0E0???xE0??zE0?1?2?K0? 1 points
?zUnder laterally confined condition ?z?Es 1 points
The relationship between the deformation modulus and the compression modulus is given as
E0??(1?2?21??)Es 1 points
七、A saturated clay layer of thickness 20m overlays an pervious(透水) uncompressible dense sand stratum. A vertical uniform pressure p=200kPa is applied on the clay layer. The initial void ratio is e1?1.0, the compression coefficient a?2.5?10?4kPa?1, and the coefficient of permeability k?2.0cm/year. Find : (1) settlement after 1 year loading; (2) the length of time required for achieving a settlement of 10 cm. (11 points) (U?1?
1. Final settlement S?k(1?e1)a?w8?2??2??exp??Tv?) ?4??a1?e15pH?50 2 points
Cv??1.6?10cm2/year 2 points
Tv?8CvtH2/4?0.16 2 points
U?1??2??2???0.454 exp??Tv??4??
St?U?S?0.454*50=22.69cm 2 points
2. U=10/50=0.2
Tv?0.005TvH4Cv2 2 points
?0.033t? 1 points
八、A frictionless retaining wall is shown in the figure. Determine the force per unit width of
the Rankin’s active state after tensile crack occurs. Also find the location of the resultant and give the distribution of the active pressure. (10 points)