沈阳建筑大学考试评分标准专用纸2007 年春季学期科目土力学(A) 适用年级、专业土木04-9，10 ——————————————————————————————————一Fill in the blanks (total 10 points, 1 points per blank)1. The soil fabric (结构) usually contains three kinds of basic types. (1) 单粒,(2) honeycomb fabrics, (3) 絮状.2. Basic physical indexes of soil include, bulk density of soil , G s and w3. In the triaxial test under unconsolidated-undrained (非固结非排水)，because only 一个有效应力园can be obtained, so that the internal friction angle could not be determined.4. The degree of saturation, S r, is defined as the ratio of the volume of 水to thevolume of 孔隙.5. If the soil mass pushes against a retaining wall such as to push it away, the soil becomes theactuating element and the pressure resulting thereby is known as 主动pressure. On the other hand, If the wall pushes against the soil the resultant pressure is known as 被动pressure.6. Based on Darcy’s law, for saturated soils, the average water flow velocity through soils is proportional to 水力梯度.二、Choose the right one from the four answers(total 20 points, 2 points per problem)A C CB B A A D A A三、Judge the following statement right or wrong. Mark with R for the rights and W forthe wrongs (total 10 points, 2 points per problem)R W W R W四、Explain the following concepts or definition(total 15 points, 3points per problem) 1. Relative Density of cohesionless soil (Dr)定义为：minmax max e e e e D r --=可用公式()()min max min max d d d d d d r D ρρρρρρ--=2. liquidity index I L液性指数是指粘性土的天然含水量和塑限的差值与塑性指数之比。
PPPL P L I w w w w w w I -=--=3. degree of consolidation饱和土在附加应力的作用下，孔隙中相应的一些自由水将随时间而逐渐排除，同时空隙体积也逐渐减少。
这个过程称为饱和土的渗透固结。
经历t 时间的固结变形量与最终变形量的比值或孔隙水压力的消散程度称为固结度。
4. net contact pressure基底压力与基底处建造前土中应力之差。
5． a dditional stress由上部建筑荷载（基底附加压力）等外界因素在地基中产生的应力。
五、Answer the following questions simply(total 10 points, 5 points per problem)1． Give out the meanings of the concepts e+11 andee +1 in 3-phase diagram (3 相草图)e +11： 土粒子占总体积的比率 ee +1：孔隙所占总体积的比率2. Explain “stress in soil ”, why do we calculate “stress in soil ”?土体在自身重力，建筑物荷载，交通荷载或其他外界因素等的作用下，产生土中应力。
按起因可分为资中应力和附加应力。
因土中应力将引起土体或地基发生变形，试土工建筑物发生沉降，倾斜以及水平位移。
变形过大将影响建筑物的正常使用。
并且，土中应力过大，会导致土体的强度破坏，使土工建筑物发生土坡失稳或使地基的承载力不足而发生失稳。
因此须计算土中应力。
六. A soil specimen has a water content w 1 of 10% and unit weight1γ of 18.0kN/m 3. Keepvoid ratio constant and increase water content to w 2 =20%. How much water will be infused into 1 m 3 soil . (8 points)()111111-+=γγw G e ws ()112222-+=γγw G e ws 2 points21s s G G = 21e e = 2 pointsSo that31212/64.1911m kN w w =++=γγ 2 pointskN w 64.1=∆ 2 points七. For a soil, the friction angle30=φ, cohesion c=10kPa, would failure occur on a planewithin a mass of this soil at point A where the principal stresses are 100kPa and 400kPa respectively, and point B where the shear stress is 100kPa and the normal stress 200kPa?(8 points)1.kPac f 6.334245tan 2245tan 231=⎪⎭⎫ ⎝⎛++⎪⎭⎫⎝⎛+=φφσσ 2 points11σσ<fffailure at A 2 points2.5.125tan =+=φστc f2 pointsττ<fnot failure at B 2 points八. A saturated clay layer of thickness 10m overlays an impervious hard rock. A vertical uniform pressure p=200kPa is applied on the clay layer . The initial void ratio is 0.11=e , thecompression coefficient14105.2--⨯=kPaa , and the coefficient of permeabilityyearcm k /0.2=.Find : (1) settlement after 1 year loading; (2) the length of time required for achieving asettlement of 20 cm. (12 points)1. Final settlement 2511=+=pH e a S 2 pointsy e a r cma e k C wv /106.1)1(251⨯=+=γ2 points16.02==Ht C T v v 2 points2 points=⨯=S U S t 0.45*25=11.25cm 2 points2. U=20/25=0.857.0=v T 2 points56.32==vv C H T t 2 points九 A frictionless retaining wall is shown in the figure. Determine the force per unit width of the Rankin ’s active state. Also find the location of the resultant and give the distribution of the active pressure. (12 points) 1 .31)23045tan(245tan 21=-=⎪⎭⎫ ⎝⎛-=ϕa K2．顶部与交界处上部主动土压力kPaK c qKp a aa 67.6)3/1(202=⨯=-=()kPaK c K q H p a a a 67.23)3/1()20317(2=⨯+⨯=-+=γ3.271.0)23545(tan 245tan 222=-=⎪⎭⎫ ⎝⎛-=ϕ a K4. 交界处下部主动土压力()kPaK q H p a a 24.19271.0)20317(=⨯+⨯=+=γ5. 底部主动土压力6.()kPaK q H H p a a 88.33271.0)20318317(2211=⨯+⨯+⨯=++=γγ7. 全主动土压力合力mkN E a /2.125)24.1988.33(32124.193)67.667.23(32167.63=-⨯⨯+⨯+-⨯⨯+⨯=8. 作用点从底部起为X 处mE X a66.2]3)24.1988.33(211324.195.1)67.667.23(321467.635.4[1=⨯-⨯⨯+⨯⨯+-⨯⨯⨯+⨯⨯=9．分布图2 points2 points2 points2 points———————————————————————————— 注意事项：1.请将评分标准连同考试题一并上交。
2.客观题注明每题的总分，每小题的分数。
3.主观性试题必须注明得分点及分值。
2 points3mEa ： 125.2kN/m。