(1) Class Test Solution (SOIL) Answer key. 31. (c) 32. (d) 33. (b) IES MASTER. 34. (c) 35. (c) 36. (c) 37. (c) 38. (d) 39. (d) 40.

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1 (1) Clss Test Solution (SOIL) Answer key 1. (). (b). (c) 4. (c) 5. () 6. (b) 7. (b) 8. () 9. (). (b) 11. (c) 1. () 1. (b) 14. (c) 15. (c) 16. (b) 17. () 18. (b) 19. () 0. () 1. (b). (c). (c) 4 () 5. () 6. () 7. () 8. (b) 9. () 0. (c) 1. (c). (). (b) 4. (c) 5. (c) 6. (c) 7. (c) 8. () 9. () 40. () 41. () 4. (c) 4. (c) 44. () 45. () 46. () 47. (c) 48. (b) 49 () 50. (c) 51. (b) 5. () 5 () 54. () 55. (b) 56. (c) 57. (c) 58. () 59. () 60. () 61. (c) 6. () 6. () 64. () 65. (c) 66. (b) 67. (b) 68. () 69. () 70. (c) 71. (b) 7. () 7. (c) 74. () 75. () Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

2 () CIVIL ENGINEERING CLASS TEST (SOIL) CLASS TEST [SOIL] SOLUTIONS 1. (). (b). (c) W L 60% 4. (c) For uniformly gre corse grine soil mximum voi rtio occurs when prticles re rrnge in cubicl rry n corresponing mximum voi rtio is 91%. Minimum possible voi rtio will be when prticles re rrnge in primoil rry. The minimum voi rtio is 5%. W 0% I W L W 40% rticle greter thn mm sie 80% % of clyey prticle (less thn micron) 0% Activity of smple I C A C 40 % 0 V V 0.5 V (given)...(ii) V L V 0.4 V L (given)...(i) V L V V S W S W W L Subtrcting (i) from (ii), we get V L V 0.4 V L 0.5 V or or 0.66 V L 0.75 V V L 1.16 V From geometry of fig. we cn write W V W V S WL W ; V L V where W 0.5 W L W + I W S shrinkge limit. 0.5 W V V S From (i), 0.75 V V. or or 5. () 0.5 W V V V V 0.16 V S 0.5 W 0.5 V S V V W S 0.9, i.e..9% V 1 V V Also Shrinkge rtio (SR) W1 W or S.R V W W V L V L 1.16 V V V (b) oorly gre sns will hve prticle of uniform sie leing to poor pcking of soil structure. Hence they will hve lower friction ngle. 7. (b) At the surfce 0 k C k C k When verticl surchrge of q kn/m is pplie then Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

3 CLASS TEST (SOIL) CIVIL ENGINEERING () K q 1. () For totl ctive thrust to be ero K q c K 0 q c k k H 4 m st 0. kn/m 8. () 9. () q c k T/m 7 4 CL CI MI ML ML CH Alive I 0.7(w 0) MH. (b) More thn 50% of totl wt is finer thn 11. (c) 75 sieve so soil is fine soil. I I (A line) 0.7 (W L 0) 0.7 (8 0) 1.14 lot the I n LL on the plsticity chrt the plot lies bove A line so clssifiction is CI. or C u D D C u D D 60 l C C C 0 D D 0 c D0 D D 60 D 60 D0 D0 D D60 D D () 14. (c) w H k0h H 4 m 0. st 0. kn/m st w kn/m k Erth pressure t bottom of the retining wll p H p H 49.6 kn/m Totl erth pressure force kn 0 1 p H H (per unit length of wll) 0 K 1 Cu 0 k 1 C K H CH K kn 15. (c) These soils re quite strong n cn resist Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

4 (4) CIVIL ENGINEERING CLASS TEST (SOIL) 16. (b) 17. () 18. (b) externl forces becuse of strong bon ue to ttrction between prticles. h 80%; b 60% W 80 kn; H 60 cm S 0 mm cm C 5 mm.5 cm Q u Q u Q u C S h b WH kn kg (1) Bulk ensity 1855 kg/m m () 19. () b kg/m 1 w n G w 1 wg 1 n n %. e mx 0.8 min Mx ry ensity,mx Fiel ensity e 0.4 e 0.6,mx w G 1 e s min kn/m () 1. (b). (c). (c) 4. () 5. () 6. (),fiel kn/m Reltive compction Totl pressure t 87.5% x t/m. L 1.5 cos L 1.5 totl he t A (h p ) A + (h ) A totl he t B 0.95 m sub m L 1.5 i H L 1.5 q 0.1 cc/sec i q AK t/m 1 gm/cc eff. stress upwr h sub i w [ h 0.5 cm] Accoring, to converse-lebrre eqution g 1 where m(n 1) n(m 1) mn 90 tn tn s 1 1 Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

5 CLASS TEST (SOIL) CIVIL ENGINEERING (5) 18.4 Erthenm As its squre pile group so m n 4 g %. 7. () Consistency represents the reltive ese with which soil cn be eforme. This term is minly use for clyey soil n is relte to wter content i.e., how with chnge in wter content the consistency of soil chnges. 8. (b) 9. () 0. (c) The ynmic he rop per equipotentil is, HA HB ( h) N 14 rops eq ressure he t A +.86 m ressure he t B + 6. m The uplifting force F is, F.57 m/rop h () h () A B L w 50 (9.81) kn/m. totl he loss t x cm 40 totl he cm elevtion he 0 cm h p (c). (). (b) Bse prbol In erthen m hretic line hretic line is flow line or strem line which is perpeniculr to u/s wette surfce which is lso clle 0% equipotentil line. hretic line represents top flow line of seepge flow n follows pth of bse prbol with smll correction t entry point. Eqution (x 6y) represents prbolic profile thus it is correct. q nu Df B C b L kn/m Net sfe bering cpcity i c 79. kn/m. sub Seepge pressure hl w w G 1 I e, 4. (c) Stress t epth just below the point lo Q. Q Q kb Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

6 (6) CIVIL ENGINEERING CLASS TEST (SOIL) 5. (c) 6. (c) 7. (c) N k B 1 r 1 Q kb (5) kn/m N C N C N R / N C sy 55. C N 55 R which is less thn n greter thn 1.5 So correcte N vlue 55. tn 0.5 B ( 0.55) kn/m 8. () Since 0, it is locl sher filure. It is lso given tht C 50 kn/m, 17.5 kn/m, B 1.5 m n D 1m. For 0, N C 1.60, N 1.4 n N q.80. Let us ssume the fctor of sfety to be.5 Strip footing 9. () q f C. N C DN q 0.5 BN ( ) ( ) kn/m q nf q f D (17.5 1) kn/m q ns qnf kn/m F.5 q s q ns D.64 + (17.5 1).14 kn/m. Q C N C A b + C A S (0.5) () 9 (0.5) ( 5) U e0 e f e e %. 41. () Tv is fctor which epens on the egree of consolition n istribution of initil excess pore wter pressure. C V is more Rte of settlement is more C c (W L ) 4. (c) In comprison to tterberg limits of norml soils, expnsive soils hve More liqui limit Less plstic limit Less shrinkge limit More volumetric shrinkge. This essentilly mens expnsive soils hve lrge plstic region, represente by higher vlues of plsticity inex. Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

7 CLASS TEST (SOIL) CIVIL ENGINEERING (7) 4. (c) 44. () 45. () 46. () t t 1 H H 1 H 1 H, H H 15 t H H t 60 yers The cly lyer is times more permeble n 4 times more compressible therefore time require for 90% consolition t 80 yers When over buren exits, the effective stress in soil t certin level is high but once it is eroe, effective stress reuces so tht soil become preconsolite. For soil below glcier, glcier cts s overburen, fter melting of glcier effective stress on soil got reuce. Due to lowering of groun wter tble cpillry pressure sets up which increses the effective stress of soil. S c 47. (c) H. C c log e0 0 C c (w L ) S c log (b) 49. () cm D 7.5 cm m H 11.5 cm m T 40 N-m 40 kn-m 50. (c) 51. (b) 5. () S S S T H D D 6 T H D D (0.075) 6 S.9 kn/m B U e c 60 B B 0.70 AB AB U A A 0. In unrine trixil test. 1 Assume t rest 1 1 K Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

8 (8) CIVIL ENGINEERING CLASS TEST (SOIL) () Generlly, the filure strin is to 4% for ense sn n 1 to 16% for loose sn. 54. () (Sher stress) e (Voi Rtio) e c r H (Strin) L Criticl voi rtio Loose sn Strin Dense sn Stress strin curve Loose sn Voi Rtio Strin Curve Dense sn Assumptions of Terghi s theory (i) Fountion is shllow (D f B) (ii) The bse of fountion is rough. (iii) Footing is continuous such s strip footing, which mkes nlysis two imensionl. 55. (b) (iv) Terghi consier only bse resistnce n ignore sie resistnce. Given, slope 1:1 i.e. 45 for & 45 S n (c) S n 0.8 F C HF F Criticl height for slope H C m. Resisting Moment CL r r kn.m. Actuting moment W knm FOS Resisting moment Actuting moment (c) Mximum inclintion in cohesionless soil in infinite slope is equl to ngle of internl friction. Stbility is ffecte neither by the unit weight of soil nor by wter content. 58. () 59. () 60. () Sttement n 4 re obviously correct s inclue in ll options. Otherwise : K 0 for OC clys 1-4 K 0 (OC cly) K 0 (NC cly) For Sttement 1, O.C.R For perfectly cohesionless soil (c 0) K 0 So it is lso correct. 1 sin s sin will be between 0 to 1 so K 0 < 1 Hence sttement is lso correct. For sttement 5, Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

9 CLASS TEST (SOIL) CIVIL ENGINEERING (9) for ense sn k for loose sn k After mechnicl compction k Hence, it is lso correct. Option () All re correct. 61. (c) The correltion is not perfect. A liberl fctor of sfety shoul be provie if the esign is bse only on inex properties. 6. () 6. () 64. () The Rnkine s theory ssume tht the wll surfce is smooth wheres in prctice, lot of friction my evelop between the wll surfce n the soil fill. This friction will epen upon the wll mteril. This friction les to the evelopment of smller ctive pressure n lrger pssive pressure thn tht estimte by Rnkine s theory. 0 Thus, the estimtion of the ctive pressure using Rnkine s theory will be slightly higher thn the ctul (reuce ue to friction) ssive pressure will be slightly lower. 65. (c) In ctul prctice, the friction les to the evelopment of smller ctive pressure thn tht estimte by Rnkine s theory n the lrger pssive pressure thn the theoreticl. 66. (b) The chrcteristics of flow net cn be summrise s uner : The funmentl conition tht is to be stisfie is tht every intersection between flow line n n equipotentil line shoul be t right ngles. The secon conition to be stisfie is tht the ischrge between ny two jcent flow lines is constnt n the rop of he between the two jcent equipotentil lines is constnt. The rtio of the length n with of ech fiel is constnt. The rtio is generlly tken s unity for convenience. In other wors, the flow net consists of pproximte squres. 67. (b) An isobr is curve joining the points of equl stress intensity. In other wors, n isobr is contour of equl stress. An isobr is sptil curve surfce of the shpe of n electricl bulb or n onion. The curve surfce is symmetricl bout the verticl xis pssing through the lo point. 68. () Stress pth cn be plotte for stress conition uring trixil test. 69. () rocess of consolition There re four min stges s follows: 1. Initilly: equilibrium (or stey stte) pore wter pressure, u 0 is constnt (n is simply the he of wter, or hyrsttic pressure ) w. Lo pplie to soil surfce increses totl stress on soil smple, which generte rise in pore wter pressure Soil prticles try to move closen together but prevente by incompresible pore wter. Wter pressure rises u (excess pore wter pressure), to equl the totl stresses increse; u w + pplie stress u + 0 u. Dissiption of pore wter pressure: Over perio of time (Months to yers), the excess pwp, u, issiptes (rins slowly out of the cly ue to low permebility uner sustine lo i.e squeeing from vois of pressurise pore flui). The cly pricles tke up new positions, resulting in settlement n increse in effective stress: totl ( ) effective ( ) constnt effective ( ) incresing totl ( ) incresing constnt + p.w.p (u) ecresing p.w.p (u) ecresing 4. Full issiption of excess pwp ( u 0): In the long term, excess pwp becomes ero n there is mximum increse in effective stress, n pwp returns to its originl vlue, u 0. Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

10 () CIVIL ENGINEERING CLASS TEST (SOIL) 70. (c) Sn with n initil voi rtio equl to criticl voi rtio will show no volume chnge when subject to shering strin. 71. (b) 7. () Since flow through one lrge chnnel will be much greter thn flow through number of smll chnnels hving the sme sie of totl chnnel re s the one lrge chnnel. 7. (c) A person cn esily wlk on mp sn ner the se bech becuse it possesses strength ue to cpillry moisture. On the sme sn in sturte conitions, it becomes ifficult to wlk s the cpillry ction is estroye. 74. () 75. () Uner-reme piles hve enlrge bulb, ue to which bering cpcity is more thn tht of stright bore pile of the sme imeter. Reg. office : F-16, (Upper Bsement), Ktwri Sri, New Delhi-1016 hone : Mob. : , E-mil: ies_mster@yhoo.co.in, info@iesmster.org

Solutions to Supplementary Problems

Solutions to Supplementary Problems Solutions to Supplementry Problems Chpter 8 Solution 8.1 Step 1: Clculte the line of ction ( x ) of the totl weight ( W ).67 m W = 5 kn W 1 = 16 kn 3.5 m m W 3 = 144 kn Q 4m Figure 8.10 Tking moments bout