Soil Mechanics lec4 - 東京工業大学

1 , (JGS) 2009. 8 32p 50 Rm 0 50 Sm-R. 0 Sm [ ].. 75mm .. R Rock C Clay . R1 Boulder O Organic Soil . 19 75 300 (mm) R2 Cobble V Volcanic Cohesive Soil . G G-Soil or Gravel Pt Highly Organic Soil Peat .. ( ) ( ) S S-Soil or Sand MK Muck . (clay) (silt) F Fine Soil Wa Wastes . (sand) (gravel) (stone). Cs Cohesive Soil I I-Soil or Improved Soil . JGS) 1 M Mo . cobble boulder 2. ASTM P15 ASTM P15. Let's see P23. F,S: F,S : 4. 3. (grain size analysis) Stokes' law: . (Hydrometer analysis) R: . (2mm 75mm) Sieve analysis i R 3 d v . d: , (20 ) . (sec m) N sec/m2 .. ( ) (75 m 2mm).

2 V . 2mm 75 m . Li R= :F. grading curve) d 3. 100.. F g ( s w ) v:const R. 6.. 80. 1 g ( s w ) 2 F. v d . (%). 60. 18.. C B A . (t) .. 40. dispersant (L=vt).. 18 L. 20. P21 d .. g ( s w ) t 75mm ~75 m 0. Li ti ,di . 1 10 100. D (mm). 5 ( i) 6. sieve opening ?? di . (grain distribution curve).. z 100. Li . V . 90 Let's see P22. Ms ti z di 80 . di pi . D60. di 70. Uc . 60 coefficient of D10. uniformity ti pM 50. di ms i s ( D30 ) 2. 40 U 'c . V coefficient of D10 D60. curvature pM pM 30. => vs i s => vm 1 i s V s V s 20 (W) (P). Uc > 10 Uc < 10. 10. 1 < U'c<3 . pM pM M.

3 I i s 1 i s w pi s 1 w w 0. V V s V s . D30 D50 D60. 1 10 100. D ). ( ).. ( w ) sV . di pi i :mean diameter 8. ( s w )M s 7. Why . Mitchell Fundamentals of Soil Behavior 1st ed (1976). < . Uc D10. P16. Uc, U'c D50, . but not enough for why?? 5 m 10 1 m not enough).. , m 17 m montmorillonite Kaolinite . 9 10. P26.. :illite .. 10 . O2- Si4+. (a) (b) .. G O OH Van der Waals .. ( Mitchell: Fundamental of Soil Behavior 2nd, 1993). Al3+). - 4 50 200 - >10 . B 3000 4000 (stacks) up to 10 10-50 up to 10 1-5 .. OH- (Al3+,Mg2+ Mg2 ) Specific surface:m2/g). 50 - 120. 10 - 20 65 - 100.

4 (a) (b) 700-840(interlayers). 11 Cation Exchange Capacity(CEC): mEq/100gm). 12. 3 - 15 10 - 40 80 -150. H. Technical terms . O. coarse soil; fine soil cohesive soil . H. organic soil; volcanic cohesive soil ( : peat grain size analysis sieve analysis;. 1. O hydrometer analysis; dispersant .. grading curve, grain distribution curve ;. 2. Si Al Al .. mean diameter; coefficient of uniformity;. Mg . coefficient of curvature; : intermediate soils;.. kaolinite montmorillonite ; illite . 3.. OH specific surface .. H+ .. ) . (adsorption layer): diffuse double layer 6/24 . 3 2 2 (1) p5 A,B,C D50 Uc).

5 Al Ca Mg NH K H Na Li 4 (2) A,B,C JGS . ASTM . Interfacial effect ) ) 13 14. Na wL=700% P24. Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System) ASTM. Flow Chart for Classifying Coarse-Grained Soils (More than 50 % Retained on No. 200 Sieve).. 75 m . Cu=Uc Cc=U'c . US: 75mm>Gravel> . >sand> .. 16. 15.. 3/4 .. 17 18.. 100. 90.. 80 .. (%). 70. 60 . 50 . 40 . 30.. 20 .. 10.. 0 75um . 1 10. (mm). 19 20.. 100.. 80 . Percentage finer (%). 60 . 50. 40.. 20.. 0. 1 10. 21 Particle size (mm) 22.. 24. 23. SEM .. Na montmorillonite DL.

6 S= s= 60g 30g . Ms= 30g Ms= 40g 5 m 10 m Vs=Ms/ s= Vs=Ms/ s= w=200% e=Gsw/Sr> w=75% e> . 60g 30g . Ms= 15g Ms= 20g 200 m 50 m Vs=Ms/ s= Vs=Ms/ s= 26. w=400% e> w=150% e> 25.