23, 1 Vol123, No11 2006 1 JOURNAL OF SHENZHEN UN IVERSITY SC IENCE AND ENGINEER ING Jan1 2006 : 100022618 ( 2006) 0120042206 2 1, 2, 2 (1., 518060; 2., ) : 2. PFC 2D, 2., 2.,, ;,,,.. : ; 2 ; ; : TUY 435 : A,. 50, ( ) 2, [ 1 ].,.,.,, p2y [ 227 ].,,,,.,, 2,,. Cundall Strack [ 8 ],,. 2, 6 2,,,,. 1 111 2, 2,,. PFC 2D ( Particle flow code in 2 dimensions) : 2005209210; : 2005211214 : (HKUST6084 /00E) : (19782), ( ),,. E2mail: sudong@ tsinghua1org1cn
1, : 2 43,, 2,. PFC 2D, [ 9 ] :, ; ;. 2 m,, 1., 9166 m 12 300 01054 m.,, F. 12,. ( ) 115,,,. 0108 m, 1 /25, 1. 1 g/cm 3,, 100 MN /m, ( ) 015., 100 MN /m.,,. M3: x, y. x 2, y 3 ; M4: x, y. x 3, y 3 ; M5: x, y. x 4, y 3 ; M6:., 3. 2 211,,,. 2 M1 y 2, ( / ). 2, 2D,, ; 4D,. 2. F = 1 a + b ( y /D ) (1), a = 01116; b = 01105. 2,. 1 F ig11 M odel after so il expan sion 112,,. 6 : M1: y, 6 ; M2: y, 3 ; 2 M 1 2 F ig12 Force2d isplacem en t rela tion sh ip in M 1
44 23,,,, 2.., n, n = A void A circle = 1 - A ball A circle (2),,. p, ( p) ij = -, x ( c) 1 V ( P) i F ( c) j x ( c) i F ( c) j (3) N c c. V V ij = 1 V ( p) ij V ( p). (4) N p, ( p) ij. 3 (MC1) 2 p ; V ( p) p ( b ) 1 (MC2)., MC1, MC2,,. 3 ( c) yy, MC1 1 900 kpa 4 MPa, MC2 1 800 kpa 450 kpa., MC1, MC2,. 212 M2, 3D. 4 ( a) 4 ( b) 2 2. 3 M 1 F ig13 Var ia tion of physica l quan tities in M 1 4 F ig14 Rela tion sh ip under c ircular load ing
1, : 2 45,. 4 ( b),, 3 7158 MN /m, 6181 MN /m 4127 MN /m.. 213. 5 M2 M4 y., M4 M2, 68%, M4 x, y,. x y -, M2 y 1 m. x,, xx yy ;, xx yy ;, xx yy, 70% 80% ( 7)., x M2 y.,. 5 F ig15 Influence of orthogona l pre2load ing 7 F ig17 D egrada tion of norma l stresses 214. M3 M4 M5 x M1 M5, 2D, 3D 4D. 6 3, Y 2. 6,.,,, M3, M4 M5 614 MN /m 511., MN /m 415 MN /m., M6. 8 M6., ;, X, x - 114 MN /m; y x, y 616 MN /m, x 413 MN /m,,., 6. 9 F ig16 Influence of orthogona l pre2load ing am plitude 18,
46 23 8 ig18 Tra jectory of force dur ing sem ic ircular load ing.,,,,,, 2.,,. 9,,.,,. 9 F ig19 Evolution of d irection s of force increm en t dur ing sem ic ircular load ing.,,.,, ;.,,,. 2,. : [ 1 ] JGJ - 94. [ S]. [ 2 ],. [ J ]., 2001, 23 (4) : 4762480. [ 3 ],,,. m [ J ]., 2002, 23 (1) : 232 26. [ 4 ] Chen L T, Poulos H G, Hull T S. [ R ]. R729,,, 1996 ( ). [ 5 ] Murchison J M, OπNeillM W. p2y. [ C ]. : 1984, 1742191 ( ). [ 6 ] Gazioglu S M, Oπneill M W. p2y. [ C ]. : 1984, 1922213 ( ). [ 7 ] Reese L C, Cox W R, Koop F B.. [ C ],, 1974: 2080 ( ). [ 8 ] Cundall P A, Strack O D L. [ J ]., 1979, 29: 47265 ( ). [ 9 ] [ Z]. : Itasca Consulting Group, 1999 ( ). PFC 2D, 2 6 2, 2. :,, ;,
1, : 2 47 Abstract: 100022618( 2006) 01200472EA Num er ica l study on la tera l so il2pile interaction by particle flow code 1) College of A rchitecture and Civil Engineering, Shenzhen U niversity Shenzhen 518060 P. R. China SU D ong 1, L I X ia 2, and L I X iang2song 2 2) Civil Engineering D epartment Hong Kong U niversity of Science and Technology, Hong Kong P. R. China Abstract: Numerical modeling of soil2p ile interaction under lateral loading was perform ed by Particle Flow Code in two dimensions, loading paths of which include monotonic, periodic, cross and sem icircular paths. Force2disp lace2 ment relationship s were measured while their connections w ith m icroscop ic soil behavior were studied by monitoring variations of some physical quantities. The num erical simulations show that the p reloading along the orthogonal direc2 tion would cause stress degradation in soils and induce orthogonal loading effect. Under nonlinear loading path, the direction of load increment deviates gradually from the direction of disp lacement increment as the disp lacement in2 creases. The phenomena and corresponding mechanism s obtained from num erical tests benefit design and imp lemen2 tation of physical model tests. Key words: numerical modeling of particle flow; soil2p ile interaction; orthogonal loading effect; non2coaxial References: [ 1 ] JGJ294. Technical Code for Building Pile Foundations [ S]. [ 2 ] WANG Cheng, DENG An2fu. Analysis of soil2p ile coopera2 tion under horizontal loading [ J ]. Chinese Geotechnical Engineering Journal. 2001, 23 ( 4 ) : 4762480 ( in Chi2 nese). [ 3 ] WANG M ei, LOU Zhi2gang, L I J ian2xiang, et al. Experi2 mental study on nonlinear m app roach of single p ile under horizontal loading [ J ]. M echanics of Rock and Soil, 2002, 23 (1) : 23226 ( in Chinese). [ 4 ] Chen L T, Poulos H G, Hull T S. Model tests on p ile group s subjected to lateral soil movement [ R ]. R729. Australia, University of Sydney, 1996. [ 5 ] Murchison J M, OπneillM W. Evaluation of p2y relationship s in cohesionless soils. Proceedings of the ASCE Symposium on Analysis and Design of Pile Foundations [ C ]. Califor2 nia, 1984: 1742191. [ 6 ] Gazioglu S M, OπneillM W. Evaluation of p2y relationship s in cohesive soils. Proceedings of the ASCE Symposium on Analysis and Design of Pile Foundations [ C ]. ASCE Na2 tional Convention, California, 1984: 1922213. [ 7 ] Reese L C, CoxW R, Koop F B. Analysis of laterally load2 ed p iles in sand. Proc Offshore Technology Conf [ C ]. Houston, 1974: Geo 2080. [ 8 ] Cundall P A, Strack O D L. A D iscrete Numerical Model for Granular A ssemblies [ J ]. Geotechnique, 1979, 29: 47265. [ 9 ] PFC 2D ( Particle Flow Code in 2 D imensions) U serπs Guide [ Z]. USA: Itasca Consulting Group, Inc, 1999. : ; :