Application of long-short pile retaining system in braced excavation 2 2 In soft soil areas, equal-length piles are often adopted in the retaining system. A decrease in the bending moment value borne by the retaining structure along the pile depth (below the excavation bottom), leads to an inadequate use of the pile bending capacity near the pile bottom. This paper presents retaining systems with long and short pile combinations, in which the long piles ensure integral stability of the excavation while the short piles give full play to bearing the bending moment. For further analysis on pile and bottom heaves deformations and inner-force characteristics, three-dimensional models were built in order to simulate the stage construction of the excavation. The ratio between long and short pile numbers, and the effects on short pile length pile horizontal deformation, pile bending moment and bottom heave are investigated in detail. In the end, a feasible long-short pile combination is established. Obtained results from the simulation data and the field data prove that the long-short pile retaining system is feasible. 81 89 2013/10/23 1392/8/1 2015/03/4 1393/12/13 Changjie XU Changjie XU PhD, Professor, School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, Jiangxi, 330013, China China xucj@zju.edu.cn Yuanlei XU Yuanlei XU Junior engineer, Zhejiang Academy of Building Research & Design Co. Ltd., Hangzhou, 310058, China China xuyl@zju.edu.cn Honglei SUN Honglei SUN PhD, Associate professor, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China China saitholy@gmail.cm Long-short piles Soft soil Excavation Retaining strutting system FEM simulation. [1] Ou CY. Deep Excavation, Taylor & Francis Group, London, 2006.##[2] Zhou AQ, Gong XN, Liu HX, Zhang HJ. Research on optimum design of retaining piles structure with interior bracing, Chinese Journal of Rock and soil mechanics, 2010, No. s1, Vol. 31, pp. 245-260.##[3] Hong SH, Lee FH, Yong KH. Three-dimensional pile-soil interaction in soldier-piled excavations, Computers and Geotechnics, 2003, Vol. 30, pp. 81-107.##[4] Gao XN, Liu SY, Tong LY. Analysis of ratio of embedded depth of multi-pivot secant piles to excavation depth in suzhou subway stations, Chinese Journal of Southeast University (Natural Science Edition), 2012, No. 2, Vol. 42, pp. 352-357.##[5] Leung CF, Chow YK, Shen RF. Behavior of pile subject to excavation-induced soil movement, Journal of Geotechnical and Geoenvironmental Engineering, 2000, No. 11, Vol. 126, pp. 947-954.##[6] Liang FY, Chen LZ, Shi XG. Numerical analysis of composite piled raft with cushion subjected to vertical load, Computers and Geotechnics, 2003, No. 2, Vol. 30, pp. 443-453.##[7] Wu YD, Shi CH, Liu J, Li ZG. Study on the bearing characteristics of long-short piles composite foundation under embankment load, Forensic Engineering, New York, 2012, pp. 673-681.##[8] Li Z, Zheng G, Wang HX. model tests on work behaviors of retaining piles with different lengths and horizontal support, Chinese Journal of Geotechnical Engineering, 2010, No. s1, Vol. 32, pp. 440-446.##[9] Zheng G, Cheng XS. Experimental study on cantilever contiguous retaining piles with different lengths, Chinese Journal of Geotechnical Engineering, 2008, No. s1, Vol. 30, pp. 410-415.##[10] Faheem HV, Cai F, Ugai K. Two-dimensional base stability of excavations in soft soils using FEM, Computers and Geotechnics, 2003, Vol. 30, pp. 141-163.##[11] Wong KS. How to avoid failures in deep excavations, International Conference on Structural and Foundation Failures, Singapore, 2004, pp. 384-397.##[12] Zhang YD, Gong XN. Improvement on basal heave stability analysis for excavations in soft clay, Chinese Journal of Geotechnical Engineering, 2006, No. S1, Vol. 28, pp. 1378-1382.##[13] Technical Specification for Retaining and Protection of Building Foundation Excavations of the People\'s Republic of China, Beijing, China Building Industry Press, 2012.##[14] Technical Code for Monitoring of Building Excavation Engineering of the People\'s Republic of China, Beijing, China Architecture & Building Press, 2009.##[15] Brinkgreve RBJ. Selection of soil models and parameters for geotechnical engineering application in soil constitutive models, Proceedings of the Sessions of the Geo-Frontiers Congress, Texas, 2005, pp. 69-98.##[16] Xu ZH, Wang WD. Selection of soil constitutive models for numerical analysis of deep excavations in close proximity to sensitive properties, Chinese Journal of Rock and Soil Mechanics, 2010, No.1, Vol. 31, pp. 258-264.##[17] Tolooiyan A, Gavin K. Modelling the cone penetration test in sand using cavity expansion and arbitrary lagrangian eulerian finite element methods, Computers and Geotechnics, 2010, No. 4, Vol. 38, pp. 482-490.## ##

Numerical analysis on Buried pipes protected by combination of geocell reinforcement and rubber-soil mixture 2 2 A numerical simulation of laboratory model tests was carried out to develop an understanding of the behaviour of pipes in a trench prepared with 3-Dimensional reinforced (namely "geocell-reinforced" in the present study) sand and rubber-soil mixtures, under repeated loadings. The study reports overall performance of buried pipes in different conditions of pipe-trench installations and the influence of pipe stiffness on backfill settlements, stress distribution in the trench depth and stress distribution along the pipe's longitudinal axis. Good agreements between the numerical results and experimental results were observed. The results demonstrate that combined use of the geocell layer and rubber-soil mixture can reduce soil surface settlement and pipe deflection and eventually provide a secure condition for buried pipe even under strong repeated loads. 90 104 2013/10/232014/07/1 1393/4/10 2015/03/42015/06/30 1394/4/9 Gh. Tavakoli Mehrjardi Gh. Tavakoli Mehrjardi Assistant Professor, Department of Civil Engineering, Kharazmi University, Tehran, Iran ghtavakoli@khu.ac.ir S.N. Moghaddas Tafreshi S.N. Moghaddas Tafreshi Professor, Department of Civil Engineering, K.N. Toosi University of Technology, Tehran, Iran nas_moghaddas@kntu.ac.ir A.R. Dawson A.R. Dawson Associate Professor, Nottingham Transportation Engineering Centre, University of Nottingham, Nottingham, UK andrew.dawson@nottingham.ac.uk Numerical analysis Geocell Buried pipes Rubber-soil mixture Stress transfer. [1] Choo YW, Abdoun TH, O’Rourke MJ, Ha D. Remediation for buried pipeline systems under permanent ground deformation. Soil Dynamics and Earthquake Engineering, 2007, No. 12, Vol. 27, pp. 1043-1055.##[2] Moghaddas Tafreshi SN, Tavakoli Mehrjardi Gh. Analysis of buried plastic pipes in reinforced sand under repeated-load using neural network and regression model, International Journal of Civil Engineering, IJCE, 2007, No. 2, Vol. 5, pp. 118-133.##[3] Jafarzadeh F, Farahi Jahromi H, Abazari Torghabeh E. Investigating dynamic response of a buried pipeline in sandy soil layer by 1g shaking table test, International Journal of Civil Engineering, IJCE, 2010, No. 2, Vol. 8, pp. 107-124.##[4] Collins KJ, Jensen AC, Mallinson JJ, Roenelle V, Smith IP. Environmental impact assessment of a scrap tyre artificial reef, Journal of Marine Science and Engineering, 2002, Vol. 59, pp. 243-249.##[5] Humphrey DN, Katz LE. Five-year field study of the effect of tire shreds placed above the water table on groundwater quality, J Transportation Research Record, Transportation Research Board, 2000, Vol. 1714, pp. 18-24.##[6] Feng ZY, Sutter KG. Dynamic properties of granulated rubber sand mixtures, Geotechnical Testing Journal, 2000, No. 3, Vol. 23, pp. 338-44.##[7] Yoon S, Prezzi M, Siddiki NZ, Kim B. Construction of a test embankment using a sand–tire shred mixture as fill material, Journal of Waste Management, 2006, Vol. 26, pp. 1033-44.##[8] Attom MF. The use of shredded waste tires to improve the geotechnical engineering properties of sands, Environmental Geology, 2006, Vol. 49, 497-503.##[9] Edinçliler A, Avhan V. Influence of tire fiber inclusions on shear strength of sand, J Geosynthetics International, 2010, No. 4, Vol. 17, pp. 183-192.##[10] Moghaddas Tafreshi SN, Tavakoli Mehrjardi Gh, Dawson AR. Buried pipes in rubber-soil backfilled trenches under cyclic loading, Journal of Geotechnical and Geoenvironmental Engineering, 2012, No. 11, Vol. 138, pp. 1346-56.##[11] Thakur JK, Han J, Pokharel SK, Parsons RL. Performance of geocell-reinforced recycled asphalt pavement (RAP) bases over weak subgrade under cyclic plate loading, J Geotextiles and Geomembranes, 2012, Vol. 35, pp. 14-24.##[12] Pokharel SK, Han J, Leshchinsky D, Parsons RL, Halahmi I. Investigation of factors influencing behavior of single geocell-reinforced bases under static loading, J Geotextiles and Geomembranes, 2010, No. 6, Vol. 28, pp. 570-578.##[13] Sitharam TG, Sireesh S, Dash SK. Model studies of a circular footing supported on geocell-reinforced clay, J Canadian Geotechnical Journal, 2005, No. 2, Vol. 42, pp. 693-703.##[14] Sitharam G, Sireesh ST, Dash SK. Performance of surface footing on geocell-reinforced soft clay beds, Journal of Geotechnical and Geoenvironmental Engineering, 2007, Vol. 25, pp. 509-524.##[15] Moghaddas Tafreshi SN, Dawson AR. Comparison of bearing capacity of a strip footing on sand with geocell and with planar forms of geotextile reinforcement, J Geotextiles and Geomembranes, 2010a, Vol. 28, pp. 72-84.##[16] Moghaddas Tafreshi SN, Dawson AR. Behaviour of footings on reinforced sand subjected to repeated loading - Comparing use of 3D and planar geotextile, J Geotextiles and Geomembranes, 2010b, Vol. 28, pp. 434-447.##[17] Tavakoli Mehrjardi Gh, Moghaddas Tafreshi SN, Dawson AR. Combined use of geocell reinforcement and rubber-soil mixtures to improve performance of buried pipes, J Geotextiles and Geomembranes, 2012, No. 4, Vol. 34, pp. 116-130.##[18] Tavakoli Mehrjardi Gh, Moghaddas Tafreshi SN, Dawson AR. Pipe response in a geocell reinforced trench and compaction considerations, J Geosynthetics International, 2013, No. 2, Vol. 20, pp. 105-18.##[19] Babu GLS, Vasudevan AK, Haldar S. Numerical simulation of fiber-reinforced sand behaviour, J Geotextiles and Geomembranes, 2008, Vol. 26, pp. 181-88.##[20] Saride S, Gowrisetti S, Sitharam TG, Puppala AJ. Numerical simulation of geocell-reinforced sand and clay, J Ground Improvement, 2008, No. GI4, Vol. 162, pp. 185-98.##[21] Leshchinsky B, Ling HI. Numerical modeling of behavior of railway ballasted structure with geocell confinement, J Geotextiles and Geomembranes, 2013, Vol. 36, pp. 33-43.##[22] Brown SF, Brodrick BV. 25 years\' experience with the pilot-scale nottingham pavement test facility, International Conference on Accelerated Pavement Testing Reno, Nevada, 1999, pp. 1-39.##[23] American Society for Testing and Materials Standard practice for underground installation of thermoplastic pipe for sewers and other gravity-flow applications, ASTM D 2321-08, 2008.##[24] British Standard Institute Plastics pipework (thermoplastics materials): Code of practice for the installation of unplasticized PVC pipework for gravity drains and sewers, BS 5955, 1980.##[25] Moghaddas Tafreshi SN, Tavakoli Mehrjardi Gh. The use of neural network to predict the behaviour of small plastic pipes embedded in reinforced sand and surface settlement under repeated load, Engineering Applications of Artificial Intelligence, 2008, No. 6, Vol. 21, pp. 883-894. ##[26] FLAC-3D Fast Lagrangian Analysis of Continua in Threedimensions. ITASCA Consulting Group, Inc, Minneapolis, MN, 2002.##[27] Rajagopal K, Krishanaswamy NR, Latha GM. Behaviour of sand confined with single and multiple geocells, J Geotextiles and Geomembranes, 1999, Vol. 17, pp. 171-84.##[28] Zhang MX, Zhou H, Javadi AA, Wang ZW. Experimental and theoretical investigation of strength of soil reinforced with multi-layer horizontal–vertical orthogonal elements, J Geotextiles and Geomembranes, 2008, No. 1, Vol. 26, pp. 1-13.##[29] Gotteland P, Lambert S, Balachowski L. Strength characteristics of tyre chips-sand mixtures, J Studia Geotechnica et Mechanica, 2005, Nos. 1-2, Vol. XXVII, pp. 55-66.##[30] Erickson HL, Drescher A. Bearing capacity of circular footings, J Geotechnical and Geoenvironmental Engineering, 2002, No. 1, Vol. 128, pp. 38-43.##[31] Moghaddas Tafreshi SN, Tavakoli Mehrjardi Gh, Ahmadi M. Experimental and numerical investigation on circular footing subjected to incremental cyclic loads, International Journal of Civil Engineering, IJCE, 2011, No. 4, Vol. 9, pp. 265-274.##[32] Rogers CDF, Feleming PR, Loeppky MWJ, Faragher E. The structural performance of profile-wall drainage pipe-stiffness requirements contrasted with the results of laboratory and field tests, Journal of the Transportation Research Board, 1995, Vol. 1514, pp. 83-92.##[33] Werkmeister S, Dawson AR, Wellner F. Pavement design model for unbound granular materials, Journal of Transportation Engineering, 2004, No. 5, Vol. 13, pp. 665-674.##[34] Arnold GK. Rutting of Granular Pavements, PhD Dissertation, University of Nottingham, 2004.##[35] Rodriguez AR, Castillo HD, Sowers GF. Soil Mechanics in Highway Engineering, Trans Tech Publications Inc, 1988.##[36] Garcya-Rojo R, Herrmann HJ. Shakedown of unbound granular material, J Granular Matter, 2005, No. 7, Vol. 7, pp. 109-11.##[37] Werkmeister S, Dawson AR, Wellner F. Permanent deformation behavior of unbound granular materials and the shakedown theory, Journal of the Transportation Research Board, 2001, Vol. 1757, pp. 75-81.##[38] Moser AP, Folkman S. Buried Pipe Design, McGraw-Hill Professional, 2008.##[39] American Society for Testing and Materials. Standard Specification for Poly (Vinyl Chloride) (PVC) Corrugated Sewer Pipe With a Smooth Interior and Fittings, ASTM F 949-06, 2006.##[40] American Society for Testing and Materials. Standard Specification for Type PSM Poly(Vinyl Chloride) (PVC) Sewer Pipe and Fitting, ASTM D 3034-08, 2008 s.## ##

The new empirical formula based on dynamic probing test results in fine cohesive soils 2 2 The Dynamic Probe is an effective tool used in site investigation. It is more economic than the use of direct drilling, particularly in explorations with moderate depth. This paper presents an experimental study to investigate the capability of using dynamic probing to evaluate the shear strength and compaction percent of fine soil. A series of dynamic probe tests were carried out at 6 different sites in the Khozestan, Hormozgan and Qom provinces in the central and southern regions of Iran. The repeatability of the results is considered and new empirical equations relating the dynamic point resistance to undrained shear strength and compaction percent are proposed. For undrained shear strength evaluation of fine soils, i.e. clay and silty clay soils, a reliable site-specific correlation between qd and Cu can be developed when considering the correlation between log qd and log Cu. Also compaction present can be evaluated by qd. These equations can be developed to provide site-specific relationships based upon geotechnical data at each new location. Using this approach an estimation of the undrained shear strength Cu and compaction percent CP can be determined from dynamic probe tests with acceptable accuracy. The present paper also encourages the wider application of dynamic probing for site investigation in fine soils. 105 113 2013/10/232014/07/12015/01/18 1393/10/28 2015/03/42015/06/302015/05/30 1394/3/9 M. Khodaparast M. Khodaparast Associate Profeser, Civil Engineering Department, University of Qom, Qom, Iran Iran Khodaparast@qom.ac.ir A.M. Rajabi A.M. Rajabi Associate Profeser, Civil Engineering Department, University of Qom, Qom, Iran Iran amrajabi@ymail.com M. Mohammadi M. Mohammadi Assistant Profeser, Civil Engineering Department, University of Qom, Qom, Iran Iran mostafa4p@yahoo.com Dynamic probing Repeatability Undrained shear strength Fine soil Compaction percent [1] Hvorslev MJ. Subsurface Exploration and Sampling of Soil for Civil Engineering Purposes, U.S. Waterways Experimental Station, Vicksburg, Mississippi, 1949, 521 p.##[2] Sanglerat, G. The Penetrometer and Soil Exploration. Elsevier Publishing Company, Amsterdam, the Netherlands, 1972, 464 pp. Dfl.85.00.##[3] Naeini S, Ziaie-Moayed R. Evaluation of undrained shear strength of loose silty sands using CPT results, IJCE, 2007, No. 2, Vol. 5, pp. 104-117.##[4] Jamshidi Chenari R, Pishgah Gilani P. Reliability measures for consolidation settlement by means of CPT data, IJCE, 2014, No. 2, Vol. 12, pp. 180-185.##[5] Shahnazari H, Shahin M, Tutunchian M. Evolutionary-based approaches for settlement prediction of shallow foundations on cohesionless soils, IJCE, 2014, No. 1, Vol. 12, pp. 55-64.##[6] Huntley SL. Use of dynamic penetrometer as a ground investigation and design tool in Hertfordshire, Field Testing in Engineering Geology Geological Society Engineering Geology Special Publication, 1990, No. 6, pp. 145-159.##[7] Sabtan AA, Shehata WM, Mackintosh Probe as an exploration tool, Bulletin of the International Association of Engineering Geology, Paris, 1994, No. 50, pp. 89-94.##[8] Pitts J. The use of Swedish ram sounding and weight sounding in residual soils and weathered rocks, Field Testing in Engineering Geology, Geological Society Engineering Geology Special Publication, 1990, No. 6, pp. 161-171.##[9] Spagnoli G. An empirical correlation between different dynamic penetrometers, EJGE, 2008, pp. 1-12.##[10] British Standards Institution, Code of Practice For Site Investigations,1999, BS 5930, pp. 59-60.##[11] Butcher AP, McElmeel K, Powell JJM. Dynamic probing and its use in clay soils, In Proceedings of the International Conference on Advances in Site Investigation Practice, ICE London, Thomas Telford, 1996, pp. 383-395.##[12] Cassn M. Les essays in situ en méchanique des sols, Réalisation et Interprétation, Eyrolles, 1988, Vol. 1, pp. 146-151.##[13] Langton DD. ‏‏‏‏The panda light-weight penetrometer for soil investigation and monitoring material compaction, Soil Solution Ltd, 8 Marlowe court, Macclsfield, Cheshire, SK118AY, 2000.##[14] Amor SJ, Burtwell MH, Turner AS. Panda dynamic cone penetrometer assessment, Transport Research Laboratory, Old Wokingham Road, Crowthorne, Berkshire, 1999, RG45 6AU.##[15] Rahim AM, George KP. Dynamic cone penetrometer to estimate subgrade resilient modulus for low volume roads design, Proceedings of the 2nd International Conference Geotechnical and Geophysical Site Characterization, Porto, 2004, pp. 367-371.##[16] Mohammadi SD, Nikoudel MR, Rahimi H, Khamehchiyan M. Application of the dynamic cone penetrometer (DCP) for determination of the engineering parameters of sandy soils, Journal of Engineering Geology, 2008, Vol. 101, pp. 195-203.##[17] Berazvan S, Fakhri M. Investigation of correlation between CBR, DCP and cyclic triaxial result in Qom-Semnan road, Journal of transportation, 2012, No. 1, pp. 11-21 (in Persian).##[18] Lee c, Kim KS, Woo W, Lee W. Soil stiffness gauge (SSG) and dynamic cone penetrometer (DCP) tests for estimating engineering properties of weathered sandy soils in Korea, Journal of Engineering Geology, 2014, Vol. 169, pp. 91-99.##[19] Deutsches Institut fur Normung, Dynamic and static penetrometers, Dimensions of apparatus and method of operation, DIN 4094, e. V. Berlin, 1974.##[20] ISO 22476-2, Geotechnical investigation and testing, Field testing, Part 2: Dynamic probing, Case postal 56, CH-1211 Geneva 20, 2005.##[21] Fakher A, Khodaparast M, Jones CJFP. The use of mackintosh probe for site investigation in soft soils, Q.J.E.G, 2006, No. 39, pp. 189-196.##[22] American Society of Testing Materials, Standard test method for use of the dynamic cone penetrometer in shallow pavement applications (D 6951-03), ASTM International, West Conshohocken, PA, 2003.##[23] Souloki H. Study of dispersive soil due to geological condition in Khozestan province, Postgraduate Thesis, Engineering Geology Department, Tarbiat Modarres University,( in Persian), 1998.##[24] SAHEL Consultant Engineers, Final report of Emamie Port geotechnical site investigations, 2003, (In Persian).##[25] SAHEL Consultant Engineers, Final report of Khamir Port geotechnical site investigations, 2002, (In Persian).##[26] Sahel Consultant Engineers, Final report of Emam-Khomeini Port geotechnical site investigations, 2001, (In Persian).##[27] Sahel Consultant Engineers, Final report of Mahmoudabad industrial zone geotechnical site investigations, 2005, (In Persian).##[28] Sahel Consultant Engineers, Final report of Shokouhieh industrial zone geotechnical site investigations, 2006, (In Persian).##[29] Sahel Consultant Engineers, Final report of Shahid Rajaee port geotechnical site investigations, 2004, (In Persian).##[30] Card GB, Roche DP, Herbert SM. Application of Continuous Dynamic Probing in Ground Investigation, Field testing in Engineering Geology, Geological Society Engineering Geology Special Publication, 1990, No 6, pp. 129-135.##[31] Herrick EH, Jones TL. A dynamic cone penetrometer for measuring soil penetration resistance, Soil Science Society of America Journal, 2002, Vol. 66, pp. 1320-1324.##[32] Lee IK, White W, Ingles OG. Geotechnical Engineering, Copp Clark Pitman, Inc, 1983, pp. 57-89.##[33] Khodaparast M, Fakher A. The use of dynamic probing for the investigation of fine soils and evaluation of undrained shear strength, Modarres Civil Engineering Journal, 2011, No. 2, Vol. 11, pp. 101-110.## ##

Centrifuge modeling of non-connected piled raft system 2 2 In present research, 17 centrifuge tests have been conducted to study the effect of various parameters such as the number of piles, the distance between piles, gradation and thickness of the granular layer on the load-settlement behavior of a pile raft system. The results showed the importance of granular layer to reduce the settlement of non-connected pile raft system when the roles of piles are to reduce the settlement. In other words when the piles have major contribution on the bearing capacity of pile raft system, presence of a granular layer may increase the settlement. 114 123 2013/10/232014/07/12015/01/182015/02/12 1393/11/23 2015/03/42015/06/302015/05/302015/07/6 1394/4/15 A. Saeedi Azizkandi A. Saeedi Azizkandi Assistant Professor, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran asaeedia@yahoo.com M.H. Baziar M.H. Baziar Professor, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran baziar@iust.ac.ir H. Rasouli H. Rasouli MSc. Student, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran Rasouli.habib@gmail.com M. Modarresi M. Modarresi MSc. Student, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran modarresi@civileng.iust.ac.ir H. Shahnazari H. Shahnazari Associate Professor, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran hshahnazari@iust.ac.ir Piled raft foundation Non-connected piled raft Load-settlement behavior and settlement reduction. [1] Davis E, Poulos H. The analysis of pile raft systems, Australian Geomechanics Journal, 1972, No. 1, Vol. 62, pp. 21-27.##[2] Burland J, BB B, De Mello VFB. Behavior of foundations and structures, Proceeding 13th International Conference on Soil Mechanics and Foundation Engineering, 1977, Tokyo, pp. 495-546.##[3] Hansbo S. Foundations on friction creep piles in soft clays, International Conference on Case Histories in Geotechnical Engineering, St. Louis, Prakash, 011-922.##[4] Horikoshi K, Randolph M. A contribution to optimum design of piled rafts, Geotechnique, 1998, No. 3, Vol. 48, pp. 301-317.##[5] Viggiani C. Analysis and design of piled foundations, 1st Arrigo Croce Lecture, Rivista Italiana di Geotecnica, 2001, No. 1, Vol. 35, pp. 47-75.##[6] Poulos H. Piled raft foundations: design and applications, Geotechnique, 2001, No. 2, Vol. 51, pp. 95-113.##[7] Russo G, Viggiani C. Factors controlling soil-structure interaction for piled rafts, Proceedings of the International Conference on Soil-Structure Interaction in Urban Civil Engineering, Darmstadt, 1998, pp. 79-102.##[8] Mandolini A. Design of piled raft foundations: practice and development, Proceedings of Deep Foundations on Bored and Auger Piles–BAP IV, Ghent, Belgium, 2003, pp. 2-4.##[9] Randolph M, Jamiolkowski M, Zdravkovic L. Load carrying capacity of foundations, Proceedings of the Skempton Memorial Conference, London, 2004, pp. 207-240.##[10] Clancy P, Randolph M. An approximate analysis procedure for piled raft foundations, International Journal for Numerical and Analytical Methods in Geomechanics, 1993, No. 12, Vol. 17, pp. 849-869.##[11] Haghbin M. Study on behavior of soil reinforcing pile in piled raft systems, International Journal of Civil Engineering, 2014, No. 4, Vol. 12, pp. 304-315.##[12] Wong I, Chang M, Cao X. 17. Raft foundations with disconnected, Design Applications of Raft Foundations, 2000, pp. 469.##[13] Giretti D. Modelling of piled raft foundations in sand: Università degli Studi di Ferrara, 2010.##[14] Liang FY, Chen LZ, Shi XG. Numerical analysis of composite piled raft with cushion subjected to vertical load, Computers and Geotechnics, 2003, No. 6, Vol. 30, pp. 443-453.##[15] Oh EYN, Huang M, Surarak C, Adamec R, Balasurbamaniam A. Finite element modelling for piled raft foundation in sand, Eleventh East Asia-Pacific Conference on Structural Engineering & Construction (EASEC-11)“Building a Sustainable Environment”, Taipei, Taiwan, 2008.##[16] Eslami A, Veiskarami M, Eslami M. Study on optimized piled-raft foundations (PRF) performance with connected and non-connected piles-three case histories, International Journal of Civil Engineering, 2012, No. 2, Vol. 10, pp. 100-111.##[17] Sharma V, Vasanvala S, Solanki C. Effect of cushion on composite piled–raft foundation, Journal of Engineering Research and Studies, 2011, Vol. 2.##[18] Cao XD, Wong IH, Chang MF. Behavior of model rafts resting on pile-reinforced sand, Journal of Geotechnical and Geoenvironmental Engineering, 2004, No. 2, Vol. 130, pp. 129-138.##[19] El Sawwaf M. Experimental study of eccentrically loaded raft with connected and unconnected short piles, Journal of Geotechnical and Geoenvironmental Engineering, 2010, No. 10, Vol. 136, pp. 1394-1402.##[20] Fioravante V, Giretti D. Contact versus noncontact piled raft foundations, Canadian Geotechnical Journal, 2010, No. 11, Vol. 47, pp. 1271-1287.##[21] Zhang H, Shi ML. Mechanical performance of settlement-reducing pile foundation with cushion, Advanced Materials Research, 2012, Vol. 368, pp. 2545-2549.##[22] Craig W. Centrifuge modelling for site-specific prototypes, Publication of: Balkema (AA), 1985.##[23] Bolton M, Gui M, Garnier J, Cooke R, Bagge G, Laue J, et al. Centrifuge cone penetration tests in sand, Geotechnique, 1999, No. 4, Vol. 49, pp. 543-552.##[24] Gui M, Bolton M. Geometry and scale effects in CPT and pile design, Geotechnical site characterization Edited by PK Robertson and PW Mayne Balkema, Rotterdam, 1998, pp. 1063-1068.##[25] Gui M, Bolton M, Garnier J, Corte J, Bagge G, Laue J, et al. Guidelines for cone penetration tests in sand, Centrifuge, 1998, pp. 155-160.##[26] Shahnazari H, Salehzade H, Askarinejad A. Determination of virtual cohesion in unsaturated sand trenches, using geotechnical centrifuge, International Journal of Civil Engineering, 2008, No. 1, Vol. 6, pp. 1-9.##[27] Azizkandi AS, Baziar M, Modarresi M, Salehzadeh H, Rasouli H. Centrifuge modeling of pile-soil-pile interaction considering relative density and toe condition, Scientia Iranica, 2014, No. 4, Vol. 21, pp. 1330-1339.##[28] Mostefa Kara E, Meghachou M, Aboubekr N. Contribution of particles size ranges to sand friction, Engineering, Technology & Applied Science Research, 2013, No. 4, Vol. 3, pp. 497-501.## ##

A new seismic isolation system: sleeved-pile with soil-rubber mixture 2 2 To increase the safety of structures against strong ground motions and their life due to environmental issues on the earth and saving in terms of materials, it is necessary to expand and upgrade seismic resistant systems. However, more cost-effective systems which have sufficient influence on the seismic performance of structures and also more compatibility with the regional conditions, will be more desirable than other systems. One of the seismic resistance systems is seismic isolation. In the event of interest in using the seismic isolation system for a mounted building on piles, the costly construction of piles and isolation equipment shall be provided simultaneously. The seismic isolating using sleeved-piles which is generally used in combination with various damper systems, can help to overcome this issue. In this research a seismic isolator system using sleeved-pile has been studied while considering the damping behavior of the soil-rubber mixture as the only source of damping. To investigate the proposed system, a series of tests including static lateral load test, dynamic free and forced vibration tests, were performed on a model pile in a field laboratory which has been constructed for this purpose. According to results of tests the proposed system has a good deformation ability and damping characteristics, and as a method of seismic isolation is completely efficient. 124 132 2013/10/232014/07/12015/01/182015/02/122014/08/26 1393/6/4 2015/03/42015/06/302015/05/302015/07/62015/07/6 1394/4/15 A. Komak Panah A. Komak Panah Associated Professor of Civil Engineering Department, Tarbiat Modarres University, Tehran, Iran, P.O.Box 14115/143 a-panah@modares.ac.ir A.H. Khoshay A.H. Khoshay PhD Student of Civil Engineering Department, Tarbiat Modarres University, Tehran, Iran, P.O.Box 14115/143 khoshay@modares.ac.ir Seismic isolation Sleeved pile Soil-rubber Mixture [1] Kelly JM, Naeim F. Design of Seismic Isolated Structures: From Theory to Practice, John Wiley & Sons: New York, 1999.##[2] Boardman PR., Wood BJ, Carr AJ. :union: house-a crossbraced structure with energy dissipators, Bulletin of the New Zealand National Society for Earthquake Engineering, 1983, No. 2, Vol. 16, pp. 83-97.##[3] Charleson AW, Wright PD, Skinner RI. Wellington central police station, base isolation of an essential facility, Proceedings of the Pacific Conf on Earthquake Engineering, New Zealand National Society for Earthquake Engineering, New Zealand, 1987, Vol. 2, pp. 377-388.##[4] Robinson WH, Greenbank LR. An extrusion energy absorber suitable for the protection of structures during an earthquake, Bulletin of the New Zealand National Society for Earthquake Engineering, 1975, No. 3, Vol. 8, pp. 187-191.##[5] Ishimaru Sh, Niiya T, Morikawa K, Uotsu T, Yamazaki S, Yoshida A. A Feasibility Study for Seismic Isolation by Use of a Soil-Pole-Structure System. Part1: Fundamental Concept and Results of Static Load Tests, 1999.##[6] Ishimaru Sh, Hata I, Shimomura Y, Ikeda Y, Ishigaki H, Ogushi Y. A feasibilty study of new type seismic isolation - composed system of piles covered by pipes and dampers with partial soil improvement, 13th World Conference on Earthquake Engineering , Canada, 2004.##[7] Kramer SL. Geotechnical Earthquake Engineering, Charter 6: Dynamic Soil Properties, Prentice-Hall: New Jersey, 1996.##[8] Kokusho T, Yoshida Y, Esashi Y. Dynamic properties of soft clay for wide strain range, Soils and Foundations, 1982, No. 4, Vol. 22, pp. 1-18.##[9] Dobry R, Vucetic M. Dynamic properties and seismic response of soft clay deposits, Proceedings, International Symposium on Geo technical Engineering of Soft Soils, Mexico City, 1987, Vol. 2, pp. 51-87.##[10] Sun JI, Golesorkhi R, Seed HB. Dynamic moduli and damping ratios for cohesive soils, Report No. EERC-88/15, Earthquake Engineering Research Center, University Of California, Berkeley, 1988.##[11] Mahmoudi M, Komakpanah A. Investigation on the cyclic parameters of soil-rubber mixed material for using in seismic isolation of structures, Thesis Submitted in Partial Fulfillment of the Requirements of the Degree of M. Sc, Tarbiat Modares University, 2012.##[12] Chopra AK. Dynamics of Structures: theory and applications to earthquake engineering, Prentice-Hall: New Jersey, 1995.##[13] Shimomura Y, Ohshima K, Ishimaru Sh, Niiya T. A Feasibility Study for Seismic Isolation by Use fo a Soil-Pile-Structure System. Part3: An Analytical Investigation in Consideration of Dynamic Soil-Structure Interaction, 1999.##[14] Boardman PR, Wood BJ, Carr AJ. :union: house - a cross braced structure with energy dissipators, Bulletin of the New Zealand National Society for Earthquake Engineering, 1983, No. 2, Vol. 16, pp. 83-97.## ##

A generalized plasticity constitutive model for sand-gravel mixtures 2 2 This paper presents a model for prediction of the mechanical behavior of sand-gravel mixtures using generalized plasticity and critical state concepts. Proposed model is based on the difference between critical state lines of sand and sand-gravel mixture in e-Lnp' plane. A generalized plasticity model is considered as the base model for sandy soil. Its state parameter, dilation rate and hardening function are modified to involve the effects of gravel particles on the behavior of mixture. Gravel content is considered as a physical parameter for determination of four new added parameters of the model. Verification of the proposed model performed considering four sets of experiments conducted by different researchers on poorly graded sand-gravel mixtures. According to the results, proposed model provides satisfactory qualitative and quantitative predictions of the behavior of sand-gravel mixture. Stress- strain behavior besides volumetric strains in drained condition and induced pore pressure during undrained loading are satisfactory predicted which indicates the possibility of its application in boundary value problems of geotechnical engineering. 133 145 2013/10/232014/07/12015/01/182015/02/122014/08/262015/05/4 1394/2/14 2015/03/42015/06/302015/05/302015/07/62015/07/62015/08/23 1394/6/1 Mehdi Goorani Mehdi Goorani Graduate Student, Kharazmi University, Tehran, Iran mehdicvl@gmail.com Amir Hamidi Amir Hamidi Associate Professor, School of Engineering, Kharazmi University, P.O.Box 15614, Tehran, Iran hamidi@khu.ac.ir Constitutive modeling Sand-gravel mixture Generalized plasticity Critical state Deviatoric stress Volume change. [1] Fragaszy RJ, Su J, Siddiqi FH, Ho CL. Modeling strength of sandy gravel, Journal of Geotechnical Engineering, ASCE, 1992, No. 6, Vol. 118, pp. 920-935.##[2] Evans MD, Zhou S. Liquefaction behavior of sand-gravel composites, Journal of Geotechnical Engineering, ASCE, 1995, No. 3, Vol. 121, pp. 287-298.##[3] Kokusho T, Hara T, Hiraoka R. Undrained shear strength of granular soils with different particle gradations, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2004, No. 6, Vol. 130, pp. 621-629.##[4] Flora A, Lirer S, Silvestri F. Undrained cyclic resistance of undisturbed gravelly soils, Soil Dynamics and Earthquake Engineering, 2012, Vol. 43, pp. 366-379.##[5] Choi C, Arduino P. Behavioral characteristics of gravelly soils under general cyclic loading conditions, International Conference on Cyclic Behavior of Soils and Liquefaction Phenomena, Bochum, Germany, 2004.##[6] Yagiz S. Brief note on the influence of shape and percentage of gravel on the shear strength of sand and gravel mixture, Bulletin of Engineering Geology and the Environment, 2001, No. 4, Vol. 60, pp. 321-323.##[7] Vallejo LE. Interpretation of the limits in shear strength in binary granular mixtures, Canadian Geotechnical Journal, 2001, No. 5, Vol. 38, pp. 1097-1104.##[8] Kuenza K, Towhata I, Orense RP, Wassan TH. Undrained torsional shear tests on gravelly soils, Landslides, 2004, No. 3, No. 1, pp. 185-194.##[9] Hosseini SM, Haeri SM, Toll DG. Behavior of gravely sand using critical state concepts, Scientia Iranica, 2005, No. 2, Vol. 12, pp. 167-177.##[10] Bolton MD. The strength and dilatancy of sands, Géotechnique, 1986, No. 1, Vol. 36, pp. 65-78.##[11] Simoni A, Houlsby GT. The direct shear strength and dilatancy of sand-gravel mixtures, Geotechnical and Geological Engineering Journal, 2006, No. 3, Vol. 24, pp. 523-549.##[12] Verdugo R, De la Hoz K. Caracterización geomecánica de suelos granulares gruesos, Revista Internacional de Desastres Naturales, Accidentes e Infraestructura Civil, 2006, No. 2, Vol. 6, pp. 199-213.##[13] Verdugo R, De la Hoz K. Strength and stiffness of coarse granular soils, Solid Mechanics and Its Applications, 2007, No. 3, Vol. 146, pp. 243-252.##[14] Seif el dine B, Dupla JC, Frank R, Canou J, Kazan Y. Mechanical characterization of matrix coarse-grained soils with a large size triaxial device, Canadian Geotechnical Journal, 2010, No. 4, Vol. 47, pp. 425-438.##[15] Hamidi A, Yazdanjou V, Salimi N. Shear strength characteristics of sand-gravel mixtures, International Journal of Geotechnical Engineering, 2009, No. 1, Vol. 3, pp. 29-38.##[16] Hamidi A, Alizadeh M, Soleimani SN. Effect of particle crushing on shear strength and dilation characteristics of sand-gravel mixtures, International Journal of Civil Engineering, 2009, No. 1, Vol. 7, pp. 61-71.##[17] Hamidi A, Salimi N, Yazdanjou V. Shape and size effects of gravel particles on shear strength characteristics of sandy soils, Scientific Quarterly Journal of GeoSciences, 2011, No. 80, Vol. 20, pp. 189-196.##[18] Hamidi A, Azini E, Masoudi B. Impact of gradation on the shear strength-dilation behavior of well graded sand-gravel mixtures, Scientia Iranica, 2012, No. 3, Vol. 19, pp. 393-402.##[19] Soroush A, Jannatiaghdam R. Behavior of rockfill materials in triaxial compression testing, International Journal of Civil Engineering, 2012, No. 2, Vol. 10, pp. 153-161.##[20] Heidarzadeh M, Mirghasemi AA, Sadr Lahijani SM. Application of cement grouting for stabilization of coarse materials, International Journal of Civil Engineering, 2013, No. 1, Vol. 11, pp. 71-77.##[21] Khan MA. A CBR based study evaluating subgrade strength of flexible pavements having soil flyash interfaces, International Journal of Civil Engineering, 2013, No. 1, Vol. 11, pp. 10-18.##[22] Heshmati AA, Tabibnejad AR, Salehzadeh H, Hashemi Tabatabaei S. Experimental evaluation of collapse deformation behavior of rockfill material, International Journal of Civil Engineering, 2015, No. 2, Vol. 13, pp. 40-53.##[23] Salim W, Indraratna B. A new elastoplastic constitutive model for coarse granular aggregates incorporating particle breakage, Canadian Geotechnical Journal, 2004, No. 4, Vol. 41, pp. 657-671.##[24] Chu BL, Jou YW, Weng MC. A constitutive model for gravelly soils considering shear-induced volumetric deformation, Canadian Geotechnical Journal, 2010, No. 6, Vol. 47, pp. 662-673.##[25] Daouadji A, Hicher PY. An enhanced constitutive model for crushable granular materials, International Journal for Numerical and Analytical Methods in Geomechanics, 2010, No. 6, Vol. 34, pp. 555-580.##[26] Xiao Y, Liu HL, Zhu JG. A 3D bounding surface model for rockfill materials, Science China Technological Sciences, 2011, No. 11, Vol. 54, pp. 2904-2915.##[27] Pastor M, Zienkiewicz OC, Chan AHC. Generalized plasticity and the modeling of soil behavior, International Journal for Numerical and Analytical Methods in Geomechanics, 1990, No. 3, Vol. 14, pp. 151-190.##[28] Zienkiewics OC, Mroz Z. Generalized plasticity formulation and application to geomechanics, Mechanics of Engineering Materials, 1984, No. 2, Vol. 44, pp. 655-679.##[29] Ling HI, Liu H. Pressure level dependency and densification behavior of sand through the generalized plasticity model, Journal of Engineering Mechanics, 2003, No. 8, Vol. 129, pp. 851-860.##[30] Ling HI, Yang S. A unified sand model based on critical state and generalized plasticity, Journal of Engineering Mechanics, 2006, No. 12, Vol. 132, pp. 1380-1391.##[31] Santaguliana R, Schrefler BA. Enhancing the Bolzon-Schrefler-Zienkiewicz constitutive model for partially saturated soil, Transport in Porous Media, 2006, Vol. 65, pp. 1-30.##[32] Lashkari A, Latifi M. A constitutive model for sand liquefaction under continuous rotation of principal stress axes, Mechanics Research Communications, 2009, Vol. 36, pp. 215-223.##[33] Liu H, Ling HI. Constitutive description of interface behavior including cyclic loading and particle breakage within the framework of critical state soil mechanics, International Journal for Numerical and Analytical Methods in Geomechanics, 2008, No. 12, Vol. 32, pp. 1495-1514.##[34] Lashkari A. Modeling of sand-structure interfaces under rotational shear, Mechanics Research Communications, 2010, Vol. 37, pp. 32-37.##[35] Weng MC, Ling HI. Modeling the behavior of sandstone based on generalized plasticity concept, International Journal for Numerical and Analytical Methods in Geomechanics, 2013, Vol. 37, pp. 2154-2169.##[36] Manzanal D, Merodo JAF, Pastor M. Generalized plasticity state parameter-based model for saturated and unsaturated soils: Saturated state, International Journal for Numerical and Analytical Methods in Geomechanics, 2011, No. 12, Vol. 35, pp. 1347-1362.##[37] Been K, Jefferies MG. A state parameter for sands, Geotechnique, 1985, No. 2, Vol. 35, pp. 99-112.##[38] Li XS, Wang Y. Linear representation of steady-state line for sand, Journal of Geotechnical and Geoenvironmental Engineering, 1998, No. 12, Vol. 124, pp. 1215-1217.## ##

Settlement analysis considerng sand mat induced initial settlement in soft ground improved by PBD 2 2 The ground improvement using Plastic Board Drain (PBD) in soft soil was undertaken by sand mat formation, PBD installation, preloading surcharge, and removal of surcharge. During this procedure, the sand mat formation induced an initial settlement. However, it was very difficult to estimate that settlement due to PBD installation, which frequently destroyed the instruments installed in the ground. Consequently, the initial settlement was not properly included in total settlement. In this study, the initial settlement was estimated using ground level measurement and cone penetration test. Both predicted almost the same amount of initial settlement. The initial settlement is linearly increased with the depth of the sand mat. The degree of consolidation and the time of surcharge removal were estimated using the settlement included the initial settlement. Correct estimation of initial settlement is very important because it is a critical factor, which affects total settlement and the time of surcharge removal. If the initial settlement is not considered, the preloading surcharge may be overloaded or the time of surcharge removal may be predicted incorrectly. Consequently, the prediction of settlement, which requires to management of construction procedure of the project, may be wrong 146 152 2013/10/232014/07/12015/01/182015/02/122014/08/262015/05/42013/10/29 1392/8/7 2015/03/42015/06/302015/05/302015/07/62015/07/62015/08/232015/05/30 1394/3/9 T.H. Kim T.H. Kim Professor, Department of Civil Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-Gu, Busan 606-791, KOREA kth67399@kmou.ac.kr S.H. You S.H. You Director, Geotechnical Research & Development Co., Ltd., Korea soilno1tech@naver.com Initial settlement Sand mat Prediction settlement Time of surcharge removal Plastic board drain (PBD) [1] Barron RA. Consolidation of fine-grained soils by drain wells, Trans ASCE, 1948, Vol. 113, pp. 718-748.##[2] Hansbo S. Consolidation of clay by band-shaped prefabricated drains, Ground Engineering, 1979, No. 2, Vol. 12, pp. 16-25. ##[3] Hansbo S. Consolidation by vertical drains, Geotechnique, 1981, No. 5, Vol. 31, pp. 45-66. ##[4] Yoshikuni H, Nakanodo H. Consolidation of soils by vertical drain wells with finite permeability, Soils and Foundation, 1974, No. 2, Vol. 14, pp. 35-46. ##[5] Onoue A. Consolidation of multilayered anisotropic soils by vertical drains with well resistance, Soils and Foundations, 1988a, No. 4, Vol. 28, pp. 75-90. ##[6] Onoue A. Consolidation by vertical drains taking well resistance and smear into consideration, Soils and Foundations, 1988b, No. 4, Vol. 28, pp. 165-174. ##[7] Zeng GX, Xie KH. New development of the vertical drain theories, Proceedings of the 12th International Conference on Soil Mechanics and Foundation Engineering Rio de Janeiro, Brazil, 1989, Vol. 2, pp. 1435-1438.##[8] Holts RD, Jamiolkowski M, Lancellotta R, Perroni S. Behavior of bent prefabricated vertical drains, Proceedings of the 12th ICSMFE, 1989, pp. 13.##[9] Chai JC, Miura N. Investigation on some factors affecting vertical drain behavior, Journal of Geotechnical and Geoenvironmental Engineering, 1999, No. 3, Vol. 125, pp. 216.##[10] Kiyama M, Oshima A, Kusakabe F, Harada K. The new accelerated consolidation method combining the dewatering and plastic-board-drain by floating system (PDF) methods, Proceedings of the Soft Ground Technology Conference sponsored by the United Engineering Foundation, the Geo-Institute of the American Society of Civil Engineers, May 28-June 2, Noordwijkerhout, the Netherlands, 2000, pp. 246-258 ##[11] Kim DW, Lee SY, Cho KS, Seo MH, Kim H. Evaluation of discharge capacity of plastic board drain in simulated service situation, Polymer testing, 2006, No. 8, Vol. 25, pp. 986-993.##[12] Basu D, Prezzi M. Effect of the smear and transition zones around prefabricated vertical drains Installed in a triangular pattern on the rate of soil consolidation, International Journal of Geomechanics, 2007, No. 1, Vol. 7, pp. 34-43.##[13] Yoshikuni H, Nakanodo H. Consolidation of fine-grained soils by prefabricated drain, Proceedings of the 10th ICSMFE, Stockholm, 1981, Vol. 3, pp. 677-682. ##[14] Tan SA, Chew SH. Comparison of the hyperbolic and Asaoka observational method of monitoring consolidation with vertical drains. Soils and Foundations, Japanese Geotechnical Society, 1996, No. 3, Vol. 36, pp. 31-42.##[15] Chu J, Bo MW, Choa V. Practical considerations for using vertical drains in soil improvement projects, Geotextiles and Geomembranes, 2004, Vol. 22, pp. 101-117.##[16] Robertson PK, Campanella RG. Interpretation of cone penetration tests, Parts 1 and 2, Canadian Geotechnical Journal, 1983, Vol. 20, pp. 718-745.## ##