RESIDUAL DEFORMATION OF GEOSYNTHETIC-REINFORCED SAND IN PLANE STRAIN COMPRESSION AFFECTED BY VISCOUS PROPERTIES OF GEOSYNTHETIC REINFORCEMENT

A series of plane strain compression (PSC) tests were performed on large sand specimens unreinforced or reinforced with prototype geosynthetic reinforcements, either of two geogrid types and one geocomposite type. Local tensile strains in the reinforcement were measured by using two types of strain gauges. Sustained loading (SL) under fixed boundary stress conditions and cyclic loading (CL) tests were performed during otherwise monotonic loading at a constant strain rate to evaluate the development of creep deformation by SL and residual deformation by CL of geosynthetic-reinforced sand and also residual strains in the reinforcement by these loading histories. It is shown that the creep deformation of geosynthetic-reinforced sand develops due to the viscous properties of both sand and geosynthetic reinforcement, while the residual deformation of geosynthetic-reinforced sand during CL (defined at the peak stress state during CL) consists of two components: i) the one by the viscous properties of sand and reinforcement; and ii) the other by rate-independent cyclic loading effects with sand. The development of residual deformation of geosynthetic-reinforced sand by SL and CL histories had no negative effects on the subsequent stress-strain behaviour and the compressive strength was maintained as the original value or even became larger by such SL and CL histories. The local tensile strains in the geosynthetic reinforcement arranged in the sand specimen subjected to SL decreased noticeably with time, due mainly to lateral compressive creep strains in sand during SL of geosynthetic-reinforced sand. This result indicates that, with geosynthetic-reinforced soil structures designed to have a sufficiently high safety factor under static loading conditions because of seismic design, it is overly conservative to assume that the tensile load in the geosynthetic reinforcement is maintained constant for long life time. Moreover, during CL of geosynthetic-reinforced sand, the residual tensile strains in the geosynthetic reinforcement did not increase like global strains in the geosynthetic-reinforced sand that increased significantly during CL. These different trends of behaviour were also due to the creep compressive strains in the lateral direction of sand that developed during CL of geosynthetic-reinforced sand.

[1]  Fumio Tatsuoka,et al.  A theoretical framework to analyse the behaviour of polymer geosynthetic reinforcement in temperature-accelerated creep tests , 2007 .

[2]  Fumio Tatsuoka.  Inelastic Deformation Characteristics of Geomaterial , 2007 .

[3]  Masanori Ishihara,et al.  Time-Dependent Shear Deformation Characteristics of Geomaterials and their Simulation , 2002 .

[4]  Fumio Tatsuoka,et al.  VISCOUS BEHAVIOUR OF GEOGRIDS; EXPERIMENT AND SIMULATION , 2007 .

[5]  Fumio Tatsuoka,et al.  Effects of Geosynthetic Reinforcement Type on the Strength and Stiffness of Reinforced Sand in Plane Strain Compression , 2007 .

[6]  H. Di Benedetto,et al.  Viscous behaviour of dry sand , 2007 .

[7]  Warat Kongkitkul.  Effects of material viscous properties on the residual deformation of geosynthetic-reinforced sand , 2004 .

[8]  H. S. Roh,et al.  Effects of Preloading and Prestressing on the Strength and Stiffness of Geosynthetic Reinforced Clay in Plane Strain Compression , 2001 .

[9]  Fumio Tatsuoka,et al.  RATE-DEPENDENT LOAD-STRAIN BEHAVIOUR OF GEOGRID ARRANGED IN SAND UNDER PLANE STRAIN COMPRESSION , 2007 .

[10]  Richard J. Bathurst,et al.  In-Isolation Cyclic Load-Extension Behavior of Two Geogrids , 1994 .

[11]  太郎 内村.  Seismic Stability Against High Seismic Loads of Geosynthetic-Reinforced Soil Retaining Structures , 1998 .

[12]  Kimitoshi Hayano,et al.  Some new aspects of time effects on the stress-strain behaviour of stiff geomaterials , 2000 .

[13]  Taro Uchimura,et al.  Viscous deformation of geosynthetic reinforcement under cyclic loading conditions and its model simulation , 2004 .

[14]  Fumio Tatsuoka,et al.  VARIOUS VISCOSITY TYPES OF GEOMATERIALS IN SHEAR AND THEIR MATHEMATICAL EXPRESSION , 2008 .

[15]  Fumio Tatsuoka,et al.  TIME-DEPENDENT SHEAR DEFORMATION CHARACTERISTICS OF SAND AND THEIR CONSTITUTIVE MODELLING , 2002 .

[16]  Taro Uchimura,et al.  Geosynthetic-Reinforced Soil Retaining Walls as Important Permanent Structures 1996 - 1997 Mercer Lecture , 1997 .

[18]  Fumio Tatsuoka,et al.  Creep rupture curve for simultaneous creep deformation and degradation of geosynthetic reinforcement , 2007 .

[19]  Fumio Tatsuoka,et al.  MODELLING AND SIMULATION OF RATE-DEPENDENT STRESS-STRAIN BEHAVIOUR OF GRANULAR MATERIALS IN SHEAR , 2008 .

[20]  Taro Uchimura,et al.  Time-dependent deformation characteristics of stiff geomaterials in engineering practice , 1999 .

[21]  Taro Uchimura,et al.  Time-dependent stress–strain behaviour due to viscous properties of geogrid reinforcement , 2003 .

[22]  Fumio Tatsuoka,et al.  PLANE STRAIN COMPRESSION BEHAVIOUR OF GEOGRID-REINFORCED SAND AND ITS NUMERICAL ANALYSIS , 2000 .

[23]  F. Tatsuoka,et al.  VISCOUS BEHAVIOUR OF UNBOUND GRANULAR MATERIALS IN DIRECT SHEAR , 2008 .

[24]  F. Tatsuoka,et al.  QUALITY OF THE LUBRICATION LAYER USED IN ELEMENT TESTS ON GRANULAR MATERIALS , 1993 .

[25]  Kenichi Matsushima,et al.  Remedial treatment of soil structures using geosynthetic-reinforcing technology , 2007 .

[26]  Fumio Tatsuoka,et al.  A reinforcing method for steep clay slopes using a non-woven geotextile , 1986 .

[27]  F. Tatsuoka,et al.  Viscous Effects on the Stress-Strain Behavior of Gravelly Soil in Drained Triaxial Compression , 2006 .

[28]  F. Tatsuoka.  Seismic stability against high seismic loads of geosynthetic-reinforced soil retaining structures, Keynote Lecture , 1998 .

[29]  Richard J. Bathurst,et al.  Short-Term Strain and Deformation Behavior of Geosynthetic Walls at Working Stress Conditions , 2002 .

[30]  Fumio Tatsuoka,et al.  Time effects on the behaviour of geomaterials , 2005 .

[31]  Dov Leshchinsky,et al.  Creep and Stress Relaxation of Geogrids , 1997 .

[32]  Fumio Tatsuoka,et al.  VISCOUS PROPERTY OF LOOSE SAND IN TRIAXIAL COMPRESSION, EXTENSION AND CYCLIC LOADING , 2006 .

[33]  Richard J. Bathurst,et al.  Strain Measurement of Geogrids Using a Video-Extensometer Technique , 2004 .

[34]  Fumio Tatsuoka,et al.  PERFORMANCE OF ANISOTROPIC GEOSYNTHETIC-REINFORCED COHESIVE SOIL MASS , 1994 .

[35]  Fumio Tatsuoka.  Effects of Viscous Properties and Ageing on the Stress-Strain Behaviour of Geomaterials , 2005 .

[36]  S. Emerson,et al.  AASHTO (American Association of State Highway and Transportation Officials). 2001. A Policy on Geometric Design of Highways and Streets. Fourth Edition. Washington, D.C. , 2007 .