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WO1991018150A1 - Elements et procedes servant a renforcer le sol ou materiaux similaires - Google Patents

Elements et procedes servant a renforcer le sol ou materiaux similaires Download PDF

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Publication number
WO1991018150A1
WO1991018150A1 PCT/US1991/003355 US9103355W WO9118150A1 WO 1991018150 A1 WO1991018150 A1 WO 1991018150A1 US 9103355 W US9103355 W US 9103355W WO 9118150 A1 WO9118150 A1 WO 9118150A1
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WO
WIPO (PCT)
Prior art keywords
soil
arms
elements
hub
reinforcing element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1991/003355
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English (en)
Inventor
Nathaniel Sill Fox
Evert C. Lawton
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Individual
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Individual
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Filing date
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Application filed by Individual filed Critical Individual
Publication of WO1991018150A1 publication Critical patent/WO1991018150A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
    • E02D3/02—Improving by compacting
    • E02D3/08—Improving by compacting by inserting stones or lost bodies, e.g. compaction piles

Definitions

  • This invention relates generally to a composite construction engineering material consisting of structural reinforcing elements of discontinuous, non-fibrous configuration, i.e., three-dimensional structural reinforcing elements rather than slender, threadlike structures (or combinations of threadlike structures) .
  • This composite construction engineering material can be constructed to possess enhanced engineering properties, as well as improved index properties, as compared to the unreinforced matrix material.
  • This invention relates also to elements of a composite construction engineering material, with improved characteristics. It further relates to methods to incorporate these special structural reinforcing elements into an artificial construction material or to form an essentially artificial construction material.
  • the projected primary application of this invention relates to the improvement, reinforcement, enhancement, and/or stabilization of soil or soil-like materials in geotechnical engineering applications.
  • additional applications include, but are not necessarily limited to, the improvement, reinforcement, enhancement, and/or stabilization of other construction materials such as, but not limited to, Portland cement, concrete, asphalt, lime, stone, slag, or any mixture or combination of these materials with or without soil.
  • other construction materials such as, but not limited to, Portland cement, concrete, asphalt, lime, stone, slag, or any mixture or combination of these materials with or without soil.
  • the present invention improves these characteristics by producing a composite (reinforced) geotechnical engineering material or an artificial soil material, which can increase the strength, decrease the compressibility, increase the ductility, increase the permeability, decrease the weight, and increase the constructibility (compactibility) in comparison with unreinforced soil.
  • a composite (reinforced) geotechnical engineering material or an artificial soil material which can increase the strength, decrease the compressibility, increase the ductility, increase the permeability, decrease the weight, and increase the constructibility (compactibility) in comparison with unreinforced soil.
  • These improvements can be achieved without the use of continuous reinforcement elements (commonly called geotextiles or geofabrics) or without the use of additive fibers.
  • Soil reinforcement in the form of stabilizing or improving soil characteristics for construction purposes is not a new concept.
  • Chemical stabilization by introducing hydrated lime or quicklime into a soil was utilized two thousand years ago. Introduction of sticks, tree parts, or straw to soils to improve soil properties was practiced by ancient peoples on a number of continents. However, manufactured products introduced into a soil matrix to enhance its properties are a relatively recent innovation.
  • the impetus to this industry was provided by the introduction of flat, thin strips of reinforcing materials to a soil backfill. The strips were constructed of galvanized steel, and later synthetic materials such as polypropylene have been used. These strips were placed horizontally between lifts of soil backfill. The most common use of the invention was to improve retaining wall design and performance.
  • thermoplastic grids are generally constructed of thermoplastics or polyesters. They are utilized as continuous sheets, normally placed horizontally or near horizontally between lifts of soil. The primary purposes of these reinforcing sheets are to improve the bearing capacity of the soil and to reduce lateral soil pressures against retaining walls or to increase stability within sloped embankments.
  • a primary objective of the present invention is to produce a composite geotechnical engineering material with improved engineering characteristics and index properties, which can be controlled in both the laboratory and in the field environments so that improvements will be verifiable, significant, practicable, and predictable. Furthermore, an objective of the present invention is to provide several different methods of introducing the structural reinforcing elements into the soil to construct an improved composite geotechnical engineering material. Another objective of the present invention is to provide several different methods of introducing the structural reinforcing elements into the soil to construct an improved composite geotechnical engineering material.
  • Another objective of the present invention is to provide synthetic, non-fibrous reinforcing elements by themselves, or essentially by themselves, as an artificial soil for certain geotechnical applications- Important features of these non-fibrous, discontinuous structural reinforcing elements include the following: 1. Designed resistance to shear displacement and deformations, including resistance to pull-out, resistance to rolling and resistance to sliding by interlocking. 2. Ease of mixing the structural reinforcing elements with the soil, by virtue of its three dimensional configuration rather than a fiber-like configuration.
  • Figure 1A is a partial side elevational view of a section of soil or other material, illustrating the present structural reinforcing elements in random orientation
  • Figure IB is a partial side elevational view illustrating the placement of the present reinforcing elements in a layered configuration
  • Figure 2A is a perspective view of a first embodiment of the present invention
  • Figure 2B is a perspective view of an alternate embodiment of the present invention.
  • Figure 2C is a perspective view of another alternate embodiment of the present invention.
  • Figure 3A is an enlarged perspective view of a first embodiment of the surface of the reinforcing element;
  • Figure 3B is an enlarged perspective view of an alternate embodiment of the surface of the reinforcing element
  • Figure 3C is an enlarged perspective view of an alternate embodiment of a terminal end of the present reinforcing element
  • Figure 3D is a cross-sectional view of a further alternate embodiment of the terminal end shown in the preceding figure.
  • the practice of the present invention is to place discrete, non-fibrous structural reinforcing elements in a matrix of soil or stone, either by blending the elements 12 with the soil 14 as shown in Figure 1A ("soil” as used herein refers to clay, silt, sand, Portland cement, concrete, asphalt, flyash, slag, lime, stone, and other construction engineering materials, and stone, or any proportion of a mixture thereof) or by placing the elements 12 in layers with the soil placed in layers on the elements as shown in Figure IB, or the elements, may be a used by themselves to form an "artificial" soil. Examples of the latter may be columnar configuration of elements spaced within a soil matrix, or an entire soil volume, such as behind a retaining wall, may be constructed of the structural reinforcing elements. Other uses can be seen by those skilled in the art.
  • the structural reinforcing elements may be constructed of any suitable material, including, but not limited to steel or other metals, wood or other natural materials, fiberglass, thermoplastic polymers and copolymers, to name the more obvious materials which could be utilized in a practical manner. Wood or other natural materials will have the disadvantages of deterioration in time due to organic decay, but still may be practicable under certain conditions and for limited life of the reinforced soil application.
  • the preferred material considering manufacturing characteristics as well as material properties (including stress-strain characteristics, tensile strength, compressive strength, creep resistance, and density) is high density polypropylene, although many other manufacturable materials such as fiberglass, nylon, etc. may be used.
  • the geometric configuration of the structural reinforcing element is important, as is the surface configuration of the element. Since a reinforcing element may tend to roll, slide or pull out as the soil matrix is stressed, resistance provided by the element to rolling, sliding, and pull out form the basis of its function in reinforcing the soil. In many applications (although not all applications) , the element will be blended with the soil, and may therefore assume any possible random orientation with respect to a stress application, as shown in Figure 1A. The element, ideally, should therefore provide the same, or as similar as practicable, resistance to rolling, sliding, or pull out in any possible orientation. The structural element should therefore ideally be three dimensional - and should have equal geometric shape in any orientation.
  • Figure 2A illustrates the element 12 having a central hub 16 with a plurality of spokes or arms 18 extending radially therefrom. The opposite ends of the arms 18 may be provided with matrix engaging means such as cubes 20.
  • the cubes and arms may have a smooth surface, as shown in Figure 2A, a surface containing gripping means such as groove means 22 and cubical protruding extensions 24 as shown in Figure 3A, a roughened surface 26, similar to a coarse sandpaper, as shown in Figure 3B, dimples, or like means for increasing the surface area thereof.
  • FIG. 2B A tetrahedral configuration is illustrated in Figure 2B by element 28.
  • Element 28 also includes a control hub 30, with arm means 32 emanating radially therefrom.
  • Cubical matrix engaging means 20 are disposed at the ends of the arm means 32 opposite the hub 30.
  • the matrix engaging elements and arms may have a smooth outer surface, a grooved surface, a roughened surface, or other configuration which increases the surface area of the elements.
  • Two additional possible configurations of the matrix engaging elements are shown in Figures 3C and 3D, when, in 3C a cylindrical arm 40 with a spherical member 42 is shown having a roughened surface.
  • the spherical member 44 includes outwardly projecting spike means 46 as additional matrix engaging elements.
  • an important aspect of the element configuration is the surface roughness or surface condition of the element.
  • An element with a smooth surface although it may improve the soil being reinforced, may not provide the same or similar resistance to rolling, sliding, or pull-out as would be provided by the same element with a rough surface.
  • the surface roughness may also be provided by indentations such as dimples on the surface, or by irregular grooves cut into the surface of the element. Other methods, such as sandblasting, or rough splitting, etc. can be utilized to form rough surfaces of the structural reinforcing elements.
  • FIG. 2C Another embodiment of the present invention is illustrated in Figure 2C.
  • This element 50 is formed in an amorphous configuration, with a central hub portion 52 and a plurality of irregular matrix engaging members 54 randomly extending from the hub portion 52.
  • the configuration of the non-fiber inclusion structural reinforcing element initially selected by the inventors for experimental work was the configuration of a playing "jack” used primarily by children as a game.
  • the "jack” is three dimensional, has six legs, is multi-oriented, and is, or can be, a structural element. It does not have equal geometric shape in all orientations, but it does have reasonably similar geometric shape in any given direction.
  • the jack used was made of a thermoplastic.
  • the inventors have conducted two preliminary studies related to the invention.
  • the first study involved the improvement in strength and stress-strain characteristics effected by the incorporation of discontinuous, multi- oriented inclusion elements in granular soil.
  • Multistage, consolidated-drained triaxial tests were conducted on several samples of dry standard Ottawa sand and dry Ottawa sand reinforced with multi-oriented inclusions.
  • Ottawa sand is a poorly-graded fine sand (Unified Soil Classification group symbol of SP) .
  • Two types of inclusions were used: (1) Commercial "jacks" as described above which were unaltered and had smooth surfaces, and (2) "jacks" which had Ottawa sand particles glued to their surface to provide roughness. All soil samples tested were 2.8 inches in diameter by 6 inches long.
  • Reinforced samples were prepared by placing reinforcing elements in five layers within the sand matrix, thereby forming one inch horizontal intervals between layers of elements. No elements were placed at either the bottom or the top of the sample.
  • the initial density of .the sand in all samples was 108 pcf.
  • the initial density of the sand for the reinforced samples was maintained the same as for the unreinforced samples by calculating the volume of the inclusions and reducing the amount of sand accordingly. Therefore, any improvement in engineering properties and behavior of the reinforced soil can be attributed only to the presence of the inclusions.
  • type A refers to unreinforced Ottawa sand
  • type B refers to Ottawa sand reinforced with 5.6% (by volume) unaltered (smooth) "jacks”
  • types C and D refers to Ottawa sand reinforced with 2.8% and 5.6% (by volume) rough “jacks”, respectively.
  • Tables 1 and 2 The results of the triaxial tests are summarized in Tables 1 and 2. Comparison of types A and B with types C and D shows that the incorporation of rough "jacks" within the Ottawa sand, results in substantial improvement in the strength and stress-strain characteristics. The increases in the friction angles and cohesion intercepts (at effective confining stresses ranging from 3 to 50 psi) for types C and D compared to type A were substantial.
  • the smooth surface "jacks” did not show a significant improvement in strength or stress-strain characteristics, in the Ottawa sand, however, they may improve soils other than dry sand.
  • Ratio Ratio of confining stresses at failure; reinforced soil divided by unreinforced soil
  • the first CBR test was conducted on an unreinforced sample of very soft clayey silt, while the second CBR test was performed on a nearly identically prepared sample of the same clayey silt that was reinforced with a single 1.0 in. diameter, 4 in. deep column of well-graded sand with rough "jacks".
  • the column was formed by pushing a 0.5 in. diameter rod into the matrix soil and vibrating it back and forth to create the approximately 1.0 in. diameter column.
  • the columnar material consisting of sand and "jacks" was compacted vertically and laterally in layers within the void.
  • the CBR value for the reinforced soil was 733% greater than the unreinforced clayey silt.
  • FIG. 1A through 3D An improved configuration for the structural reinforcing elements is shown in Figures 1A through 3D. Also, as shown in Figure 2A, the two vertical element extension have the same length and mass as the four element extensions in the perpendicular plane. Surface roughness may be incorporated by several methods including cutting grooves in the element surfaces. Some other general configurations which may be utilized for structural reinforcing elements are shown. These are only a few of the possible two dimensional and three dimensional configurations which could be used. Other geometries will be developed in time to produce different shaped inclusion elements for different uses. The elements may range from smaller than 0.5 inches in outside dimension to greater than six inches in outside dimension, depending on the environment in which they will be placed.
  • non-fiber inclusion structural reinforcing elements Reinforced subgrades for pavement design construction; reinforced subbases and base courses for pavement design and construction; stabilization of soft or loose soils for general construction, for slab support, for footing support, and for roadway and airfield support (including non-paved roadways and airfields) ; retaining wall backfill for reinforced soil retaining wall design and construction; reinforced soil columns to improve foundation bearing soils; slope reinforcement to stabilize slopes, including improvement in stability of existing slopes as well as design and construction of steeper slopes utilizing the structural reinforcing elements; seawall backfill and reinforced seawall design; improved strength and stress- strain characteristics of other construction materials, in addition to soil, including, but not limited to, concrete, asphalt, and stone.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Structural Engineering (AREA)
  • Agronomy & Crop Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Soil Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)

Abstract

Petits éléments de renforcement structural discrets (12) disposés dans le sol (14) ou autre agrégat afin de le stabiliser. Chaque élément de renforcement est un élément unitaire en plastique ayant un moyeu commun (16) d'où partent une pluralité de bras (18). Les extrémités des bras comportent une partie de fixation (20) qui est plus grande que la section transversale du bras. Ces parties de fixation ont la forme de cubes, de sphères, ou des configurations irrégulières. La surface des parties de fixation est rugueuse dans une variante, striée ou dentée dans une autre variante.
PCT/US1991/003355 1990-05-15 1991-05-14 Elements et procedes servant a renforcer le sol ou materiaux similaires Ceased WO1991018150A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US52336690A 1990-05-15 1990-05-15
US523,366 1990-05-15

Publications (1)

Publication Number Publication Date
WO1991018150A1 true WO1991018150A1 (fr) 1991-11-28

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WO (1) WO1991018150A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008105878A1 (fr) * 2007-03-01 2008-09-04 Prs Mediterranean Ltd. Article géosynthétique de haute performance
US7501174B2 (en) 2007-03-01 2009-03-10 Prs Mediterranean Ltd. High performance geosynthetic article
CN107804986A (zh) * 2017-10-31 2018-03-16 重庆工程职业技术学院 一种具有混凝土阻裂作用的金属结构制备方法

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1474389A (en) * 1923-11-20 And otto w
US1976832A (en) * 1932-08-12 1934-10-16 Charles S Brown Concrete wall and reenforcing insert therefor
US2062944A (en) * 1931-07-13 1936-12-01 Sloan Lon Grid structure for floors and the like
US2909037A (en) * 1958-10-27 1959-10-20 Robert Q Palmer Component for rubble-mound breakwaters
US3165036A (en) * 1963-03-01 1965-01-12 California Research Corp Paving structure
US3355894A (en) * 1963-03-27 1967-12-05 Vidal Henri Charles Structure for use in river and sea
US3846085A (en) * 1972-01-27 1974-11-05 Versatile Structures Inc Ferrous aggregate for concrete
US4033781A (en) * 1976-01-09 1977-07-05 Amtech, Inc. Fiber reinforced structural material
US4078940A (en) * 1972-11-28 1978-03-14 Australian Wire Industries Proprietary Limited Concrete reinforcing elements and reinforced composite incorporating same
FR2388945A1 (fr) * 1977-04-29 1978-11-24 Porraz Mauricio Modules destines a la construction d'ouvrages de defense contre l'erosion marine
JPS5612413A (en) * 1979-07-10 1981-02-06 Kawatetsu Shoji Kk Construction method for foundation ground
US4370390A (en) * 1981-06-15 1983-01-25 Mcdonnell Douglas Corporation 3-D Chopped-fiber composites
US4645381A (en) * 1980-03-19 1987-02-24 Etienne Leflaive Building material, its application for embankment, surfacing, or as foundation mass over a loose ground, and method and installation for the production of said material
US4662946A (en) * 1982-10-05 1987-05-05 Mercer Frank B Strengthening a matrix
JPS63151711A (ja) * 1986-12-15 1988-06-24 Asahi Chem Ind Co Ltd 地盤強化用埋設体
US4916855A (en) * 1987-03-30 1990-04-17 The Royal Hong Kong Jockey Club Reinforcing a grassed surface

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1474389A (en) * 1923-11-20 And otto w
US2062944A (en) * 1931-07-13 1936-12-01 Sloan Lon Grid structure for floors and the like
US1976832A (en) * 1932-08-12 1934-10-16 Charles S Brown Concrete wall and reenforcing insert therefor
US2909037A (en) * 1958-10-27 1959-10-20 Robert Q Palmer Component for rubble-mound breakwaters
US3165036A (en) * 1963-03-01 1965-01-12 California Research Corp Paving structure
US3355894A (en) * 1963-03-27 1967-12-05 Vidal Henri Charles Structure for use in river and sea
US3846085A (en) * 1972-01-27 1974-11-05 Versatile Structures Inc Ferrous aggregate for concrete
US4078940A (en) * 1972-11-28 1978-03-14 Australian Wire Industries Proprietary Limited Concrete reinforcing elements and reinforced composite incorporating same
US4033781A (en) * 1976-01-09 1977-07-05 Amtech, Inc. Fiber reinforced structural material
FR2388945A1 (fr) * 1977-04-29 1978-11-24 Porraz Mauricio Modules destines a la construction d'ouvrages de defense contre l'erosion marine
JPS5612413A (en) * 1979-07-10 1981-02-06 Kawatetsu Shoji Kk Construction method for foundation ground
US4645381A (en) * 1980-03-19 1987-02-24 Etienne Leflaive Building material, its application for embankment, surfacing, or as foundation mass over a loose ground, and method and installation for the production of said material
US4370390A (en) * 1981-06-15 1983-01-25 Mcdonnell Douglas Corporation 3-D Chopped-fiber composites
US4662946A (en) * 1982-10-05 1987-05-05 Mercer Frank B Strengthening a matrix
JPS63151711A (ja) * 1986-12-15 1988-06-24 Asahi Chem Ind Co Ltd 地盤強化用埋設体
US4916855A (en) * 1987-03-30 1990-04-17 The Royal Hong Kong Jockey Club Reinforcing a grassed surface

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008105878A1 (fr) * 2007-03-01 2008-09-04 Prs Mediterranean Ltd. Article géosynthétique de haute performance
US7501174B2 (en) 2007-03-01 2009-03-10 Prs Mediterranean Ltd. High performance geosynthetic article
US7842373B2 (en) 2007-03-01 2010-11-30 Prs Mediterranean Ltd. High performance geosynthetic article
CN107804986A (zh) * 2017-10-31 2018-03-16 重庆工程职业技术学院 一种具有混凝土阻裂作用的金属结构制备方法

Also Published As

Publication number Publication date
AU7887691A (en) 1991-12-10

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