Showing papers on "Soil stabilization published in 1973"

Causes and mechanisms of cohesive soil erosion: the state of the art

Abstract: THE PROCESSES OF EROSION OF COHESIVE SOIL ARE EXAMINED THROUGH A STUDY OF BASIC SOIL INDEX PROPERTIES, SOIL STRUCTURE AND FABRIC, AND PHYSICOCHEMICAL INTERACTION OF SOIL AND WATER. REPORTED STUDIES ARE EVALUATED TO DETERMINE THE FACTORS THAT INITIATE AND SUSTAIN EROSION. A WIDE VARIETY OF TEST PROCEDURES ARE STUDIED, INCLUDING JETS, ROTATING CYLINDERS, TUBE FLOW, FLUMES, AND FIELD DATA. IT IS FOUND THAT GENERALLLY USED SOIL CLASSIFICATION INDEXES HAVE NOT PROVED USEFUL AS EROSION PREDICTORS. STRUCTURAL INDEXES AND INDEXES DESCRIBING THE QUALITY OF THE PORE FLUID AND ERODING FLUID MUST BE ESTABLISHED FOR EACH CASE. INTERNAL AND EXTERNAL FORCE SYSTEMS ARE DEFINED TO ESTABLISH THE RATE AND INITIATION OF EROSION. THE PAPER CONCLUDES WITH A BRIEF STUDY OF SOME CURRENT METHODS USED TO STABILIZE ERODIBLE SOILS IN THE FIELD. /AUTHOR/

Control of volume changes in expansive earth materials

Abstract: METHODS FOR THE CONTROL OF VOLUME CHANGES IN EXPANSIVE SOILS HAVE BEEN DIVIDED INTO (1) TECHNIQUES THAT DO NOT REQUIRE ADDITIVES: COMPACTION CONTROL, PREWETTING, HEATING; AND (2) TECHNIQUES USING ADDITIVES: LIME, CEMENT, CHEMICALS. MUCH CAN BE DONE THROUGH CONTROL OF COMPACTION. A MODERATE DENSITY WET OF OPTIMUM WATER CONTENT USING A SHEEPSFOOT ROLLER SHOULD MINIMIZE SWELL, AND CURRENT KNOWLEDGE OF THE PROPERTIES OF COMPACTED CLAY SHOULD ENABLE DESIGNS ACCOUNTING FOR STRENGTH, VOLUME CHANGE, AND PERMEABILITY CRITERIA. PREWETTING IS AN EFFECTIVE MANS OF VOLUME CHANGE CONTROL WHEN TIME IS NOT CRITICAL. LIME TREATMENT OF THE UPPER 6 TO 12 INCHES OF THE WETTED SOIL CAN BE USED TO INCREASE STRENGTH AND FACILITATE CONSTRUCTION. LIME CONTINUES TO BE THE MOST EFFECTIVE ADDITIVE FOR STABILIZATION, AND THE DEEP- PLOW METHOD PROVIDES MEANS FOR TREATMENT TO DEPTHS UP TO 36 INCHES. ON THE OTHER HAND STABILIZATION USING LIME SLURRIES AND LIME PILES IS OF DOUBTFUL VALUE, EXCEPT IN DRIED, FISSURED MATERIALS. NO CHEMICALS HAVE BEEN FOUND THAT ARE COMPETITIVE WITH LIME FOR TREATMENT OF EXPANSIVE CLAYS. PROPRIETARY CHEMICAL STABILIZERS AND COMPACTION AIDS HAVE NOT YET BEEN SHOWN EFFECTIVE FOR CONTROL OF VOLUME CHANGE.

Erodibility of a cement-stabilized sandy soil

Abstract: CEMENT-STABILIZED SOIL HAS BEEN SUCCESSFULLY USED AS FACING OR LINING FOR HIGHWAY EMBANKMENTS AND DRAINAGE DITCHES TO REDUCE THE PERIL OF EROSION. HOWEVER, VERY LITTLE INFORMATION REGARDING ITS ERODIBILITY IS AVAILABLE. IN AN EFFORT TO CHARACTERIZE THE ERODIBILITY OF COMPACTED CEMENT-STABILIZED SOIL UNDER VARIOUS PHYSICAL AND ENVIRONMENTAL CONDITIONS, BOTH EROSION AND UNCONFINED COMPRESSIVE STRENGTH TESTS WERE CARRIED OUT ON A SANDY SOIL MIXED WITH VARIOUS AMOUNTS OF CEMENT (1, 1 1/2, 2, AND 3 PERCENT OF CEMENT BY DRY WEIGHT). THE VARIOUS SAMPLES WERE COMPACTED BY KNEADING TO A DRY DENSITY OF 132.4 PCF AT A MOISTURE CONTENT OF 8.1 PERCENT AND THEN CURED FOR 7 DAYS IN A CONSTANT- TEMPERATURE MOISTURE ROOM. A SPECIFIED NUMBER OF WET- DRY OR FREEZE-THAW CYCLES (0, 3, 6, 9, AND 12) WERE APPLIED TO DIFFERENT SAMPLES TO DETERMINE THE EFFECT OF ENVIRONMENTAL CHANGES ON THE MECHANICAL AND HYDRAULIC STABILITY OF THE SOIL. FOR THE UNCYCLED SAMPLES (NO TREATMENT) THE CRITICAL BOUNDARY SHEAR STRESS INCREASED AS THE UNCONFINED COMPRESSIVE STRENGTH (OR THE CEMENT CONTENT) OF THE SAMPLE INCREASED. A SIMPLE RELATIONSHIP BETWEEN THE UNCONFINED COMPRESSIVE STRENGTH AND THE CRITICAL BOUNDARY SHEAR STRESS WAS OBTAINED FOR THE RANGE OF CEMENT CONTENTS USED IN THIS INVESTIGATION. ERODIBILITY CHARACTERIZATION OF CEMENT- STABILIZED SOIL CONSIDERING THE INFLUENCE OF CLIMATIC CHANGES IS VERY COMPLEX. THE CRITICAL BOUNDARY SHEAR STRESS IS NO LONGER A UNIQUE PARAMETER TO DEFINE THE HYDRAULIC STABILITY OF THE SOIL. THE ALTERNATING ACTION OF FIELD WEATHERING AND EROSION IS DETERMINED TO THE INTEGRITY OF THE SOIL. HOWEVER, THE NATURE OF THE TIME- AND ENVIRONMENT- DEPENDENT ERODIBILITY OF THE CEMENT- STABILIZED SOIL IS NOT FULLY KNOWN; MORE BASIC INFORMATION CONCERNING THE INTERACTION AMONG SOIL, WATER, AND ENVIRONMENTAL FACTORS IS URGENTLY NEEDED. /AUTHOR/

Membranes and encapsulation of soils for control of swelling

Abstract: THE ADVANTAGES OF PEVENTING THE ENTRANCE OF MOISTURE FROM ABOVE OR BELOW A LAYER OF SOIL ARE OBVIOUS TO DESIGNER AND CONSTRUCTION ENGINEERS ALIKE. ONE PROCEDURE USED IN AN ATTEMPT TO SEAL OUT MOISTURE INVOLVES THE TECHNIQUE OF PLACING IMPERVIOUS MEMBRANES BETWEEN THE SOIL LAYER AND POSSIBLE SOURCES OF MOISTURE. PREVIOUSLY, THE MAJOR DRAWBACK TO EXTENSIVE EMPLOYMENT OF SUCH CONSTRUCTION TECHNIQUES HAS BEEN EITHER THE LACK OF INTEGRITY OF LOW-COST MEMBRANE MATERIALS OR THE RELATIVELY HIGH COST OF MEMBRANE MATERIALS HAVING BETTER DURABILITY TRAITS. HOWEVER, RECENT WORK COMPLETED BY THE U. S. ARLMY ENGINEER WATERWAYS EXPERIMENT STATION HAS DEVELOPED A DURABLE, INEXPENSIVE COMBINATION OF MEMBRANES AND PROPER CONSTRUCTION TECHNIQUES, WHICH TOGETHER OVERCOME THE PAST RESTRICTIONS FOR USE OF MEMBRANE WATERPROOFING. THIS REPORT DESCRIBES A MEMBRANE- ENVELOPED SOIL LAYER (MESL) SYSTEM. IT CONSISTS OF A SUBGRADE UPON WHICH A FOUNDATION LAYER OF COMPACTED SOIL (CONSTRUCTED FROM NATURAL SUBGRADE OR LOCALLY AVAILABLE SOIL) LIES BETWEEN A LOWER AND UPPER WATERPROOF MMBRANE. THE MEMBRANES ARE JOINTED AND SEALED ALONG THE EDGES, FORMING A WATERPROOF ENCAPSULATED SOIL SYSTEM. FOLLOWING A BRIEF DISCUSSION OF MATERIALS DEVELOPMENT, THE CONSTRUCTION TECHNIQUE FOR SUCCESSFUL INSTALLATION OF A MESAL SYSTEM IS PRESENTED. RESULTS OF STRUCTURAL AND COST ANALYSIS STUDIES ARE GIVEN AND THE LIMITATIONS OF THE SYSTEM ARE POINTED OUT. BRIEF MENTION IS MADE OF AN ALTERNATE CONSTRUCTION PROCEDURE WHICH IS CURRENTLY BEING INVESTIGATED.

Some studies on the cracking of soil-cement in japan

Abstract: This paper mainly treats of the phenomenon of cracking in soil-cement under repeated loads, compared with the case of static loads, and the usefulness of the immediate opening of a soil-cement base to general traffic is emphasized from the good results of an in situ experiment. Concerning the cracking of soil-cement due to climatic action, the merits of a sandwich structure are pointed out. A method to reduce the shrinkage caused by the hydration of portland cement is reported based on an experiment using specimens in which ferrous oxide powder and calcium chloride are added to the soil-cement mixture.

Rain erodibility of compacted soils

Abstract: The effects of different independent variables on the magnitude of soil erosion caused by rainfall were investigated. Ten variables are included in this study: slope inclination, rain intensity, grain size distribution, water content and dry density, compactive effort, method of compaction, curing conditions, temperature at testing, plasticity, and sample length exposed to runoff. Three approaches are used to compare the amount of erosion. First, variables are plotted in relation to erosion; second, complete comprehensive tables relating these variables to erosion are presented. Third, erosion is related to combined variables of quantitative values such as slope steepness and rain intensity, using multi­ linear regression formulas that show the degree of signifi­ cance of each of the variables. For qualitative variables, such as method of compaction, a direct comparison by the use of tables and graphs is presented.

Shrinkage of cement treated mixtures

Abstract: The shrinkage of cement stabilised soil often results in extensive cracking of the pavement layer. This paper reports the influence of some factors on shrinkage during curing of a cement stabilised soil. The factors of during period, degree of saturation, cement content and dry density were investigated in a completely randomised full factorial experiment. The value of factorial method of design and the importance of rigid statistical analysis of evaluate the shrinkage characteristics of cement treated soil is demonstrated. An empirical relationship between each factor and shrinkage is defined and discussed. In addition, a multiple linear regression equation is advanced which predicts moist cured shrinkage very reliably. /Author/

Fill stabilization using non-biodegradable waste products

Abstract: THIS STUDY IS A LABORATORY INVESTIGATION OF THE STABILIZING EFFECTS OF INCLUDING VARIOUS SOLID NON-BIODEGRADABLE WASTE MATERIALS IN FOUR TYPICAL HIGHWAY EMBANKMENT SOILS. WASTE MATERIALS INCLUDED PORTIONS OF DISCARDED RUBBER AUTOMOBILE TIRES, BROKEN GLASS CONTAINERS AND TIN AND ALUMINUM CARS. COMPACTED SOIL SPECIMENS WITH VARIOUS PERCENTAGES OF WASTE MATERIALS IN DIFFERENT LAYERING SYSTEMS WERE SUBJECT TO LARGE-SCALE TRIAXIAL COMPRESSION TESTING TO DETERMINE CHANGES IN SHEAR STRENGTH PARAMETERS. FLATTENED TIN AND ALUMINUM CONTAINERS WERE FOUND TO PROVIDE THE GREATEST STABILIZING BENEFIT AND STRENGTH IMPROVEMENT.

Moisture stabilization by membranes, encapsulation and full depth paving

Abstract: FROM A REVIEW OF SEVERAL EXPERIMENTAL PROJECTS (AT CLIFTON, ORDWAY, ELK SPRINS, AND OTHER SITES) CONSTRUCTED ON EXPANSIVE SOILS IN VAROUS REGIONS OF COLORADO THE FOLLOWING CONCLUSIONS WERE DRAWN: (1) CATALYTICALLY BLOWN ASPHALT MEMBRANES CAN BE PLACED FOR ABOUT 50 CENTS PER SQUARE YARD AND ARE EFFECTIVE IN MAINTAINING AS-CONSTRUCTED MOISTURE IN SUBGRADE SOILS. (2) FULL DEPTH ASPHALT BASES ARE EFFECTIVE IN REDUCING MOISTURE BUILDUP IN SUBGRADE SOILS. SPECIAL PRECAUTIONS ARE NEEDED, HOWEVER, TO PREVENT MOISTURE CHANGE CYCLES AT THE SHOULDERS IN ORDER TO PREVENT LONGITUDINAL CRACKING IN THE PAVEMENT A FEW FEET IN FROM THE SHOULDER. (3) GRANULAR UNTREATED BASES, EITHER DIRECTLY OR INDIRECTLY, ARE RESPONSIBLE FOR THE HIGHER MOISTURES FOUND UNDER SUCH BASES IN COMPARISON TO FULL DEPTH ASPHALT BASES. (4) ENCAPSULATED OR ENVELOPED SUBGRADE SOILS REMAIN AT A LOWER MOISTURE CONTENT. THIS COES NOT APPEAR TO BE ECONOMICALLY PRACTICAL, HOWEVER, SINCE ON THE ELK SPRINGS PROJECT, ENOUGH ADDTIONAL SOIL SUPPORT WAS NOT GAINED OVER THAT UNDER ASPHALT BASE TO OFFSET THE EXTRA COST OF PLACING THE MEMBRANE. (5) SOIL SUPPORT VALUES UNDER ASPHALT MEMBRANES AND FULL DEPTH ASPHALT BASES ARE CONSIDERABLY HIGHER THAN UNDER GRANULAR UNTREATED BASES WHEN COMPARED FOR SIMILAR CONDITIONS. A NEW CORRELATION OF LABORATORY STABILOMETER R VALUES AND FIELD SOIL SUPPORT VALUES FOR THE DRIER CONDITIONS IS SUGGESTED. UNDER CONDITIONS SIMILAR TO ORDWAY AND ELK SPRINGS, THIS WOULD RESULT IN A DECREASED THICKNESS OF THE PAVEMENT STRUCTURE OF ABOUT 0.45 STRUCTURAL NUMBER BELOW THAT CALLED FOR BY THE CURRENT COLORADO FLEXIBLE PAVEMENT DESIGN PROCEDURE. (6) THE CURRENT COLORADO DESIGN PROCEDURE FOR FLEXIBLE PAVEMENTS IS REASONABLY ACCURATE FOR UNTREATED GRANULAR BASES AND SHOWS NO NEED FOR ADJUSTMENT. (7) IT IS NOT PRACTICAL TO REPRODUCE FIELD MOISTURE CONDITIONS WHEN MOLDING STABILOMETER SPECIMENS IN THE LABORATORY TO PREDICT ACTUAL FIELD SOIL SUPPORT VALUES.

Method for determing the potential vertical rise, pvr (texas test method tex-124-e)

Abstract: A PROCEDURE IS PESENTED WHICH PROVIDES A MEANS FOR THE DETERMINATION OF THE POTENTIAL VERTICAL RISE (PVR) IN A SOIL STRATA, SUCH AS MAY BE ENCOUNTERED IN THE PLACEENT OF A ROADWAY, BRIDGE, OR BUILDING FOUNDATION. A SHORT EXAMPLE IS GIVEN WHICH ILLUSTRATES HOW THE TEST METHOD WORKS. BY USING THE DETERMINATION OF PVR IN CONJUNCTION WITH THE UNIT LOADS TO BE IMPOSED BY THE STRUCTURE, THE ENGINEER CAN MAKE CHOICES ON THE METHODS OF CONSTRUCTION TO BE EMPLOYED AND THE REMEDIAL PROCEDURES TO USE IN SECURING THE GREATEST VALUE FOR HIS CONSTRUCTION MONEY. SOME OF THE CHOICES, DEPENDENT UPON THE DEPTH, AMOUNT OF SWELLING CLAYS, AND OTHER CONDITIONS ARE AS FOLLOWS: (1) REMOVAL OF NEAR THE SURFACE CLAY LAYERS AND REPLACEMENT WITH GRANULAR MATERIAL; (2) PONDING WITH WATER FOR THIRTY OR MORE DAYS TO BRING DRIER CLAYS TOWARD OPTIMUM CONDITIONS; (3) STABILIZATION OR MODIFICATION OF CLAY LAYERS NEAR THE SURFACE USUALLY USING LIME; (4) UTILIZATION OF DENSITY AND MOISTURE CONTROL METHODS AND MOISTURE PRESERVATION SUCH AS ASPHALT MEMBRANES OR WIDE GRANULAR SECTIONS, WHICH IS OF GREAT MERIT AFTER PONDING; (5) EMPLOYING IN BUILDINGS THE USE OF AMPLE STEEL IN GRADE BEAMS, TOP AND BOTTOM, OR THE USE OF HEAVY STEEL IN FOUNDATION SHAFTS AND INSULATING THEM FROM THE CLAY; AND (6) SUCH OTHER MEASURES AS LEAVING AIR SPACE UNDER GRADE BEAMS, SUSPENSION OF FLOORS FROM FOUNDATION SHAFTS OR THE USE OF EXPANSION JOINTS TO SEPARATE THE FLOOR FROM FOUNDATION GRADE BEAMS.

Lime stabilization of frost-susceptible soils

Abstract: Depending on (1) nature and composition of the soil, (2) curing (time-temperature), (3) lime type, (4) lime percentage, and (5) density of compacted mixture, lime-treated soils display a wide range of engineering properties. Extensive studies have shown that all fine-grained soils react with lime to effect beneficial changes in workability, plasticity and swell properties. The extent to which the lime-soil poxxolanic reaction proceeds is influenced primarily by natural soil properties. The difference between the compressive strengths of the natural and lime-treated soil is an indication of the extent to which the lime-soil pozzolanic reaction has proceeded. Substantial strength increase indicates that the soil is reactive with lime and can probably be stabilized to produce a quality paving material (base or subbase). The validity of using initial unconfined compressive strength ()-cycles) as a measure of freeze-thaw resistance was demonstrated in extensive studies. Recent studies of different types of cementitious stabilized materials (lime-soil, soil-cement, lime-flyash) have confirmed that initial mixture compressive strength can be used to predict the cyclic freeze-thaw resistance of a stabilized soil. Factors influencing strength development, influence cyclic freeze-thaw resistance in the same fashion. Studies show that cured lime-soil mixtures with good freeze-thaw resistance can be developed when reactive soils are stabilized with quality lime. The strength required to prevent excessive heaving of cured lime-soil mixtures, approximately 200 psi, compares favorably with the strength required to restrict the heave of cement stabilized materials. Adequate mixture design, construction, and quality control procedures must be utilized to insure the successful utilization of lime stabilized soils in pavement construction.

Expansive soils in wyoming highways

Abstract: THIS PAPER BRIEFLY SUMMARIZES THE PROBLEMS ENCOUNTERED IN CONSTRUCTING HIGHWAYS IN WYOMING IN AREAS WITH EXPANSIVE SOILS, AND MENTIONS THE METHODS WHICH WERE USED TO SOLVE THEM.

Stabilisation of alluvial soil with lime and fly ash

Abstract: The paper reports the results of laboratory investigations and field research on the stabilization of alluvial soil with lime and fly ash and the use of such stabilized soil as base or subbase in the lower layers of the pavement system for both roads and airfields. The investigation using fly ashes from three thermal power stations of Delhi, Kanpur and Faridabad showed that alluvial soils could be staisfactorily stabilized with 15 percent of lime and fly ash in the proportion of 1:4. These proportions enabled an increase in the CBR value from 8-14 to 52-110 without any additive. With the addition of 1 percent gypsum by weight of soil, lime and fly ash, the CBR value increased to 73-190. Improvement was also noticed in the unconfined compressive strength of the lime-fly ash stabilized soil when 1 percent gypsum was added. Higher concentration of lime improved neither the CBR value nor the compressive strength of the stabilized soil. Other additives such as sodium carbonate (0.1 percent) and calcium chloride (0.25 percent) improved the CBR value of the stabilized soil significantly but the compressive strength only marginally. The results show that lime-fly ash stabilized soil base/subbase course would be about 50 percent cheaper than conventional stone soling or granular layer with oversized stone metal, which it can replace, in areas, where fly ash is locally available and good quality stones are either costly or have to be transported from a long distance. /Author/

Lime-Cement Combination Stabilization

Abstract: : Soil stabilization is used extensively in road and airfield construction. In particular, soil-cement appears to be a favorite among the engineers. As the plasticity of a soil increases, the ability to adequately mix the cement with the soil becomes a critical factor. Also the quantity of cement required to stabilize the soil becomes excessive. The objective of the study was to determine the effect of reduced compacted density on the durability of cement stabilized clays, pretreated with lime. The reduction in density did not impair the durability of cement stabilized clay soils, which were pretreated with lime. Most of the test results indicated an improved resistance to freeze- thaw. An evaluation of the unconfined compressive strength results obtained during freeze-thaw shows that lime pretreatment improved the strengths.

Triaxial classification of the surface soils of texas as grouped by soil conservation service series

Abstract: LABORATORY AND FIELD STUDIES ON 710 SOIL SERIES HAVE BEEN CONDUCTED IN ORDER TO SECURE TRIAXIAL CLASSIFICATIONS FOR AS MANY AS POSSIBLE. OF THESE 710 SOILS, 46 PERCENT WERE CLASSIFIED AS A RESULT OF THE SURVEY OF ESTIMATES AND TESTS CONTAINED IN THE FILES OF THE MATERIALS AND TESTS DIVISION. TABULATION OF ADDITIONAL INFORMATION INCREASED THE CLASSIFICATIONS TO OVER 70 PERCENT. TRIAXIAL CLASSIFICATIONS ALSO INCREASED FROM 303 TO 498 AS A RESULT OF THE ADDITIONAL INFORMATION. THE STUDY REVEALED THAT CLAY SUBGRADES, WITH HIGH P.I. AND RESULTANT SWELLING, PRESENTED THE MOST SERIOUS PROBLEMS TO HIGHWAY CONSTRUCTION. HOUSTON BLACK - HOUSTON CLAY WHICH IS A PRIME EXAMPLE OF THIS TYPE OF MATERIAL, HAS A TRIAXIAL CLASSIFICATION OF 5.4 BASED ON A TOTAL OF 247 TESTS. TRIAXIAL CLASSIFICATION'S FOR SUBGRADE SOILS ARE OBTAINED BY A COMBINATION OF TESTS PUBLISHED IN THE MANUAL OF TESTING PROCEDURES OF THE MATERIALS AND TEST DIVISION. LOCATION OF SOIL MATERIALS ARE MADE BY STATION NUMBERS ON LARGE-SCALE MAPS USED BY THE PROJECT ENGINEER DURING CONSTRUCTION OF THE ROADWAY. THE MAPPING AND CLASSIFICATION OF SOILS IS REVIEWED AS IS ALSO THE USE OF INFORMATION IN LOAD ZONING. RESULTS OF THE STUDY ARE TABULATED AND DISCUSSED. CONTROL OF MOISTURE CONTENT BOTH BEFORE AND AFTER COMPACTION OF THE SUBGRADE SOILS, TOGETHER WITH PROPER COMPACTION IS THE MOST ECONOMICAL METHOD OF STABILIZATION. THE SECOND BEST METHOD IS TO STABILIZE THESE MATERIALS WITH LIME, CEMENT OR ASPHALT. SUGGESTED USAGE OF THE STUDY DATA IS OUTLINED.