Showing papers on "Soil stabilization published in 1979"

Driven piles in clay - the effects of installation and subsequent consolidation

Abstract: This paper describes the results of numerical analysis of the effects of installing a driven pile. The geometry of the problem has been simplified by the assumption of plane strain conditions in addition to axial symmetry. Pile installation has been modelled as the undrained expansion of a cylindrical cavity. The excess pore pressures generated in this process have subsequently been assumed to dissipate by means of outward radial flow of pore water. The consolidation of the soil has been studied using a work-hardening elasto–plastic soil model which has the unique feature of allowing the strength of the soil to change as the water content changes. Thus it is possible to calculate the new intrinsic soil strength at any stage during consolidation. In particular the long-term shaft capacity of a driven pile may be estimated from the final effective stress state and intrinsic strength of the soil adjacent to the pile. A parametric study has been made of the effect of the past consolidation history of the soil...

Stabilized earth roads

Abstract: Keywords: Stabilite des sols ; Fondation Reference Record created on 2004-09-07, modified on 2016-08-08

Static and Dynamic Properties of Sand-Cement

Abstract: The construction of a nuclear power plant on a liquefiable sand deposit required the treatment of the foundation A scheme involving excavation and replacement with cement-stabilized sand was foreseen An extensive laboratory testing program on different mixtures was undertaken to assess the design characteristics (static and dynamic) and to check the durability and cyclic strength of the backfill material In the course of the testing program, it was necessary to develop new methods for interpretation of the dynamic characteristics of the soil-cement Finally, it was proved that a 5% soil-cement mixture made with ordinary portland cement is suitable

Lime Columns—A New Foundation Method

Abstract: A new foundation method is described where columns manufactured in situ by mixing soft clay with unslaked lime are used as foundation for light structures to reduce settlements and to increase the bearing capacity. Methods have been developed for the calculation of total and differential settlements based on results from full-scale tests. The lime columns also function as drains in soft clay which increase the consolidation rate of the soil.

Silicate-stabilized sands

Abstract: Strengthening and stiffening of a chohesionless, sandy soil in-situ by means of injection of a silicate solution that gels with time, is a technique that is finding growing applicability to geotechnical problems. This paper presents the results of a comprehensive series of tests designed to provide an engineering data base to describe the behavior of silicate-stabilized sands. Basically, it is found that the injection of the grout solution into the sand adds a cohesion component to its strength without significantly altering its frictional component of strength. Key variables that influence the behavior of the silicate are the grout mix components, confining pressure, loading rate, curing environment, curing time, and grain size of the soil. Loading rate is important because the grouted soil tends to creep with time and can fail in creep rupture. Only 50% of the strength defined in a rapid load test can be relied upon for long-term load conditions.

Soil stabilization in pavement structures-a user's manual volume 2: mixture design considerations

Abstract: This two volume user's manual was developed to provide guidance for pavement design, construction and materials engineers responsible for soil stabilization operations associated with transportation systems. The present volume has been prepared for materials engineers. It describes methods for selection of the type and amount of stabilizers. Methods of estimating stabilizer contents are presented as well as detailed test methods, mixture design criteria and typical mixture criteria.

Field Experiment of Reinforced Earth Wall

Abstract: A field test conducted at the U.S. Army Engineer Waterways Experiment Station indicated that the reinforced earth concept provides another alternative for constructing earth structures which may prove to be more economical when compared with conventional methods under certain conditions. Based on instrumentation measurements collected during construction and during loading of a retaining wall backfilled with sand and reinforced with galvanized steel ties, it appears that the Rankine earth pressure theory provides a good approximation for the measured lateral pressure when the wall is carrying little or no surcharge load. Prior to failure under a substantial surcharge loading, the measured lateral earth pressure was maximum at the middle third of the wall and varied from 1.0 to 1.2 times the Rankine active earth pressure. The curve connecting the points where maximum tensile stress occurred in the reinforcing ties did not coincide with the theoretical Rankine failure surface.

Calcium polysulfide soil stabilization method and compositions

Abstract: Soil is stabilized and strengthened by application of solutions of calcium polysulfides. Compositions useful for soil stabilization comprise aqueous solutions of calcium polysulfide or aqueous mixtures of calcium polysulfides and dispersed organic polymers. Emulsifiers provide soil penetration.

Dispersive Soil Problem at Los Esteros Dam

Abstract: Dispersive soil was discovered in the impervious borrow area at Los Esteros Dam and, through the use of sand filters and lime treatment of specific areas, the dispersive soil was used in the impervious core of the dam. Testing of the soil at the first laboratory was inconclusive, but testing at the second confirmed the soil to be dispersive. Tests were then conducted on the dispersive soil, sand filters, and lime-treated dispersive soil to determine whether sand filters and lime treatment could be used to control and alter the dispersive clay for use in the impervious core of the dam. Results of the program confirmed that a properly graded sand filter will control dispersive erosion through the impervious core and lime treatment alters the soil to a nondispersive material. A sand filter was constructed downstream of the impervious core and, where the base of the impervious core is founded on a fractured sandstone, a 5-ft (1.5-m) thick layer of the core was treated with lime.

Soil stabilization in pavement structures, a user's manual. volume ii: mixture design considerations. implementation package

Abstract: The primary purpose of this manual is to provide background information for those engineers responsibe for utilizing soil stabilization as an integral part of a pavement structure. Information is included which will allow the pavement design engineer to determine the thickness of stabilized layer(s) for a pavement in a specific climate and subjected to definable highway traffic. The construction engineer will find information on quality control, specifications, and construction sequences. The materials engineer is provided with information that will allow the determination of the type and amount of stabilizers that are suitable for a particular soil. The manual has not been written to endorse one type of a chemical stabilizer over another, nor is it intended to provide the specific features of one manufacturer's products. Rather, it explains the general characteristics of chemical soil stabilization and offers a method for evaluating the benefits of chemical stabilization versus the conventional mechanical stabilization operations.

Structural evaluation of new concepts for long-span culverts and culvert installations

Abstract: Analytical structural evaluations of long-span and conventional culvert installations are made using a finite element soil-structure model. Included in the evaluation are the relative merits of conventional soil-structure design parameters of soil quality and compaction, footing width (for arches), metal liner thickness, metal liner shape, scale of structure, and special manufacturing features, such as thrust beam, rib stiffeners, and soil bin. Results indicate that soil stiffness is the most significant parameter related to deformations in the structure. Maximum thrust force is generally insensitive to all conventional design parameters. Further analytical evaluations are made of new concepts, including reinforced earth, stabilized soil zones, selective placement of soft inclusions, and controlled joint slippage. Results suggest that soil reinforcement used in conjunction with long-span culverts may be a cost-effective technique to limit structural deformations and enhance structural capacity. It also appears that controlled joint slippage may be the most cost-effective method to reduce thrust. Other parameters investigated included selective placement of stabilized soil, V-notch void, and fluid jackets for concrete pipe, all of which appeared to improve the structural performance of culverts. /FHWA/

Treatment of Peaty Clay by High Energy Impact

Abstract: For a warehouse construction in Singapore, 3 m to 4.5 m depth of peaty clay overlain by 3.5 m to 6 m of medium silty clay posed a problem for the foundation construction. In order to avoid excessive settlements for the foundation and the floor slab, the methods available were to drive piles to a good bearing and suspend the flooring or to replace the highly compressible peaty clay with a better soil type which could be compacted to receive the spread footings and flooring slab. For the small column and floor loads involved, both these approaches were found to be expensive and the latter method was also impractical for the site conditions. The method of applying high energy impacts on the top of the silty clay layer overlaying the peaty clay was adopted in order that the improvement in strength and compressibility characteristics could be brought about for the peaty clay to the desired levels.

Overview for design of foundations on expansive soils

Abstract: : Numerous structures constructed on expansive clay soil experience significant damage from differential heave and settlement. The types of structures most often damaged from heaving soil include highways, foundations and walls of residential and light commercial buildings, canal and reservoir linings, and retaining walls. The leading cause of foundation heave or settlement is change in soil moisture attributed to change in the field environment (e.g., climatic changes, prevention of evaporation beneath covered areas, improper drainage following construction and from usage requirements of the structure. This report provides background information for establishing the preliminary design of structures in swelling soil areas based on field studies conducted by the Army Engineer Waterways Experiment Station and experiences of numerous investigators. The overview includes analyses of site and soil investigations, topography and landscaping including drainage and soil stabilization techniques, and selection of the foundation and super-structure. General suggestions for remedial repair of existing structures are provided. Analyses of the movement of cast-in-place concrete piers in swelling soil are included to provide a basis for design of these foundations. Appendices include: Determination of soil suction by thermocouple psychrometers; and Prediction of pier movement.