Showing papers on "Soil stabilization published in 1985"

The stabilization of some arid zone soils with cement and lime

Abstract: Summary Tests on three groups of Australian arid zone soils indicate that cement is a more effective stabilizing agent than lime. Sandy soils rich in gypsum and bassanite do not respond to stabilization. The cement stabilized clayey soils must be adequately protected against increase in moisture content.

Development and application of a combined soil water - slope stability model

Abstract: Summary A general one-dimensional soil water infiltration scheme is coupled to an infinite slope stability analysis model to illustrate the potential of exploring the impact of soil suction and parameter variability in stability analysis. The primary data base used for this investigation is published data for the Mid-Levels area of Hong Kong. The model is used to show that current procedures in the estimation of c′ and φ′ derived from strength tests do not perhaps accurately reflect the strength of the residual soils examined. More generally, the desirability of two-dimensional modelling in the context of both soil suction/pore pressure models and stability analysis is discussed, but the parameterization and validation problems of such a scheme are considered to be immense.

Soil stabilization with portland cement

Abstract: Soil sampled from Islamiat Block, Peshawar University was stabilized with different percentages of Portland Cement type I (by weight of dry soil), to study the effect of cement contents and curing age on the compressive strength of soil. Cement in varying proportions (2, 4, 6, 8 and 10%) was added to the soil and standard Proctor Compaction Test was performed on each sample to find the maximum dry density and optimum moisture content. Samples of soil-cement mixtures at optimum moisture content and maximum dry density were made and compressive strength determined after curing for 7, 14 and 28 days. Soil cement losses, moisture and volume changes at 12 number of wetting and drying cycles were studied. This study has indicated that the soil was responsive to cement stabilization. Soil stabilized with cement content of 6% developed compressive strength of 250 p.s.i. at the age of 7 days. 350 p.s.i. at the age of 14 days and 490 p.s.i. at 28 days. It was concluded that the soil can be stabilized with 6% of cement, for use as construction material for the sub-base and base course.

Uplift Behavior of Shallow Soil Anchors—An Overview

Abstract: An overview is presented of the static uplift (tensile) behavior of shallow anchors used for foundations in soil. Basic anchor types are described, and their general installation and behavioral characteristics are discussed. Anchor failure modes are evaluated, from which a general and consistent framework is presented for the geotechnical analysis and design of the different anchor types. Recommended criteria for design parameter assessment also are included.

Tensile Fracture and Fatigue of Cement Stabilized Soil

Abstract: Portland cement stabilized soil is widely used as a base material for roads, airfields, and similar structures. Cracking in this material is studied using fracture mechanics concepts. Fracture toughnesses in the form of the plane strain stress intensity factor and in the form of the J-integral are used as primary descriptors in the study. A simple power law is used in the case of fatigue loading to describe the relationship between the change in crack length per load cycle and the fluctuation in the stress intensity factor. Approximate relationships are developed which define the relationship between the physical and chemical nature of the material and its engineering usage. These relationships consider cement content, compactive effort, and fracture toughness.

Improvement of Liquefiable Foundation Conditions Beneath Existing Structures.

Abstract: : The stabilization and improvement of liquefiable soils beneath existing structures is currently feasible within the state of knowledge and assumptions concerning liquefiable soils and earthquake excitation. This can be done directly or indirectly to mitigate the effects of liquefaction and to assure safe performance. At the present time there has been essentially no experience with remedial actions in liquefiable soils at existing structures and no general method is applicable for all conditions. Each site is unique and will require specific engineered solutions. This report presents and briefly discusses methodologies that have been deemed potentially applicable for remediating liquefiable soils beneath existing structures. A comprehensive bibliography is included on the feasible methods. The most important factors for construction in choosing remedial methods/techniques are: (a) the verfiability of improvement and stabilization, and (b) the assurance that the method itself will not create unsafe and unstable conditions under static and dynamic loading. Originator-supplied keywords: Admixture stabilization; Compression; In-situ deep compaction; Injection and grouting; Liquefaction; Pore-water pressure relief; Remedial treatments; Soils; Soil reinforcement; and Thermal stabilization.

Evaluation of alternate surfacing systems for temporary and intermittent use roads

Abstract: approved: Robert D. Lay The purpose of this study was to provide the USDA-Forest Service, Bureau of Land Management (BLM), and other agencies or industries that may deal with temporary and intermittent use roads with the necessary background information for the identification, economic evaluation, and selection of the alternate surfacing systems and to determine the applicability and cost effectiveness of each system compared with crushed aggregate roads. Alternate systems considered include those which: 1) are capable of being moved as the hauling or mining activity moves, 2) degrade after use, and 3) significantly reduce the amount of rock required. A comprehensive market and literature search was performed. Potential surfacing types identified in this study are biodegradable materials, chemical stabilization, geotextile or geogrid separation, marginal aggregates, sand-sealed subgrade, metal mats, reusable aggregate with or without geotextile separation, membrane-encapsuRedacted for privacy lated soil layer (MESL), and Geoweb stabilization. Numerous properties of these materials are evaluated, including size, weight, cost, expected performance, mechanical properties, and availability. A two-step evaluation procedure is developed. First is the preliminary evaluation step, which screens various alternate materials based on their characteristics, limitations, and availability. The second step is economic evaluation, which determines the most feasible economical alternatives. Two examples are analyzed to describe the evaluation procedure. The results of this analysis indicate that alternate surfacings can be economical compared to aggregate in most situations. A probabilistic approach using the Beta estimation procedure is recommended for the analysis and evaluation of the uncertainty associated with various elements of the alternate surfacings. Furthermore, a detailed sensitivity analysis is performed for crushed aggregate and soil stabilization surfaces. The results of this research indicate that the feasible alternatives for surfacing temporary and intermittent use roads are biodegradable materials, soil stabilization, marginal aggregates, conventional geotextile and extruded plastic mats, steel mats (M8A1), and sand-sealed native subgrade. Evaluation of Alternate Surfacing Systems for Temporary and Intermittent Use Roads by Mojtaba B. Takallou A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed June 13, 1985 Commencement June 1986

Effect of soil conditioners on the permeability and stability of soils

Abstract: Permeability and wet sieving tests were carried out to study the effect of soil conditioner treatments on aggregate stability of a loam, clay loam and silty clay soil, and to evaluate possible applications in drainage, such as treating the trench backfill in soils of low permeability. The permeability test and prolonged wet sieving test were considered to be valid methods for determining the behaviour of soil aggregates. The permeability and stability of a soil are strongly affected by soil texture and soil moisture conditions after treatment. Treatments with polymer solutions are effective with regard to both stability and permeability, even in situations where the soil remains moist after treatment. Treatments with emulsions were effective for loam soil when the samples were dried out, and for the silty clay soil at higher moisture contents. For the clay loam soil the highest permeability was found at higher moisture contents although a high instability index was obtained after prolonged wet sieving. Treatment with soil conditioners, especially polymer solutions, results in highly permeable and stable aggregates under a wide range of moisture conditions after treatment.

Design Manual for Geotextile-Retained Earth Walls.

Abstract: : Soil, especially granular, is relatively strong under compressive stresses. A typical reinforcing material, on the other hand, can carry significant tensile forces. When combined, a reinforced soil is attained. Because of the interaction of the reinforcement and soil, the resulted composite structure possesses higher strength. This extra strength means, for example, that a slope can be built steeper. Geotextile, a fabric made of polymer material, was introduced as a soil reinforcing agent in the late 1950s. Since the early 1970s, it has been utilized in the construction of retained soil walls. In these walls, the geotextile sheets are used to wrap compacted soil in layers producing a stable composite structure. Geotextile-retained soil walls somewhat resemble the popular sandbag walls. Contrary to sandbag walls, however, geotextile reinforced walls can be constructed to significant height because of the geotextile's higher strength and a simple mechanized construction procedure.

Design parameters for deep stabilized soil evaluated from in-situ and laboratory tests. proceedings of the eleventh international conference on soil mechanics and foundation engineering, san francisco, 12-16 august 1985

Abstract: Deep stabilization has been used in Finland since 1974 Some problems remain to be solved, in particular the question of how to evaluate the parameters of the stabilized soil and the selection of the correct design method An attempt was made to evaluate shear strength and compressibility in the laboratory using samples taken in-situ, as samples mixed in the laboratory had in some cases given values deviating greatly from in-situ measured values The laboratory prepared samples also deviate in respect of temperature and pressure Temperature in particular is essential for the strengthening of the stabilized column This paper gives results of research on the effect of temperature on strengthening, on the decrease in the strength of lime-stabilized clay due to the presence of humus and sulphur, on the effect of air trapped during construction in the column, and on the compression of the column For the covering abstract of the conference see IRRD 287689 (TRRL)

Electrical technique for in-place stabilization of contaminated soils

Abstract: In situ vitrification is discussed as an emerging technology that is currently being tested for the potential in-place stabilization of radioactive, transuranic wastes at Pacific Northwest Laboratory. The advantages to in situ vitrification are listed and include: long-term stabilization of radioactivity; cost effectiveness; applicability to varying soil and conditions; minimal occupational exposure to the waste during processing; and, low energy requirements.

Environmental Impact Research Program. Restoration of Problem Soil Materials at Corps of Engineers Construction Sites.

Abstract: : This report contains information on the planning and implementation of vegetative restoration for problem soil materials at Corps of Engineers construction sites. Problem soil materials described include acid soils, saline and alkaline soils, excessively drained soils, poorly drained soils, dispersive clays, and wind-erodible soils. Plant materials are listed for different regions of the United States as well as information on seeding and planting procedures. The report should be a valuable resource document for planners and engineers that are required to control soil erosion and vegetate project sites that contain problem soil materials. Contents: Identification of Problem Soil Environments; Planning the Restoration of Problem Soil Material Sites; Land Treatment and Soil/Regolith Conditioning Measures; Vegetative Stabilization of Problem Soil Materials; Nonvegetative Stabilization Practices.

Interaction of soil and buried rigid structure. proceedings of the eleventh international conference on soil mechanics and foundation engineering, san francisco, 12-16 august 1985

Abstract: Deep mixing method has been applied in Japan to reinforce soft clay by manufacturing an extraordinarily stiff treated soil mass in-situ. Interaction of soft alluvial soil and the treated soil walls resting on reliable stratum is investigated to improve current design procedure. It is known from the centrifuge model test that the external forces are carried solely by the treated soil walls, that the magnitude and distribution of contact pressures at the surface of treated soil mass are dependent on the magnitude of factor of safety against external stability, and that the pressures change with time due to consolidation process of soft soil. For the covering abstract of the conference see IRRD 287689. (Author/TRRL)

Type C Fly Ash and Clay Stabilization

Abstract: Because the soils onsite have a high swell potential, a 37 foot high retaining wall was designed with counterforts and was supported by pier foundations to limestone. In order to reduce the lateral earth pressures on the wall a sufficient amount to eliminate both the counterforts and the piers, a laboratory study was carried out using two Type C fly ashes to stabilize the backfill soils. The two Type C fly ashes came from different Kansas City Power & Light plants that have similar designs and operate similarly. However, the influence of the two ashes on the mechanical properties of local weathered shales and silty clays is significantly different.

A new method of soil stabilization. polymer grid reinforcement: proceedings of a conference sponsored by the science and engineering research council and netlon ltd and held in london 22-23 march 1984

Abstract: The paper describes a novel method of soil stabilization which involves mixing into the soil molecularly oriented mesh elements in the form of squares, rectangles and ribbons. Laboratory compaction, CBR, triaxial and model footing tests are detailed in which 40 mm square mesh elements are mixed into sand in order to identify the important properties of the mesh and the effect of the mesh element content on the behaviour of the stabilised soil. The results indicate that the basic operating mechanism is that each mesh interlocks with the adjacent soil particles to form an aggregation and these aggregations are locked together by the surrounding mesh elements to form a coherent matrix with improved stress resistant properties and increased ductility. These benefits are obtained even when the mesh element content is small. For the covering abstract of the symposium see IRRD 284425. (Author/TRRL)

The Potential of Alginic Acid and Polygal for Soil Stabilization

Abstract: The potential of two carbohydrate polymers, alginic acid and polygal for soil stabilization is examined in the light of soil gradation, clay mineralogical type and additive type and content. It is found that in line with their strategic occurrences in nature both alginic acid and polygal can improve the strength of (i.e. stabilize) some soils. Their ability to do so increases with the surface activity of the clay mineralogy and best results are achieved with clays which are weathered. However this ability is rapidly lost with soils containing increasing quantities of sand or on immersion of the stabilized soil samples in water at normal atmospheric conditions. The additives are thus best used with soils containing nearly hundred percent clay and the finished products should be protected from direct contact with water. The advantage of polysaccharides over other soil additives is advanced and stressed.

Soil stabilization for remote area roads. final report

Abstract: A laboratory study has been completed which shows that the sands to silty sands typical of the Yukon-Kuskokwim Delta area of Alaska can be significantly improved or stabilized by use of emulsified asphalt and Portland cement. The Yukon and Kuskokwim Deltas are sedimentary areas where the high silt loadings of these rivers are deposited as the river velocities drop on approach to the Bering Sea. Soils are predominantly organic sandy silts, with occasional silty sand deposits. Gravels are generally not present, and are barged in for embankment construction at considerable expense. Samples of the best available soils for roadway construction were taken at each of thirteen different villages. The best of the available materials, fine silty sands, were selected from three sites for laboratory stabilization testing. Stabilizers considered were restricted to asphalt emulsions and cement. The study shows that stability levels can be achieved which should allow use of locally available sands or silty sands for the construction of roadway and airport surfacing and base stabilzation projects. (Author)

Stabilitätsrelevante Mineralreaktionen in chemisch behandeltem bindigen Baugrund

Abstract: Soil stabilization was used already in ancient times in road and building eonstruetion as well. Its fundamental rules have been developed in the past decades and are still worked out in our days by the method of “trial and error”. Only few attempts have been made to learn the chemical mechanisms of the soil — Stabilisator interaction.