Showing papers on "Soil stabilization published in 1988"

Stabilisation and treatment of clay soils with lime. part 1 - basic principles

Abstract: Clay soil can be stabilised by the addition of a small percentage, by weight, of lime. This produces an improved construction material. Generally the amount of lime needed to modify a clay soil varies from 1 to 3 per cent, whilst that required for cementation varies from 2 to 8 per cent. Montmorillonitic clay soils respond more rapidly to lime treatment than do those in which kaolinite is the dominant clay mineral. When lime is added to clay soils, calcium ions are combined initially with or adsorbed by clay minerals which leads to an improvement in soil workability, that is, to an increase in the plastic limit of the clay and generally to a decrease in its liquid limit. The optimum lime additive for maximum increase of the plastic limit of the soil is referred to as the lime fixation point. Lime added in excess of the fixation point is utilised in the cementation process and gives rise to an increase in soil strength. The initial increase in strength has been attributed to the formation of poorly ordered reaction products which surround the clay materials. However, the development of long-term strength appears to be due to the gradual crystallisation of structurally-ordered new minerals from the initial disordered reaction products. The principle uses of the additions of lime to clay soils is for, firstly, stabilisation of subbases and subgrades in pavement construction and, secondly, to dry out wet soils. Lime treatment also has been used to stabilise embankments and canal linings, and to improve foundation soils. In the latter instance soil is stabilised beneath strip or raft foundations, or lime piles or columns are formed. (TRRL)

Effects of pulverization on the strength and durability of highly active clay soils stabilized with lime and portland cement

Abstract: This paper presents the results of a laboratory investigation exploring the effects of varying degrees of pulverization, from laboratory-quality gradations to field gradations, on the strength and durability of highly plastic clay soils stabilized with lime and portland cement. Background information is presented on the mechanisms of stabilization and on previously reported studies of other materials. A 6-cu yd sample was used to provide 198 large specimens, which were tested in unconfined compression and wet-dry tests. Considerable differences were found in the strength of a highly active clay soil, depending on the gradations used to make specimens. Significant differences were found in the durabilities of specimens, depending on the stabilizer and the gradations used. Lime appears to be a more effective stabilizer for durability and portland cement more effective for strength, provided the gradation is fine enough. Recommendations, subject to further research, include longer curing times and the use of field gradations for all mix designs.

Chemical soil stabilization

Abstract: There is disclosed a method for chemically stabilizing cohesive soils. Sulfuric acid, citrus stripper oil, and water are admixed to the soil. Then the soil is packed to consolidate the soil particles.

Comparison of quicklime and hydrated lime slurries for stabilization of highly active clay soils

Abstract: Research is presented that was used to compare the stabilizing effects of quicklime and hydrated lime slurries when applied to three samples of highly active clay soils from each of two geologic formations from North Central Texas. In addition, slurries made of the commercial lime products used in the research were studied and compared. The results obtained included soil properties measured before and after stabilization with these two slurries. These results were compared by using statistical methods to determine the significant differences. It was found that the quicklime slurries had a less detrimental effect on compactibility of the soil, provided somewhat lower swell, caused the soil to have lower plasticity and higher strength, and allowed a lower percentage of lime to be used. In addition, significant differences in time-related changes in properties are discussed in the analyses and conclusions.

Special Topics in Foundations

Abstract: This book contains papers presented at a session related to various theoretical and experimental developments on foundation analysis, design and construction. The papers were written by both researchers and practitioners. Topics include the development of a nonlinear model for prediction of movement of drilled shafts in expansive clay; new techniques for lime stabilization of expansive clay for foundation construction; evaluation of soil improvement achieved by sand columns for foundation construction by means of plate load tests; uplift capacity of vertical multihelix, and inclined plate anchors; bearing capacity and settlement characteristics of shallow foundations on granular trench made in clay, and with geoweb used as reinforcement in granular soil.

Soft soil stabilization using geosynthetics

Abstract: Part 1 - Design. Fabric reinforced embankment test section, Plaquemines Parish, Louisiana. Soft soil stabilization designs using geosynthetics. Stabilization of very soft soils using high strength geosynthetics: the role of finite element analyses. Influence of fabric geometry on the shear strength parameters of various plain wave geotextiles. Discussion. `Current Design Methods' by R.M. Koerner, B.-L. Hwu and M.H. Wayne. Part 2 - Details. Seaming and joining methods. Preloading with prefabricated vertical strip drains. Geosynthetic/soil studies using a geotechnical centrifuge. Testing and monitoring of high strength geosynthetics. Part 3 - Manufacturing and Construction. Method to establish the maximum allowable load under working conditions of polyester reinforcing fabrics. Design optimization of geosynthetic reinforced embankments over soft foundations. Shore line extension with high strength geotextile and ice assistance - a manufacturers view. Geosynthetic material and physical properties relevant to soil reinforcement applications. Geogrid reinforcement for cochrane bridge embankment. Overview of Wilmington Harbor south project. Index.

Soil-stabilizing powdery product, and method of use

Abstract: The invention is in the field of soil stabilization. It is more precisely a powdery stabilizer produced soil in place and its implementation method. This product is made by combining a fatty amine such as chloride distearyl dimethyl ammonium chloride in powder form and at least one pulverulent product chosen from cements, slaked limes, fly ash, hydrophobizing and mixtures with fillers and compatible admixtures.

Technical note. assessment of the unconfined compressive strength of a lime stabilized soil by an abrasion test

Abstract: Stabilization by lime, which is frequently carried out to improve the mechanical properties of soils, results from the formation and development of cementitious calcium silicate aluminate hydrate gel. The gel produces interlocking and bonding of the soil particles, hence increasing the strength and abrasion resistance. The proposed method to assess the compressive strength of the existing structure of lime stabilized soil using a simple mechanical abrasion technique, provides an alternative means by which the strength characteristics can be assessed. The advantages of employing the abrasion method are (1) the relative ease of specimen collection and preparation as the test is not particularly sensitive to specimen size and shape and (2) the ease of application to existing structures as large-scale mechanical testing equipment would not be required once a calibration chart has been esablished, and testing could be carried out on site.

Assessment of the Unconfined Compressive Strength of a Lime Stabilized Soil by an Abrasion Test

Abstract: Stabilization by lime, which is frequently carried out to improve the mechanical properties of soils, results from the formation and development of cementitious calcium silicate aluminate hydrate gel. The gel produces interlocking and bonding of the soil particles, hence increasing the strength and abrasion resistance. The proposed method to assess the compressive strength of the existing structure of lime stabilized soil using a simple mechanical abrasion technique, provides an alternative means by which the strength characteristics can be assessed. The advantages of employing the abrasion method are (1) the relative ease of specimen collection and preparation as the test is not particularly sensitive to specimen size and shape and (2) the ease of application to existing structures as large-scale mechanical testing equipment would not be required once a calibration chart has been established, and testing could be carried out on site.

Reinforced Soil-Metal Structures

Abstract: Many of the existing soil-metal structures have shown signs of serious distress, including local failures. A major cause of these distress conditions is believed to be due to poor compaction of the soil backfill. To correct this shortcoming, research work was underaken to examine the following design concept: (1) The metal structure is tied back into the surrounding granular soil; and (2) the soil cover above the metal structure is reinforced. Experimental results, obained from tests on five models, were compared to analytical results based on the finite-element method. The results show that adopting this new design concept: (1) Provides greater stability to the metal structure; (2) improves the stiffness of the soil; (3) activates the entire reinforced-soil medium to assist in the transmission of the load; (4) enhances the arching effect; and (5) makes it possible to observe very large deformations in the metal structure before its collapse and thus avoid catastrophic failure. A simplified design method and an illustrated design example are presented.

A study on the relationship between strength and pore size distribution in compacted stabilized soils

Abstract: Recently, chemical soil stabilizations are actively adopted for the improvement of the soft ground on which roads or buildings will be constructed. In addition to traditional stabilizers of Poltland cement and lime, the industrial by-products such as fly ash and pulverized blastfurnace slag are also used for the purpose of increasing the effectiveness of cement and lime as a stabilizer and their effective utilization in soil stabilization. The objective of this study is to reveal the mechanisms of strength development of the compacted stabilized soils from a microstructural view-point. The compressive strength, modulus of deformation and pulse velocity of various compacted soils stabilized with cement, lime and lime-fly ash (or pulverized blastfurnace slag) were measured. Their microstructures were also characterized by the SEM observation and pore size distributions obtained by the mercury intrusion porosimeter. The relationships between strength and changes in microstructure in compacted stabilized soils are discussed.

Soil-cement for low cost roads

Abstract: In ensuring rapid development to take place, provision of good roads is inevitable. The high cost of the conventional roads has not being served with graded latrite roads or none at all. Laterite road is notoripus for being dusty during the dry season., causing accumulation of undesiable blanket of dust on to house and vegitations. The dust may also have serious effect on health. Formation of deep ruts which are unpassable to vehicles at times is a common occurance in the wet seasons. Thus a high cost is incurred if the roads are to be maintained. The paper intends to present the works carried out at the University Pertanian Malaysia on the stabilization of lateritic soils using cement to act both as the road base and surfacing. The works include conducting basic soil mechanics tests on the soil-cement mixture and evaluating the effects of additives such as sand and rice husk ash on strength. A field trial on the construction of the soil-cement road was also done to evaluate the weathering effect under exposure.

Initial stage hardening characteristics of marine clay improved cement

Abstract: Laboratory vane shear strength tests were conducted in order to study the various characteristics of the initial hardening stages of treated soils, such as the influence of moderate heat portland cement (MP) and blast-furnace slag (slag) mixture ratios, regional differences in marine clays, the influence of the quantity of additive to the slow hardening cement, and the influence of the water/cement ratio, and so forth, with respect to slow hardening cement, which is considered suitable for operations by the deep mixing method of soil stabilization in Japan. The results were that when the quantity of MP in the mixture is decreased, the shear strength of the treated soil decreases. The progress of hardening is closely related to the reactivity of the clay. The influence of the quantity of additives appears after hardening has progressed to a certain extent. When the water/cement ratio is increased, the shear strength decreases. Such characteristics were made clear, and it also became clear that the vane shear strength test is the most suitable method for studying these initial stage hardening characteristics. (A) For the covering abstract see IRRD 863366.