Showing papers on "Soil stabilization published in 1982"

Soil Improvement with Quicklime and Filter Fabric

Abstract: The multiple strip-sandwich method is a specially devised method using quicklime and filter fabric for embankments with difficult cohesive soils. A quicklime layer of 5 cm (2 in.) thick, sandwiched between two sheets of filter fabric of 30 cm (12 in.) wide, is placed in a triangular configuration with a horizontal pitch of about 2 m (6.6 ft) at each stage of piling the cohesive soil. Owing to combined actions resulted from the hydration of quicklime, particularly the absorption of water, the cohesive soil is effectively dewatered resulting in consolidation in success, to be able to achieve a high embankment efficiently due to an adequate increase in the shear strength of the cohesive soil by a certain depth both on and beneath the respective sandwich layers. This paper describes a case history for the construction of a high embankment, 32 m (105 ft) high, using the method with cohesive soil of a strongly weathered tuff. The work was successful and the multiple strip-sandwich method proved to be useful for constructing high embankments with difficult cohesive soils.

Road pavements on expansive clays

Abstract: This paper briefly outlines the world-wide problems that can result from the construction of road pavements on expansive clay subgrades. Initially the basic concept of clay soil heave is discussed, including the effects of site drainage and pavement loading. A seasonal heave prediction method for Australian conditions is also presented. A brief "state of the art" on the major techniques most commonly used in an attempt to overcome these problems is presented as well as a list of references for more extensive information. These common techniques include lime stabilisation, prewetting, and the use of membranes to prevent moisture migration within the subgrade. The need for appropriate site drainage and edge treatments are emphasised and the paper concludes that from the point of view of expansive clay behaviour, road pavements are best constructed on initially wet subgrades. (Author/TRRL)

The potential use of a degradable erosion control membrane in the United Kingdom

Abstract: In simple terms, erosion is the removal and loss of soil by the action of water, ice, gravity or wind. In the UK and elsewhere, on construction sites of all kinds, erosion by water is the major problem. There are three steps involved in water erosion: detachment, movement and deposition. Of these three phases, detachment is the most critical, since this is where erosion starts. In this first phase soil particles are detached from the soil mass by raindrop impact or by water running over the soil. Initially some moisture may be absorbed, depending upon soil condition, but eventually water impact causes splashing and brings the soil particles into suspension by breaking down soil aggregates. This process has two consequences. The first is the obvious: direct erosion. Since the soil particles are detached from the soil mass they are much more susceptible to being transported by surface run-off. The second, the splashing soil particles, creates a turbid fine suspension which, when it enters the soil, clogs the soil pores. Continued raindrop impact compacts and seals the soil surface and reduces the possibility of penetration by water. This then allows greater run-off and more erosion. This secondary factor can be important and it has been demonstrated that rain falling on to an exposed soil for less than 4 min can decrease water penetration to the point where 98% of water falling thereafter runs off. The problems associated with erosion are both environmental and economic. Detachment and movement of soil means a

Use of fabric reinforcement for reinstating unstable slopes

Abstract: Following the failure of a large section of cutting in London clay on the M4 motorway in Berkshire reinstatement was undertaken using the lime modified original soil reinforced by layers of fabric. Notwithstanding that the failure zone was much more extensive than had been initially realised the reinstatement costs proved considerably less than the estimated cost of the conventional procedure of replacing the unsuitable material with a granular soil. The report presents some aspects of the site geology, gives details of the soil testing and methods of analysis, describes construction technique and discusses cost considerations. (Author/TRRL)

Resilient characteristics of brazilian soils

Abstract: Resilient properties of twenty soil samples from subgrades, sub-bases, and mechanical stabilized soil bases of flexible pavements in the South and Southeast of Brazil were evaluated. Soils are mostly residual in origin. Correlations of resilient moduli with confining pressure or deviator stress were established. Correlations of resilient moduli with CBR values were established for finegrained soil samples. A tentative soil classification according to resiliency is developed. Also reference is made to the applications to pavement deflection calculations.

Soil Improvement by Deep Cement Continuous Mixing Method and Its Effect on the Environment

Abstract: : Since the coastal area of Japan, is mainly composed of soft alluvial clay, it is important to know how to improve the soft clay deposits. In order to achieve rapid construction of structures with heavy super structures and to meet environmental restrictions which are strengthened year after year, new improvement techniques are needed. The deep cement continuous mixing method (DECOM) was developed for this purpose. This method is based on cementation rather than the usual concepts of consolidation, drainage, compaction, and replacement. Since the DECOM method enables rapid stabilization without pollution, many soil improvements using this method have been conducted. In this paper, the problem of how to achieve the quality between previously improved and newly improved zones, called 'the overlapping problem,' is discussed as well as the effect of DECOM on environment conditions using field measurements from Yokohama Harbour.

Economic analysis of soil-cement base construction as compared to crushed rock base

Abstract: Cement stabilization operations involve some special equipment with relatively high initial investment; this equipment is generally more expensive than conventional one. There is some doubt as to the economy of employing soil-cement to replace crushed rock base. An economic analysis is made of the cost of renting and operating the equipment, cost of cement, and cost of the soil. The results of the analysis indicate that soil-cement bases are cheaper than crushed rock bases by about 35 to 46 percent when the crushed rock has to be transported to the construction site over a distance of 200 to 300 kilometers. It was found that the most expensive item was the cost of cement, and the cheapest one was that of machinery. Cement cost accounted for 57% while the cost of machinery was only 19% of the total cost. (TRRL)

Research on rice husk ash for stabilising black cotton soil

Abstract: Problems associated with the use of black cotton soil in India are usually caused by swelling and shrinkage on the absorption or depletion of moisture. The stabilisation of the soil is therefore of importance and ways of overcoming the shrinkage and swelling characteristics are considered. Stabilisers such as cement and lime have been widely used to counteract these problems although to achieve greater economy the use of rice husk ash in this application is examined in the paper. Tests described were carried out to stabilise black cotton soil using lime and rice husk ash as a 12% admixture. It was found that the 28-day shear strength with such an admixture in the proportion 1:4.5 indicated that almost 50% savings in lime could be made with such an admixture compared with soil treated with only 12% lime. (TRRL)

Use of waste materials from coal combustion in road construction

Abstract: This report is a literature study dealing with what is written about the use of waste materials in road construction in different countries. Fly ash from coal powder combustion is used in concrete and cement industry, road construction, etc. The chemical and physical properties of fly ash, the stabilization of it, its behaviour in embankments and the treatment of the soil materials with fly ash, are discussed. Other subjects which are studied are fly ash as filler in asphaltic mixes, treatment with lignite, fly ash, waste material from flue gas desulphurization, waste material from fluidized bed combustion, use of bottom ash and stoker slag. (TRRL)

Soil stabilization work by planting vegetation

Abstract: PURPOSE:To permit the planting of vegetation even in pumice stone layer, etc., by adding bentonite as a cultivating agent to the planting base ground so as to avoid the saturation of moisture and also to gretly raise the durability of a soil sheathing plate. CONSTITUTION:A mixture of seeds, fertilizer, soil, a curing agent, and a soil stabilizer is mixed with a mixture of bentonite, polyvinyl acetate emulsion, and a starch glue, together with, as needed, flint coat. Then, on the planting base ground thus obtained and placed on a slope, vegetations are planted through soil sheathing plates driven at proper intervals.

Lime-fly ash stabilization for pavement repair

Abstract: The paper reports how mixed-in-place base stabilization was used in Illinois in an area subject to frequent flooding in an effort to reduce maintenance costs.

Comparative evaluation of different low cost specifications for rural roads in black cotton soil areas

Abstract: The paper contains detailed data on the subgrade and site conditions, ground water table, locally available materials of construction, design and construction specifications adopted on the test sections laid in 1964 by the Central Road Research Institute on black cotton soil areas in Madhya Pradesh State of India. The performance evaluation records for the years 1966, 1969, 1973 and finally 1980 are presented. The study revealed that moorum soils as such, and after stabilization with 1 to 3 percent lime, are the most suitable and economical materials of construction for rural roads catering for light to medium traffic. Black cotton soil after stabilization with 3 percent lime attains high strength, and can be used successfully in the construction of sub-bases or rural roads. (TRRL)

A field study of the use of the dynamic consolidation ground treatment technique on soft alluvial soil

Abstract: Field observations have been made at a site where dynamic consolidation has been used in an attempt to increase the undrained shear strength of saturated soft alluvial soil. Pore water pressures and undrained shear strength have been monitored before, during and subsequent to dynamic consolidation. The effectiveness of this ground treatment technique on soft alluvial soil has been assessed. (Author/TRRL)

Studies on Soil Cements: 1 - Role of Hydrated Lime and Dolomitic Monohydrate in Montmorillonite Stabilization

Abstract: Montmorillonite clay was stabilized by either hydrated lime or the dolomitic monohydrate (Ca(OHh. MgO) during suspension hydration at 25 and 600C for 45 days. The distinct phases produced from the hydration of each stabilized clay suspension were identified by means of X-ray diffraction analysis. The role of either Ca(OHh and/or MgO in soil stabilization could be clearly understood in order to extend the use of portland cement for the stabilization of montmorillonite to produce soil cements.