Showing papers on "Soil stabilization published in 2000"

Soil improvement by the vacuum preloading method for an oil storage station

Abstract: This paper presents a case study on the application of the vacuum preloading method for a soil improvement project in Tianjin, China. The site area was 50 000 m2, and the soft clay treated was about 20 m thick, including a very soft muddy clay layer 4–5 m thick, formed from dredged slurry. The water contents of the clays were higher than or as high as the liquid limits. A vacuum load of 80 kPa was applied for 4 months. The ground settled nearly 1 m, and the average degree of consolidation was greater than 80%. The undrained shear strength of the soil increased two- to threefold after treatment. The procedures used for soil improvement, the field instrumentation programme, and the field monitoring data are described and discussed.

Field and Laboratory Evaluation of Cement Kiln Dust as a Soil Stabilizer

Abstract: A field and laboratory study was conducted to evaluate cement kiln dust (CKD) as a soil stabilizer. The performance of CKD from three different cement manufacturers was compared with that of quicklime. Field-work involved construction of test sections along a rural highway in Oklahoma. Observations were made to compare construction requirements for CKD and lime. Treated soil samples were collected from the field to prepare specimens for unconfined compression testing in the laboratory. In situ testing included dynamic cone penetration testing in the stabilized subbase and falling weight deflectometer testing after completion of the pavement. Chemical testing was conducted to determine the chemical makeup of each dust, and soil-CKD mixtures were tested for pH response. Chemical tests on the CKD and CKD-soil mixtures revealed aspects of the CKD composition that can be correlated with the degree of stabilization. Regarding strength improvements, results showed that CKD from one cement plant performed signifi...

Stabilization of Clay with Inorganic By-Products

Abstract: New binder alternatives based on industrial by-products were studied for stabilization of clayey soils. The main emphasis was on pulverized, granulated blast-furnace slag activated in different ways, and on binder combinations based on fly ash and waste from desulfuration units. Cement was used as the control binder. The aim of this study was to evaluate the stabilization characteristics of new binder alternatives with different mixture combinations and to understand the effects of geotechnical index properties of clay and chemical/mineralogical composition on stabilization characteristics. The results of the laboratory tests indicate that the strength of stabilized clay is strongly dependent on the water-binder ratio, and that the strengthening effect is minimal at water-binder ratios below a certain threshold value. For the clay types examined in this study, blast-furnace slag activated with cement generally gives higher strengths than cement alone after the relatively long hardening periods usually emp...

Engineering properties of loess-fly ash mixtures for roadbase construction

Abstract: Southwest Indiana has large deposits of wind-blown loess. Similar deposits are found in other states, including Illinois, Kentucky, Iowa, Minnesota, Missouri, and Nebraska. These soils consist of uniform silt with a plasticity index ranging from 0 to 10. This material is suitable for road construction if it is compacted dry of optimum. However, the material is difficult to work after it becomes wet, which commonly results in construction delays. Indiana also has large stockpiles of Class C fly ash from coal-burning power plants. The ash has cementitious properties after hydration (because of the high calcium content) and can be mixed with native soil to produce a weakly cemented soil. Significant interest exists at the Indiana Department of Transportation about the possibility of using Class C fly ash to improve the engineering properties of Indiana loess soils. The results of a laboratory testing program on the properties of loess-fly ash mixtures are presented. Various percentages of fly ash were mixed with loess soil and specimens were permitted to cure for 3 h to 28 days. Pure loess also was tested for comparison. Changes in Atterberg limits, moisture-density relationships, swell potential, and unconfined compression strength are presented. Based on this testing program, a simple method was developed to determine the optimum fly ash content for construction of a workable loess roadbed to avoid delays in construction due to wet conditions. The data presented will be useful for evaluating the stabilization of loess soils with Class C fly ash in Indiana and other states with significant loess soil deposits.

Incorporating subgrade lime stabilization into pavement design

Abstract: The benefits of subgrade lime stabilization are incorporated, for the first time, into the design of a major interstate highway pavement in Pennsylvania. The project comprises widening and complete reconstruction of 21 km of the Pennsylvania Turnpike in Somerset County. Field explorations indicated that the subgrade is fairly homogeneous and consists primarily of medium to stiff clayey soils. To safeguard against potential softening due to rain, lime modification has been traditionally utilized as a construction expedience for highway projects with clayey subgrade. Such an approach, however, does not take advantage of the added strength of the lime-stabilized subgrade in pavement design. Lime improves the strength of clay by three mechanisms: hydration, flocculation, and cementation. The first and second mechanisms occur almost immediately upon introducing the lime, and they have been investigated in the study; the third is a prolonged effect. Laboratory tests were performed to accurately capture the immediate benefits of lime stabilization for design. Both treated and natural clayey samples were subjected to resilient modulus and California bearing ratio testing. To prevent cementation, the lime-treated specimens were not allowed to cure. Nevertheless, they showed significant increases in strength, which, when incorporated into design, reduced the pavement thickness and resulted in substantial savings.

Slope stabilization with recycled plastic pins

Abstract: A scheme to stabilize minor slope instabilities is currently being developed. The scheme uses a distributed network of "pins" fabricated from recycled plastics and other waste materials to provide positive reinforcement of a soil mass. Although the application is similar to stabilization of slopes with soil nails or micropiles, significant modifications to conventional design and construction are necessary to account for the reduced strength and increased ductility and creep exhibited by plastic materials compared with concrete and steel. Using recycled plastics has the advantage of providing reinforcing members with low susceptibility to degradation and provides a market for materials that otherwise might be buried in a landfill. An extensive investigation is under way to evaluate the potential for using recycled plastic pins (RPPs) to stabilize minor slope failures. This evaluation includes quantification of appropriate material and engineering properties of RPPs, evaluation of RPP resistance to degrada...

Laboratory performance evaluation of cement-stabilized soil base mixtures

Abstract: In-place cement-stabilized soils have served as the primary base material for the majority of noninterstate flexible pavements in Louisiana for many years. These materials are economically and easily constructed and provide outstanding structural characteristics for flexible pavements. However, these cement-treated materials crack due to shrinkage, with the cracks reflecting from the base to the surface. A laboratory study examined the performance of four different cement-stabilized soil mixtures recently used in the construction of test lanes at the Louisiana Pavement Testing Facilities. Laboratory tests included the indirect tensile strength and strain, unconfined compressive strength, and indirect tensile resilient modulus tests. The four mixtures were (a) in-place-mixed cement-treated soil with 10 percent cement, (b) plant-mixed cement-treated soil with 10 percent cement, (c) plant-mixed cement-treated soil with 4 percent cement, and (d) plant-mixed cement-treated soil with 4 percent cement and fiber ...

Stability of Structural Form during Infiltration Laboratory Measurements on the Effect of De-inking Sludge

Abstract: An adequate understanding of the mechanisms involved in the structural stabilization of soil by different sources of organic matter is needed to help design management strategies aimed at maintaining a stable soil structure. The objective of this study was to identify mechanisms involved in soil structure stabilization by paper sludge application, either by increasing the soil resistance to external stresses (aggregate stability) or by decreasing the magnitude of the external stresses (diminution of the wetting rate). A laboratory study was conducted on three different soil types with application of paper sludge at three rates (8, 16, and 24 dry t ha -1 ). The mean weight diameter, bulk density, hydraulic conductivity, and water retention properties were measured before and after a wetting event. The results indicate that most of the changes in physical properties resulting from rapid wetting took place at the soil surface (0-50 mm) and the magnitude of these changes gradually decreased down to a depth of 150 mm. Paper sludge application significantly improved the stability of 1-to 4-mm aggregates to the destructive action of wetting in all three soil types. Paper sludge application increased porosity at potential > 2 kPa, which resulted in higher hydraulic conductivity values (up to 88%) and a smaller increase in soil bulk density (down to 67%) relative to a control following rapid wetting. The wetting rates observed during the wetting event were similar regardless of the treatment, because the increase in the water potential at the wetting front was compensated for by an increase in hydraulic conductivity with increasing rates of sludge application.

Essay competition: Green, ground and great: soil stabilization with slag

Abstract: The reuse of materials, which would in the past have been considered as waste to be dumped at some land® ll site, possibly in the middle of attractive countryside, has now become a very desirable option. It is a popular way for companies to demonstrate and advertise environmentally friendly behaviour and has in some cases proved to have considerable economic advantages. Within the context of increasing land® ll taxes and possible health hazards often associated with stockpiling of the waste, no material can afford to be stigmatized as a `waste product’ any more. Labelled as `by-products’ or r̀ecycled goods’ , the `waste’ material is now fed into the industry from whence it originated to be reprocessed for a wide range of other applications. Thus old tyres, brick waste or even empty soda and lager cans are ® nding new and innovative uses and many yet undreamt of applications wait to be tried. A less visible but nonetheless useful `waste’ material has already found reapplication in the construction industry: ground granulated blast furnace slag (GGBS) has been known for some time to improve the sulphate resistance of concrete, when incorporated into cement. Its application for geotechnical purposes, however, has been rather limited in the past.

Chemical and mechanical stabilization

Abstract: In the construction and maintenance of transportation facilities, geomaterials--soils and rocks--must be stabilized through chemical and mechanical processes. In applying these techniques, it is necessary to ensure the properties of stabilized geomaterials and their mixtures as applicable for use in the design of foundations, embankments, shoulders, subgrades, bases, and surface courses. In the new millennium, the challenge will be to develop better chemical stabilizers and mechanical stabilization techniques; new, quicker, and better testing methods; and better and environmentally safe methods for using waste materials for highway construction. This paper discusses some of the areas where research is needed to develop the materials and methods required to meet this challenge.

Applicability of cement-stabilized pond-mud soil as embankment material for irrigation pond dam repairment

Abstract: ため池内に堆積した底泥土は貯水容量の減少や水質の悪化などため池機能の低下の原因になる. このため一部で機能回復のための底泥土の浚渫除去が行われている. しかしこの浚渫された底泥土は, 粘土・シルト分を多く含み含水比が極端に高い超軟弱土で, その捨て場所の確保も難しくなってきている. このような底泥土がため池堤体の改修あるいは補強のための盛土材として利用できれば, 捨土処分が不要になりかつ必要な盛土材を原石山の用地買収を伴う形で求める必要がなくなるなどの利点があり, 効率的な底泥土の処理とため池の改修・補強が可能となる. そこで, 本研究は, このようなため池に堆積した底泥土をセメント系固化材で固化処理した改良土により, ため池の堤体を改修あるいは補強するための盛土材としての適用性を検討したものである.

Construction Methods for Slope Stabilization with Recycled Plastic Pins

Abstract: A new method for reinforcement of surficial slope failures is currently being developed that utilizes reinforcing elements, similar to soil nails, manufactured from recycled plastics and other waste materials. Using recycled plastics has the advantage of providing reinforcing members with high resistance to degradation while providing a market for materials that might otherwise be landfilled. A key aspect of development of the new stabilization scheme is development and evaluation of equipment and methods for installing the plastic reinforcing members. In this paper, results of a series of laboratory and field tests performed to evaluate alternative installation techniques are presented and installation activities performed to construct a full-scale field demonstration are described. Results of development activities to date indicate that recycled plastic members can be reliably and efficiently installed to produce a cost-effective alternative to more conventional slope stabilization techniques. Evaluation of the suitability of recycled plastic pin stabilization schemes for effecting long-term stabilization is ongoing.

Pelletized straw mulch and method of use thereof for soil stabilization and grass and wildflower seed enhancement

Abstract: The present invention is for a mulch device for soil stabilization and grass and wildflower seed enhancement comprising pelletized straw mulch having high bulk density, straw fibers, and fertilizing qualities. The pelletized straw mulch is spread onto a surface to reduce soil erosion, to promote seed establishment, to promote water infiltration and retention, to promote soil stabilization and to enhance soil fertilization. Also disclosed is a novel method of using straw for soil stabilization and grass and wildflower seed enhancement.

Behaviour of geogrid reinforced abutments on soft soil in the br 101-sc highway, brazil

Abstract: This work presents the behaviour of geogrid reinforced bridge abutments in the BR-101 highway, in the state of Santa Catarina, Brazil. Unidirectional geogrid layers were used as reinforcement for the embankments. A coarse sand was employed as fill material and the foundation layer consisted of an organic soft clay. Because of the nature of the foundation soil and the proximity of existing structures, geotechnical instrumentation was installed to assess the reinforced structure displacements. The results showed that the presence of the reinforcement layers reduced the soft soil lateral displacements and the damages to the existing structures. A preliminary stability analysis of one of the abutments is also presented and discussed.

Dynamic calculation model of shanghai soft soil

Abstract: In this paper, Shanghai saturated soft soil is modeled as a two-phase porous media system consisting of solid and fluid phases. On the basis of resonant column test and dynamic triaxial test data of Shanghai saturated soft soil, the dynamic calculation model including a set of relationships of stress, strain, pore water pressure and earthquake subsidence is developed to compute the seismic response of soil. The procedure to identify soil constants for the dynamic calculation model is also reported in detail. Subsequently, a dynamic effective stress analysis with the finite element method has been recommended to predict the seismic response of soil. Finally, the developed dynamic calculation model together with the dynamic effective stress analysis is utilized to predict the seismic response of Shanghai soil strata through the finite element method and some valuable conclusions are obtained from the results.

Formula to Get Desired Soil Density

Abstract: Changing the soil characteristics is a main concern to all civil engineers. Highway and foundation engineers are particularly more concerned with the subject. There are several methods to improve the soil characteristics. One of these methods is to add fine material, which fills the voids between the grains of the soil, helping to make the soil denser, thus gaining high resistance to penetration. This study uses statistical parameters of the soil grains distribution to predict the soil maximum dry density, then uses the fine biasness coefficient to predict the new density of the soil after mixing any amount of fine particles with the original soil. A mathematical formula is developed to make such a prediction. Lab testing results were compared with the results of the prediction. They were found to be in total agreement, and the margin of error was found to be quite low.

Vegetated Erosion Control Mats for Site Stabilization

Abstract: We grow grasses directly on erosion control mats in the nursery and then transport the sod to sites where establishing permanent vegetation is difficult due to adverse human or environmental factors. The vegetated erosion control mats system is a simple, viable method that can be effectively used to provide immediate erosion control and visual appeal.

Soil Stabilization/Soil Cement: Mark-Lang, Inc.'s Approach

Abstract: Bidding soil cement is somewhat unique. The nature of mix in-place soil cement does not allow a 7 a.m. to 3 p.m. work schedule. When the cement is applied the material cannot be left overnight. The operation must be completed even if overtime work is necessary. Working around utilities can be a very challenging matter. Of major concern during a soil cement operation is the amount of rock in excess of softball size. Successful completion of a project requires the use of proper equipment. It is important to determine and use the appropriate pulvermixer for the soil type.

Building a pad from lime stabilized soil

Abstract: This article describes a lime stabilized soil process that generally is considerably less expensive than either concrete or asphalt. Lime soil stabilization produces an impervious layer so water does not penetrate, as well as an all-weather surface that allows vehicular traffic under all conditions. Although most soils can be lime stabilized, some soils are more easily stabilized than others.

Evaluation Plan for the Group Evaluation of Soil Stabilization and Dust Suppression Products

Abstract: This Evaluation Plan describes the nature and scope of an evaluation to determine the performance aspects and the environmental impacts of soil stabilization and dust suppression products. A number of agencies using soil stabilization and dust suppression products have expressed a desire to have performance and baseline environmental data performed on these products, which will give them a general picture of how these products perform as well as their impact to the environment. The agencies want this information to make some initial inferences about the products performance and potential impact on local waterways, soils, and plant and animal life.

Stress-strain characteristics of cement treated materials under unconfined compression test

Abstract: Stress-strain characteristics of cement treated materials under unconfined compression test are investigated for use in asphalt pavement analysis and design. Four types of material are Bangkok clay, silty sand, lateritic soil and crushed rock. Each material is mixed with different percentage amounts of ordinary portland cement and molded to form the Proctor sized specimens. After being cured for seven days, they are tested under unconfined compression and the stress-strain curves for each type of cement treated materials are drawn. Test results indicated that stress-strain characteristics of all types of cement treated materials tend to be a polynomial regression with a linear portion up to about 34 percent of maximum stress, and about 25 percent of maximum strain. In other words the linear elastic property of the cement treated material will be held at the stress ratio of 0.34 and strain ration of 0.25. This result is close to the one investigated under flexural test by other researchers who found that the stress ratio and strain ratio are 0.34 and 0.25, respectively. As the unconfined compression test on Proctor sized specimens is more convenient than the flexural test, the result will be useful for determining whether the induced stress due to wheel loads in Thailand is within the elastic limit of the cement treated materials. If not, it is anticipated that micro-cracks should occur in the cement-treated base/subbase, under a particular value of wheel load, and pavement design should be revised. (a) For the covering entry of this conference, please see ITRD abstract no. E204151.

Physical and chemical stability of pure silicate grout and prediction of the long-term strength of grouted sand

Abstract: 薬液注入材の耐久性に関して, ゲル化した注入材の物理・化学的安定性と注入固結砂の長期砂強度の予測法を検討した. 物理・化学的安定性としては, ゲル化した注入材の体積変化と溶脱シリカを長期的に調査した. その結果, 体積変化と溶脱シリカは, 一定期間の経過で, ほぼ停止した. また, 溶脱したシリカは未反応シリカで, 化学的な分解によるシリカはないものと推測でき, 少なくとも4500日間 (12年) は化学的に安定していることがわかった. 耐久性に関連したもう一つの研究として, 長期強度の予測法についても検討を行った. その結果, 外挿法による予測と, 同形アレニュウスプロットによる予測, 2通りの方法で予測が可能であった.