Durmusoglu, Ertan; Sanchez, Itza M.; Corapcioglu, M. Yavuz
Four series of laboratory tests were conducted to evaluate the permeability and compression characteristics of municipal solid waste (MSW) samples. While the two series of tests were conducted using a conventional small-scale consolidometer, the two others were conducted in a large-scale consolidometer specially constructed for this study. In each consolidometer, the MSW samples were tested at two different moisture contents, i.e., original moisture content and field capacity. A scale effect between the two consolidometers with different sizes was investigated. The tests were carried out on samples reconsolidated to pressures of 123, 246, and 369 kPa. Time settlement data gathered from each load increment were employed to plot strain versus log-time graphs. The data acquired from the compression tests were used to back calculate primary and secondary compression indices. The consolidometers were later adapted for permeability experiments. The values of indices and the coefficient of compressibility for the MSW samples tested were within a relatively narrow range despite the size of the consolidometer and the different moisture contents of the specimens tested. The values of the coefficient of permeability were within a band of two orders of magnitude (10-6-10-4 m/s). The data presented in this paper agreed very well with the data reported by previous researchers. It was concluded that the scale effect in the compression behavior was significant. However, there was usually no linear relationship between the results obtained in the tests.
is lightly smeared with silicon grease to minimise side friction during consolidation. Prior to filling the consolidometer Druck pore pressure...measured on specimens aubjected to different consolidation stress ratioa, Kc. l00 Ph 00 400 0> S *0m VELOCITY c -" -A (u/sec)0 3D . Ps Ph 0.3 A 4 INDCE
Lipiński, Mirosław J.; Wdowska, Małgorzata K.; Jaroń, Łukasz
Various behaviour of soil under loading results to large extent from kind of soil considered. There is a lot of literature concerning pure sand or plastic clays, while little is known about materials, which are from classification point of view, between those soils. These materials can be considered as cohesionless soils with various fines content. The paper present results of tests carried out in large consolidometer on three kinds of soil, containing 10, 36 and 97% of fines content. Consolidation, permeability and compressibility characteristics were determined. Analysis of the test results allowed to formulate conclusion concerning change in soil behaviour resulting from fines content.
Heslin, G.M.; Baxter, D.Y.; Filz, G.M.; Davidson, R.R.
The American Petroleum Institute (API) filter press is frequently used to measure the hydraulic conductivity of soil-bentonite backfill during the mix design process and as part of construction quality controls. However, interpretation of the test results is complicated by the fact that the seepage-induced consolidation pressure varies from zero at the top of the specimen to a maximum value at the bottom of the specimen. An analytical solution is available which relates the stress, compressibility, and hydraulic conductivity in soil consolidated by seepage forces. This paper presents the results of a laboratory investigation undertaken to support application of this theory to API hydraulic conductivity tests. When the API test results are interpreted using seepage consolidation theory, they are in good agreement with the results of consolidometer permeameter tests. Limitations of the API test are also discussed
Kayser, Claudia; Larkin, Tam; Singhal, Naresh
Residuals from wastewater treatment operations (biosolids) were mixed with lime, fly ash, lime kiln dust, or two smelter slags to assess their efficacy as potential stabilisation agents by assessing their effects on the shear strength, compressibility, and solids content of mixtures. In addition, the minerals formed and leachate produced during stabilisation were determined. Tests were performed to explore the change of the geoenvironmental properties of the amended biosolids, while under pressure, at different scales using laboratory, pilot and field scale tests. The settlement characteristics of the amended biosolids under a range of applied pressures were determined using a consolidometer. All amended biosolids mixtures showed higher strength than the unamended biosolids, with mixtures containing a combination of 20% fly ash and 20% lime giving the highest (up to eightfold) increase in strength, and that with lime kiln dust and the smelter slags showing the lowest (up to twofold). The biosolids mixtures with only lime gave the second highest increase in strength (up to fourfold), but produced the largest amount of leachate, with higher level of dissolved calcium. The increase in strength correlated with availability of calcium oxide in the mixtures which lead to calcium carbonate formation, accompanied with higher leachate production and settlement during consolidation. Copper, nickel and zinc concentrations increased with alkaline additives and corresponded to higher pH and DOC levels. Nonetheless, concentrations were within the New Zealand regulatory limits for Class A landfills. Copyright © 2015 Elsevier Ltd. All rights reserved.
Ala Nasir Aljorany
Full Text Available Soft clays are generally characterized by low shear strength, low permeability and high compressibility. An effective method to accelerate consolidation of such soils is to use vertical drains along with vacuum preloading to encourage radial flow of water. In this research numerical modeling of prefabricated vertical drains with vacuum pressure was done to investigate the effect of using vertical drains together with vacuum pressure on the degree of saturation of fully and saturated-unsaturated soft soils. Laboratory experiments were conducted by using a specially-designed large consolidometer cell where a central drain was installed and vacuum pressure was applied. All tests were conducted with a vacuum pressure of 40 kPa applied for a period of 30 days where a degree of soil consolidation of 90% was attained. At the end of the test period fifteen samples were taken from different locations distributed along the depth and radially to measure the water content. Consolidation settlements were recorded with time for all tests. The results showed that using vacuum pressure with vertical drains is a very effective method to accelerate consolidation of soils. As the thickness of unsaturated top layer increases, the settlement of soil surface decreases. The water content decreased after 30 days of application of the vacuum pressure.
Ayodele Ebenezer Ajayi
Full Text Available In agriculture, the soil strength is used to describe the susceptibility to deformation by pressure caused by agricultural machine. The purpose of this study was to compare different methods for estimating the inherent soil strength and to identify their suitability for the evaluation of load support capacity, compaction susceptibility and root growth. The physical, chemical, mineralogical and intrinsic strength properties of seven soil samples, collected from five sampling pits at different locations in Brazil, were measured. Four clay (CS and three sandy clay loam (SCL soils were used. The clay soils were collected on a farm in Santo Ângelo, RS (28 º 16 ' 16 '' S; 54 º 13 ' 11 '' W 290 m; A and B horizons at the Universidade Federal de Lavras, Lavras, MG (21 º 13 ' 47 '' S; 44 º 58 ' 6'' W; 918 m and on the farm Sygenta, in Uberlandia, MG (18 º 58 ' 37 '' S; 48 º 12 ' 05 '' W 866 m. The sandy clay loam soils were collected in Aracruz, ES (19 º 47 ' 10 '' S; 40 º 16 ' 29 '' W 81 m, and on the farm Xavier, Lavras, MG (21 º 13 ' 24 '' S; 45 º 05 ' 00 '' W; 844 m. Soil strength was estimated based on measurements of: (a a pneumatic consolidometer, (b manual pocket (non-rotating penetrometer; and (c automatic (rotating penetrometer. The results of soil strength properties were similar by the three methods. The soil structure had a significant influence on soil strength. Results of measurements with both the manual pocket and the electric penetrometer were similar, emphasizing the influence of soil texture. The data showed that, to enhance the reliability of predictions of preconsolidation pressure by penetrometers, it is better to separate the soils into the different classes, rather than analyze them jointly. It can be concluded that the consolidometer method, although expensive, is the best when evaluations of load support capacity and compaction susceptibility of soil samples are desired.Na agricultura, a resistência do solo é usada