排序方式： 共有23条查询结果，搜索用时 31 毫秒
1.
Sarat Kumar Das Pijush Samui Shakilu Zama Khan Nagarathnam Sivakugan 《Central European Journal of Geosciences》2011,3(4):449-461
Stability with first time or reactivated landslides depends upon the residual shear strength of soil. This paper describes prediction of the residual strength of soil based on index properties using two machine learning techniques. Different Artificial Neural Network (ANN) models and Support Vector Machine (SVM) techniques have been used. SVM aims at minimizing a bound on the generalization error of a model rather than at minimizing the error on the training data only. The ANN models along with their generalizations capabilities are presented here for comparisons. This study also highlights the capability of SVM model over ANN models for the prediction of the residual strength of soil. Based on different statistical parameters, the SVM model is found to be better than the developed ANN models. A model equation has been developed for prediction of the residual strength based on the SVM for practicing geotechnical engineers. Sensitivity analyses have been also performed to investigate the effects of different index properties on the residual strength of soil. 相似文献
2.
Sanjay Kumar Shukla Ashish Gupta Nagaratnam Sivakugan 《Geotechnical and Geological Engineering》2011,29(4):613-618
In this paper, an analytical expression for the deflection of a thin circular elastic plate resting on the Pasternak foundation
is derived by adopting the strain energy approach. The parametric study is carried out to observe the location of the plate
lift-off and the variation of the deflection profiles for comparing the variation pattern reported in the literature based
on an approximate solution technique. It is found that the radial distance of the point of lift-off of the plate decreases
with increase in the values of both the shear modulus and the modulus of subgrade reaction of the foundation soil; the reduction
being more for their lower values. It is also observed that the variation in deflection of the plate at any radial distance
due to change in soil subgrade conditions is significant for lower values of modulus of subgrade reaction. 相似文献
3.
Naguleswaran Niroshan Nagaratnam Sivakugan Ryan Llewellyn Veenstra 《Geotechnical and Geological Engineering》2018,36(4):2261-2272
Cemented paste backfill (CPB) is primarily used for backfilling underground voids at George Fisher Mine (Mount Isa, Australia). The objective of this paper is to summarise the geotechnical characterisation of the tailings and the rheological properties of the CPB as determined from a laboratory testing program undertaken at James Cook University. Two binders were examined [a General Purpose cement and a slag blend cement] over a range of dosages from 0 to 6% and CPB mix solids content in the range of 72–78%. The slump tests were carried out using the standard cone (ASTM C 143) used for concrete and a cylinder with 110 mm (diameter) × 110 mm (height), whereas the yield stress was measured using a shear vane (Brookfield vane spindle V-73). The index characteristics of the tailings including the grain size distribution, liquid limit, plastic limit, specific gravity were determined as per ASTM standards. This paper will then discuss the interrelationships among the solid content, slump, saturated density and the yield stress of the CPB. It is shown that there is strong correlation between the two different slump test devices used in this study. The smaller cylindrical device appears to have good potential for slurries like mine tailings or dredged mud that have high water content for slump test. There is also strong inter-relationship among solid content, slump, yield stress, and bulk density. Increasing the solid content increases the bulk density and yield stress, but reduces the slump. While there is hardly any difference between the two binder types used in this study in terms of flow parameters, namely the yield stress and slump, the binder dosage has an effect. At any specific solid content, higher binder dosages lead to a drop in the slump and increase in the yield stress. The difference is more pronounced in dense slurries. It is also strongly believed that the trends and relationships developed in this study may be valuable for the other mining operations using CPB. 相似文献
4.
Mona Malekzadeh Julie Lovisa Nagaratnam Sivakugan 《Geotechnical and Geological Engineering》2016,34(3):759-776
Electrokinetic stabilization is one of the techniques that improve the geotechnical properties of the soils. It was pioneered by Casagrande in late 1940s and has not seen much development since then, especially in large-scale field applications. Some bench scale studies have been carried out during the past two decades and there have been some small scale field studies and limited field applications, mostly on soft soils. Due to lack of understanding of the physiochemical and electrochemical changes in the soil during electrokinetic stabilization, uncertain energy costs, loss of efficiency with time and the corrosion of electrodes, this method is usually considered as a last resort for large-scale practical applications. The objective of this paper is to highlight the critical parameters affecting electrokinetic consolidation, and to discuss their effects on the efficiency of the process. A better understanding of these critical parameters and their effects will enable geotechnical engineers to design the electrokinetic consolidation operation more effectively and make it an economically viable process for many situations. 相似文献
5.
Nagaratnam Sivakugan Kirralee Rankine Rudd Rankine 《Geotechnical and Geological Engineering》2006,24(3):661-673
Permeability is one of the most important parameters in the design of hydraulic backfilling of mine stopes. A simple and reproducible
method was developed for preparing reconstituted hydraulic fill sample in the laboratory, that is representative of the hydraulic
fill in the mine stope, replicating the slurry sedimentation process taking place in the mine. Constant head and falling head
permeability tests were carried out on the samples, giving consistent results. A brick permeameter was developed to study
the flow characteristics of the porous barricade bricks under one-dimensional flow, simulating the flow conditions in the
mine. Three different methods were used to determine the permeability of the brick and the results showed very good agreement.
This is the first rational attempt to measure the permeability of the porous barricade bricks that are used to close the horizontal
access drives in the mines, thus retaining the hydraulic fill. The measurements show that the permeability of the barricade
brick is about two to three orders of magnitude greater than that of the hydraulic fill. 相似文献
6.
Lateral Variation of the Vertical Stress in Underground Mine Stopes Filled with Granular Backfills 总被引：1，自引：0，他引：1
P. Rajeev P. R. Sumanasekera N. Sivakugan 《Geotechnical and Geological Engineering》2016,34(2):481-492
Marston’s theory and its modifications are widely used to predict the average vertical stress variation with depth within mine stopes. However, this does not model the lateral variation in vertical stress at a particular depth. In this study, a mathematical expression to simulate the vertical stress variation is developed using the experimental shear stress data of granular backfill. The developed model is validated against average vertical stress measured in the experiment. Therefore, the developed model has the advantage of determining both the average vertical stress and its distribution respectively, at a particular depth and a cross sectional area of the mine stope. 相似文献
7.
Hydraulic fills used in Australian mines have similar grain size distributions whilst having quite different specific gravity
values, typically in the range of 2.7–4.4. When produced and distributed in slurry at 65–75% by solid content, they settle
to produce fills with similar geotechnical characteristics. The fills under investigation have been found to settle, in the
laboratory, to a dry density of about 0.56 × specific gravity, a saturation water content of about 17–34%, and a porosity
of 37–49%. A quick estimate of the optimum water content that gives the minimum porosity may be obtained by locating the intersection
of the saturation curve and minimum porosity line, which may simply be done on a water content vs. porosity plot. However,
transportability of the slurry requires it to be mixed at water content substantially greater than the optimum water content.
As the tailings settle out of suspension, they settle to relative density of 50–80%. This paper shows that the current empirical
relationships relating relative density and N-value to friction angle for sands will significantly underestimate the friction angle of the hydraulic fills. Based on limited
experimental data, a unique relationship between relative density and friction angle is proposed for hydraulic fills placed
in some Australian mines. 相似文献
8.
Arching is a well known phenomenon, which effects stress developments which were investigated and compared using analytical
and numerical solutions. Marston’s (1930) solution was extended to a generalised 3-dimensional rectangular stope and later modified for square and circular stopes
for comparison with FLAC results. Aubertin et al. (2003) & Li et al. (2003) models were improved significantly by placing the backfill within narrow stopes as lifts or layers in numerical modelling
where the normal stress variation with depth were found to be more realistic. The FLAC results were compared with analytical
solutions which were developed by previous researchers and modified by the authors to evaluate the arching effects in backfilled
placed in narrow and circular stopes. It appeared from the investigation herein that δ = 0.67 ϕ and K = K
o condition gives a very close match with the numerical model solutions obtained from FLAC. Many laboratory tests were conducted
to find out friction angles for four Australian mines, which were between 30 and 49 degrees. 相似文献
9.
The leachate produced by the Municipal Solid Waste Landfill of São Pedro da Aldeia (State of Rio de Janeiro, Brazil) flows almost entirely in one direction guided by a natural ditch in the bottom of a gentle valley. This landfill has been in operation with no concern to environmental protection, such as containment systems or leachate drainage and treatment. This inadequate operation causes severe damage to flora, wildlife and local farmers, due to continuous propagation of contaminants in the groundwater. Field and laboratory measurements of ionic concentrations of several contaminants found in the groundwater adjacent the landfill are presented and interpreted in this paper. Several farms are located adjacent to the landfill, comprising about 1,000 inhabitants that use the ground water for personal use and land farming activities. The main purpose of this paper is to assess the environmental hazard to the surrounding properties as the landfill is still in operation. This is accomplished by estimating the maximum distance travelled by the leachate plume based on the statistical interpretation of the measured ionic concentration of several contaminants found commonly in landfills. The main recommendation coming from the statistical assessment is that safe groundwater consumption should be limited to a minimum distance of 400 m from the contamination source, provided that the quality of ground water is continuously monitored while the MSW landfill is still in operation. 相似文献
10.
Reuse of dredged marine sediments for land reclamation is a sustainable method for disposing the large quantities of dredged spoil, accumulating every year worldwide. However, due to their high water content and low permeability, dewatering and self-sedimentation of the material takes a long time to be completed. Therefore, different methods, such as prefabricated vertical drains and vacuum preloading, are used to improve the consolidation properties of the dredged mud at the port of Brisbane. Among these stabilization methods, vacuum preloading is determined as the most effective method to increase the consolidation of the dredged mud. However, clogging during vacuum consolidation is undesirable. Therefore, electrokinetic stabilization draws attention since it is an environmentally friendly and time efficient method to dewater and consolidate dredged mud significantly. The effectiveness of the electrokinetic stabilization depends on the properties of the soil and the electrode configurations. One-dimensional and two-dimensional electrode configurations are the most popular configurations. In this study, the effect of one-dimensional electrode configuration, which is installation of electrodes in arrays of anodes and cathodes on consolidation parameters of dredged mud, is investigated. Based on this study, the dredged mud sediments can be stabilized using one-dimensional electrokinetic stabilization which resulted in improving compression index and coefficient of volume compressibility and reduction of soil plasticity index. 相似文献