Abstract:The grading entropy concept can be adapted to the field of geotechnics, to establish criteria for phenomena such as particle packing, particle migration and filtering, through a quantified expression of the order/disorder in the grain size distribution, in terms of two entropy-based parameters. In this paper, the grading entropy theory is applied in some geotechnical case studies, which serve as benchmark examples to illustrate its application to the characterisation of piping, softening and dispersive soils, and to filtering problems in the context of a leachate collection system for a landfill site. Further, since unstable cohesive (dispersive) soils are generally improved by lime, the effect of lime addition is also considered, on the basis of some measurements and a further application of the grading entropy concept, which allows evolutions in the entropy of a soil to be considered as its grading is modified. The examples described support the hypothesis that the potential for soil erosion and particle migration can be reliably identified using grading entropy parameters derived from grading curve data, and applied through an established soil structure
OPEN ACCESSEntropy 2012, 14 1080 stability criteria and a filtering rule. It is shown that lime modification is not necessarily helpful in stabilizing against particle migration.
Hungarian experience about the correlation of CPT and DPH results is summarized. A historical review of CPT-DPH and CPT-SPT correlations is presented, and the reliability of the published CPT-DPH correlations is analyzed using recent data from Hungarian geotechnical practice. Based on these data the paper defines soil types where reliable correlation exists and proposes formulas describing the relationships between the CPT and DPH results, because in the case of hard state clays and soils containing gravel an acceptable relationship cannot be stated.
The paper focuses on the numerical back analysis of the monitored deep excavation of II. János Pál pápa square of Budapest Metro Line 4. Inclinometric measurement of diaphragm wall deformations has been compared to numerical results derived by PLAXIS using HSsmall soil model. Considering the influence of small strain stiffness of plastic soils, good fit of measured and calculated deformations could be observed. Parametric analysis were carried out to observe influence of the following inputs on the numerical results:
Construction time and sequence
Consolidation effects
Small strain stiffness parameters
A detailed evaluation is given about the results of parametric analysis, considering the inherent errors of the inclinometric measurements, as well.
15004-1989 [16] allowed for the use of a so-called "permissible bearing pressure" for preliminary dimensioning, and for foundation design in case of buildings with low importance. With this method, the central, vertical limit load of strip foundations and column footings with a given geometry could be obtained by applying the permissible bearing pressure along with shape and depth factors. In the light of the popularity of this method, and given that EC7 allows for employing design methods based on prescriptive measures, the authors have developed a new calculation method which conforms to the principles of EC7 and which is similar to the former method.
In the forthcoming years intensive renovation and reconstruction works can be expected on the banks’ freshwaters of Hungary. For the rehabilitation of the shores of Lake Velence works are starting in 2020. To support these investments there has been a demand for prefabricated reinforced concrete sheet pile walls. Realizing the opportunity, a major player in the market of pre-fabricated reinforced concrete elements for water way construction, CSOMIÉP Ltd. decided to develop a reinforced concrete sheet pile wall. In this study the development and complex structural and geotechnical design concept are shown through the major structural behaviors and useable geometries.
In this study, two groups of foam glass aggregate (FGA) samples were prepared with four different compaction ratios (10%, 20%, 30%, and 40%) and subjected to a series of static compressional loads from 50kPa to 300kPa with 50kPa interval. In first group of the test (changed load samples, ChLS), for each static load value, a new sample was prepared and tested. In the other group of the test (continuously loaded samples, CLS), all prescribed static compressional loads were sequentially applied over the same sample after satisfying the required strain rate at each load. The results revealed that the overall vertical strain values of CLS were lower than ChLS except for 10%, which shows reverse behavior. For both sample types, the required time to reach the desired vertical strain rate was much higher when the compaction ratio was low, and the compressional load was above 250 kPa. The compaction methodology used in the present study led to more reliable vertical strain values for both short- and long-term loading periods compared to other reported results executed on FGA under the same static compressional load circumstances. The evolution in the particle distribution curve of FGA particles after maximum compaction ratio (40%) was nonsignificant compared to the study works that depended on traditional standard test methods of compaction and led to severe change in particles structural component. The current findings beneficially affect civil engineering applications using FGA by defining the material's final strain values when subjected to static compressional loads at different compaction ratios.
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