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Milatz Marius Hüsener Nicole Andò Edward Viggiani Gioacchino Grabe Jürgen 《Acta Geotechnica》2021,16(11):3573-3600
Acta Geotechnica - Gauging the mechanical effect of partial saturation in granular materials is experimentally challenging due to the very low suctions resulting from large pores. To this end, a... 相似文献
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The identification, remedial treatment, and monitoring of contaminated sediments are among the priorities for managers of the Tampa Bay Estuary. Tampa Bay, as an urbanized estuary, is subject to the input of watershed sources of chemical contaminants, including metals, pesticides, and organic chemicals. Although the use of biological indicators and their incorporation into multi-metric indices is not new, the refinement and applications of such techniques for determining environmental condition still require further development and exploration. We present a single Tampa Bay Benthic Index (TBBI) that was developed specifically for Tampa Bay. Stepwise discriminant analysis was applied to a comprehensive list of potential benthic metrics. Results from the stepwise procedure identified the metrics that best discriminated between "healthy" and "degraded" conditions, as defined by sediment contaminant effect levels and dissolved oxygen. Discriminant analysis was then applied to the resultant three variables to determine the linear combination for the index. 相似文献
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Coupled deformation–seepage analysis of dynamic capacity tests on open-ended piles in saturated sand
Open-ended piles such as tubular piles or I-beams are used as foundations for offshore and nearshore construction. After the pile installation a load test to estimate the bearing capacity of these open-ended piles is necessary. Due to the offshore conditions and the high bearing capacity of the installed piles a static load test is not normally feasible. Therefore, dynamic load tests are carried out where the wave propagation due to an dynamic impact at the pile head is measured. The methods to estimate the bearing capacity from the measured signal of the dynamic tests were derived for solid pile profiles. It is questionable whether these evaluation techniques are applicable for open-ended piles. Hence, the influence of various important system parameters as well as the differences between static and dynamic load tests on open-ended piles is investigated in this paper. 相似文献
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The determination of the void ratio and stress state distribution in undisturbed soil is still an ambitious aim which cannot be reached by sampling from bore holes. Therefore, an alternative method is proposed to determine soil density and stress state using dispersion wave measurements and cone penetration tests. Dispersion wave measurements and resonant-column tests are carried out to measure the shear wave velocity and shear modulus distribution with depth. Using finite element calculations a relationship between cone penetration resistance, stress state and void ratio is derived. From these results the void ratio distribution and the stress state can be calculated inversely. The inverse method is applied to real test data. The results of the inverse parameter determination are shown and assessed regarding the possibilities and the limitations of the presented method. 相似文献
5.
Granular soils subjected to flow through their soil skeleton can show a behaviour in which fine particles migrate through the pore space between coarser particles. This process is called internal instability or suffusion. This contribution deals with the numerical analysis of the migration of fine particles in a soil column subjected to fluid flow with unresolved coupled computational fluid dynamics–discrete element method (CFD–DEM) with special regards to the used drag force correlation. The contribution investigates the influence of the Schiller–Naumann model and its extension with a voidage term on the migration behaviour of fine particles. The voidage term is further varied with a parameter, which controls the impact of the change of the void fraction on the drag force. It could be observed that the Schiller–Naumann model does not yield in a suffusive behaviour while the extended models show significant particle migration. Thereby, increasing the impact of the void fraction on the drag force results in stronger particle migration. These results reveal the need for good validation techniques. They indicate how the drag force correlation can be adapted to depict the correct particle migration behaviour. 相似文献
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Numerical investigation of soil plugging inside open-ended piles with respect to the installation method 总被引:2,自引:2,他引:0
The development of a soil plug inside an open-ended pile with respect to the installation method is examined using numerical
simulations. In this paper, the penetration process of an open-ended tubular pile with diameter D = 61 cm into granular soil is investigated. The aim is to achieve a better understanding of the mechanisms of soil plugging
inside open-ended piles with respect to the installation method. As an example, the horizontal stress distribution inside
the tubular pile after installation shows significant increase depending on the installation method. The numerical results
are compared to experimental data. 相似文献
8.
By designing a quay wall construction the calculation of the active earth pressure behind the sheet pile wall is often a problem. Measurements and FE-analyses have shown that the earth pressure on a sheet pile wall is shielded due to the dowel effect of the pile rows behind the sheet piling. In conventional calculations a higher friction angle is used to take the dowel effect into account. In this study, numerical modeling using the Coupled Eulerian?CLagrangian method has been carried out to investigate the shielding effect of pile rows on the active earth pressure in sand. The failure mechanisms have been illustrated using the shear band patterns at the limit state. Based on the Terzaghi??s arching theory a new approach has been developed to estimate the shielding effect. 相似文献
9.
Structural optimization methods are used for a wide range of engineering problems. In geotechnical engineering however, only
limited experience exists with these methods. The difficulties in applying such methods to geotechnical problems are discussed
in this paper, and the adaption of the commonly known SIMP-method to geotechnical problems is introduced for a special case.
An application example is used to present the potential of topology optimization methods, and the application to geotechnical
engineering is evaluated. 相似文献
10.
Field measurements regarding the influence of the installation method on soil plugging in tubular piles 总被引:1,自引:1,他引:0
Soil plugging in open-ended piles leads to an increase in compressive bearing capacity but also influences pile driving resistance. Many different factors affect the tendency for soil plugging, for example, pile diameter, penetration depth and installation method. In this paper, the influence of the installation method on soil plugging is investigated. In situ measurements during the installation of two instrumented tubular piles are carried out to investigate the internal and external stresses acting on the pile during the installation process. Furthermore, the cone penetration resistance inside one pile is measured during the installation, and the accelerations and strains at the pile head are monitored to predict the bearing capacity. The installation method is varied between vibratory and impact pile driving. The results show that a significant increase in horizontal stresses inside the pile occurs during impact driving which leads to the conclusion that a soil plug is formed. During vibratory pile driving, no stress increase was observed. 相似文献