Dynamic earth pressure on rigid retaining walls induced by a neighboring machine foundation,by the meshless local Petrov-Galerkin method

Dynamic earth pressure induced by machine foundations on a neighboring retaining wall is analyzed with emphasis on factors which control the intensity and location of the design forces. The meshless local Petrov-Galerkin (MLPG) method is used to analyze the problem for a variety of retaining wall and machine foundation geometries. The soil medium is assumed to be homogeneous and visco-elastic. The machine foundation is idealized as a harmonic sinusoidal dynamic force often encountered in practice. A number of analyses have been made to reveal the effect of the loading frequency, the location and size of the foundation and the soil shear wave velocity on the distribution and magnitude of the dynamic earth pressure. Results indicate that there is a critical frequency and a critical location for which the passive pressure takes the maxima in the entire duration of the dynamic load.

A statistical method for assessment of the existing correlations of hydrate forming conditions

Hydrate formation in the oil and gas industries has been a serious problem for a long time. It may cause many difficulties for instance in gas pipelines blockages. In order to determine the hydrate forming condition, gas gravity method has been used. Several correlations have been proposed based on gas gravity method. Checking the accuracy of the applied correlations is important. In this paper, the leverage approach is used for this purpose. Leverage approach is a statistical method for detection outliers which identifies the applicability domain （AD） of hydrate data predicting correlations and the quality of the existing data. Moreover, the Williams plot is sketched, which is a graphical depiction for determination of the doubtful points. The obtained results showed the existing correlations are all statistically correct and valid to predict hydrate formation temperature, just one data point is out of the applicability domains, and none of the experimental data can be chosen as outliers.

Development of a constitutive model for rockfills and similar granular materials based on the disturbed state concept

Behavior of rockfills was investigated experimentally and theoretically.A series of standard triaxial compression tests were carried out on a quarried rockfill material at different stress levels.It was found that both the stress level and the shear stress ratio,like most of granular materials,controls the behavior of rockfill materials.At lower shear stress ratios the behavior is much more similar to a nonlinear elastic solid.When the shear stress goes further,the stressstrain curve shows an elasto-plastic behavior which suggests using the disturbed state concept to develop a constitutive model to predict the stress-strain behavior.The presented constitutive model complies reasonably with the experimental data.

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been presented.The kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing capacity.Both smooth and rough base strip foundations were considered associated with different collapse patterns.Presence of the groundwater flow leads to a non-symmetric collapse pattern,i.e.,a weak side and a strong side in twosided collapse patterns,depending on the direction of the flow.It was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence,a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.