فهرست مطالب مریم حق بین

Wharf is an engineering structure which is constructed generally for loading or unloading of goods. The structure may be constructed on the weak layers like gravel and sand with respect to the bank conditions. In case of incorrect design of this type of structure and its failure, the wharf activities may be stopped for a long time due to damage to adjacent facilities. For this reason, investigating the behavior of coastal structures against failure factors such as earthquake and the liquefaction due to it, is of great importance. Analysis of wharf performance against liquefaction is done generally using the numerical methods. In this article using the Flac2D software which has the capability of nonlinear analysis of effective stress and generation of excess pore water pressure in the soil continuum, the liquefaction phenomenon in the soil surrounding the wharf is simulated using the behavioral model Finn. In continuation, the impact of different earthquake parameters on the wharf behavior is investigated. Finally, the results of the excess pore water pressure, horizontal displacement, soil settlement and bending moment of piles are presented. Then, the correlation between these parameters and different earthquake parameters is investigated. As the earthquake intensity criteria have great importance in terms of statistical assessment of seismic demand of various types of structures, therefore, in this study in order to investigate the quality of earthquake intensity criteria, the determining indices such as being optimal and applicable, efficiency index, sufficiency with respect to the earthquake magnitude and distance to the center of earthquake propagation are investigated. The results show that compatibility between the earthquake parameters and soil settlement is generally better with respect to other parameters.

In the present study, the effect of geogrid layers and soil density were investigated in the sand slope model reinforced with geogrid layers. The soil slope did not have stability in normal condition and was unusable for embankment operations. But it reached to the appropriate bearing capacity for embankment operation with improvement made by reinforcing and compacting the desired soil. The main purpose was to compare the footing bearing capacity and soil swelling of the reinforced with the non-reinforced states and also to evaluate the impact of the two soil compacted states with various thicknesses. 19 different states were investigated. The main parameters studied were soil density, the number of geogrid layers, and the distance from the slope edge. The results indicated that the soil slope, which had no stability in the non-compacted -unreinforced state, achieved high bearing capacity using geogrid layers and soil compaction. So that the maximum bearing capacity in compacted reinforced state and when footing was located 30 cm from the slope edge was 433 percent higher than the only reinforced state and 325 percent higher than only compacted state. Also, swelling of first layer of slope was significantly lower relative to the tolerance amount of bearing capacity and more uniformity was observed in all slope locations.The results also indicated that, in the compacted-unreinforced state, an increase in the number of compaction layers did not affect the bearing capacity of footing in the vicinity of the slope. But by moving the footing from the slope edge to 30 cm, the increasing the number of compaction layers from 5 to 7 layers caused increasing the bearing capacity by 34%.s.

The purpose of footing design is transferring structure load to soil without causing shear failure and extra settlement in soil. Therefore, footing bearing capacity should be considered in various projects. In special case, footings are placed in various positions with respect to slope ground and position of ground slope affects footing bearing capacity. In fact, slope affects failure surface of soil beneath the foundation remarkably and therefore, footing location with respect to slope must be cared to determine exact footing bearing capacity. In present paper, analytical method is presented based on soil stability beneath the footing. Virtual retaining wall method is used in present study and by applying equilibrium between active and passive forces on virtual wall, footing bearing capacity on reinforced and unreinforced soils is determined in various positions with respect to slope ground. Also, varied parameters include soil resistance, footing spacing with respect to slope ground, width and depth of foundation and seismic coefficient. Results indicate, in various depths and widths of foundation, bearing capacity of footing on flat ground is more than top of slope and bearing capacity of footing top of slope is more than down of slope. Also, bearing capacity of footing on slope is minimum. Based on proposed method, footing location with respect to slope affects passive and active force on virtual retaining wall and footing bearing capacity remarkably. Also, the proposed method can determine effect of slope angle and reinforcement on footing bearing capacity. Presented method indicates effective distance from slope crest is almost 4.5B. Finally, the predicted results are compared with those reported from analytical and experimental methods performed by others, indicating an acceptable agreement.

Tsunami study as one of the most serious forms of coastal hazards, is favored by many engineers, planners and politicians. Depositional effects of the tsunami subdivided to sedimentary and geomorphic landforms. This article is about the sedimentation processes associated with tsunami inundation in the northern coast of Oman Sea (Makran). Tsunami inundation features of flooding are very diverse. At first, this paper presents a conceptual model of coastal tsunami sedimentation processes deduced from the case studies and outlines diagnostic features of tsunami deposits and then reviews the presence or absence of these features in a storm deposits. Random pits drilled in some of the water entries on the northern coast of Oman from Chabahar to Beris and the sedimentological sequence is investigated in them. Experiments such as granuluometry by wet and dry sieve, hydrometry, calcimetry, and X-ray Diffraction (to recognizing minerals) done. Some pits shows finning upward sequences, Rip Rap structure, shell fracture accumulation, and sudden change in sediment. According to the observed sedimentary structures, sorting, tilt, percentage of calcium carbonate and terrigenous debris, possible deposit of tsunami are detected. The aim of this study has also been to evaluate the ability of sedimentology in detecting evidence of tsunami sediment off the coast of Makran.

The choice of a suitable bearing capacity of soil becomes the most important issue to be considered in any project. This paper describes analytical investigation conducted to evaluate the ultimate bearing capacity of adjacent footings in various spacings of footings. Bearing capacity of adjacent footings is determined based on virtual retaining wall method by applying equilibrium between active and passive forces. Results indicate the ultimate bearing capacity of each foundation changes due to the interference effect of the failure surface in the soil and it depends on footings spacing. In the present study، effect of soil type، depth of adjacent footings and reinforced soil is investigated on bearing capacity of adjacent footings. Results indicate closely spaced footings، can decrease or increase bearing capacity of adjacent footings with respect to single footings. Also، reinforced soil increases bearing capacity of closely spaced footings with respect to single footings on unreinforced soil، it depends on footings spacing. Finally، the predicted results are compared with those reported from experiments، analytical and numerical results performed by others، indicating an acceptable agreement.