×
The submission system is temporarily under maintenance. Please send your manuscripts to
Go to Editorial ManagerShallow foundation suffers from considerable settlement, displacement and tilting under earthquakes. This is particularly due to the shaking associated with earthquakes that lead to the generation of horizontal seismic load transferred through the soil to the foundation. Also, liquefaction could take place during the earthquake in the saturated loose sand. To alleviate the detrimental effect of earthquakes, ground improvement is required. This study examines the response of the shallow square foundation rested on loose sand soil reinforced with geogrid reinforcement when subjected to 2023 Turkey earthquake by using a shaking table system. Different number of geogrid layers are installed; (one, two, three and four), also various geogrid configurations were examined which are (straight, trapezoidal and reverse trapezoidal). The acceleration response, settlement, horizontal displacement, rotation and pore water pressure developed in the sand soil and the shallow foundation during 2023 Turkey earthquake has been examined. The settlement and the horizontal displacement, foundation rotation, acceleration and pore water pressure were measured using rope displacement transducers, tilt sensors, accelerometers and pore water transducers respectively. The results showed that the acceleration amplifies when passing through loose sand. The results also indicated that the shallow foundation experienced noticeable settlement, horizontal displacement and rotation when subjected to the seismic loads. On the other hand, the installation of geogrid proved to be effective in controlling the problems associated with earthquakes. The optimum geogrid reinforcement is occurred when three layers of geogrid placed in reverse trapezoidal configuration (3RT) since it gave the best reduction in the acceleration amplification and the highest decrease in the foundation settlement, displacement and tilting which is about (60-66) %. Nevertheless, the effectiveness of geogrid minimizes when the sand soil becomes saturated. In addition, liquefaction occurs during earthquakes especially at the shallower depths because of the decrease in the shear strength of saturated soil.
The axial capacity and pile transference of loads under static loading have both been well reported, but further research is needed to understand the dynamic lateral responses. The pile load imposed during an earthquake may increase, but the soil’s ability to support it may fall as a side effect of the vibration leading to more settlement. The key objective of this work is to identify what led to the substantial lateral destruction of the piles during the seismic event due to the kinematic effects. These failures were related to discontinuities in the subsoil as a result of sudden changes in soil strength due to shaking. The kinematic stresses exerted in a single pipe pile constructed in two sand layers under two different situations (dry and saturated states) are investigated in this study using numerical modeling. The bending moments were higher in the saturated sand soil than in the dry one which may be attributed to liquefaction. Generally, the acceleration increased through the loose layer (from bottom to top), and then significantly settled within the dense layer. It could be shown that using this modeling, one can estimate how a pile foundation will behave under "kinematic" loading driven by earthquakes. Therefore, the design and installation of drilled aluminum or steel piles in sand soil could make use of these present observations.
In this paper, a dynamic analysis has been carried out on zoned earthdam subjected to earthquake excitation in which pore water pressure, effective stresses and displacements are calculated. The finite element method is used and the computer program Geo-Studio is adopted in the analysis through its sub-programs SEEP/W and QUAKE/W. A case study is considered to be Khassa Chai dam which is located on Khassa Chai river north of Iraq and consists of zoned embankment with a total length of 3.34 km. The selected earthquake for the analysis is El-Centro earthquake with a period of 10 sec and different amplitudes of acceleration. The time of the analysis is taken as 600 sec. with a time step (?t = 0.05 sec.) to investigate the behavior of the soil for a period of time after the earthquake has stopped, a free vibration period is included in the analysis. It was concluded that the value of pore water pressure generated at the base of the core is greater than that in the upper parts of dam. The horizontal and vertical effective stresses continue to decrease during the period of analysis 600 sec. which indicates that the soil continues to weaken during this period, the horizontal displacement increases with depth of the point from the crest and the largest horizontal displacement will be at the base of the dam at time 60 sec and There is attenuation of the acceleration to some degree depending on the amplitude of the input horizontal acceleration. The maximum horizontal displacement decreases by about 37%, 45% and 49% when using a horizontal drain 2 m thick at the downstream under a peak acceleration of 0.05g, 0.1g and 0.2g, respectively.