Numerical analysis of a finite slope improved with stone columns under the effect of earthquake force

2021 ◽  
Author(s):  
Cenk Cuma Çadır ◽  
Mustafa Vekli ◽  
Ferhat Şahinkaya
Measurement ◽  
2021 ◽  
Vol 169 ◽  
pp. 108369
Author(s):  
Fang Xu ◽  
Hossein Moayedi ◽  
Loke Kok Foong ◽  
Mohamad Jamali Moghadam ◽  
Milad Zangeneh

Author(s):  
Jakub Stacho ◽  
Monika Sulovska

Stone columns made of coarse-grained materials and crushed stone are one of the most-used technologies for soil improvement all over the world. Stone columns improve the strength and deformation properties of subsoil and reduce the time required for the consolidation of fine-grained soils. The impact of the improvement depends on the properties of the original subsoil as well as the properties of the coarse-grained materials used for the stone columns. The article deals with the effects of the properties of coarse-grained materials for stone columns on the settlement and consolidation times of improved subsoil for the foundation of a factory. Numerical modeling as a 2D task was performed using Plaxis geotechnical software. The numerical analysis included two methods of modeling stone columns in a plane strain model, i.e., one method often used by practical engineers in the region of Slovakia, and one modified method, which allowed for a more accurate determination of the final settlement and consolidation time. The method modeled stone columns as continuous walls, and the compaction of the soil between the stone columns was taken into account. The results showed that the type of coarse-grained material can significantly affect the final settlement and time of consolidation. Stone columns made of quarry stone were suitable in the given geological conditions regardless of the design of the mesh, while stone columns made of pebble gravel were suitable only with a mesh of 1.5 x 1.5 m.


2011 ◽  
Vol 94-96 ◽  
pp. 190-195 ◽  
Author(s):  
Shu Li Wang ◽  
Man Gen Mu ◽  
Jing Yu Dai ◽  
Xiao Huan Hu

A parametric study of an foundation on soft soils reinforced with stone columns is performed using Phase2D. The real foundation is modeled and its bearing capacity is decided by the columns and their surrounding soft soil. The following parameters are analysed: the replacement area ratio, the deformability, mean stress, absolute horizontal (vertical) displacement, volumetric strain, maximum shear strain of the foundation. Based on the results of this study, a new design method is proposed: for decreasing the settlement and satisfying bearing capacity, increasing the replacement area ratio is good idea.


Author(s):  
Alvin Lo ◽  
Hendy Wijaya ◽  
Amelia Yuwono

Bridges are construction structures that are built to connect parts of the road that are cut off by obstacles such as deep valleys, irrigation channel paths. In order to build a bridge, a strong, economical and easy to build foundation is needed to carry gravity loads and also earthquake force. A common problem encountered in bridge foundation is the occurrence of erosion around the piles due to scouring of water which causes exposing some portion of the piles, which are often referred as elevated reinforced concrete pile-cap foundations. In this study, a numerical analysis of pile groups on elevated reinforced concrete pile-cap foundations is carried out with lateral forces on sandy soil to see the ductility behavior of piles using geotechnical-based programs and to compare the results with the previous studies. The analysis includes the pilecap model and the soil-to-pile interaction and also considers the pile group effect. The analysis was carried out to see the structural and geotechnical conditions on the ductility behavior of a partially embedded piles on sandy soil. The result obtained is a comparison of the ductility and overstrength values that can be used as a consideration in designing elevated reinforced concrete pile-cap foundations.Keywords: Elevated RC pile-cap foundations; numerical analysis; lateral force; ductility AbstrakJembatan adalah struktur konstruksi yang dibangun untuk menghubungkan bagian jalan yang terputus oleh rintangan-rintangan seperti lembah yang dalam, alur saluran irigasi. Untuk membangun sebuah jembatan, diperlukan fondasi yang kuat, ekonomis dan mudah untuk dibangun untuk memikul beban dari jembatan dan juga gaya gempa. Masalah yang umum ditemui pada konstruksi fondasi jembatan adalah terjadinya erosi pada sekitar fondasi dikarenakan gerusan air yang menyebabkan tanah terangkat dan memperlihatkan sebagian tiang fondasi, yang sering disebut dengan elevated reinforced concrete pile-cap foundations. Pada penelitian ini dilakukan analisis secara numerik terhadap kelompok tiang pada elevated reinforced concrete pile-cap foundations yang dibebani gaya lateral pada tanah berpasir untuk melihat perilaku daktilitas tiang dengan bantuan program berbasis geoteknik dan membandingkan dengan hasil penelitian terdahulu. Analisis menyertakan model kepala tiang dan hubungan antara tanah dengan tiang serta mempertimbangkan efek kelompok tiang. Analisis dilakukan untuk melihat kondisi struktural dan geoteknikal pada perilaku daktilitas fondasi yang ditanam sebagian pada tanah pasir. Hasil yang didapatkan adalah perbandingan nilai daktilitas dan overstrength yang dapat digunakan sebagai pertimbangan dalam mendesain elevated reinforced concrete pile-cap foundations.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Begum Yurdanur Dagli ◽  
Yeşim Tuskan ◽  
Ümit Gökkuş

A dynamic behaviour of a cylindirical wind tower with variable cross section is investigated under environmental and earthquake forces. The ground acceleration term is represented by a simple cosine function to investigate both normal and parallel components of the earthquake motions located near ground surface. The function of earthquake force is simplified to apply Rayleigh’s energy method. Wind forces acting on above the water level and wave forces acting on below this level are utilized in computations considering earthquake effect for entire structure. The wind force is divided into two groups: the force acting on the tower and the forces acting on the rotor nacelle assembly (RNA). The drag and the inertial wave forces are calculated with water particle velocities and accelerations due to linear wave theory. The resulting hydrodynamic wave force on the tower in an unsteady viscous flow is determined using the Morison equation. The displacement function of the physical system in which dynamic analysis is performed by Rayleigh’s energy method is obtained by the single degree of freedom (SDOF) model. The equation of motion is solved by the fourth-order Runge–Kutta method. The two-way FSI (fluid-structure interaction) technique was used to determine the accuracy of the numerical analysis. The results of computational fluid dynamics and structural mechanics are coupled in FSI analysis by using ANSYS software. Time-varying lateral displacements and the first natural frequency values which are obtained from Rayleigh’s energy method and FSI technique are compared. The results are presented by graphs. It is observed from these graphs that the Rayleigh model can be an alternative way at the prelimanary stage of the structural analysis with acceptable accuracy.


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