scholarly journals Soil Saturated Simulation in Embankment during Strong Earthquake by Effect of Elasticity Modulus

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Behrouz Gordan ◽  
Azlan Adnan ◽  
Mariyana A. K. Aida
Keyword(s):  
Shear Stress ◽  
Strong Earthquake ◽  
Soft Soil ◽  
Strain Analysis ◽  
Vertical Direction ◽  
Horizontal Displacement ◽  
Modulus Ratio ◽  
Ground Acceleration ◽  
Maximum Displacement ◽  
Comparison Results

The dynamic analysis process was started after failure in some embankments during an earthquake. In this context, maximum displacement was reported at the crest based on interaction between structure and reservoir. This paper investigates the dynamic behavior of short embankment on soft soil. For this purpose, numerical analysis was carried out using ANSYS13 program based on finite-element method. Simulated models were vibrated by strong earthquake, so the peak ground acceleration (PGA) and duration were 0.65 g and 5.02 seconds, respectively. The comparison results were discussed in key points of plane strain analysis based on modulus ratio between saturated embankment and foundation. As concluded, the modulus ratio between 0.53 and 0.66 led to having a minimum value of horizontal displacement, relative displacement in vertical direction, and shear stress. Consequently, the shear stress was increased while the modulus ratio was decreased. Finally, to avoid more rigidity in the embankment on the soft soil, optimum modulus ratio was recommended at 0.66 in order to reduce the probabilistic of body cracks at the crest with respect to homogeneous behavior during an earthquake.

scholarly journals Effect of Material Property in Foundation during Earthquake on the Embankment

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Behrouz Gordan ◽  
Azlan Bin Adnan
Keyword(s):  
Shear Stress ◽  
Material Properties ◽  
Peak Ground Acceleration ◽  
Water Reservoir ◽  
Vertical Displacement ◽  
Ground Acceleration ◽  
Maximum Displacement ◽  
Reinforcement Structure ◽  
Analysis Process ◽  
Dynamic Settlement

The dynamic analysis process started after any loss of embankment with associated huge damages like cracks during the earthquake. Literature review indicated that the maximum displacement during the earthquake is conducted to the crest and interface between the embankment with water reservoir, and foundations were cased. This paper evaluated the effect of material properties of the foundation for the two conditions so the result is related at the end of construction with supplying water. Numerical analyses of models were performed by finite element with plane strain method and ANSYS13 software. Earthquake recording as Nagan with 5.02 seconds and peak ground acceleration equal to PGA=0.65 is used. Results indicated that with a comparison of horizontal and vertical displacement, shear strain and shear stress so nonisotropic behavior of embankment especially in the up to part of the structure was obvious. It is required to consider an improvement of dynamic settlement with reinforcement structure in the future.

scholarly journals Seismic response of cable-stayed bridge subjected to single-support excitation on various soil condition

2020 ◽  
Vol 156 ◽  
pp. 05003
Author(s):  
Masrilayanti ◽  
Ade Prayoga Nasution ◽  
Ruddy Kurniawan
Keyword(s):  
Soil Type ◽  
Soft Soil ◽  
Time History ◽  
Soil Condition ◽  
Test Model ◽  
Ground Acceleration ◽  
Maximum Displacement ◽  
Cable Stayed Bridge ◽  
Long Span Bridge ◽  
Different Response

For cable-stayed bridge, pylon and girder are one of the most important factors in the design process. Because of the length this structure, it needs to consider the type of the soil because different soil type can be resulting a different earthquake loads. In this study, the behavior of superstructure was investigated using time history analysis subjected to excitation uniformly on the pylon and girder. The test model was a cable-stayed bridge which classified as a long-span bridge. For obtaining the effects of soil type condition, different response spectrums are considered for three soil types: firm, medium, and soft soil. The response spectrums were thus converted to become ground acceleration time history and displacement time history. The displacement was then applied longitudinally and transversally to the supports of the structure to determine the behavior of the bridge. The result shows that the maximum displacement on the pylon and girder due to longitudinal load was at the top of the pylon and in the middle of the main span. As for the transverse earthquake load, the maximum displacement was in the middle area of the pylon and the middle of the main span. The results also defines that the displacement caused by firm soil is smaller than medium soil and soft soil.

Evaluation of floor acceleration demands from the 2017 Mexico City code seismic provisions using a continuous elastic model and records of instrumented buildings

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 213-237
Author(s):  
Miguel A Jaimes ◽  
Adrián D García-Soto
Keyword(s):  
Mexico City ◽  
Seismic Design ◽  
Soft Soil ◽  
Response Spectra ◽  
Elastic Model ◽  
Ground Acceleration ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

This study presents an evaluation of floor acceleration demands for the design of rigid and flexible acceleration-sensitive nonstructural components in buildings, calculated using the most recent Mexico City seismic design provisions, released in 2017. This evaluation includes two approaches: (1) a simplified continuous elastic model and (2) using recordings from 10 instrumented buildings located in Mexico City. The study found that peak floor elastic acceleration demands imposed on rigid nonstructural components into buildings situated in Mexico City might reach values of 4.8 and 6.4 times the peak ground acceleration at rock and soft sites, respectively. The peak elastic acceleration demands imposed on flexible nonstructural components in all floors, estimated using floor response spectra, might be four times larger than the maximum acceleration of the floor at the point of support of the component for buildings located in rock and soft soil. Comparison of results from the two approaches with the current seismic design provisions revealed that the peak acceleration demands and floor response spectra computed with the current 2017 Mexico City seismic design provisions are, in general, adequate.

scholarly journals Design of plate and screw anchors in dense sand: failure mechanism, capacity and deformation

2019 ◽  
Vol 92 ◽  
pp. 16010
Author(s):  
Benjamin Cerfontaine ◽  
Jonathan Knappett ◽  
Michael Brown ◽  
Aaron Bradshaw
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Failure Mechanism ◽  
Progressive Failure ◽  
Vertical Direction ◽  
Shear Plane ◽  
Design Methods ◽  
Embedment Depth ◽  
Limiting State ◽  
Dense Sand

Plate and screw anchors provide a significant uplift capacity and have multiple applications in both onshore and offshore geotechnical engineering. Uplift design methods are mostly based on semi-empirical approaches assuming a failure mechanism, a normal and a shear stress distribution at failure and empirical factors back-calculated against experimental data. However, these design methods are shown to under- or overpredict most of the existing larger scale experimental tests. Numerical FE simulations are undertaken to provide new insight into the failure mechanism and stress distribution which should be considered in anchor design in dense sand. Results show that a conical shallow wedge whose inclination to the vertical direction is equal to the dilation angle is a good approximation of the failure mechanism in sand. This shallow mechanism has been observed in each case for relative embedment ratios (depth/diameter) ranging from 1 to 9. However, the stress distribution varies non-linearly with depth, due to the soil deformability and progressive failure. A sharp peak of normal and shear stress can be identified close to the anchor edge, before a gradual decrease with increasing distance along the shear plane. The peak stress magnitude increases almost linearly with embedment depth at larger relative embedment ratios. Although further research is necessary, these results lay the basis for the development of a new generation of design criteria for determining anchor capacity at the ultimate limiting state.

scholarly journals Shear Tests and Calculation of Shear Resistance with the PC Program RFEM from Thin Partition Walls of Brick in Old Buildings

2015 ◽  
Vol 10 (2) ◽  
pp. 103-112
Author(s):  
Sinan Korjenic ◽  
Bernhard Nowak ◽  
Philipp Löffler ◽  
Anna Vašková
Keyword(s):  
Horizontal Displacement ◽  
Shear Resistance ◽  
Shear Capacity ◽  
Horizontal Force ◽  
Shear Tests ◽  
Maximum Displacement ◽  
Existing Building ◽  
Material Parameters ◽  
Partition Walls ◽  
Material Studies

Abstract This paper is about the shear capacity of partition walls in old buildings based on shear tests which were carried out under real conditions in an existing building. There were experiments conducted on different floors and in each case, the maximum recordable horizontal force and the horizontal displacement of the respective mortar were measured. At the same time material studies and material investigations were carried out in the laboratory. The material parameters were used for the calculation of the precise shear capacity of each joint. In the shear tests, the maximum displacement of a mortar joint was determined at a maximum of two to four millimetres. Furthermore, no direct linear relationship between the theoretical load (wall above it) and the shear stress occurred could be detected in the analysis of the experiment, as it was previously assumed.

scholarly journals CONCERNING THE EXTRACTION OF A SLACK SOIL LAYER FROM COMPRESSIBLE THICKNESS OF FOUNDATION STRATUM OF FINITE WIDTH FOUNDATIONS

2019 ◽  
Vol 7 (4) ◽  
pp. 49-56
Author(s):  
Zaven Ter-Martirosyan ◽  
Armen Ter-martirosyan ◽  
Valery DEMYANENKO
Keyword(s):  
Analytical Solutions ◽  
Soft Soil ◽  
Soil Layer ◽  
Horizontal Displacement ◽  
Creep Model ◽  
Shear Stresses ◽  
Finite Width ◽  
Relative Depth ◽  
Weak Layer ◽  
Horizontal Displacements

The paper provides a quantitative assessment of the deflected mode of foundation stratum of finite width foundation, in the compressible thickness of which there is a slack clay soil layer. A number of criteria for assessing the possibility or impossibility of extruding a slack layer depending on its strength and rheological properties, as well as the relative thickness of the layer to its length (h/l) and the relative depth of the layer (h/d) have been given. Closed analytical solutions are given to determine the rate of Foundation precipitation depending on the rate of extrusion of the weak layer, including taking into account the damped and undamped creep. The analytical solutions in the article are supported by the graphical part made with the help of the Mathcad program. Plots of changes in shear stresses in the layer along the x axis at different distances from the axis and at different values 0, contours of horizontal displacement velocities in the weak layer at different distances from the x axis, plots of horizontal displacement velocities in the middle of the weak layer and plots of horizontal displacement velocities in the weak layer at different distances from the x axis are given. As a calculation model for describing the creep of a slack layer, rheological ones of the soil using power and hyperbolic functions and their modifications have been considered. In addition, most modern rheological models that take into account soil hardening during creep have been considered. Based on these models, the problem is solved by means analytical and numerical methods using the Mathcad PC and the PLAXIS PC according to the Soft Soil Creep model. The graphical part shows the isofields of horizontal displacements for 300 days and 600 days and the corresponding contours of horizontal displacements.

Study on Artificial Island Ground Improvement Method and Effect

2014 ◽  
Vol 1030-1032 ◽  
pp. 1037-1040
Author(s):  
Jin Fang Hou ◽  
Ju Chen ◽  
Jian Yu
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Treatment Method ◽  
Surcharge Preloading ◽  
Porosity Ratio ◽  
Improvement Method ◽  
Consolidation Degree

The artificial island ground on an open sea is covered by thick soft soil. It must be improved before using. In accordance with a designing scheme, the ground treatment method is inserting drain boards on land and jointed dewatering surcharge preloading, the residual settlement is not more than 30cm after improvement and the average consolidation degree is more than 85%. In order to estimate ground improvement effect and construction safety, instruments are buried to monitor the whole ground improving processes. By monitoring settlement and pore water pressure, it is shown that the total ground settlement in construction is 2234mm, its final settlement is 2464mm, and consolidation degree and residual settlement respectively satisfy requirements. In ground improvement, horizontal displacement is small and construction is safe. Meanwhile, the results of soil properties and vane shear strength detection tests show the soft soil ground is greatly reduced in water content and porosity ratio, and improved in strength. It is named that the ground improvement method is reasonable and reaches expected effect.

Study on the Stratum Displacement Changes Caused by the Vertical Shaft Construction in Saturated Ultra Soft Soil

2012 ◽  
Vol 170-173 ◽  
pp. 1005-1012
Author(s):  
Lin You Pan ◽  
Xiao Bing Li ◽  
Chuang Yu ◽  
Fu Xue Sun
Keyword(s):  
Soft Soil ◽  
Field Tests ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Soil Disturbance ◽  
Soil Parameters ◽  
Finite Element Software ◽  
Total Displacement ◽  
Calculation Results ◽  
Engineering Information

In view of Wenzhou saturated super soft soil, This article studied the influence of different soil parameters for the shaft excavation construction and the stratum displacement change law by using Plaxis finite element software, according to the data obtained in field tests. The considered factors included the lateral brace stiffness, the stiffness of the underground diaphragm wall, and the surrounding soil disturbance. The calculation results provided much important engineering information, such as the horizontal displacement nephogram, the vertical displacement nephogram and the total displacement incremental vector diagram of each construction steps, which can be referred for the construction of the similar underground projects in soft soil areas.

Numerical analysis of soil deformation behind the reaction wall of an open caisson induced by horizontal parallel pipe-jacking construction

2015 ◽  
Vol 52 (12) ◽  
pp. 2008-2016 ◽  
Author(s):  
Yang Sun ◽  
Jing-bo Su ◽  
Xiao-he Xia ◽  
Zheng-liang Xu
Keyword(s):  
Reaction Force ◽  
Soil Surface ◽  
Horizontal Displacement ◽  
Element Model ◽  
Deformation Analysis ◽  
Burial Depth ◽  
Maximum Displacement ◽  
Obvious Effect ◽  
Simple Loading ◽  
Pipe Jacking

The disturbance of the soil behind the reaction wall of an open caisson can affect the efficiency and safety of jacking operation and control. This study focuses on the deformation of the soil mass behind the reaction wall used to support the jack. The stress–strain relationship of the soil behind the reaction wall was analysed, providing a theoretical basis for determining the most unfavourable combination of reactive forces using a computational model. A three-dimensional finite element model for this problem was developed, and a simple loading scenario was implemented. In addition, the mechanism of the deformation of the soil induced by horizontal parallel pipe jacking was also analysed. The results showed that for the soil behind the reaction wall of the open caisson, the uplift deformation of the soil surface increased initially and later gradually decreased, eventually achieving stability. The reaction force had a relatively obvious effect on the deformation of the soil within the range of the reaction wall burial depth and the horizontal displacement of the soil along the length of the reaction wall. The maximum displacement occurred near the axis of symmetry of the reaction wall. In addition, to consider the cyclic characteristics of the reaction force, the shakedown theorem is introduced to the deformation analysis of the soil and compared with the results obtained from simple loading. It was shown that the two deformation analysis methods have certain scopes of application, depending on the individual engineering requirements.

scholarly journals An Experimental Study on the Ecological Support Model of Dentate Row Piles

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Yousheng Deng ◽  
Zhihe Cheng ◽  
Mengzhen Cai ◽  
Yani Sun ◽  
Chengpu Peng
Keyword(s):  
Building Materials ◽  
Soft Soil ◽  
Earth Pressure ◽  
Shallow Foundation ◽  
Laboratory Model ◽  
Foundation Pit ◽  
Maximum Displacement ◽  
Single Row ◽  
The Earth ◽  
Soil Foundation

Bamboo is highly renewable and biodegradable with good short-term strength, which meets the requirement for temporal support structures in shallow foundation pits. Based on this, we conducted a laboratory model test on the dentate bamboo micropile support structure combined with environmentally friendly building materials and new type of piles, to explore the stress characteristics, stress change regularity, and the support effect of the system in soft soil foundation pits. The results show that the earth pressure on the pile sides above the excavation surface gradually decreases with an increase in the excavation depth. The bending deformation of the bamboo pile was also significant. The results also show that the earth pressure and the pile strain below the excavation surface change slightly during the excavation process. When the short sides of the foundation pit were loaded, the highest strain was recorded in the piles 4 and 11. A maximum strain of 358.93 με was recorded, and the maximum displacement of the pile in the top part was obtained to be only 2.14 mm. The most subsidence of dentate pile obtained is only 1.88 mm, whereas that of the single-row pile is 2.35 mm. Compared to the traditional single-row pile, the dentate piles can effectively reduce the horizontal deformation as well as the surface subsidence effectively. They can also support more external lateral load, and hence maintain the foundation stability and give better support. The results provide a theoretical basis for ecological bamboo support technology and have great value to be promoted.

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