Simple approach to obtain ground amplification motion of surface soil deposits with a radical change of depth

2005 ◽  
Vol 42 (2) ◽  
pp. 491-498
Author(s):  
Dae-Sang Kim ◽  
Kazuo Konagai
Keyword(s):  
Seismic Design ◽  
Surface Soil ◽  
Underground Structure ◽  
Free Field ◽  
Alluvial Soil ◽  
Radical Change ◽  
Simple Approach ◽  
Clear Understanding ◽  
Underground Structures ◽  
Soil Deposits

Earthquake observations at different sites within alluvial soil deposits have demonstrated that the motion of buried underground structures closely follows that of the surrounding soil. Therefore, it is usual in a seismic design process to apply free-field ground displacements through Winkler-type soil springs to an underground structure to evaluate stress patterns induced within its structural members. Using a simplified approach, this paper provides a clear understanding of resonant horizontal ground displacement of and strain in a surface soil deposit with a radical change of depth and of where they occur.Key words: simple approach, seismic design, earthquake, resonance, underground structures.

scholarly journals Laboratory Tests for Subgrade Reaction Coefficient in Seismic Design of Underground Engineering Domain

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Kunpeng Xu ◽  
Liping Jing ◽  
Xinjun Cheng ◽  
Haian Liang ◽  
Jia Bin
Keyword(s):  
Seismic Design ◽  
Shaking Table Test ◽  
Free Field ◽  
Deformation Mode ◽  
Shaking Table ◽  
Subgrade Reaction ◽  
Underground Structures ◽  
Testing Methods ◽  
Underground Engineering ◽  
Reaction Coefficient

Subgrade reaction coefficient is commonly considered as the primary challenge in simplified seismic design of underground structures. Carrying out test is the most reliable way to acquire this intrinsic soil property. Owing to the limitations of experimental cost, time consumption, soil deformation mode, size effect, and confined condition, the existing testing methods cannot satisfy the requirements of high-precision subgrade reaction coefficient in seismic design process of underground structures. Accordingly, the present study makes an attempt to provide new laboratory testing methods considering realistic seismic response of soil, based on shaking table test and quasistatic test. Conventional shaking table test for sandy free-field was performed, with the results indicating that the equivalent normal subgrade reaction coefficients derived from the experimental hysteretic curves are reasonable and verifying the deformation mode under seismic excitation. A novel multifunctional quasistatic pushover device was invented, which can simulate the most unfavorable deformation mode of soil during the earthquake. In addition, the first successful application of an innovative quasistatic testing method in evaluating subgrade reaction coefficient was reported. The findings of this study provide preliminary detailed insights into subgrade reaction coefficient evaluation which can benefit seismic design of underground structures.

Response of Soil and a Submerged Tunnel During a Thrust Fault Offset Based on Model Experiment and Numerical Analysis

2005 ◽  
Author(s):  
M. L. Lin ◽  
F. S. Jeng ◽  
H. J. Wang ◽  
C. P. Wang ◽  
C. F. Chung ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Surface Soil ◽  
Underground Structure ◽  
Thrust Fault ◽  
Underground Structures ◽  
Diversion Tunnel ◽  
Near Surface ◽  
Model Experiments ◽  
Numerical Stimulation ◽  
Set Up

Observed from the earthquake disasters occurred over the decades in Taiwan, the deformation of near surface soil was the major cause lead to damages of underground structures or pipe lines; for instance, the damage of diversion tunnel of Shih-Kang Dam in Chichi earthquake is a typical case. To study the process of fault propagation as well as the associated soil and structure deformation during a fault offset event, model experiments of simulating thrust fault offset were set up, in which non-cohesive sands was adopted simulating near surface soil. The results, obtained from experiment studies and numerical analyses based on finite element method were then compared to further explore the behavior of soil, structure during faulting process. The soil deformation obtained from numerical analysis complies with the outcome from model experiments. In the near future, when conducting a risk evaluation for earthquake-induced damage on underground structure, a numerical stimulation can provides helpful quantity analysis and can serve as a handy tool for the earthquake resistance design.

scholarly journals Analytical Method for Preliminary Seismic Design of Tunnels

2021 ◽  
Author(s):  
Kaveh Dehghanian
Keyword(s):  
Seismic Design ◽  
Maximum Shear Stress ◽  
Free Field ◽  
Simple Relationship ◽  
Underground Structures ◽  
Maximum Shear Strain ◽  
Buried Structures ◽  
Near Surface ◽  
A Site ◽  
Geological Formations

Buried structures are categorized based on their shape, size and location. These main categories are near surface structures (e.g., pipes and other facilities), large section structures (e.g., tunnels, subways, etc.), and vertical underground structures (e.g., shafts and ducts). Seismic assessments of these structures are important in areas close to severe seismic sources. Seismic design of tunnels requires calculation of the deformation in surrounding geological formations. The seismic hazard on a site is usually expressed as a function of amplitude parameters of free-field motion. Therefore, simplified relations between depth and parameters of ground motion are necessary for preliminary designs. The objective of this chapter is to study and review the main analytical seismic methods which are used to develop a simple relationship between maximum shear strain, maximum shear stress and other seismic parameters.

scholarly journals THE INFLUENCE OF BOUNDARY CONDITIONS ON THE RESPONSE OF UNDERGROUND STRUCTURES SUBJECTED TO EARTHQUAKE

2018 ◽  
Vol 15 ◽  
pp. 74-80
Author(s):  
Veronika Pavelcová ◽  
Tereza Poklopová ◽  
Tomáš Janda ◽  
Michal Šejnoha
Keyword(s):  
Boundary Conditions ◽  
Underground Structure ◽  
Free Field ◽  
Two Dimensional ◽  
Special Boundary ◽  
The Finite Element Method ◽  
Underground Structures ◽  
Actual Design ◽  
Vertically Propagating ◽  
Propagating Shear

The paper deals with the prediction of the response of a real underground structure subjected to earthquake. A fully dynamic analysis is carried out in the GEO5 FEM program using the Finite Element Method. Limiting our attention to a two-dimensional analysis we focus on the implementation of special boundary conditions along the vertical edges of the computational model. A simple study is carried out first to show that incorrectly applied boundary conditions may significantly influence the actual design of underground structures loaded by vertically propagating shear waves. This study promotes the combination of so called free-field and static boundary conditions as demonstrated on a simple example.

Seismic Design and Analysis of Large-Size Shield Tunnels. Part II: Modified Stiffness Solution

2011 ◽  
Vol 105-107 ◽  
pp. 1308-1312
Author(s):  
Li Yu Liu ◽  
Zhi Yi Chen ◽  
Yong Yuan
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Underground Structure ◽  
Large Diameter ◽  
Free Field ◽  
Time History ◽  
Shield Tunnel ◽  
Deformation Method ◽  
Seismic Design Method ◽  
Different Diameters

According to the extensive application of shield tunnel, large-diameter shield tunnel in particular, a simplified seismic design method is in urgent need. The equivalent static method is more suitable for the rigid underground structure, rather than flexible structure such as large-diameter shield tunnel. In this paper, shield tunnels with different diameters and thicknesses are analyzed and calculated by time-history method and free field deformation method. The calculation and analysis above help to identify the stiffness ratio to measure the relationship of structure’s stiffness and soil’s stiffness and the derivation of a revised stiffness solution based on the free field deformation method. The results indicate that this method can calculate seismic stress of shield tunnels with different diameters and thicknesses accurately.

scholarly journals Utilization of Building Information Modeling for Arranging the Structural Kingposts

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 323
Author(s):  
Vachara Peansupap ◽  
Pisal Nov ◽  
Tanit Tongthong
Keyword(s):  
Underground Structure ◽  
Visual Programming ◽  
Information Modeling ◽  
Construction Technology ◽  
Underground Structures ◽  
Building Information Modelling ◽  
Engineering Knowledge ◽  
Building Information ◽  
Rule Based Approach

The kingpost was a vertical element that was used to support the structural strut in the deep excavation. The structural kingpost was commonly arranged by experienced engineers who used two-dimensional construction drawings. Thus, it was still time-consuming and error-prone. Currently, an available construction program has been developed to arrange the structural kingpost by identifying the clash problems in the 3D environment. However, they have a limitation for detecting the clash that was unable to visualize the concurrent clashes between kingpost and many underground structures. Then, the engineer cannot see all the clash incidents with each kingpost and move the kingpost to avoid the clashes successfully. Since the kingpost arrangement was still an inefficient practice that was limited in the visualization aspect, this research used engineering knowledge and advanced construction technology to detect and solve the clashes between kingposts and underground structures. The methodology used engineering knowledge of kingpost arrangement to develop the system modules by using a rule-based approach. Then, these modules were developed into the system by using visual programming of Building Information Modelling (BIM). To test the system, an underground structure from building construction was selected as a case study to apply the developed system. Finally, the finding of this study could overcome human judgment by providing less interaction in the kingpost arrangement and visualization improvement of clash occurrences in the 3D model.

scholarly journals Overview of Anti-Seismic Researches of Underground Structures

2018 ◽  
Vol 38 ◽  
pp. 03038
Author(s):  
Ran Liao
Keyword(s):  
Research Methods ◽  
Underground Structure ◽  
Seismic Damage ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Underground Structures ◽  
Transit System ◽  
Urban Rail ◽  
Subway System ◽  
Metro System

With the vigorous development of urban rail transit system, especially the construction of subway system, the safety of subway system draws more and more attention. The study of anti-seismic for underground structures has also become an important problem to be solved in the construction of Metro system. Based on the typical underground structure seismic damage phenomenon, this paper summarizes the seismic characteristics, research methods and design methods of underground structures to offer a guide for engineers.

Residual strength of underground structures in service

2016 ◽  
Vol 53 (6) ◽  
pp. 988-999 ◽  
Author(s):  
Taous Kamel ◽  
Ali Limam ◽  
Claire Silvani
Keyword(s):  
Stress State ◽  
Residual Strength ◽  
Underground Structure ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Underground Structures ◽  
Weathering Processes ◽  
Working Face ◽  
Metro Tunnel ◽  
Loss Of Strength

Old tunnels suffer from deterioration and it is necessary to assess their residual strength to properly organize their repair and strengthen them. The stress state of underground structures evolves over time, firstly because of the advancement of the working face during construction, then due to gradual changes in soil properties and mechanical properties of materials composing the infrastructures, such as reduction of cohesion, loss of strength and (or) stiffness, etc. These changes are caused by combined actions such as creep and (or) weathering processes as well as the appearance of cracks that induce redistribution of stresses and therefore strains. This study investigates tunnels and galleries of the Paris underground. Macromodeling based on the finite element method allows consideration of different scenarios of tunnel-lining deterioration, specifically at the extrados of the galleries or tunnels. To understand changes in the stress state, and also damage occurrence and associated redistributions (stress and strain), it is necessary to model the delayed deformations. To model the infrastructure behavior, a time-dependency approach has been chosen. This approach can quantify the damage and predict the residual strength of this type of underground structure. An elastic–viscoplastic constitutive model with strain-softening is used to reproduce the appearance of the degraded zones and their behavior. The results obtained with the numerical approach reproduce Paris metro tunnel behavior, corroborate geoendoscopy results, clarify their interpretation, and improve the management of infrastructure repairs.

scholarly journals Infographics and visual aspects in the training processes of PetrSU students

2021 ◽  
Vol 9 (4) ◽  
Author(s):  
V. D. Lobashev
Keyword(s):  
Creative Thinking ◽  
Radical Change ◽  
Educational Process ◽  
Educational Institutions ◽  
Visual Images ◽  
Clear Understanding ◽  
Negative Consequences ◽  
Teachers And Students ◽  
Level Of Training ◽  
Educational Information

Introduction. The amount of information offered for study in modern educational institutions is rapidly increasing. Overcoming the inconsistency of the obligation to master the increasing flow of educational information and achieving the necessary "level" of training in fulfilling the traditional requirement of pedagogy – withstanding an acceptable amount of visibility leads to the mass introduction of multimedia tools. The folding so-called clip thinking shades the problems of filling thesaurus learning information virtually uncontrollable content and quality.Materials and Methods. Theoretical and empirical methods of research were used in the course of the work: analysis, synthesis, generalization, comparison, comparison, scientific theorization.Results. Clip-thinking interferes with a clear understanding of the context, and therefore the clip leaves no trace in semantically related phenomena. The trend of radical change in the roles of teachers and students reveals the main reasons and conditions for the transition to visualized presentation of educational information. In addition to the apparent negative consequences of the current pedagogical situation, some advantages of the protective reactions developed by modern learners to the most powerful stream of educational information are revealed. Studies have confirmed the risks of over-visibility in the learning process. Objective differences in the purpose and effectiveness of the types of visibility considered are highlighted. The main points of the formation of visual images are reflected, the obligatory maintenance of the conditions of problems in the educational process is emphasized.Discussion and Conclusions. The studies that have been carried out present an argument for the recommendations for the proposed frame-graphic approach in the organization of the educational process. The orientation of the educational process for each allocated group is justified, which requires a rather different nature of the script. One solution is to use educational information visualization tools to ensure the sustainability of the creative thinking vector.

scholarly journals The impact of heavy object on an underground structure when falling onto the ground surface

2021 ◽  
Vol 17 (4) ◽  
pp. 425-438
Author(s):  
Oleg V. Mkrtychev ◽  
Yury V. Novozhilov ◽  
Anton Yu. Savenkov
Keyword(s):  
Nuclear Power ◽  
Rocket Engine ◽  
Underground Structure ◽  
Ground Surface ◽  
Civil Defense ◽  
Main Task ◽  
Underground Structures ◽  
Building Collapse ◽  
Protective Structures ◽  
The Impact

At the objects of space infrastructure and at nuclear power facilities there are industrial structures, the main task of which is to protect a person, equipment or machinery from emergencies such as, for example, explosions, falling of various objects, fragments. In accordance with the requirements of the Federal Law On the Protection of the Population and Territories from Natural and Technogenic Emergencies, when calculating such structures, all types of loads corresponding to their functional purpose must be taken into account. So, for structures located in the area of a possible accident and the fall of space rockets, it is necessary to calculate for the fall of the destroyed parts of the rocket engine. For nuclear power plant facilities, such accidents occur when containers and other heavy objects fall on the ground, affecting underground structures located in the ground, and for civil defense protective structures built into the basement floors of buildings, it is necessary to consider situations in which the overlying floors of a building collapse when exposed to there is an air shock wave on them. Therefore, this problem is relevant, and in this study, a finite-element method for calculating an underground structure in a non-linear dynamic setting has been developed when a large overall object collides with the ground.

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