scholarly journals Modification Research of the Internal Substructure Method for Seismic Wave Input in Deep Underground Structure-Soil Systems

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xin Bao ◽  
Jingbo Liu ◽  
Dongyang Wang ◽  
Shutao Li ◽  
Fei Wang ◽  
...  
Keyword(s):  
Free Surface ◽  
Seismic Wave ◽  
Soil Structure ◽  
Underground Structure ◽  
Computational Effort ◽  
Seismic Loads ◽  
Underground Structures ◽  
Computational Accuracy ◽  
Substructure Method ◽  
Deep Underground

A new internal substructure method for seismic wave input in soil-structure systems was recently proposed. This method simplifies the calculation of equivalent input seismic loads and avoids the participation of artificial boundaries in the process of seismic wave input. However, in previous research and applications, the internal substructures are usually intercepted down from the free surface, which forms large substructures and increases the computational effort for data management on the substructure nodes, especially for deep underground structures. In this study, the internal substructure method is modified by intercepting the internal substructures entirely beneath the free surface and adjacently around the underground structures. Then, the equivalent input seismic loads are obtained through the dynamic analysis of the internal substructures and applied to the corresponding positions of the total soil-structure models. Thus, the earthquake energy can be more efficiently input into the region near the underground structures without losing computational accuracy. We provide the detailed implementation procedures of this modified method and validate its applicability and accuracy through the scattered problems of underground cavities in homogeneous and layered half-space sites.

scholarly journals EVALUATION OF UNDERGROUND STRUCTURES SUBJECTED TO SEISMIC LOADS

2019 ◽  
Vol 23 ◽  
pp. 38-43
Author(s):  
Jan Pruška
Keyword(s):  
Soil Structure ◽  
Free Field ◽  
Fem Analysis ◽  
Field Analysis ◽  
Seismic Loads ◽  
Dynamic Effects ◽  
Underground Structures ◽  
Arbitrary Geometry ◽  
Fem Model ◽  
Fem Method

The paper is focused on the evaluation of the effect of earthquakes on underground structures. Free-field analysis is one solution of this task common mainly in engineering tunnelling practice, but it has some rather simplified aspects (e.g. equivalent shear strain is constant). Pseudostatic finite element calculation combines free-field analysis and the advantages of a FEM model. Dynamic effects are introduced in the form of displacements prescribed along the vertical boundaries of the FEM model in a usually static manner. This approach also implies constant material parameters for the geological profile in the horizontal direction, an arbitrary geometry of excavation, soil structure interaction and description of share waves as a time-dependent 1D analysis of the so called free-field column. Moreover, there is shown an example comparing pseudo-static FEM analysis with an analytical method. Finally, the advantages of the pseudo-static FEM method are presented.

scholarly journals Analysis of Shaking Table Tests of Underground Structures considering the Influence of the Structure-Soil Interface

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Feng Shuang Guo ◽  
Yun Sheng Wang ◽  
Chang Bao Wang ◽  
LiJuan Wang
Keyword(s):  
Contact Surface ◽  
Soil Structure ◽  
Surface Effect ◽  
Underground Structure ◽  
Shaking Table ◽  
Peak Acceleration ◽  
Underground Structures ◽  
Stress Strain ◽  
Contact Effect ◽  
Soil Interface

To investigate the seismic performance of underground structures under the action of the structure-soil interface, in this study, experiments were performed using plexiglass structures (two pieces) and a concrete structure (one piece) as the research objects. The surface of one plexiglass structure was prepainted with a layer of cement mortar as the contact surface between the structure and soil, and the other plexiglass structure was not treated and used for comparison. A rigid model box measuring 2.25 m × 2.25 m × 1.5 m was placed on a 3 m × 3 m shaking table, and the box was filled with the configured model soil and the underground structure prepared in advance. Input transverse uniform excitation was imparted to the whole system. A shaking table model test was performed on the underground structures to analyse the acceleration response, stress strain, and earth pressure changes in the underground structure, and the influence of the contact surface on the seismic dynamics of the underground structure was evaluated. The test results showed that under uniform excitation, the dynamic characteristics of the underground structures were greatly affected by the intensity and depth of the seismic waves. (1) When the soil-structure contact was considered, the stress and strain of the structures increased significantly, and the stress-strain value was significantly greater than the stress-strain value of the soil-structure interface in a fully bonded state. (2) There were inconsistencies between the acceleration peak curve of the plexiglass structure considering the contact effect and the acceleration peak curve of the plexiglass structure without considering the contact effect. The difference between the two lies mainly in the corresponding maximum peak acceleration and the Fourier spectrum amplitude. With respect to the value and frequency composition, regardless of whether the input acceleration intensity was 0.2 g or 0.5 g, the peak acceleration of the organic structure was greater when the contact surface effect was considered than without the contact surface effect. Therefore, the structure-soil interface needs to be considered in actual engineering. The presence of the contact surface improves the safety of the structure and is helpful for seismic design. The results of this study provide a basis for further research on the influence of soil-pipe contact on the seismic response of underground structures.

About Contemporary Seismic Analysis of Underground Structures

2018 ◽  
Vol 931 ◽  
pp. 91-99
Author(s):  
Alexander M. Belostotskiy ◽  
Pavel A. Akimov ◽  
Dmitry S. Dmitriev
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Soil Structure ◽  
Seismic Analysis ◽  
Underground Structure ◽  
Soil Structure Interaction ◽  
Underground Structures ◽  
Structure Interaction ◽  
Second Stage ◽  
Element Method

This paper is devoted to actual problems of seismic analysis of underground structures. Brief classification and overview of corresponding methods of analysis (force-based methods, displacement-based methods, numerical methods of seismic analysis of coupled system “soil – underground structure” and approaches to problems of soil-structure interaction) is presented. Special static finite element method with substructure technique for seismic analysis of underground structures is described. Dynamic soil-structure interaction system can be decomposed into three sub-structures: structure, near-field and far-field soil. The first stage of static finite element method is solving the free field shear stress, acceleration, velocity and displacement, when the moment that the relative displacement of the soil that the underground structure located in reaches the maximum. The second stage is computing of internal forces and parameters of boundary conditions. The third stage is construction of the static finite element model and imposing the loads and constrains computed at the second stage and then making a static analysis.

The Research Methods of Soil and Structural Dynamic Interaction

2011 ◽  
Vol 250-253 ◽  
pp. 2068-2073
Author(s):  
Xiao Li Dong
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Underground Structure ◽  
Dynamic Interaction ◽  
Subway Station ◽  
Underground Structures ◽  
Structural Dynamic ◽  
Advantages And Disadvantages ◽  
Urban Construction ◽  
Structure Dynamic

This paper will introduce the basic methods of soil-structure dynamic interaction at home and abroad, and analysis the advantages and disadvantages of these methods. Finally, the paper will put forward opinions on the research tendency of soil-structure dynamic interaction. With the development of urbanization, the urban population, planning area and urban environment are faced with tremendous stress, so developing and utilizing the underground space becomes the concerns of many cities. In recent decades, the underground structure has been widely used in urban construction, transportation, national defense engineering, and hydraulic engineering and so on. Especially in the urban construction, with underground railway which has been seemed as the large-capacity backbone and fast public transport system has become an important issue of urban passenger traffic solution. In our country, there are still large potential in developing and utilizing the underground structure and the structure forms will become more and more complicated. China is a strong and frequent earthquake country, the earthquake-proof problems about the underground structures such as Long-span subway station has become city astigmatic engineering and the important research content on disaster prevention and mitigation. These researches can ensure the safe use of underground structures and reduce natural disasters to humankind. To the subway station and the tunnel structure, soil characteristics significantly influence the structure seismic response and destruction features. In seismic response process, the overburden of gravitational can greatly affect on the structural seismic response. The solution to the underground structure seismic problem should focus on two aspects: on one hand we should focus on the research of soil-structure dynamic interaction; on the other hand, we should deal with soil’s half-limitlessness simulation problem.

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.

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.

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