scholarly journals Numerical Investigation of Factors Influencing Oil and Gas Lifelines Behavior due to Normal Faulting Geo-Hazard

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 806-813
Author(s):  
Reza Khaksar ◽  
Majid Moradi
Keyword(s):  
Oil And Gas ◽  
Hanging Wall ◽  
Small Scale ◽  
Foot Wall ◽  
Buried Pipeline ◽  
Normal Faulting ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Factors Influencing ◽  
Centrifuge Model Tests

In this study, some factors influencing the response of buried oil and gas lifelines subjected to normal faulting are investigated. Due to such phenomenon, the stress, strain and displacement are induced in pipeline. Finite element code of Abaqus has been employed to model pipe and its surrounding soil considering material nonlinearities, soil-pipe interaction and foot wall and hanging wall interface. The numerical model has been calibrated through some small scale geotechnical centrifuge model tests and based on such calibrated model, some factors influencing the response of buried pipeline has been investigated.

Validation of Coupled FDM-DEM Approach on the Soil-Raft Foundation Interaction Subjected to Normal Faulting

2021 ◽  
Author(s):  
Fang Ru-Ya ◽  
Lin Cheng-Han ◽  
Lin Ming-Lang
Keyword(s):  
Active Fault ◽  
Ground Deformation ◽  
Numerical Models ◽  
Hanging Wall ◽  
Normal Fault ◽  
Small Scale ◽  
Foot Wall ◽  
Normal Faulting ◽  
Raft Foundation ◽  
Overburden Soil

<p>Recent earthquake events have shown that besides the strong ground motions, the coseismic faulting often caused substantial ground deformation and destructions of near-fault structures. In Taiwan, many high-rise buildings with raft foundation are close to the active fault due to the dense population. The Shanchiao Fault, which is a famous active fault, is the potentially dangerous normal fault to the capital of Taiwan (Taipei). This study aims to use coupled FDM-DEM approach for parametrically analyzing the soil-raft foundation interaction subjected to normal faulting. The coupled FDM-DEM approach includes two numerical frameworks: the DEM-based model to capture the deformation behavior of overburden soil, and the FDM-based model to investigate the responses of raft foundation. The analytical approach was first verified by three  benchmark cases and theoretical solutions. After the verification, a series of small-scale sandbox model was used to validate the performance of the coupled FDM-DEM model in simulating deformation behaviors of overburden soil and structure elements. The full-scale numerical models were then built to understand the effects of relative location between the fault tip and foundation in the normal fault-soil-raft foundation behavior. Preliminary results show that the raft foundation located above the fault tip suffered to greater displacement, rotation, and inclination due to the intense deformation of the triangular shear zone in the overburden soil. The raft foundation also exhibited distortion during faulting. Based on the results, we suggest different adaptive strategies for the raft foundation located on foot wall and hanging wall if the buildings are necessary to be constructed within the active fault zone. It is the first time that the coupled FDM-DEM approach has been carefully validated and applied to study the normal fault-soil-raft foundation problems. The novel numerical framework is expected to contribute to design aids in future practical engineering.</p><p><strong>Keywords</strong>: Coupled FDM-DEM approach; normal faulting; ground deformation; soil-foundation interaction; raft foundation.</p>

Geotechnical Centrifuge Shaking Table Tests and Numerical Simulation of Soil-Structure

2012 ◽  
Vol 256-259 ◽  
pp. 372-376 ◽  
Author(s):  
Jing Bo Liu ◽  
Dong Dong Zhao ◽  
Wen Hui Wang ◽  
Xiang Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Soil Structure ◽  
Shaking Table ◽  
Vertical Line ◽  
Shaking Table Tests ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Soil Structures ◽  
Input Motion ◽  
Centrifuge Model Tests

Two geotechnical centrifuge model tests of a soil-structure system with different burial depths are performed to investigate the interaction between soil and structure. The tests are performed at 50 gravitational centrifuge accelerations and the input motion is Kobe wave. This paper focuses on the accelerations and displacements in the soil-structures system. The peak accelerations and displacements along the axis of the structure and along the vertical line 17cm away from the axis are presented. The acceleration and displacement response due to the interaction between soil and structure are studied.

Blast Wave Effect on Apparatus and Propagation Laws in Dry Sand in Geotechnical Centrifuge Model Tests

2011 ◽  
Vol 105-107 ◽  
pp. 626-629 ◽  
Author(s):  
Yi Kai Fan ◽  
Xiang Qian Liang ◽  
Xin Huang ◽  
Xue Dong Zhang
Keyword(s):  
Blast Wave ◽  
Empirical Relation ◽  
Model Tests ◽  
Peak Acceleration ◽  
Wave Effect ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Dry Sand ◽  
Increasing Function ◽  
Centrifuge Model Tests

7 geotechnical centrifuge model tests for buried explosion in dry sand were investigated by using 450 g-t geotechnical centrifuge apparatus. Blast wave effect on apparatus and propagation laws in dry sand were studied under the conditions of different explosive charges and different centrifuge acceleration levels. 11 accelerometers were buried around the explosives for recording the acceleration response in sand. Other 1 accelerometer was installed on the centrifuge arm to monitor blast wave effect on centrifuge apparatus. The results demonstrate that: The effect of blast wave on centrifuge apparatus can be ignored. The peak acceleration is a power increasing function of the acceleration level. An empirical relation of exponent can be found between the proportional peak acceleration and the proportional distance.

Numerical Simulation and Analysis of Centrifuge Model Tests with Nonhomogeneous Materials in Geotechnical Engineering

2013 ◽  
Vol 353-356 ◽  
pp. 495-501
Author(s):  
Lie Xian Tang ◽  
Lian Jun Guo ◽  
Da Ning Zhang ◽  
Jian Ming Zheng
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Geotechnical Engineering ◽  
Model Tests ◽  
Centrifuge Model Test ◽  
Test Model ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Centrifuge Tests ◽  
Centrifuge Model Tests

The primary methods are antetype observation and model tests which to check the actual engineering status in geotechnical engineering field. The antetype observation is the best direct and convictive method, but approach miscellaneous and spend hugely. The general model tests can not fulfil the same stress between model and antetype. Geotechnical centrifuge model test can not only minish the measure of model and fulfil the comparability condition, but also can found all kinds of non-symmetrical models and simulation all kinds of complicated engineering. So the geotechnical centrifuge model test is applied widely in the geotechnical engineering. This paper used the RFPA-Centrifuge and recured to the principle of geotechnical centrifuge model test, evaluated the safety of model only by increase the physical strength. Though the numerical calculating in nonhomogeneous models with different scales showed that stress, displacement and failure mode were accord with conform ratio of centrifuge model tests. Showed the advantage that the results of RFPA can be validated each other with results of physical tests. For some specifical complicated items in geotechnical engineering, make a good test model is not only very hard and have to spend much time, but also need expensive test equipment and much money for test materials. It is very good if we can use a method to conquer these shortages. So it is advisable that using the mechod which geotechnical centrifuge tests combine RFPA-Centrifuge numerical simulation analysis method.

scholarly journals Instrumental and field observations for the determination of the seismogenic structure of the 7 September 1999 Athens earthquake

2001 ◽  
Vol 34 (4) ◽  
pp. 1457 ◽  
Author(s):  
Γ. Α. ΠΑΠΑΔΟΠΟΥΛΟΣ ◽  
Α. ΓΚΑΝΑΣ ◽  
Σ. ΠΑΥΛΙΔΗΣ
Keyword(s):  
Main Shock ◽  
Hanging Wall ◽  
Strong Motion ◽  
Small Scale ◽  
Foot Wall ◽  
Seismogenic Structure ◽  
Rock Falls ◽  
Field Evidence ◽  
Athens Earthquake ◽  
Fili Fault

The earthquake of 7 Sept. 1999 (Ms= 5.9) that struck the metropolitan area of Athens, occurred only at a distance of '18 NW from the historical center of the city and has been the most destructive shock in modern history of Greece. Therefore, it is of great importance to identify the seismogenic structure. Focal mechanisms of the main shock as well as the lateral and vertical distributions of the aftershocks , determined by several institutes, are consistent in that the main shock was associated with a normal faulting striking WNE-ESE and dipping SW. The only geological faults known in the area to have the geometrical characteristics that are compatible with the seismographic results are the fault of Thriassion Pedion and the Fili fault. We support that the Fili fault, striking 110° - 150° Ν at an observable length of 8-10 Km, has been very probably the seismogenic structure of the Athens earthquake because ( i) it proved to be an active fault as revealed by the striations we observed on several segments of the fault mirror, ( ii) the meizoseismal region as well as the most important ground failures, like local small-scale landslides and rock-falls, all are located on the hanging-wall domain and very close to the surface trace of the fault as it is theoretically expected (e.g. Oglesby et al., 2000), ( iii) we observed a possibly co-seismic displacement by 3-6 cm of the SW (hanging-wall) segment towards SW . On the contrary, the fault of Thriassion Pedion is recognizable in satellite images but in the field it is evident only as a series of alluvium cones which is an evidence of a possibly inactive structure. Moreover, the meizoseismal area and the ground failures observed in association with the Athens earthquake are located in its foot-wall, that is in the domain where strong motion should not expected to occur. In addition, if that fault was the seismogenic one then the earthquake focus would fit the fault geometry only if it was shifted at least 15 km southwestwards. The last possibility that the Athens earthquake was associated with a blind fault is not supported by any kind of instrumental or field evidence.

Geotechnical centrifuge model tests for explosion cratering and propagation laws of blast wave in sand

2012 ◽  
Vol 13 (5) ◽  
pp. 335-343 ◽  
Author(s):  
Yi-kai Fan ◽  
Zu-yu Chen ◽  
Xiang-qian Liang ◽  
Xue-dong Zhang ◽  
Xin Huang
Keyword(s):  
Blast Wave ◽  
Model Tests ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Centrifuge Model Tests

Experimental Study on Stresses Distribution under Embankment

2011 ◽  
Vol 97-98 ◽  
pp. 17-22
Author(s):  
Hong Bing Xiao ◽  
Guan Lu Jiang
Keyword(s):  
Experimental Study ◽  
Numerical Analysis ◽  
High Speed ◽  
Model Tests ◽  
High Speed Railway ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Side Slope ◽  
Simplified Method ◽  
Centrifuge Model Tests

For high-speed railway subgrade settlement, there was usually a big difference between calculated and measured value. Studying the stresses distribution under embankment, giving more accurate simplified method，was a approach to improve the accuracy of calculated settlement. The stresses distribution under embankment were studied through tests on experimental embankment segment, geotechnical centrifuge model tests, and numerical analysis and calculation. Studies showed that the measured stresses distribution was curve, the stresses under the embankment centre were highest, under the vicinity of shoulder the stresses changed smoothly, the stresses was above zero at toe of the side slope.

scholarly journals Analysis and Monitoring of Small-Scale Rock Fracture Zone Deformation and Shaft Failure in a Metal Mine

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Rong Lu ◽  
Fengshan Ma ◽  
Jie Zhao ◽  
Jianbo Wang ◽  
Guilin Li ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Rock Fracture ◽  
Hanging Wall ◽  
Wall Rock ◽  
Ground Movement ◽  
Small Scale ◽  
Foot Wall ◽  
Fracture Zones ◽  
Metal Mine ◽  
Deep Fracture

Rock fracture zones were distributed in a metal mine, and their deformation was always neglected because they are available on a small scale. However, the deformation of the small-scale fracture zone may lead to serious consequences, such as underground building and structure failure. Combined with the ground movement and surface fissure monitoring, the deformation of several fracture zones was analyzed by field monitoring, experimental test, and numerical simulation. The results showed that fracture deformation promoted the surface fissure movement. The horizontal movement of the foot wall rock of the fracture was found to be larger than the hanging wall rock. Deep mining engineering resulted in the squeezing of the shallow fracture, and the shallow fracture deformed more severely than the deep fracture. In the study area, fracture zone displacements were estimated according to a numerical model. The deformation and stress comparison of the shallow fracture zone and the deep fracture zone provided the characteristic of the broken structure in the field investigation.

Centrifuge model tests on backfill stability

1986 ◽  
Vol 23 (3) ◽  
pp. 341-345 ◽  
Author(s):  
Robert J. Mitchell
Keyword(s):  
Key Words ◽  
Model Tests ◽  
Unconfined Compression ◽  
Cemented Sand ◽  
Mine Backfill ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Centrifuge Tests ◽  
Behavioural Effects ◽  
Centrifuge Model Tests

The 6 m diameter, 30 g-tonne geotechnical centrifuge at Queen's University is described. Results from eight model tests, carried out on plain cemented sand samples representing mine backfills, are presented. These data show that the stable prototype backfill heights obtained from centrifuge tests exceed the failure heights predicted from unconfined compression testing by factors averaging about 1.8. This factor is explained by a combination of geometrical and behavioural effects. Still photographs of typical backfill failures in the centrifuge are included and these indicate that unacceptable ore dilution and recovery costs would be associated with the prototype failures in plain cemented tailings backfills. Key words: geotechnical centrifuge, mine backfill, model tests, cemented sand.

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