The ground deformation field induced by a listric thrust fault with an overburden soil layer

2013 ◽  
Vol 7 (4) ◽  
pp. 501-507
Author(s):  
Shaogang Zeng ◽  
Yong’en Cai
2021 ◽  
Author(s):  
Fang Ru-Ya ◽  
Lin Cheng-Han ◽  
Lin Ming-Lang

<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>


2011 ◽  
Vol 480-481 ◽  
pp. 1278-1282
Author(s):  
Zhuan Yun Yang

Considering the current domestic situation that there is no provision for shallow pipe-jacking (with overburden soil layer not thicker than 3 m and 1.5 times of the pipe external diameter) in the existing water supply and drainage pipeline engineering design and construction specifications, a comprehensive analysis and discussion, based on the actual domestic condition, is made on the feasibility of shallow pipe-jacking technology in urban drainage systems. The problems confronting the shallow pipe-jacking technology theory research are also analyzed and the research status of shallow curve pipe-jacking technology is introduced.


Author(s):  
Ming-Lang Lin ◽  
Fu-Shu Jeng ◽  
Tisan-Hwei Huang ◽  
Chun-Fu Chung ◽  
Hung-Hwei Lee

When an under-lain thrust fault slips, especially triggered by earthquakes, the overburden soil may deform and fail so that a fault zone also develops inwardly. The research about the deformation and the failure of the overburden soil is an essential issue to evaluating the safety of ground or underground structures near the potential faulted zone. In this study, a MRT tunnel, closed to a thrust fault and fault dip 60 degree, is considered, both of the sandbox experiment and the numerical analyses are adopted to discuss the damage degree of a tunnel submerged in an overburden soil under the thrust faulting. In the numerical analyses, a small-scale model, simulation of the sandbox, is justified according to the experimental results and used to discuss the base behavior of the overburden soil. In addition, a full-scale model is used to evaluate the damage degree of tunnel segments by defining a dangerous factor. Moreover, considering the real behaviors of sand particles, the distinct element method is adopted as well. In the sandbox experiment, the results indicate that the development of the shear zone was apparently hindered by the existence of a model tunnel near the fault tip, and induced significant deformation of the tunnel. In addition, the results from numerical analyses, the finite element method and the distinct element method, are similar to the experimental results. The numerical analysis results of the full-scale model indicate that the damage degree is increased while the tunnel is close to the fault tip, and the footing wall is more dangerous than the hanging wall. The defined dangerous factor is able to reflect the damage degree of the tunnel. In the distinct element analysis, the full-scale model, it can be observed that a fault zone extends from the fault tip to the ground surface, but discussions on the distribution of stress and moment in the tunnel are not included and will be considered in the future study.


Author(s):  
J. Beavan ◽  
S. Samsonov ◽  
M. Motagh ◽  
L. Wallace ◽  
S. Ellis ◽  
...  

High quality GPS and differential InSAR data have been collected for determining the ground deformation associated with the September 2010 Darfield (Canterbury) earthquake. We report preliminary results from a subset of these data and derive a preliminary source model for the earthquake. While the majority of moment release in the earthquake occurred on the strike-slip Greendale Fault a number of other fault segments were active during the earthquake including a steeply southeast-dipping thrust fault coincident with the earthquake hypocentre.


2016 ◽  
Vol 57 ◽  
pp. 257-264 ◽  
Author(s):  
Michael A. Mooney ◽  
Jacob Grasmick ◽  
Bernadette Kenneally ◽  
Yong Fang

2006 ◽  
Vol 88 (1-2) ◽  
pp. 70-89 ◽  
Author(s):  
Ming-Lang Lin ◽  
Chun-Fu Chung ◽  
Fu-Shu Jeng

2020 ◽  
Author(s):  
Andrea Barone ◽  
Raffaele Castaldo ◽  
Maurizio Fedi ◽  
Susi Pepe ◽  
Giuseppe Solaro ◽  
...  

<p>The development of the satellite remote sensing technologies is providing a great contribution to monitor volcanic phenomena. Specifically, the large amount of the ground deformation field data (i.e., DInSAR measurements) holds information about the changes of physical and geometrical parameters of deep and shallow volcanic reservoirs; therefore, the exploitation of these data becomes an important task since they actively contribute to the hazard evaluation.</p><p>Currently, DinSAR measurements are mostly used for modeling the volcanic deformation sources through the optimization and the inversion procedures; although the latter provide a physical and geometrical model for the considered volcanic site, their results strongly depend on the availability of a priori information and on the considered assumptions about the physical settings; therefore, they do not provide a single solution and they unlikely guarantees a correct analysis  for the multi-source cases.</p><p>In this scenario, we consider a new methodology based on the use of edge-detection methods for exploiting DInSAR measurements and characterizing the active volcanic sources. Specifically, it allows the estimation of the source geometrical parameters, such as its depth, horizontal position, morphological features and horizontal sizes, by using Multiridge, ScalFun and Total Horizontal Derivative (THD) methods. In particular, it has been proved the validity of Multiridge and ScalFun methods for modeling the point-spherical source independently from its physical features, such as the pressure variation, the physical-elastic parameters of the medium, such as the shear modulus, and low signal-to-noise ratio.</p><p>Now, we extend the proposed Multiridge and ScalFun methods from the hydrostatic-pressure point source to the tensile one, and then to the others (rectangular tensile-fault and the prolate spheroid analytical models) in order to investigate volcanic sources as sills, dikes and pipes.</p><p>Specifically, after the analysis of the physical and mathematical features of the considered models, we apply Multiridge and ScalFun methods to the synthetic vertical and E-W components of the ground deformation field. We carefully evaluate the advantages and the limitations which could characterize these cases, showing how to solve critical aspects. We especially focus on the sill-like source, for which the edge-detection methods provide very satisfying results. In addition, we perform a joint exploitation of the edge-detection methods to model the deformation source of Fernandina volcano (Galapagos archipelago) by analyzing COSMO-SkyMed acquisitions related to the 2012-2013 time interval.</p><p>In conclusion, this approach allows retrieving univocal information about the geometrical configuration of the analyzed deformation pattern. We remark that, although a subsequent analysis is required to fully interpret the ground deformation measurements, this methodology provides a reliable geometrical model, which can be used as a priori information to constrain the entire interpretation procedure during next analyzes.</p>


2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Wu Zhu ◽  
Yan Zhang ◽  
Zhanke Liu ◽  
Qian Zhu

On the evening of 7 February 2018, a deadly collapse of a metro tunnel under construction in the Southern China city of Foshan caused 11 deaths, 8 injuries, and 1 missing person. For disaster prevention and mitigation, the spatiotemporal ground deformations before and after the collapse event were derived from 55 Sentinel-1A synthetic aperture radar (SAR) images spanning from March 2017 to January 2019. The results showed that prominent ground subsidence in the shape of a funnel with a maximum rate of 42 mm/year was observed in the vicinity of the collapse area before the accident. After the accident, the area and magnitude of subsidence decreased compared with precollapse subsidence. This decrease is related to the progress of tunnel excavation and groundwater changes. In the temporal domain, continuous subsidence was observed over a year before and after the accident, and accelerated subsidence appeared one month before the collapse accident. Soft soil consolidation and tunnel-induced soil losses were the main reasons for the subsidence over the study area. The leakage of groundwater accounted for the collapse event. The leaked groundwater eroded the soil, resulting in the formation of an arched hole. The connection between the arched hole and the tunnel reduced the bearing capacity of the soil layer above the arched hole, triggering the collapse event. The findings provide scientific evidence for future collapse monitoring and early warning due to tunnel excavation.


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