Pub Date : 2024-10-07DOI: 10.1016/j.soildyn.2024.109001
Chunli Yan , Jin Tu , Hui Liang , Shengshan Guo , Deyu Li
In this study, a high arch dam-foundation system model with more than ten million degrees of freedom was constructed. The model innovatively incorporates multiple nonlinear couplings of the strength failure of the dam body and stability failure of dam abutment blocks for the first time. A nonlinear dynamic response analysis of the coupling system was performed at different overload coefficients. The maximum damage depth-thickness ratio and sliding area ratio are proposed as performance evaluation indices. The failure mechanism of the model under strong earthquakes was elucidated. The residual displacement of the dam crest relative to the dam bottom in the stream direction is proposed as another performance evaluation index. Sudden changes and rapid growth are suggested as evaluation criteria to assess the ultimate seismic capacity of arch dams based on proposed multi-nonlinear coupled model. The results show that the strength failure of the dam body and stability failure of the dam abutments vary dynamically with the duration and intensity of the earthquake. Earthquake energy can be fully released by only one failure mode at low seismic intensity, whereas it is gradually released by both failure modes as the seismic intensity increases. The overload coefficient corresponding to the ultimate seismic capacity of the dam is concluded to be 2.0.
{"title":"Seismic failure analysis of a high arch dam-foundation multiple nonlinear coupling system","authors":"Chunli Yan , Jin Tu , Hui Liang , Shengshan Guo , Deyu Li","doi":"10.1016/j.soildyn.2024.109001","DOIUrl":"10.1016/j.soildyn.2024.109001","url":null,"abstract":"<div><div>In this study, a high arch dam-foundation system model with more than ten million degrees of freedom was constructed. The model innovatively incorporates multiple nonlinear couplings of the strength failure of the dam body and stability failure of dam abutment blocks for the first time. A nonlinear dynamic response analysis of the coupling system was performed at different overload coefficients. The maximum damage depth-thickness ratio and sliding area ratio are proposed as performance evaluation indices. The failure mechanism of the model under strong earthquakes was elucidated. The residual displacement of the dam crest relative to the dam bottom in the stream direction is proposed as another performance evaluation index. Sudden changes and rapid growth are suggested as evaluation criteria to assess the ultimate seismic capacity of arch dams based on proposed multi-nonlinear coupled model. The results show that the strength failure of the dam body and stability failure of the dam abutments vary dynamically with the duration and intensity of the earthquake. Earthquake energy can be fully released by only one failure mode at low seismic intensity, whereas it is gradually released by both failure modes as the seismic intensity increases. The overload coefficient corresponding to the ultimate seismic capacity of the dam is concluded to be 2.0.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109001"},"PeriodicalIF":4.2,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1016/j.soildyn.2024.109007
Zhenning Ba , Shujuan Han , Mengtao Wu , Yan Lu , Jianwen Liang
This study aims to propose an enhanced hybrid approach that combines physics-based simulation and machine learning to investigate the spatial distribution of seismic liquefaction characteristics. This innovative approach comprises two main components: Firstly, the physics-based frequency-wavenumber method is employed to construct the spatial-temporal field of ground motion in the study area, which provides ground motion quantities for assessing the liquefaction characteristic (e.g., liquefaction potential index) of the site. Subsequently, the seismic liquefaction parameters of the region are predicted using a machine learning (ML)-based SSA-XGBoost model. Due to the integration of physics-based simulation and machine learning techniques, which consider the effects of near-fault ground motion characteristics on seismic liquefaction, the proposed solution enables the evaluation of the spatial distribution of seismic liquefaction parameters under scenario earthquakes. In this study, the SSA-XGBoost model, constructed using the sparrow search algorithm (SSA) to automate and optimize the hyper-parameter tuning of the eXtreme gradient boosting (XGBoost), incorporates factors such as peak ground acceleration, magnitude scaling factor, ground water level, soil depth, vertical total overburden stress, vertical effective overburden stress, and fine content to evaluate their influence on liquefaction potential index. To demonstrate the effectiveness of the enhanced hybrid approach, the Jinnan district of Tianjin is taken as an example to evaluate liquefaction potential under various scenario earthquakes (Mw = 5.0, 5.5 and 6.0). The results show that the constructed SSA-XGBoost model has excellent predictive ability and is suitable for evaluating the liquefaction potential index of large-scale site soils. In the case of Mw 6.0 earthquake, most of the northern region of Jinnan district has the possibility of liquefaction, and some areas are seriously liquefied, and the liquefaction grade gradually decreases from the north to the south. These findings distinctly illustrate the spatial distribution of liquefaction characteristic parameters across the entire region, providing new insights and methods for similar studies and serving as a decision-making basis for the prevention and control of seismic liquefaction hazards.
{"title":"An enhanced hybrid approach for spatial distribution of seismic liquefaction characteristics by integrating physics-based simulation and machine learning","authors":"Zhenning Ba , Shujuan Han , Mengtao Wu , Yan Lu , Jianwen Liang","doi":"10.1016/j.soildyn.2024.109007","DOIUrl":"10.1016/j.soildyn.2024.109007","url":null,"abstract":"<div><div>This study aims to propose an enhanced hybrid approach that combines physics-based simulation and machine learning to investigate the spatial distribution of seismic liquefaction characteristics. This innovative approach comprises two main components: Firstly, the physics-based frequency-wavenumber method is employed to construct the spatial-temporal field of ground motion in the study area, which provides ground motion quantities for assessing the liquefaction characteristic (e.g., liquefaction potential index) of the site. Subsequently, the seismic liquefaction parameters of the region are predicted using a machine learning (ML)-based SSA-XGBoost model. Due to the integration of physics-based simulation and machine learning techniques, which consider the effects of near-fault ground motion characteristics on seismic liquefaction, the proposed solution enables the evaluation of the spatial distribution of seismic liquefaction parameters under scenario earthquakes. In this study, the SSA-XGBoost model, constructed using the sparrow search algorithm (SSA) to automate and optimize the hyper-parameter tuning of the eXtreme gradient boosting (XGBoost), incorporates factors such as peak ground acceleration, magnitude scaling factor, ground water level, soil depth, vertical total overburden stress, vertical effective overburden stress, and fine content to evaluate their influence on liquefaction potential index. To demonstrate the effectiveness of the enhanced hybrid approach, the Jinnan district of Tianjin is taken as an example to evaluate liquefaction potential under various scenario earthquakes (<em>M</em><sub>w</sub> = 5.0, 5.5 and 6.0). The results show that the constructed SSA-XGBoost model has excellent predictive ability and is suitable for evaluating the liquefaction potential index of large-scale site soils. In the case of <em>M</em><sub>w</sub> 6.0 earthquake, most of the northern region of Jinnan district has the possibility of liquefaction, and some areas are seriously liquefied, and the liquefaction grade gradually decreases from the north to the south. These findings distinctly illustrate the spatial distribution of liquefaction characteristic parameters across the entire region, providing new insights and methods for similar studies and serving as a decision-making basis for the prevention and control of seismic liquefaction hazards.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109007"},"PeriodicalIF":4.2,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1016/j.soildyn.2024.109010
Yuxin Han , Yan-Gang Zhao , Haizhong Zhang
Similar to the horizontal-to-vertical Fourier spectral ratio (HVF) of ground motions, the horizontal-to-vertical response spectral ratio (HVR) is a valuable tool for evaluating site effects. Although these two spectral ratios often exhibit similar behaviours, each possesses its own set of properties, prompting increased attention to their relationship. Previously, the relationship between HVF and HVR has been statistically investigated to explore which is more reasonable for predominant period estimation. However, the theoretical link between them remains unexplored. To clarify their theoretical relationship, in this study, an expression relating HVR to HVF based on random vibration theory was derived. The accuracy of the derived expression was confirmed through a comparison with the results obtained via direct numerical integration using real seismic records. Subsequently, based on the derived expression, the theoretical relationship between HVF and HVR was systematically explored. HVR was found to be the result of smoothing the square of the HVF, and the spectral window for this smoothing operation was determined using the Fourier amplitude spectrum of the vertical ground motion and the oscillator transfer function.
{"title":"Theoretical relationship between the horizontal-to-vertical response and Fourier spectral ratios of ground motions","authors":"Yuxin Han , Yan-Gang Zhao , Haizhong Zhang","doi":"10.1016/j.soildyn.2024.109010","DOIUrl":"10.1016/j.soildyn.2024.109010","url":null,"abstract":"<div><div>Similar to the horizontal-to-vertical Fourier spectral ratio (HVF) of ground motions, the horizontal-to-vertical response spectral ratio (HVR) is a valuable tool for evaluating site effects. Although these two spectral ratios often exhibit similar behaviours, each possesses its own set of properties, prompting increased attention to their relationship. Previously, the relationship between HVF and HVR has been statistically investigated to explore which is more reasonable for predominant period estimation. However, the theoretical link between them remains unexplored. To clarify their theoretical relationship, in this study, an expression relating HVR to HVF based on random vibration theory was derived. The accuracy of the derived expression was confirmed through a comparison with the results obtained via direct numerical integration using real seismic records. Subsequently, based on the derived expression, the theoretical relationship between HVF and HVR was systematically explored. HVR was found to be the result of smoothing the square of the HVF, and the spectral window for this smoothing operation was determined using the Fourier amplitude spectrum of the vertical ground motion and the oscillator transfer function.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109010"},"PeriodicalIF":4.2,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.soildyn.2024.109013
Burak Ozturk , Ahmed Fouad Hussein , M. Hesham El Naggar , Hongjuan Chen
This paper investigates the dynamic response of a model pile-soil-bridge system subjected to seismic loading using a finite element model (FEM) developed in OpenSees. The numerical model is validated against shake table test data from a companion experimental study, which tested a piles-bridge model fabricated from organic glass. The bridge model comprised four piers, each supported by two-by-two pile groups, with edge piers featuring 60 × 60 mm rubber pads between the pier and deck. Two earthquake ground motions, El Centro and Tianjin, were applied at three intensity levels. The calculated and measured responses show good agreement. The validated FEM reveals that the El Centro earthquake typically induces higher acceleration and moment responses in structural elements compared to the Tianjin earthquake, while the Tianjin earthquake results in greater displacement responses. These findings highlight the impact of earthquake wave characteristics, such as predominant period, on the bridge system's response. Furthermore, the bending moments at the pier top for edge piers remain relatively consistent across different earthquake motions and intensity levels, indicating the role of rubber pads in mitigating seismic forces in the piers.
{"title":"Seismic response of a model soil-pile-bridge system in cohesive soil","authors":"Burak Ozturk , Ahmed Fouad Hussein , M. Hesham El Naggar , Hongjuan Chen","doi":"10.1016/j.soildyn.2024.109013","DOIUrl":"10.1016/j.soildyn.2024.109013","url":null,"abstract":"<div><div>This paper investigates the dynamic response of a model pile-soil-bridge system subjected to seismic loading using a finite element model (FEM) developed in OpenSees. The numerical model is validated against shake table test data from a companion experimental study, which tested a piles-bridge model fabricated from organic glass. The bridge model comprised four piers, each supported by two-by-two pile groups, with edge piers featuring 60 × 60 mm rubber pads between the pier and deck. Two earthquake ground motions, El Centro and Tianjin, were applied at three intensity levels. The calculated and measured responses show good agreement. The validated FEM reveals that the El Centro earthquake typically induces higher acceleration and moment responses in structural elements compared to the Tianjin earthquake, while the Tianjin earthquake results in greater displacement responses. These findings highlight the impact of earthquake wave characteristics, such as predominant period, on the bridge system's response. Furthermore, the bending moments at the pier top for edge piers remain relatively consistent across different earthquake motions and intensity levels, indicating the role of rubber pads in mitigating seismic forces in the piers.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109013"},"PeriodicalIF":4.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.soildyn.2024.109006
Chao Ma , Jing-wei Chi , Dong-xu Li , Fan-chao Kong , De-chun Lu , Wei-zhang Liao
The plastic rotation angle or deflection is typically used as the indicator to evaluate the earthquake-induced damage and classify the seismic performance levels of reinforced concrete (RC) beams. Herein, one of the most important issues is to determine the seismic performance level limits of RC beams. Whereas, different countries provided their specific method to determine the limit values by considering the loading-carrying capacity of RC beams, which could not be used to describe the earthquake-induced seepage of structures, especially for underground structures. Therefore, in this study, the seismic performance level limits of RC beams were predicted by using the machine learning methods and considering the development of cracks. Firstly, the seismic performance level limits of RC beams were presented after discussing the methods in different codes and the development of cracks. Then an earthquake performance test database of RC beams was established after collecting 452 test results of RC beams, and Pearson correlation analysis was conducted for feature selection to determine the input mechanical parameters and dimensional parameters for machine learning. Meanwhile, the correlation between the inputs and limit values was analyzed using the mutual information method. Regression models of seven machine learning methods were then established to predict the performance level limits of RC beams, and the hyperparameters of the machine learning models were optimized with the TPE optimization algorithm and cross-validation. The generalization ability of the prediction models was evaluated and the accuracy of predicted results by different methods was analyzed. Finally, the predicted seismic performance level limits of RC beams could be used to evaluate the earthquake-induced damage of RC beams by combining them with the seismic behavior of RC beams.
{"title":"Prediction on seismic performance levels of reinforced concrete beams by considering crack development","authors":"Chao Ma , Jing-wei Chi , Dong-xu Li , Fan-chao Kong , De-chun Lu , Wei-zhang Liao","doi":"10.1016/j.soildyn.2024.109006","DOIUrl":"10.1016/j.soildyn.2024.109006","url":null,"abstract":"<div><div>The plastic rotation angle or deflection is typically used as the indicator to evaluate the earthquake-induced damage and classify the seismic performance levels of reinforced concrete (RC) beams. Herein, one of the most important issues is to determine the seismic performance level limits of RC beams. Whereas, different countries provided their specific method to determine the limit values by considering the loading-carrying capacity of RC beams, which could not be used to describe the earthquake-induced seepage of structures, especially for underground structures. Therefore, in this study, the seismic performance level limits of RC beams were predicted by using the machine learning methods and considering the development of cracks. Firstly, the seismic performance level limits of RC beams were presented after discussing the methods in different codes and the development of cracks. Then an earthquake performance test database of RC beams was established after collecting 452 test results of RC beams, and Pearson correlation analysis was conducted for feature selection to determine the input mechanical parameters and dimensional parameters for machine learning. Meanwhile, the correlation between the inputs and limit values was analyzed using the mutual information method. Regression models of seven machine learning methods were then established to predict the performance level limits of RC beams, and the hyperparameters of the machine learning models were optimized with the TPE optimization algorithm and cross-validation. The generalization ability of the prediction models was evaluated and the accuracy of predicted results by different methods was analyzed. Finally, the predicted seismic performance level limits of RC beams could be used to evaluate the earthquake-induced damage of RC beams by combining them with the seismic behavior of RC beams.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109006"},"PeriodicalIF":4.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study on liquefaction mitigation using cement-based materials in soils with liquefaction potential is of great interest. As cement production is a costly and environmentally polluting process, replacing part of it with environmentally friendly and cheaper materials such as natural zeolite is very important and attractive. In the present study, to evaluate the improvement of the liquefaction resistance in loose sand using zeolite-cement injection, a series of triaxial tests was performed. Also, the liquefaction potential of injected specimens was investigated based on the results of bender element, unconfined compressive strength and monotonic triaxial tests. The results of the study indicated that the injection of tested sand with zeolite-cement grout is significantly effective in liquefaction mitigation of the sand. Even under very strong earthquakes, liquefaction did not occur in the injected specimens with water to cementitious materials' ratio (W/CM) of 3 and a cement replacement with zeolite (Z) up to 70 %. The optimum amount of zeolite (Zopt) corresponding to the maximum liquefaction resistance was 30 %. It was shown that, considering the optimization of energy consumption as well as environmental considerations, for earthquakes with a CSR ≤ 0.2, by grout injection with Z90 and W/CM of 5, the used sand liquefaction resistance is more than double. For more severe earthquakes (CSR ≤ 0.3), injection with a grout containing Z70 and W/CM of 7 resulted in no liquefaction. To counteract the liquefaction under very strong earthquakes (CSR0.5), grout injection with Z50 and W/CM of 5 can be effective.
{"title":"Laboratory investigation of liquefaction mitigation in sand using zeolite-cement injection","authors":"Afshin Kordnaeij , Reza Ziaie Moayed , Peyman Jafarpour , Hosein Mola-Abasi","doi":"10.1016/j.soildyn.2024.109014","DOIUrl":"10.1016/j.soildyn.2024.109014","url":null,"abstract":"<div><div>The study on liquefaction mitigation using cement-based materials in soils with liquefaction potential is of great interest. As cement production is a costly and environmentally polluting process, replacing part of it with environmentally friendly and cheaper materials such as natural zeolite is very important and attractive. In the present study, to evaluate the improvement of the liquefaction resistance in loose sand using zeolite-cement injection, a series of triaxial tests was performed. Also, the liquefaction potential of injected specimens was investigated based on the results of bender element, unconfined compressive strength and monotonic triaxial tests. The results of the study indicated that the injection of tested sand with zeolite-cement grout is significantly effective in liquefaction mitigation of the sand. Even under very strong earthquakes, liquefaction did not occur in the injected specimens with water to cementitious materials' ratio (<em>W/CM</em>) of 3 and a cement replacement with zeolite (<em>Z</em>) up to 70 %. The optimum amount of zeolite (<em>Z</em><sub><em>opt</em></sub>) corresponding to the maximum liquefaction resistance was 30 %. It was shown that, considering the optimization of energy consumption as well as environmental considerations, for earthquakes with a <em>CSR</em> ≤ 0.2, by grout injection with <em>Z</em><sub><em>90</em></sub> and <em>W/CM</em> of 5, the used sand liquefaction resistance is more than double. For more severe earthquakes (<em>CSR</em> ≤ 0.3), injection with a grout containing <em>Z</em><sub><em>70</em></sub> and <em>W/CM</em> of 7 resulted in no liquefaction. To counteract the liquefaction under very strong earthquakes (<em>CSR</em><sub>0.5</sub>), grout injection with <em>Z</em><sub><em>50</em></sub> and <em>W/CM</em> of 5 can be effective.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109014"},"PeriodicalIF":4.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.soildyn.2024.108992
Yao Hu , Haoran Tang , Yinggang Xu , Huayang Lei , Junfu Lu , Xuejian Chen , Zilin Gao
Stacked tunnel constructions adjacent to operating metro lines are frequently encountered in dense underground space, leading to undesired settlement and existing tunnel deformation. In this paper, ground movement and tunnel deformation were studied due to stacked shield tunnelling using field monitoring and numerical simulation, particularly the effect of adjacent moving train load on ground and tunnel responses was mainly investigated. Numerical model was implemented based one engineering project of the stacked shield tunnel in Tianjin, China. The results indicate that the ground vertical deformation is influenced by the position of new tunnel and existing tunnel, while the ground horizontal deformation occurs specifically at the top of the new tunnel. The train load contributes to an increase in both vertical and horizontal deformations of the ground and an intensified longitudinal settlement deformation in the existing tunnel. A ground settlement prediction was proposed that considers the stiffness of the existing tunnel and effect of train load. This study provides an in-depth investigation into the deformation of ground and existing tunnel and addressed the non-negligible effect of adjacent train load when evaluating safety of stacked shield tunnelling.
{"title":"Effect of moving train load on ground movement and tunnel deformation due to stacked shield tunnelling","authors":"Yao Hu , Haoran Tang , Yinggang Xu , Huayang Lei , Junfu Lu , Xuejian Chen , Zilin Gao","doi":"10.1016/j.soildyn.2024.108992","DOIUrl":"10.1016/j.soildyn.2024.108992","url":null,"abstract":"<div><div>Stacked tunnel constructions adjacent to operating metro lines are frequently encountered in dense underground space, leading to undesired settlement and existing tunnel deformation. In this paper, ground movement and tunnel deformation were studied due to stacked shield tunnelling using field monitoring and numerical simulation, particularly the effect of adjacent moving train load on ground and tunnel responses was mainly investigated. Numerical model was implemented based one engineering project of the stacked shield tunnel in Tianjin, China. The results indicate that the ground vertical deformation is influenced by the position of new tunnel and existing tunnel, while the ground horizontal deformation occurs specifically at the top of the new tunnel. The train load contributes to an increase in both vertical and horizontal deformations of the ground and an intensified longitudinal settlement deformation in the existing tunnel. A ground settlement prediction was proposed that considers the stiffness of the existing tunnel and effect of train load. This study provides an in-depth investigation into the deformation of ground and existing tunnel and addressed the non-negligible effect of adjacent train load when evaluating safety of stacked shield tunnelling.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 108992"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.soildyn.2024.108939
Xiufeng Wu , Peng Ji , Chengyang Liu , Longfei Li , Zhongwei Zhao , Zhiyuan Zhang
Sharp and significant changes in the relative angle between beam and column during earthquakes often lead to failure of structural joints. This study proposed a novel passive Energy Dissipation system (PEDs) consisting of a viscoelastic damper (VED) and an angle-reaction controller (ARC). The ARC provides mutual support to the joint by establishing temporary supports in reinforced concrete or steel frames to allow for free-angle multilevel control in the case of excessive relative angle. This feature distinguishes the novel PEDs from previous systems as it allows the reaction force of the temporary support to compensate for the loss of joint rotational stiffness. The cyclic loading tests were conducted by constructing fundamental components, and then a mechanical model for the novel PEDs was established. Numerical simulations were performed to analyze parameter variations and to provide a comprehensive methodology for evaluating the seismic performance of the novel PEDs. The results demonstrated that two mechanisms were effectively incorporated into the novel PEDs: vibration energy dissipation and protection against excessive angles. The multistage flag hysteresis curve confirmed the reliability of our theoretical model in representing this novel PEDs. Therefore, supplementing rotational stiffness while achieving energy dissipation can be considered a new approach for enhancing seismic performance in frame structures.
{"title":"Experimental and numerical investigation of a novel passive energy dissipation system with viscoelastic damper and angle-reaction controller","authors":"Xiufeng Wu , Peng Ji , Chengyang Liu , Longfei Li , Zhongwei Zhao , Zhiyuan Zhang","doi":"10.1016/j.soildyn.2024.108939","DOIUrl":"10.1016/j.soildyn.2024.108939","url":null,"abstract":"<div><div>Sharp and significant changes in the relative angle between beam and column during earthquakes often lead to failure of structural joints. This study proposed a novel passive Energy Dissipation system (PEDs) consisting of a viscoelastic damper (VED) and an angle-reaction controller (ARC). The <span>ARC</span> provides mutual support to the joint by establishing temporary supports in reinforced concrete or steel frames to allow for free-angle multilevel control in the case of excessive relative angle. This feature distinguishes the novel PEDs from previous systems as it allows the reaction force of the temporary support to compensate for the loss of joint rotational stiffness. The cyclic loading tests were conducted by constructing fundamental components, and then a mechanical model for the novel PEDs was established. Numerical simulations were performed to analyze parameter variations and to provide a comprehensive methodology for evaluating the seismic performance of the novel PEDs. The results demonstrated that two mechanisms were effectively incorporated into the novel PEDs: vibration energy dissipation and protection against excessive angles. The multistage flag hysteresis curve confirmed the reliability of our theoretical model in representing this novel PEDs. Therefore, supplementing rotational stiffness while achieving energy dissipation can be considered a new approach for enhancing seismic performance in frame structures.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 108939"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.soildyn.2024.109008
Baozhuang Zhang , Xiaobin Song , Yu Lu , Xingjie Chen
This paper investigated the influence of the damage to column-foot (C-F) joints and the gaps of mortise-tenon (M-T) joints on the seismic behavior of Li-Tie style timber frames with masonry-infilled wall. Five full-scale Li-Tie type brick masonry-infilled timber frames, two without the joint damage, two with the damage to C-F, and one with the gaps of M-T joints, were cyclically tested. The failure modes, mechanical and deformation mechanisms were revealed. The second-order effect, strength degradation law, and the changing laws of the equivalent viscous damping coefficient and strain of the specimens were analyzed. The results showed that when the maximum inter-layer drift ratio was less than 2.4 %, the second-order effect of Li-Tie type timber structure with the masonry infill can be ignored. The masonry infilled timber frames considering the joint deterioration suffered a large strength degradation degree, and a more significant loss of the peak load and ductility. The equivalent viscous damping coefficient of the masonry infilled timber frame considering C-F damage increased by up to 24.67 %, while that of the one including the gaps of M-T joint decreased by 6.67 %. The C-F damage led to an increase in the strain at the beam end, the damage to M-T joint resulted in an decrease in the strain at the beam end. However, the damage to C-F and the gaps in M-T joint had little influence on the strain distribution in the C-F area. Based on the hysteretic, stiffness and strength degradation characteristics, and tests results of the specimens, the new tri-linear hysteretic models of Li-Tie type brick masonry infilled wooden frames with and without the joint damage were established and verified. Good agreement between the model predictions and test results was observed.
{"title":"Seismic performance of Li-Tie type brick masonry infilled wooden frames considering joint damage: Degradation mechanism and hysteretic model","authors":"Baozhuang Zhang , Xiaobin Song , Yu Lu , Xingjie Chen","doi":"10.1016/j.soildyn.2024.109008","DOIUrl":"10.1016/j.soildyn.2024.109008","url":null,"abstract":"<div><div>This paper investigated the influence of the damage to column-foot (C-F) joints and the gaps of mortise-tenon (M-T) joints on the seismic behavior of Li-Tie style timber frames with masonry-infilled wall. Five full-scale Li-Tie type brick masonry-infilled timber frames, two without the joint damage, two with the damage to C-F, and one with the gaps of M-T joints, were cyclically tested. The failure modes, mechanical and deformation mechanisms were revealed. The second-order effect, strength degradation law, and the changing laws of the equivalent viscous damping coefficient and strain of the specimens were analyzed. The results showed that when the maximum inter-layer drift ratio was less than 2.4 %, the second-order effect of Li-Tie type timber structure with the masonry infill can be ignored. The masonry infilled timber frames considering the joint deterioration suffered a large strength degradation degree, and a more significant loss of the peak load and ductility. The equivalent viscous damping coefficient of the masonry infilled timber frame considering C-F damage increased by up to 24.67 %, while that of the one including the gaps of M-T joint decreased by 6.67 %. The C-F damage led to an increase in the strain at the beam end, the damage to M-T joint resulted in an decrease in the strain at the beam end. However, the damage to C-F and the gaps in M-T joint had little influence on the strain distribution in the C-F area. Based on the hysteretic, stiffness and strength degradation characteristics, and tests results of the specimens, the new tri-linear hysteretic models of Li-Tie type brick masonry infilled wooden frames with and without the joint damage were established and verified. Good agreement between the model predictions and test results was observed.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109008"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.soildyn.2024.108996
Chang Liu , Yunong Li , Liwei Wang
Earthquakes and groundwater are pivotal factors affecting slope stability. However, the majority of previous studies have focused on these factors individually, neglecting their combined effects. Hence, this paper aims to develop a framework using the kinematic approach of limit analysis to investigate the stability of slopes in partially saturated soils under the combined effects of seismic force and pore-water pressure. The pseudo-dynamic method (PDM) was employed to capture the temporal-spatial effect of horizontal and vertical seismic waves. Variations in suction and effective unit weight profiles with moisture content under steady-state unsaturated flow were considered. External rates arising from both static pore-water pressure and earthquake-induced excess pore-water pressure were incorporated into the energy-balance equation. With the aid of gravity increase method (GIM), an explicit expression of safety factor (FS) was derived and optimized using a genetic algorithm (GA). The validity of this approach was verified through a comparison with existing solutions. Parametric analyses were conducted to explore the influence of varying groundwater level, seismic coefficients, suction, three-dimensional effects, excess pore water pressure, unsaturated flow types, and pseudo-dynamic parameters, on the FS and critical sliding surface of slopes in partially saturated slopes. This framework can provide a good reference for the safety design of reservoir slope under the combined effects of earthquakes and groundwater.
{"title":"Stability of slopes in partially saturated soils: Incorporating the combined effects of seismic forces and pore water pressure","authors":"Chang Liu , Yunong Li , Liwei Wang","doi":"10.1016/j.soildyn.2024.108996","DOIUrl":"10.1016/j.soildyn.2024.108996","url":null,"abstract":"<div><div>Earthquakes and groundwater are pivotal factors affecting slope stability. However, the majority of previous studies have focused on these factors individually, neglecting their combined effects. Hence, this paper aims to develop a framework using the kinematic approach of limit analysis to investigate the stability of slopes in partially saturated soils under the combined effects of seismic force and pore-water pressure. The pseudo-dynamic method (PDM) was employed to capture the temporal-spatial effect of horizontal and vertical seismic waves. Variations in suction and effective unit weight profiles with moisture content under steady-state unsaturated flow were considered. External rates arising from both static pore-water pressure and earthquake-induced excess pore-water pressure were incorporated into the energy-balance equation. With the aid of gravity increase method (GIM), an explicit expression of safety factor (FS) was derived and optimized using a genetic algorithm (GA). The validity of this approach was verified through a comparison with existing solutions. Parametric analyses were conducted to explore the influence of varying groundwater level, seismic coefficients, suction, three-dimensional effects, excess pore water pressure, unsaturated flow types, and pseudo-dynamic parameters, on the FS and critical sliding surface of slopes in partially saturated slopes. This framework can provide a good reference for the safety design of reservoir slope under the combined effects of earthquakes and groundwater.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 108996"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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