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光栅干涉仪;光学编码器;位移测量;精密测量 1

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Lateral displacement of soft ground under vacuum pressure and surcharge load

Chin-Yee ONG, Jin-Chun CHAI

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 239-248 doi: 10.1007/s11709-011-0110-1

摘要: Surcharge load (e.g. embankment fill) will induce settlement and outward lateral displacement, while vacuum pressure will induce settlement and inward lateral displacement of a ground. Ideally, combination of surcharge load and vacuum pressure can reduce or minimize the lateral displacement. Laboratory large scale model (length: 1.50 m, width: ~0.62 m, height: 0.85 m) tests and finite element analyses (FEA) were conducted to investigate the main influencing factors on lateral displacement of a soft clayey ground under the combination of vacuum pressure and surcharge load. For the conditions investigated, the results indicate that the outward lateral displacement increases with the increase of the ratio of surcharge load to vacuum pressure ( ) and the loading rate of the surcharge load ( ). Also, it is shown that for a given and condition, lateral displacement reduces with the increase of the initial undrained shear strength ( ) of the ground. To predict the lateral displacement of a ground under the combination of surcharge load and vacuum pressure, the loading conditions in terms of and , and value of the ground have to be considered.

关键词: vacuum consolidation     lateral displacement     PVD     finite element analysis     surcharge load    

Evaluation of liquefaction-induced lateral displacement using Bayesian belief networks

Mahmood AHMAD, Xiao-Wei TANG, Jiang-Nan QIU, Feezan AHMAD

《结构与土木工程前沿(英文)》 2021年 第15卷 第1期   页码 80-98 doi: 10.1007/s11709-021-0682-3

摘要: Liquefaction-induced lateral displacement is responsible for considerable damage to engineered structures during major earthquakes. Therefore, an accurate estimation of lateral displacement in liquefaction-prone regions is an essential task for geotechnical experts for sustainable development. This paper presents a novel probabilistic framework for evaluating liquefaction-induced lateral displacement using the Bayesian belief network (BBN) approach based on an interpretive structural modeling technique. The BBN models are trained and tested using a wide-range case-history records database. The two BBN models are proposed to predict lateral displacements for free-face and sloping ground conditions. The predictive performance results of the proposed BBN models are compared with those of frequently used multiple linear regression and genetic programming models. The results reveal that the BBN models are able to learn complex relationships between lateral displacement and its influencing factors as cause–effect relationships, with reasonable precision. This study also presents a sensitivity analysis to evaluate the impacts of input factors on the lateral displacement.

关键词: Bayesian belief network     seismically induced soil liquefaction     interpretive structural modeling     lateral displacement    

Predicting lateral displacement caused by seismic liquefaction and performing parametric sensitivity

Nima PIRHADI, Xiaowei TANG, Qing YANG, Afshin ASADI, Hazem Samih MOHAMED

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 506-519 doi: 10.1007/s11709-021-0677-0

摘要: Lateral displacement due to liquefaction ( ) is the most destructive effect of earthquakes in saturated loose or semi-loose sandy soil. Among all earthquake parameters, the standardized cumulative absolute velocity ( ) exhibits the largest correlation with increasing pore water pressure and liquefaction. Furthermore, the complex effect o fine content( ) at different values has been studied and demonstrated. Nevertheless, these two contexts have not been entered into empirical and semi-empirical models to predict This study bridges this gap by adding to the data set and developing two artificial neural network (ANN) models. The first model is based on the entire range of the parameters, whereas the second model is based on the samples with values that are less than the 28% critical value. The results demonstrate the higher accuracy of the second model that is developed even with less data. Additionally, according to the uncertainties in the geotechnical and earthquake parameters, sensitivity analysis was performed via Monte Carlo simulation (MCS) using the second developed ANN model that exhibited higher accuracy. The results demonstrated the significant influence of the uncertainties of earthquake parameters on predicting

关键词: lateral spreading displacement     cumulative absolute velocity     fine content     artificial neural network     sensitivity analysis     Monte Carlo simulation    

Response of basement wall in tall buildings foundation under lateral loading

Irfan JAMIL; Irshad AHMAD; Aqeel Ur REHMAN; Aqib AHMED; Ameer HAMZA; Wali ULLAH

《结构与土木工程前沿(英文)》 2022年 第16卷 第11期   页码 1415-1423 doi: 10.1007/s11709-022-0885-2

摘要: With increasing population and limitation of availability of land, tall buildings supported on piled raft foundations are increasingly used in the modern world. To increase the ratio of floor area to height, and to fulfill storage and parking facilities requirements, these tall buildings usually have more than one basement level. Conventionally, during the foundation design, engineers have not considered the basement wall contribution to resisting lateral load induced by earthquake or wind and this can result in an uneconomical construction of foundations. In this research work, an experimental study was performed on small-scale models, in order to study basement wall contribution, and the raft contribution including for piled raft foundations, to resisting lateral load. Three configurations of piles in 2 × 2, 2 × 3, and 3 × 3 patterns were tested as a pile group, piled raft and piled raft with a basement wall. Results show that when a basement wall is present, the lateral displacement decreases and the demand on each pile decreases. The piled raft design can become more economical for tall buildings if the basement’s walls are taken into account.

关键词: basement wall     lateral load     displacement     piled raft    

基于链置换环介导等温扩增的量子点纳米珠标记侧流免疫检测试纸条快速灵敏检测鼠伤寒沙门氏菌 Article

Yuting Shang,Shuzhen Cai,Qinghua Ye,Qingping Wu,Yanna Shao,Xiaoying Qu,Xinran Xiang,Baoqing Zhou,Yu Ding,Moutong Chen,Liang Xue,Honghui Zhu,Jumei Zhang

《工程(英文)》 2022年 第19卷 第12期   页码 62-70 doi: 10.1016/j.eng.2021.03.024

摘要:

快速、灵敏、即时检测致病菌对食品安全至关重要。在这项研究中,开发了一种新的量子点纳米珠标记的侧流免疫检测试纸条(QB-labelled LFIAS)结合链置换环介导的等温扩增(SD-LAMP)技术,用于定量检测鼠伤寒沙门氏菌(ST)。量子点纳米珠(QB)作为荧光报告材料,具有良好的检测效率。在LAMP中使用了可定制的链置换(SD)探针,以提高方法的特异性并防止副产物捕获。检测基于夹心免疫分析法。荧光条读取器测量测试(T)线和对照(C)线的荧光强度(FI)。条带的线性检测范围为每毫升102 ~ 108个菌落形成单位(CFU)。视觉检出限为103 CFU·mL−1,表明该系统的灵敏度是AuNP 标记试纸的10 倍。根据聚合酶链反应(PCR)和SD-LAMP的琼脂糖凝胶输出分析ST 特异性。在食品中检测到ST,回收率为85%~110%。该方法快速、简便,几乎不需要设备,适用于食品中的细菌检测和临床诊断。

关键词: 鼠伤寒沙门氏菌     量子点纳米珠     侧流免疫检测试纸条     环介导等温扩增     链置换探针    

Deformation control criterion of shield tunnel under lateral relaxation of soft soil

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 780-795 doi: 10.1007/s11709-023-0944-3

摘要: Metro shield tunnels under the lateral relaxation of soil (LRS) are susceptible to significant lateral deformations, which jeopardizes the structural safety and waterproofing. However, deformation control standards for such situations have not been clearly defined. Therefore, based on a specific case, a model test is conducted to realize the LRS of a shield tunnel in a sandy stratum to reveal its effect on segment liners. Subsequently, a deformation control criterion is established. The LRS is simulated by linearly reducing the loads applied to the lateral sides of the segment structure. During lateral unloading, the lateral earth pressure coefficient on the segment decreases almost exponentially, and the structural deformation is characterized by horizontal expansion at the arch haunches and vertical shrinkage at the arch vault and arch bottom. Based on the mechanical pattern of the segment structure and the acoustic emission, the deformation response of a segment can be classified into three stages: elastic and quasi-elastic, damage, and rapid deformation development. For a shield tunnel with a diameter of approximately 6 m and under the lateral relaxation of sandy soil, when the ellipticity of the segment is less than 2.71%, reinforcement measures are not required. However, the segment deformation must be controlled when the ellipticity is 2.71% to 3.12%; in this regard, an ellipticity of 3% can be used as a benchmark in similar engineering projects.

关键词: shield tunnel     lateral relaxation of soil     deformation control criterion of segment structure     model test    

Association of gene variants with juvenile amyotrophic lateral sclerosis

《医学前沿(英文)》 doi: 10.1007/s11684-023-1005-y

摘要: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive degeneration of motor neurons, and it demonstrates high clinical heterogeneity and complex genetic architecture. A variation within TRMT2B (c.1356G>T; p.K452N) was identified to be associated with ALS in a family comprising two patients with juvenile ALS (JALS). Two missense variations and one splicing variation were identified in 10 patients with ALS in a cohort with 910 patients with ALS, and three more variants were identified in a public ALS database including 3317 patients with ALS. A decreased number of mitochondria, swollen mitochondria, lower expression of ND1, decreased mitochondrial complex I activities, lower mitochondrial aerobic respiration, and a high level of ROS were observed functionally in patient-originated lymphoblastoid cell lines and TRMT2B interfering HEK293 cells. Further, TRMT2B variations overexpression cells also displayed decreased ND1. In conclusion, a novel JALS-associated gene called TRMT2B was identified, thus broadening the clinical and genetic spectrum of ALS.

关键词: TRMT2B     amyotrophic lateral sclerosis     mitochondrial complex I     tRNA methylation     reactive oxygen species    

Model testing of tripod caisson foundations in silty clay subjected to eccentric lateral loads

《结构与土木工程前沿(英文)》 2023年 第17卷 第3期   页码 467-476 doi: 10.1007/s11709-023-0933-6

摘要: In this study, model tests were conducted to investigate the bearing capacities of tripod caisson foundations subjected to eccentric lateral loads in silty clay. Lateral load–rotation curves of five eccentric-shaped tripod suction foundations were plotted to analyze the bearing capacities at different loading angles. It was observed that the loading angle significantly influenced the bearing capacity of the foundations, particularly for eccentric tripod caisson foundations. Compared with eccentric tripod caisson foundations, the traditional tripod foundation has a relatively high ultimate lateral capacity at the omnidirectional loading angle. By analyzing the displacement of the caissons, a formula for the rotational center of the tripod caisson foundation subjected to an eccentric lateral load was derived. The depth of the rotation center was 0.68–0.92 times the height of the caisson when the bearing capacity reached the limit. Under the undrained condition, suction was generated under the lid of the “up-lift” caisson, which helps resist lateral forces from the wind and waves.

关键词: tripod caisson foundation     silty clay     eccentric lateral capacity     model tests    

深海采矿扬矿管横向运动动态分析

刘江,毛纪陵,刘北英

《中国工程科学》 2001年 第3卷 第11期   页码 74-79

摘要:

运用非线性有限元方法对深海采矿扬矿管的横向运动特性进行了研究;对影响扬矿管横向变形和动 态应力的各种因素作出详细的分析,提出了“位移滞后期”的概念,并分析了影响位移滞后的因素。

关键词: 深海采矿     扬矿管     动态应力     位移滞后期     非线性有限单元法    

Increased expression of coronin-1a in amyotrophic lateral sclerosis: a potential diagnostic biomarker

《医学前沿(英文)》 2022年 第16卷 第5期   页码 723-735 doi: 10.1007/s11684-021-0905-y

摘要: Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease. At present, no definite ALS biomarkers are available. In this study, exosomes from the plasma of patients with ALS and healthy controls were extracted, and differentially expressed exosomal proteins were compared. Among them, the expression of exosomal coronin-1a (CORO1A) was 5.3-fold higher than that in the controls. CORO1A increased with disease progression at a certain proportion in the plasma of patients with ALS and in the spinal cord of ALS mice. CORO1A was also overexpressed in NSC-34 motor neuron-like cells, and apoptosis, oxidative stress, and autophagic protein expression were evaluated. CORO1A overexpression resulted in increased apoptosis and oxidative stress, overactivated autophagy, and hindered the formation of autolysosomes. Moreover, CORO1A activated Ca2+-dependent phosphatase calcineurin, thereby blocking the fusion of autophagosomes and lysosomes. The inhibition of calcineurin activation by cyclosporin A reversed the damaged autolysosomes. In conclusion, the role of CORO1A in ALS pathogenesis was discovered, potentially affecting the disease onset and progression by blocking autophagic flux. Therefore, CORO1A might be a potential biomarker and therapeutic target for ALS.

关键词: amyotrophic lateral sclerosis     coronin-1a     autophagy     pathogenesis    

Experimental and theoretical investigations of the lateral vibrations of an unbalanced Jeffcott rotor

Ali ALSALEH, Hamid M. SEDIGHI, Hassen M. OUAKAD

《结构与土木工程前沿(英文)》 2020年 第14卷 第4期   页码 1024-1032 doi: 10.1007/s11709-020-0647-y

摘要: The current work experimentally explores and then theoretically examines the lateral vibrations of an unbalanced Jeffcott rotor-system working at several unbalance conditions. To this end, three conditions of eccentric masses are considered by using a Bently Nevada RK-4 rotor kit. Measurements of the steady-state as well as the startup data at rigid and flexible rotor states are captured by conducting a setup that mimics the vibration monitoring industrial practices. The linear governing equation of the considered rotor is extracted by adopting the Lagrange method on the basis of rigid rotor assumptions to theoretically predict the lateral vibrations. The dynamic features of the rotor system such as the linearized bearing induced stiffness are exclusively acquired from startup data. It is demonstrated that, with an error of less than 5%, the proposed two-degrees-of-freedom model can predict the flexural vibrations at rigid condition. While at flexible condition, it fails to accurately predict the dynamic response. In contrast to the other works where nonlinear mathematical models with some complexities are proposed to mathematically model the real systems, the present study illustrates the applicability of employing simple models to predict the dynamic response of a real rotor-system with an acceptable accuracy.

关键词: rotor-dynamics     Jeffcott rotor     lateral vibrations     Lagrange method     system-equivalent stiffness     sleeve bearings     oil film induced stiffness    

Optimum lateral extent of soil domain for dynamic SSI analysis of RC framed buildings on pile foundations

Nishant SHARMA, Kaustubh DASGUPTA, Arindam DEY

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 62-81 doi: 10.1007/s11709-019-0570-2

摘要: This article describes a novel approach for deciding optimal horizontal extent of soil domain to be used for finite element based numerical dynamic soil structure interaction (SSI) studies. SSI model for a 12 storied building frame, supported on pile foundation-soil system, is developed in the finite element based software framework, OpenSEES. Three different structure-foundation configurations are analyzed under different ground motion characteristics. Lateral extent of soil domain, along with the soil properties, were varied exhaustively for a particular structural configuration. Based on the reduction in the variation of acceleration response at different locations in the SSI system (quantified by normalized root mean square error, ), the optimum lateral extent of the soil domain is prescribed for various structural widths, soil types and peak ground acceleration levels of ground motion. Compared to the past studies, error estimation analysis shows that the relationships prescribed in the present study are credible and more inclusive of the various factors that influence SSI. These relationships can be readily applied for deciding upon the lateral extent of the soil domain for conducting precise SSI analysis with reduced computational time.

关键词: soil structure interaction     optimum lateral extent of soil domain length     multi-storyed framed building     pile foundation     OpenSEES     L-K boundaries     dynamic analysis    

Influence of advanced engineering measures on displacement and stress field of surrounding rock in tunnels

《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0966-x

摘要: Based on significant improvements in engineering materials, three advanced engineering measures have been proposed—super anchor cables, high-strength concrete anti-fault caverns, and grouting modification using high-strength concrete-to resist fault dislocation in the surrounding rock near tunnels crossing active strike-slip faults. Moreover, single- or multiple-joint advanced engineering measures form the local rock mass-anti-fault (LRAF) method. A numerical method was used to investigate the influence of LRAF methods on the stress and displacement fields of the surrounding rock, and the anti-fault effect was evaluated. Finally, the mechanism of action of the anchor cable was verified using a three-dimensional numerical model. The numerical results indicated that the anchor cable and grouting modification reduced the displacement gradient of the local surrounding rock near the tunnels crossing fault. Furthermore, anchor cable and grouting modifications changed the stress field of the rock mass in the modified area. The tensile stress field of the rock mass in the modified anchor cable area was converted into a compressive stress field. The stress field in the modified grouting area changed from shear stress in the fault slip direction to tensile stress in the axial tunnel direction. The anti-fault cavern resisted the dislocation displacement and reduced the maximum dislocation magnitude, displacement gradient, and shear stress. Among the three advanced engineering measures, the anchor cable was the core of the three advanced engineering measures. An anchor cable, combined with other LRAF measures, can form an artificial safety island at the cross-fault position of the rock mass to protect the tunnel. The research results provide a new supporting idea for the surrounding rock of tunnels crossing active strike-slip faults.

关键词: anti-fault effect     engineering measures     LRAF method     stress and displacement field     tunnel-crossing active faults    

Quality control based on electrode displacement and force in resistance spot welding

Chuntao JI, Lipeng DENG

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 412-417 doi: 10.1007/s11465-010-0114-x

摘要: The behaviors of electrode displacement and force during spot welding under various conditions, such as different weld currents, electrode forces, and welding times, were studied. Tests were conducted on a 170?kVA MFDC spot welder. Data were collected via a multichannel high-speed data acquisition system and were analyzed with MATLAB. Behaviors of 5182 aluminum and mild steel in spot welding were compared. Results show that nugget expansion rate does not reach zero for aluminium as it does for mild steel as nugget grew to a certain size. A linear relationship is found between the nugget size and maximum expansion that facilitates online weld quality evaluation. An electrode force peak is observed and believed relevant to the sufficient nugget size.

关键词: aluminum     electrode displacement     electrode force     nugget size     data acquisition    

Numerical investigation of the ultimate lateral resistance of piles in soft clay

Konstantinos P. TZIVAKOS,Michael J. KAVVADAS

《结构与土木工程前沿(英文)》 2014年 第8卷 第2期   页码 194-200 doi: 10.1007/s11709-014-0251-0

摘要: The paper presents a numerical study on the undrained lateral response of a single, free-head, reinforced concrete pile in soft clays. Soil conditions simulating normally consolidated clays are examined—undrained shear strength increasing with depth—and the pile-soil interaction under static lateral loading is analyzed. The nonlinear ? curves proposed in literature for soft clays are imported into a beam-on-nonlinear-Winkler-foundation simulation in order to predict the pile head lateral load—displacement curve and the distribution of the horizontal displacement and bending moment along the pile. The striking differences among these methods require further investigation via 3D finite element analyses. The determination of the ultimate soil resistance from the results of the finite element analyses aims at providing the estimation of a range of values for the ultimate soil resistance coefficient with depth and the comparison of the derived values to the corresponding ones proposed by existing methodologies.

关键词: laterally loaded     pile     soft clay     p?y curves     finite element method (FEM)    

标题 作者 时间 类型 操作

Lateral displacement of soft ground under vacuum pressure and surcharge load

Chin-Yee ONG, Jin-Chun CHAI

期刊论文

Evaluation of liquefaction-induced lateral displacement using Bayesian belief networks

Mahmood AHMAD, Xiao-Wei TANG, Jiang-Nan QIU, Feezan AHMAD

期刊论文

Predicting lateral displacement caused by seismic liquefaction and performing parametric sensitivity

Nima PIRHADI, Xiaowei TANG, Qing YANG, Afshin ASADI, Hazem Samih MOHAMED

期刊论文

Response of basement wall in tall buildings foundation under lateral loading

Irfan JAMIL; Irshad AHMAD; Aqeel Ur REHMAN; Aqib AHMED; Ameer HAMZA; Wali ULLAH

期刊论文

基于链置换环介导等温扩增的量子点纳米珠标记侧流免疫检测试纸条快速灵敏检测鼠伤寒沙门氏菌

Yuting Shang,Shuzhen Cai,Qinghua Ye,Qingping Wu,Yanna Shao,Xiaoying Qu,Xinran Xiang,Baoqing Zhou,Yu Ding,Moutong Chen,Liang Xue,Honghui Zhu,Jumei Zhang

期刊论文

Deformation control criterion of shield tunnel under lateral relaxation of soft soil

期刊论文

Association of gene variants with juvenile amyotrophic lateral sclerosis

期刊论文

Model testing of tripod caisson foundations in silty clay subjected to eccentric lateral loads

期刊论文

深海采矿扬矿管横向运动动态分析

刘江,毛纪陵,刘北英

期刊论文

Increased expression of coronin-1a in amyotrophic lateral sclerosis: a potential diagnostic biomarker

期刊论文

Experimental and theoretical investigations of the lateral vibrations of an unbalanced Jeffcott rotor

Ali ALSALEH, Hamid M. SEDIGHI, Hassen M. OUAKAD

期刊论文

Optimum lateral extent of soil domain for dynamic SSI analysis of RC framed buildings on pile foundations

Nishant SHARMA, Kaustubh DASGUPTA, Arindam DEY

期刊论文

Influence of advanced engineering measures on displacement and stress field of surrounding rock in tunnels

期刊论文

Quality control based on electrode displacement and force in resistance spot welding

Chuntao JI, Lipeng DENG

期刊论文

Numerical investigation of the ultimate lateral resistance of piles in soft clay

Konstantinos P. TZIVAKOS,Michael J. KAVVADAS

期刊论文