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Parametric sensitivity analysis of cellular diaphragm wall

Xi CHEN, Wei XU

《结构与土木工程前沿（英文）》 2012年第6卷第4期页码 358-364 doi: 10.1007/s11709-012-0177-3

摘要： The deformation law of the cellular diaphragm wall in deep foundation pits was studied through numerical simulation. Based on the example of the dock wall in engineering, the full three-dimensional finite element model was used to simulate the excavation of the foundation pit. Interaction between the cellular diaphragm wall and the soil was also taken into account in the calculation. The results indicated that the maximum lateral displacement, which is the evaluation index of sensitivity analysis, appeared on the top of the interior longitudinal wall with an excavation depth of 10 m. The centrifuge model test was carried out to study the deformation regulation for a cellular diaphragm wall. The most sensitive factor was found by adjusting the length of the partition wall, the spacing of the partition wall and the thickness of the wall. In the end, a suggestion was proposed to optimize the cellular diaphragm by adjusting the length of the partition wall.

关键词： cellular diaphragm wall sensitivity analysis optimization centrifuge model test

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Diaphragm wall-soil-cap interaction in rectangular-closed- diaphragm-wall bridge foundations

Hua WEN, Qiangong CHENG, Fanchao MENG, Xiaodong CHEN

《结构与土木工程前沿（英文）》 2009年第3卷第1期页码 93-100 doi: 10.1007/s11709-009-0015-4

摘要： Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation. Diaphragm wall-soil-cap interaction was studied using a model test. It was observed that the distribution of soil resistance under the cap is not homogeneous. The soil resistance in the corner under the cap is larger than that in the border; and that in the center is the smallest. The distribution of soil resistance under the cap will be more uniform, if the sectional area of soil core is enlarged within a certain range. Due to the existence of cap, there is a “weakening effect” in inner shaft resistance of the upper wall segments, and there is “enhancement effect” in the lower wall segments and in toe resistance. The load shearing percentage of soil resistance under the cap is 10%-20%. It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.

关键词： diaphragm wall bridge foundation low cap interaction

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The behavior of a rectangular closed diaphragm wall when used as a bridge foundation

Qiangong CHENG, Jiujiang WU, Zhang SONG, Hua WEN

《结构与土木工程前沿（英文）》 2012年第6卷第4期页码 398-420 doi: 10.1007/s11709-012-0175-5

摘要： The rectangular closed diaphragm (RCD) wall is a new type of bridge foundation. Compared to barrette foundation, measuring the performance of RCD walls is relatively complicated because of their incorporation of a soil core. Using the FLAC3D software, this paper investigates the deformation properties, soil resistance and skin friction of a laterally loaded RCD wall as well as the settlement, axial force and load-sharing ratio of a vertically loaded RCD wall. Special attention is given to the analysis of factors that influence the performance of the soil core. It was found that under lateral loading, the RCD wall behaves as an end-bearing friction wall during the entire loading process. The relative displacement between the wall body and the soil core primarily occurs below the rotation point, and the horizontal displacement of the soil core is greater than that of the wall body. Under vertical loading, the degree of inner skin friction around the bottom of the soil core and the proportion of the loading supported by the soil core increase with increased cross-section size. The wall depth is directly proportional to the loading supported by the outer skin friction and the tip resistance of the wall body and is inversely proportional to the loading borne by the soil core.

关键词： diaphragm wall soil core bridge foundation FLAC3D bearing behavior

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Soil arching effect of Lattice-Shaped Diaphragm Wall as bridge foundation

Jiujiang WU, Lingjuan WANG, Qiangong CHENG

《结构与土木工程前沿（英文）》 2017年第11卷第4期页码 446-454 doi: 10.1007/s11709-017-0397-7

摘要： As a new type of bridge foundation, Lattice-Shaped Diaphragm Wall (hereinafter for LSDW) is highly concerned in relevant construction area but its research is far from achievement. Based on PFC , the soil arching effect of LSDWs is studied thoroughly in this paper and the special attention is given to its influencing factors. It turns out to be that a differential wall-soil settlement can be found at the lower location of soil core of an LSDW which is one of the trigger factors of soil arching; meanwhile, the differential settlement degree can reflect the exertion degree of soil arching; the shape of soil arching is basically a hemisphere which can be explained by the theory proposed by Hewlett and Randolph; normally, the chamber number is a negative factor for the development of soil arching; the soil arching effect is significantly influenced by the distance of two adjacent wall elements and the foundation depth, and a relatively large or small value of these factors is disadvantageous to the exertion of soil arching; in addition, the soil arching effect increase with the growth of stiffness and friction coefficient of particles and the friction coefficient of particles has insignificant influence on the development of soil arching effect compared with particle stiffness.

关键词： LSDW soil arching PFC^2D shape of soil arching influencing factors

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Finite element modeling of thermo-active diaphragm walls

Yi RUI, Mei YIN

《结构与土木工程前沿（英文）》 2020年第14卷第3期页码 646-663 doi: 10.1007/s11709-020-0584-9

摘要： There are two major challenges faced by modern society: energy security, and lowering carbon dioxide gas emissions. Thermo-active diaphragm walls have a large potential to remedy one of these problems, since they are a renewable energy technology that uses underground infrastructure as a heat exchange medium. However, extensive research is required to determine the effects of cyclic heating and cooling on their geotechnical and structural performance. In this paper, a series of detailed finite element analyses are carried out to capture the fully coupled thermo-hydro-mechanical response of the ground and diaphragm wall. It is demonstrated that the thermal operation of the diaphragm wall causes changes in soil temperature, thermal expansion/shrinkage of pore water, and total stress applied on the diaphragm wall. These, in turn, cause displacements of the diaphragm wall and variations of the bending moments. However, these effects on the performance of diaphragm wall are not significant. The thermally induced bending strain is mainly governed by the temperature differential and uneven thermal expansion/shrinkage across the wall.

关键词： thermo-active diaphragm wall finite element analysis thermo-hydro-mechanical coupling ground source heat pump

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南京长江第四大桥南锚碇地下连续墙支护结构设计

董萌,贾立峰,李丹

《中国工程科学》 2013年第15卷第8期页码 26-30

摘要：

南京长江第四大桥南锚碇基础为支护开挖深埋扩大基础，采用井筒式地下连续墙支护体系，平面形状为“∞”形，长82 m，宽59 m，由两个外径59 m的非完整圆和一道隔墙组成，壁厚为1.5 m。隔墙为前后两个非完整圆的支撑结构，抬高隔墙底标高，使得基础底板为一整体结构；填心混凝土施工完成后凿除部分墙体，既解决了开挖状态下的支护问题，又使基础顶板有效连为整体。采用“∞”形比圆形或矩形结构形式布置平面面积小，截面惯性矩大，且半径较小，墙体环向应力小，安全性及可实施性高，有效降低了工程投入，提高了结构的安全性。

关键词：锚碇地下连续墙 “∞”形南京长江第四大桥

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Power performance of circular piezoelectric diaphragm generators

TANG Kehong, KAN Junwu, YANG Zhigang, CHENG Guangming, PENG Taijiang

《机械工程前沿（英文）》 2008年第3卷第4期页码 434-440 doi: 10.1007/s11465-008-0069-3

摘要： Energy generation performance of a piezoelectric generator depends mainly on several elements such as the structural style, boundary conditions, geometry parameters, materials, vibration-source frequency, and external load. To obtain the optimal energy-harvesting device, the Raleigh method is used to establish the analysis model of circular piezoelectric composite diaphragms. Simply supported and clamped boundary conditions were considered. The relationships between the output power and the structural parameters of piezoelectric composite diaphragms, and the external load resistance and frequency were shown. Given the correlative material parameters and boundary conditions, the output power, using structural parameters, external load, or vibrating frequency as variables, can be calculated. Simulation results show that there are optimal structural parameters and load for a composite diaphragm to achieve the maximum output power. A piezoelectric diaphragm generator with given dimensions tends to achieve higher output power under clamped boundary conditions than that under simply supported boundary conditions.

关键词： clamped boundary energy-harvesting composite diaphragm piezoelectric composite maximum

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behavior of stiffened joints between concrete-filled steel tubular column and steel beam with narrow outer diaphragm

Chunyan QUAN,Wei WANG,Jian ZHOU,Rong WANG

《结构与土木工程前沿（英文）》 2016年第10卷第3期页码 333-344 doi: 10.1007/s11709-016-0357-7

摘要： This paper presented an investigation on a stiffened joint in practical engineering which was between concrete-filled steel tubular column and steel beam with narrow outer diaphragm and partial joint penetration welds. Through the low-frequency cyclic loading test, the cyclic behavior and failure mode of the specimen were investigated. The results of the test indicated the failure mode and bearing capacity of the specimen which were influenced by the axial compression ratio of the concrete-filled tubular column. On the contrary, the inner diaphragm and inner stiffeners had limited impacts on the hysteretic behavior of the joint. There was no hysteresis damage fracture on the narrow outer diaphragm connected to the concrete-filled steel tubular column with partial joint penetration welds. Due to the excellent ductility and energy dissipating capacity, the proposed joint could be applied to the seismic design of high-rise buildings in highly intensive seismic region, but axial compression ratio should be controlled to avoid unfavorable failure modes.

关键词： narrow outer diaphragm concrete-filled tubular column joint inner and outer stiffening cyclic behavior

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南京长江第四大桥工程建设及关键技术

武焕陵

《中国工程科学》 2013年第15卷第8期页码 4-11

摘要：

南京长江第四大桥是世界上首座主跨1 418 m的三跨连续弹性支承体系钢箱加劲梁悬索桥，首次采用了弹性支承体系以及缆索的分布传力锚固系统，克服了复杂地质条件下超大“∞”形地下连续墙（以下简称地连墙）及超大规模沉井深基础的设计施工技术难题，提出了主缆缆索混编技术及富氩气体保护焊技术，采用了复合浇筑式沥青钢桥面铺装技术，运用综合技术手段严格控制大体积混凝土施工质量。本文从建设管理及关键技术创新方面进行了综述。

关键词：建设管理关键技术创新复杂地质条件超大“∞”形地连墙超大规模沉井

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Regulation of T cell immunity by cellular metabolism

null

《医学前沿（英文）》 2018年第12卷第4期页码 463-472 doi: 10.1007/s11684-018-0668-2

摘要：

T cells are an important adaptive immune response arm that mediates cell-mediated immunity. T cell metabolism plays a central role in T cell activation, proliferation, differentiation, and effector function. Specific metabolic programs are tightly controlled to mediate T cell immune responses, and alterations in T cell metabolism may result in many immunological disorders. In this review, we will summarize the main T cell metabolic pathways and the important factors participating in T cell metabolic programming during T cell homeostasis, differentiation, and function.

关键词： T cell immunity metabolic pathways nutrient uptake metabolic checkpoints

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Liver cell therapies: cellular sources and grafting strategies

《医学前沿（英文）》 2023年第17卷第3期页码 432-457 doi: 10.1007/s11684-023-1002-1

摘要： The liver has a complex cellular composition and a remarkable regenerative capacity. The primary cell types in the liver are two parenchymal cell populations, hepatocytes and cholangiocytes, that perform most of the functions of the liver and that are helped through interactions with non-parenchymal cell types comprising stellate cells, endothelia and various hemopoietic cell populations. The regulation of the cells in the liver is mediated by an insoluble complex of proteins and carbohydrates, the extracellular matrix, working synergistically with soluble paracrine and systemic signals. In recent years, with the rapid development of genetic sequencing technologies, research on the liver’s cellular composition and its regulatory mechanisms during various conditions has been extensively explored. Meanwhile breakthroughs in strategies for cell transplantation are enabling a future in which there can be a rescue of patients with end-stage liver diseases, offering potential solutions to the chronic shortage of livers and alternatives to liver transplantation. This review will focus on the cellular mechanisms of liver homeostasis and how to select ideal sources of cells to be transplanted to achieve liver regeneration and repair. Recent advances are summarized for promoting the treatment of end-stage liver diseases by forms of cell transplantation that now include grafting strategies.

关键词： liver regeneration hepatocytes cholangiocytes stem cells organoids regulatory mechanisms transplantation/grafting strategies

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Optimization of Land-use Based on the Theory of Cellular Automata and Value of Ecosystem Services

Lian-fu Jiang,Guo-xian Xu,Hao Jiang

《工程管理前沿（英文）》 2014年第1卷第4期页码 395-401 doi: 10.15302/J-FEM-2014058

摘要： The main objective of the study was to confirm the location and configuration of “Habitat Conservation Area” in Dongguan City. The land utilization condition in the target city was simulated using Arc GIS and Geo SOS software basing on multi-criteria decision model of Cellular Automata (CA). Both the simulation result and accuracy satisfied well the basic requirements. In addition to multi-criteria decision model, space optimization technique was used as well in simulation experiments.

关键词： Ecosystem service function optimization of land use Cellular Automata (CA)

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Influence of construction-induced damage on the degradation of freeze–thawed lightweight cellular concrete

《结构与土木工程前沿（英文）》 2021年第15卷第3期页码 781-792 doi: 10.1007/s11709-021-0733-9

摘要： During the construction of lightweight cellular concrete (LCC), material damage frequently occurs, causing the degradation and deterioration of the mechanical performance, durability, and subgrade quality of LCC. The construction-induced damage can be more significant than those from the service environment of LCC, such as freeze–thaw (F–T) action in cold regions. However, the effect of construction-induced damage on LCC during F–T cycles is often ignored and the deterioration mechanisms are not yet clarified. In this study, we investigated the factors causing damage during construction using a sample preparation method established to simulate the damage in the laboratory setting. We conducted F–T cycle tests and microstructural characterization to study the effect of microstructural damage on the overall strength of LCC with different water contents under F–T actions. We established the relationship between the pore-area ratio and F–T cycle times, pore-area ratio, and strength, as well as the F–T cycle times and strength under different damage forms. The damage evolution is provided with the rationality of the damage equation, verified by comparing the measured and predicted damage variables. This study would serve as a guide for the construction and performance of LCC in cold regions.

关键词： lightweight cellular concrete construction-induced damage freeze-thaw action microstructure degradation mechanism

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Macro-architectured cellular materials: Properties, characteristic modes, and prediction methods

Zheng-Dong MA

《机械工程前沿（英文）》 2018年第13卷第3期页码 442-459 doi: 10.1007/s11465-018-0488-8

摘要：

Macro-architectured cellular (MAC) material is defined as a class of engineered materials having configurable cells of relatively large (i.e., visible) size that can be architecturally designed to achieve various desired material properties. Two types of novel MAC materials, negative Poisson’s ratio material and biomimetic tendon reinforced material, were introduced in this study. To estimate the effective material properties for structural analyses and to optimally design such materials, a set of suitable homogenization methods was developed that provided an effective means for the multiscale modeling of MAC materials. First, a strain-based homogenization method was developed using an approach that separated the strain field into a homogenized strain field and a strain variation field in the local cellular domain superposed on the homogenized strain field. The principle of virtual displacements for the relationship between the strain variation field and the homogenized strain field was then used to condense the strain variation field onto the homogenized strain field. The new method was then extended to a stress-based homogenization process based on the principle of virtual forces and further applied to address the discrete systems represented by the beam or frame structures of the aforementioned MAC materials. The characteristic modes and the stress recovery process used to predict the stress distribution inside the cellular domain and thus determine the material strengths and failures at the local level are also discussed.

关键词： architectured material cellular materials multi-scale modeling homogenization method effective material properties computational method

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A review of intelligent optimization for group scheduling problems in cellular manufacturing

《工程管理前沿（英文）》页码 406-426 doi: 10.1007/s42524-022-0242-0

摘要： Given that group technology can reduce the changeover time of equipment, broaden the productivity, and enhance the flexibility of manufacturing, especially cellular manufacturing, group scheduling problems (GSPs) have elicited considerable attention in the academic and industry practical literature. There are two issues to be solved in GSPs: One is how to allocate groups into the production cells in view of major setup times between groups and the other is how to schedule jobs in each group. Although a number of studies on GSPs have been published, few integrated reviews have been conducted so far on considered problems with different constraints and their optimization methods. To this end, this study hopes to shorten the gap by reviewing the development of research and analyzing these problems. All literature is classified according to the number of objective functions, number of machines, and optimization algorithms. The classical mathematical models of single-machine, permutation, and distributed flowshop GSPs based on adjacent and position-based modeling methods, respectively, are also formulated. Last but not least, outlooks are given for outspread problems and problem algorithms for future research in the fields of group scheduling.

关键词： cellular manufacturing group scheduling flowshop literature review