资源类型

期刊论文 1511

会议视频 28

会议信息 2

年份

2024 1

2023 62

2022 116

2021 107

2020 76

2019 105

2018 85

2017 83

2016 67

2015 86

2014 80

2013 62

2012 78

2011 71

2010 72

2009 49

2008 72

2007 86

2006 36

2005 24

展开 ︾

关键词

风险分析 9

能源 7

分析 4

可持续发展 4

对策 4

影响因素 4

数值模拟 4

隧道 4

ANSYS 3

农业科学 3

抗击疫情 3

数值分析 3

环境 3

营养健康 3

裂缝 3

2035年 2

BNLAS 2

COVID-19 2

DX桩 2

展开 ︾

检索范围：

排序： 展示方式：

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 165-175 doi: 10.1007/s11709-018-0484-4

摘要： In this manuscript, we study fracture of prestressed cylindrical concrete pipes. Such concrete pipes play a major role in tunneling and underground engineering. The structure is modelled fully in 3D using three-dimensional continuum elements for the concrete structure which beam elements are employed to model the reinforcement. This allows the method to capture important phenomena compared to a pure shell model of concrete. A continuous approach to fracture is chosen when concrete is subjected to compressive loading while a combined continuous-discrete fracture method is employed in tension. The model is validated through comparisons with experimental data.

关键词： cylindrical concrete structures     limit state analysis     3D fracture modelling     prestressed composite pipes     reinforced concrete     three-point bending test    

HTML PDF 收藏

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 446-455 doi: 10.1007/s11709-013-0227-5

摘要： An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been presented. The kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing capacity. Both smooth and rough base strip foundations were considered associated with different collapse patterns. Presence of the groundwater flow leads to a non-symmetric collapse pattern, i.e., a weak side and a strong side in two-sided collapse patterns, depending on the direction of the flow. It was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence, a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.

关键词： foundation     bearing capacity     limit analysis     numerical computation     plasticity     seepage    

HTML PDF 收藏

Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 378-387 doi: 10.1007/s11709-022-0808-2

摘要： This study presents stability analyses of layered soil slopes in unsaturated conditions and uses a limit equilibrium method to determine the factor of safety involving suction stress of unsaturated soil. One-dimensional steady infiltration and evaporation conditions are considered in the stability analyses. An example of a two-layered slope in clay and silt is selected to verify the used method by comparing with the results of other methods. Parametric analyses are conducted to explore the influences of the matric suction on the stability of layered soil slopes. The obtained results show that larger suction stress provided in unsaturated clay dominates the stability of the layered slopes. Therefore, the location and thickness of the clay layer have significant influences on slope stability. As the water level decreases, the factor of safety reduces and then increases gradually in most cases. Infiltration/evaporation can obviously affect the stability of unsaturated layered slopes, but their influences depend on the soil property and thickness of the lower soil layer.

关键词： slope stability     suction stress     unsaturated soil     layered slope     limit equilibrium    

HTML PDF 收藏

Adaptive selective ES-FEM limit analysis of cracked plane-strain structures

H. NGUYEN-XUAN,T. RABCZUK

《结构与土木工程前沿（英文）》 2015年 第9卷 第4期   页码 478-490 doi: 10.1007/s11709-015-0317-7

摘要： This paper presents a simple and efficient approach for predicting the plastic limit loads in cracked plane-strain structures. We use two levels of mesh repartitioning for the finite element limit analysis. The master level handles an adaptive primal-mesh process through a dissipation-based indicator. The slave level performs the subdivision of each triangle into three sub-triangles and constitutes a dual mesh from a pair of two adjacent sub-triangles shared by common edges of the primal mesh. Applying a strain smoothing projection to the strain rates on the dual mesh, the incompressibility constraint and the flow rule constraint are imposed over the edge-based smoothing domains and everywhere in the problem domain. The limit analysis problem is recast into the compact form of a second-order cone programming (SOCP) for the purpose of exploiting interior-point solvers. The present method retains a low number of optimization variables. It offers a convenient way for designing and solving the large-scale optimization problems effectively. Several benchmark examples are given to show the simplicity and effectiveness of the present method.

关键词： cracked structure     limit analysis     von Mises criterion     edge-based strain smoothing     second-order cone programming     adaptive    

HTML PDF 收藏

capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound finite element limitanalysis

Mantu MAJUMDER, Debarghya CHAKRABORTY

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 537-551 doi: 10.1007/s11709-021-0708-x

摘要： Ensuring a safe foundation design in soft clay is always a challenging task to engineers. In the present study, the effectiveness of under-reamed piles in soft clay underlaid by stiff clay is numerically studied using the lower-bound finite element limit analysis (LB FELA). The bearing and uplift capacities of under-reamed piles are estimated through non-dimensional factors and , respectively. These factors increased remarkably and marginally compared to and of the piles without bulbs when the bulb is placed in stiff and soft clay, respectively. For a given ratio of undrained cohesion of stiff to soft clay ( / ), the factors and moderately increased with the increase in the length-to-shaft-diameter ratio ( / ) and adhesion factors in soft clay ( ) and stiff clay ( ). The variation of radial stress along the pile–soil interface, distribution of axial force in the under-reamed piles, and state of plastic shear failure in the soil are also studied under axial compression and tension. The results of this study are expected to be useful for the estimation of the bearing and uplift capacities of under-reamed piles in uniform clay and soft clay underlaid by stiff clay.

关键词： bearing capacity     uplift capacity     under-reamed pile     clay     limit analysis    

HTML PDF 收藏

Modeling limit force capacities of high force to volume lead extrusion dampers

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 609-622 doi: 10.1007/s11709-021-0724-x

摘要： Lead extrusion dampers are supplemental energy-dissipation devices that are used to mitigate seismic structural damage. Small volumetric sizes and high force capacities define high-force-to-volume (HF2V) devices, which can absorb significant response energy without sacrificial damage. However, the design of such devices for specific force capacities has proven difficult based on the complexities of their internal reaction mechanisms, leading to the adoption of empirical approaches. This study developed upper- and lower-bound force capacity estimates from analytical mechanics based on direct and indirect metal extrusion for guiding design. The derived equations are strictly functions of HF2V device geometric parameters, lead material properties, and extrusion mechanics. The upper-bound estimates from direct and indirect extrusion are denoted as (FUB,1, FUB,2) and (FUB,3, FUB,4), respectively, and the lower-bound estimates are denoted as (FLB, FLB,1) based on the combination of extrusion and friction forces. The proposed models were validated by comparing the predicted bounds to experimental force capacity data from 15 experimental HF2V device tests. The experimental device forces all lie above the lower-bound estimates (FLB, FLB,1) and below the upper-bound estimates (FUB,1, FUB,2, FUB,4). Overall, the (FLB, FUB,2) pair provides wider bounds and the (FLB,1, FUB,4/FUB,1) pair provides narrower bounds. The (FLB,1, FUB,1) pair has a mean lower-bound gap of 36%, meaning the lower bound was 74% of the actual device force on average. The mean upper-bound gap was 33%. The bulge area and cylinder diameter of HF2V devices are key parameters affecting device forces. These relatively tight bounds provide useful mechanics-based predictive design guides for ensuring that device forces are within the targeted design range after manufacturing.

关键词： extrusion     lead dampers     upper and lower bound     analytical modelling     limit force    

HTML PDF 收藏

Setting up a heart rate alarm limit to decrease oculocardiac reflex during strabismus surgery in children

ZHANG Kangkang, GU Enhua, LU Junjie

《医学前沿（英文）》 2008年 第2卷 第3期   页码 295-297 doi: 10.1007/s11684-008-0056-4

摘要： The aim of this paper is to investigate a method which may decrease the incidence and severity of oculocardiac reflex (OCR) without drugs. One hundred and sixty children undergoing strabismus surgery were allocated to two groups using double-blind randomization. OCR was defined as a decrease of more than 10% from the baseline heart rate during operation. An alarm sounded and a lamp flashed as soon as OCR occurred in group I, and neither of the above happened in group II. OCR occurred (1.151 ± 0.858) times in group I and (2.287 ± 1.371) times in group II ( < 0.05). Heart rate decreased by (23 ± 19) bpm in group I and (35 ± 28) bpm in group II ( < 0.05). The duration of OCR in group I and group II was (4.36 ± 4.26)s and (7.62 ± 6.41)s, respectively ( < 0.05). The recovery time for group I and group II was (15.36 ± 13.28)s and (32.36 ± 19.57)s, respectively ( < 0.05). The numbers of times of interruption were 8 in group I (10%) and 26 in group II (32%) ( < 0.01). This method significantly decreased the incidence and severity of OCR during strabismus surgery in children.
HTML PDF 收藏

有限元极限分析法发展及其在岩土工程中的应用

郑颖人,赵尚毅,邓楚键,刘明维,唐晓松,张黎明

《中国工程科学》 2006年 第8卷 第12期   页码 39-61

摘要：

有限元极限分析法兼有数值分析法与经典极限分析法两者的优点，特别适用于岩土工程的分析与设计。20世纪初，国内岩土工程界应用国际上通用程序，大力发展有限元极限分析法并拓宽其在岩土工程中的应用。在基本理论研究、提高计算精度、拓宽应用范围及工程实际应用等方面取得了很大成绩。重点介绍作者及其合作者的一些研究成果。主要包括岩土工程安全系数定义、方法原理、整体失稳判据、强度准则的推导、选用及提高计算精度等方面的研究。应用范围从二维扩大到三维，从均质土坡、土基扩大到有节理的岩质边坡与岩基，从稳定渗流扩大到不稳定渗流、从边坡与地基工程扩大到隧道、还用于寻找边（滑）坡中的多个潜在滑面，进行岩土与结构共同作用的支挡结构设计，计算机仿真地基承载板载荷试验等应用项目，以逐渐达到革新岩土工程设计方法的目的。

关键词： 极限分析法     有限元法     岩土工程     边坡     地基     隧道    

HTML PDF 收藏

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 566-583 doi: 10.1007/s11709-023-0905-x

摘要： The analysis of the bearing capacity of strip footings sited near an excavation is critical in geotechnics. In this study, the effects of the geometrical features of the excavation and the soil strength properties on the seismic bearing capacity of a strip footing resting on an excavation were evaluated using the lower and upper bounds of the finite element limit analysis method. The effects of the setback distance ratio (L/B), excavation height ratio (H/B), soil strength heterogeneity (kB/cu), and horizontal earthquake coefficient (kh) were analyzed. Design charts and tables were produced to clarify the relationship between the undrained seismic bearing capacity and the selected parameters.

关键词： excavation     finite element limit analysis     heterogeneous soil     strip footing     undrained bearing capacity    

HTML PDF 收藏

New pseudo-dynamic analysis of two-layered cohesive-friction soil slope and its numerical validation

Suman HAZARI, Sima GHOSH, Richi Prasad SHARMA

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1492-1508 doi: 10.1007/s11709-020-0679-3

摘要： Natural slopes consist of non-homogeneous soil profiles with distinct characteristics from slopes made of homogeneous soil. In this study, the limit equilibrium modified pseudo-dynamic method is used to analyze the stability of two-layered soil slopes in which the failure surface is assumed to be a logarithmic spiral. The zero-stress boundary condition at the ground surface under the seismic loading condition is satisfied. New formulations derived from an analytical method are proposed for the predicting the seismic response in two-layered soil. A detailed parametric study was performed in which various parameters (seismic accelerations, damping, cohesion, and angle of internal friction) were varied. The results of the present method were compared with those in the available literature. The present analytical analysis was also verified against the finite element analysis results.

关键词： layered soil     limit equilibrium method     seismic analysis     damping     PLAXIS    

HTML PDF 收藏

Slope stability analysis based on big data and convolutional neural network

Yangpan FU; Mansheng LIN; You ZHANG; Gongfa CHEN; Yongjian LIU

《结构与土木工程前沿（英文）》 2022年 第16卷 第7期   页码 882-895 doi: 10.1007/s11709-022-0859-4

摘要： The Limit Equilibrium Method (LEM) is commonly used in traditional slope stability analyses, but it is time-consuming and complicated. Due to its complexity and nonlinearity involved in the evaluation process, it cannot provide a quick stability estimation when facing a large number of slopes. In this case, the convolutional neural network (CNN) provides a better alternative. A CNN model can process data quickly and complete a large amount of data analysis in a specific situation, while it needs a large number of training samples. It is difficult to get enough slope data samples in practical engineering. This study proposes a slope database generation method based on the LEM. Samples were amplified from 40 typical slopes, and a sample database consisting of 20000 slope samples was established. The sample database for slopes covered a wide range of slope geometries and soil layers’ physical and mechanical properties. The CNN trained with this sample database was then applied to the stability prediction of 15 real slopes to test the accuracy of the CNN model. The results show that the slope stability prediction method based on the CNN does not need complex calculation but only needs to provide the slope coordinate information and physical and mechanical parameters of the soil layers, and it can quickly obtain the safety factor and stability state of the slopes. Moreover, the prediction accuracy of the CNN trained by the sample database for slope stability analysis reaches more than 99%, and the comparisons with the BP neural network show that the CNN has significant superiority in slope stability evaluation. Therefore, the CNN can predict the safety factor of real slopes. In particular, the combination of typical actual slopes and generated slope data provides enough training and testing samples for the CNN, which improves the prediction speed and practicability of the CNN-based evaluation method in engineering practice.

关键词： slope stability     limit equilibrium method     convolutional neural network     database for slopes     big data    

HTML PDF 收藏

A toughness based deformation limit for X- and K-joints under brace axial tension

Bo GU,Xudong QIAN,Aziz AHMED

《结构与土木工程前沿（英文）》 2016年 第10卷 第3期   页码 345-362 doi: 10.1007/s11709-016-0333-2

摘要： This study reports a deformation limit for the initiation of ductile fracture failure in fatigue-cracked circular hollow section (CHS) X- and K-joints subjected to brace axial tension. The proposed approach sets the deformation limit as the numerically computed crack driving force in a fatigue crack at the hot-spot location in the tubular joint reaches the material fracture toughness measured from standard fracture specimens. The calibration of the numerical procedure predicates on reported numerical computations on the crack driving force and previously published verification study against large-scale CHS X-joints with fatigue generated surface cracks. The development of the deformation limit includes a normalization procedure, which covers a wide range of the geometric parameters and material toughness levels. The lower-bound deformation limits thus developed follow a linear relationship with respect to the crack-depth ratio for both X- and K-joints. Comparison of the predicated deformation limit against experimental on cracked tubular X- and K-joints demonstrates the conservative nature of the proposed deformation limit. The proposed deformation limit, when extrapolated to a zero crack depth, provides an estimate on the deformation limits for intact X- and K-joints under brace axial loads.

关键词： circular hollow section (CHS)     tubular joint     fracture failure     deformation limit     J-integral    

HTML PDF 收藏

Effect of interface adhesion factor on the bearing capacity of strip footing placed on cohesive soil overlying rock mass

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1494-1503 doi: 10.1007/s11709-021-0768-y

摘要： The problem related to bearing capacity of footing either on pure soil or on pure rock mass has been investigated over the years. Currently, no study deals with the bearing capacity of strip footing on a cohesive soil layer overlying rock mass. Therefore, by implementing the lower bound finite element limit analysis in conjunction with the second-order cone programming and the power cone programming, the ultimate bearing capacity of a strip footing located on a cohesive soil overlying rock mass is determined in this study. By considering the different values of interface adhesion factor (αcr) between the cohesive soil and rock mass, the ultimate bearing capacity of strip footing is expressed in terms of influence factor (If) for different values of cohesive soil layer cover ratio (Tcs/B). The failure of cohesive soil is modeled by using Mohr−Coulomb yield criterion, whereas Generalized Hoek−Brown yield criterion is utilized to model the rock mass at failure. The variations ofIf with different magnitudes of αcr are studied by considering the influence of the rock mass strength parameters of beneath rock mass layer. To examine stress distribution at different depths, failure patterns are also plotted.

关键词： bearing capacity     soil-rock interface     Hoek−Brown yield criterion     plasticity     limit analysis    

HTML PDF 收藏

Limit span of self-anchored cable-stayed suspension cooperation system bridge based on strength

Zhe ZHANG , Huili WANG , Xiaomeng GE , Sifeng QIN ,

《结构与土木工程前沿（英文）》 2009年 第3卷 第3期   页码 286-291 doi: 10.1007/s11709-009-0045-y

摘要： The limit span of self-anchored cable-stayed suspension bridge is deduced. The relations among the geometrical parameters, loads and material characteristics are also analyzed. Based on the material strength and commonly used materials, the limit spans of self-anchored cable-stayed suspension bridges with concrete girder or steel girder under vertical static load are discussed in detail. The corresponding upper limit spans and the effect of the factors on the span are given. The results indicate that increasing rise-span ratio, height-span ratio and cable-stayed segment length or reducing the second dead load could increase the cooperation system span.

关键词： cable-stayed suspension     self-anchored     limit span    

HTML PDF 收藏

Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 329-333 doi: 10.1007/s11709-007-0043-x

摘要： Based on the unified strength theory [1], a unified strength criterion for strain softening materials, such as concrete or rock, was derived, and the elastic and plastic limit loads of a thick-walled cylinder made of these materials subject to external pressure were also given. In addition, the influence of some factors on the limit loads of such cylinders as the ratio of the external radius to internal radius,/, the coefficient , which reflects the effect of medium principal stress and the normal stress of the relevant surface on the material destroy degree, the ratio of tensile strength to compressed strength of the material, , and the damage variable
HTML PDF 收藏

标题 作者 时间 类型 操作

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

期刊论文

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

期刊论文

Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

期刊论文

Adaptive selective ES-FEM limit analysis of cracked plane-strain structures

H. NGUYEN-XUAN,T. RABCZUK

期刊论文

capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound finite element limitanalysis

Mantu MAJUMDER, Debarghya CHAKRABORTY

期刊论文

Modeling limit force capacities of high force to volume lead extrusion dampers

期刊论文

Setting up a heart rate alarm limit to decrease oculocardiac reflex during strabismus surgery in children

ZHANG Kangkang, GU Enhua, LU Junjie

期刊论文

有限元极限分析法发展及其在岩土工程中的应用

郑颖人,赵尚毅,邓楚键,刘明维,唐晓松,张黎明

期刊论文

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

期刊论文

New pseudo-dynamic analysis of two-layered cohesive-friction soil slope and its numerical validation

Suman HAZARI, Sima GHOSH, Richi Prasad SHARMA

期刊论文

Slope stability analysis based on big data and convolutional neural network

Yangpan FU; Mansheng LIN; You ZHANG; Gongfa CHEN; Yongjian LIU

期刊论文

A toughness based deformation limit for X- and K-joints under brace axial tension

Bo GU,Xudong QIAN,Aziz AHMED

期刊论文

Effect of interface adhesion factor on the bearing capacity of strip footing placed on cohesive soil overlying rock mass

期刊论文

Limit span of self-anchored cable-stayed suspension cooperation system bridge based on strength

Zhe ZHANG , Huili WANG , Xiaomeng GE , Sifeng QIN ,

期刊论文

Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

期刊论文