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Machine learning-based seismic assessment of framed structures with soil-structure interaction

《结构与土木工程前沿(英文)》 2023年 第17卷 第2期   页码 205-223 doi: 10.1007/s11709-022-0909-y

摘要: The objective of the current study is to propose an expert system framework based on a supervised machine learning technique (MLT) to predict the seismic performance of low- to mid-rise frame structures considering soil-structure interaction (SSI). The methodology of the framework is based on examining different MLTs to obtain the highest possible accuracy for prediction. Within the MLT, a sensitivity analysis was conducted on the main SSI parameters to select the most effective input parameters. Multiple limit state criteria were used for the seismic evaluation within the process. A new global seismic assessment ratio was introduced that considers both serviceability and strength aspects by utilizing three different engineering demand parameters (EDPs). The proposed framework is novel because it enables the designer to seismically assess the structure, while simultaneously considering different EDPs and multiple limit states. Moreover, the framework provides recommendations for building component design based on the newly introduced global seismic assessment ratio, which considers different levels of seismic hazards. The proposed framework was validated through comparison using non-linear time history (NLTH) analysis. The results show that the proposed framework provides more accurate results than conventional methods. Finally, the generalization potential of the proposed framework was tested by investigating two different types of structural irregularities, namely, stiffness and mass irregularities. The results from the framework were in good agreement with the NLTH analysis results for the selected case studies, and peak ground acceleration (PGA) was found to be the most influential input parameter in the assessment process for the case study models investigated. The proposed framework shows high generalization potential for low- to mid-rise structures.

关键词: seismic hazard     artificial neural network     soil-structure interaction     seismic analysis    

Nonlinear elastic model for compacted clay concrete interface

R. R. SHAKIR, Jungao ZHU

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 187-194 doi: 10.1007/s11709-009-0033-2

摘要: In this paper, a nonlinear elastic model was developed to simulate the behavior of compacted clay concrete interface (CCCI) based on the principle of transition mechanism failure (TMF). A number of simple shear tests were conducted on CCCI to demonstrate different failure mechanisms; i.e., sliding failure and deformation failure. The clay soil used in the test was collected from the “Shuang Jang Kou” earth rockfill dam project. It was found that the behavior of the interface depends on the critical water contents by which two failure mechanisms can be recognized. Mathematical relations were proposed between the shear at failure and water content in addition to the transition mechanism indicator. The mathematical relations were then incorporated into the interface model. The performance of the model is verified with the experimental results. The verification shows that the proposed model is capable of predicting the interface shear stress versus the total shear displacement very well.

关键词: interface modeling     friction     soil structure interface     soil structure interaction     simple shear test    

Shaking table testing of hard layered soil-pile-structure interaction system

LI Peizhen, REN Hongmei, LU Xilin, SONG Heping, CHEN Yueqing

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 346-352 doi: 10.1007/s11709-007-0046-7

摘要: Shaking table tests on a dynamic interaction system of hard layered soil, pile foundation and frame structure were carried out. The earthquake damage of the superstructure and foundation was reproduced. Based on these tests, several key issues about the seismic response of the dynamic soil-structure interaction (SSI) system were studied. The natural frequency of the system was less than that of the structure on rigid foundation if the SSI is not taken into account, while its damping ratio was larger than that of the structure. The mode shape of the system was different from that of the structure on the fixed base in that there were rocking and swinging at the foundation. Magnification or reduction of vibration transferred by soil was related to soil characteristic, excitation magnitude, and so on. Generally, sand magnifies vibration, while viscous powder soil dampens vibration. The components of the acceleration response at the top of the superstructure were based on the relative magnitude of the rocking stiffness, the swing stiffness of the foundation and the stiffness of the super-structure. The multi-direction excitations have little effect on the key issues of the horizontal SSI.

关键词: super-structure     Generally     Magnification     frequency     different    

HIGH QUALITY DEVELOPMENTAL APPROACH FOR SOIL AND WATER CONSERVATION AND ECOLOGICAL PROTECTION ON THE

《农业科学与工程前沿(英文)》 2021年 第8卷 第4期   页码 501-511 doi: 10.15302/J-FASE-2021425

摘要:

The Loess Plateau is the core area in the Yellow River basin for implementing environmental protection and high-quality development strategies. A series of ecological projects has implemented aimed at soil and water conservation and ecological management on the Loess Plateau over the past 70 years. The effects of the ecological projects are apparent mainly through a marked increase in vegetation cover, controlled soil erosion and reduced flow of sediment into the Yellow River, continual optimization of the industrial structure and increased production from arable land, poverty alleviation and greater prosperity, and optimal allocation of space for biological organisms. Major problems have also been analyzed in ecological management including the fragile ecosystem of the region, maintaining the stability of vegetation, lower agricultural productivity and continued risk from natural disasters. Some suitable schemes and models have been developed for the coordinated development of the region through research and demonstration, striking the optimum balance between rural industry and ecology, and increased regional capacity to supply high-quality ecological products. Countermeasures to address the problems are suggested to guide ecological management and high-quality development in the future.

 

关键词: ecological management     high quality development     industrial structure     soil erosion     soil and water conservation     Loess Plateau    

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    

Impacts of n-alkane concentration on soil bacterial community structure and alkane monooxygenase genes

Yueqiao Liu, Aizhong Ding, Yujiao Sun, Xuefeng Xia, Dayi Zhang

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1064-5

摘要:

Soil microbial community is not significantly shaped by alkane concentrations

Alkane concentrations alter dominant alkane degraders in soils

Different alkanes are preferentially degraded at different contamination level

Different types of alkane monooxygenase genes responsible for alkane degradation

关键词: Petroleum hydrocarbon contaminated site     n-alkane contamination level     n-alkane biodegradation     Soil bacterial community     Alkane degraders     Alkane-monooxygenase genes    

Structure creation in earthen construction materials: information from dry soil mixtures

Christopher BECKETT, Charles AUGARDE

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 151-159 doi: 10.1007/s11709-011-0109-7

摘要: There is increasing interest in the use of earthen construction materials, such as rammed earth, due to their inherent sustainability. These materials have been used by man for thousands of years and some of the earliest examples can be found in China. Features of the structures of these materials arise from the means of production. In particular, in situ earthen construction materials exhibit strong anisotropy due to their layered nature. A more subtle structure effect arises from the way that the earth mixture is deposited. This paper reviews and discusses stratification effects in dry soil mixtures, including some original experimental work, and indicates some links between the features of the dry mixtures and earthen construction materials. Improved understanding of the physical processes in play will allow more accurate specification of these materials in the future, and hence spread their use.

关键词: rammed earth     stratification     particle size distribution     pore size distribution    

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    

土基海流耦合条件下海上风电场塔架支撑结构动力特性初探

严根华,古华,陆忠民,林毅峰

《中国工程科学》 2010年 第12卷 第11期   页码 47-52

摘要:

针对海上风力机塔柱支撑结构受到土基、海洋流体作用的复杂特点,开展多介质耦合条件下塔柱支撑结构动力特性研究。在考虑流固耦合基础上,进一步考虑海床土基弹性条件对塔柱结构动力特性的影响。最后得出了水流、土基与塔柱结构三合一综合动力特性分析结果,初步取得了变化规律。研究结果对海上风电场塔架支撑结构的抗振设计及进一步的研究提供了重要基础性参考依据。

关键词: 海上风电场     支撑结构     动力特性     土基海流耦合    

A simplified method for investigating the bending behavior of piles supporting embankments on soft ground

《结构与土木工程前沿(英文)》   页码 1021-1032 doi: 10.1007/s11709-023-0952-3

摘要: In recent years, concrete and reinforced concrete piles have been widely used to stabilize soft ground under embankments. Previous research has shown that bending failure, particularly during rapid filling on soft ground, is the critical failure mode for pile-supported embankments. Here, we propose an efficient two-stage method that combines a test-verified soil deformation mechanism and Poulos’ solution for pile–soil interaction to investigate the bending behavior of piles supporting embankments on soft ground. The results reveal that there are three possible bending failure scenarios for such piles: at the interface between the soft and firm ground layers, at mid-depths of the fan zone, and at the boundary of the soil deformation mechanism. The location of the bending failure depends on the position and relative stiffness of the given pile. Furthermore, the effect of embedding a pile into a firm ground layer on the bending behavior was investigated. When the embedded length of a pile exceeded a critical value, the bending moment at the interface between the soft and firm ground layers reached a limiting value. In addition, floating piles that are not embedded exhibit an overturning pattern of movement in the soft ground layer, and a potential failure is located in the upper part of these piles.

关键词: bending behavior     pile     embankment     soil−structure interaction     failure mode    

Behavior of compacted clay-concrete interface

R. R .SHAKIR, Jungao ZHU

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 85-92 doi: 10.1007/s11709-009-0013-6

摘要: Tests of interface between compacted clay and concrete were conducted systematically using interface simple shear test apparatus. The samples, having same dry density with different water content ratio, were prepared. Two types of concrete with different surface roughness, i.e., relatively smooth and relatively rough surface roughness, were also prepared. The main objectives of this paper are to show the effect of water content, normal stress and rough surface on the shear stress-shear displacement relationship of clay-concrete interface. The following were concluded in this study: 1) the interface shear sliding dominates the interface shear displacement behavior for both cases of relatively rough and smooth concrete surface except when the clay water content is greater than 16% for the case of rough concrete surface where the shear failure occurs in the body of the clay sample; 2) the results of interface shear strength obtained by direct shear test were different from that of simple shear test for the case of rough concrete surface; 3) two types of interface failure mechanism may change each other with different water content ratio; 4) the interface shear strength increases with increasing water content ratio especially for the case of clay-rough concrete surface interface.

关键词: soil structure interaction     simple shear test     interface     friction     compacted clay     interface modeling    

近20年能源结构调整使我国土壤多环芳烃浓度下降 Article

夏星辉, 刘亚男, 张真瑞, 席楠楠, 保嘉傲, 杨志峰

《工程(英文)》 2023年 第21卷 第2期   页码 115-123 doi: 10.1016/j.eng.2021.11.023

摘要:

近几十年来,我国在快速发展和工业化的同时,在环境污染防治方面也做出了巨大努力。然而,这些全国性措施(如能源结构调整)对土壤中污染物浓度的影响尚未得到很好的量化。多环芳烃(PAHs)污染在全球范围内引发重要关注,且PAHs排放与能源结构有关。因此,我们推测我国能源结构的调整可能会降低土壤中PAHs的含量。为了验证这一假设,我们于2008 年和2019 年在北京54 个点位重复采集了土壤样品,分析了美国环境保护署(US EPA)提出的16 种优控PAHs 化合物(Σ16PAHs)的浓度,并收集了过去20 年全国1704 个土壤采样点的数据。结果表明,我国Σ16PAHs浓度沿城市-郊区-农村-背景点梯度下降,且Σ16PAHs 浓度与区域总产值(GRP)有关,在GRP 较低时Σ16PAHs 浓度随GRP 的增加而增加,随后在GRP 达到一定水平时趋于平稳。过去20 年,我国土壤Σ16PAHs 的平均浓度呈下降趋势,其中北京土壤Σ16PAHs的平均浓度从2008 年的22.7 μg⋅g‒1总有机碳(TOC)显著下降到2019 年的10.0 μg⋅g‒1 TOC。源识别分析推断,土壤PAHs浓度的下降趋势是由于我国煤炭、焦炭、部分油类消费量下降以及电力、天然气等清洁能源消费量上升所致。本研究例证了调整能源结构在降低土壤多环芳烃浓度和改善土壤环境质量中的重要作用。

关键词: 多环芳烃     土壤     黑碳     环境污染     能源结构     可持续发展    

The effect of conservation tillage on crop yield in China

Hongwen LI,Jin HE,Huanwen GAO,Ying CHEN,Zhiqiang ZHANG

《农业科学与工程前沿(英文)》 2015年 第2卷 第2期   页码 179-185 doi: 10.15302/J-FASE-2015058

摘要: Traditional agricultural practices have resulted in decreased soil fertility, shortage of water resources and deterioration of agricultural ecological environment, which are seriously affecting grain production. Conservation tillage (CT) research has been developed and applied in China since the 1960s and 1970s, and a series of development policies have been issued by the Chinese government. Recent research and application have shown that CT has positive effects on crop yields in China. According to the data from the Conservation Tillage Research Center (CTRC), Chinese Ministry of Agriculture (MOA), the mean crop yield increase can be at least 4% in double cropping systems in the North China Plain and 6% in single cropping systems in the dryland areas of North-east and North-west China. Crop yield increase was particularly significant in dryland areas and drought years. The mechanism for the yield increase in CT system can be attributed to enhanced soil water content and improved soil properties. Development strategies have been implemented to accelerate the adoption of CT in China.

关键词: conservation tillage     crop yield     soil structure     development strategies    

Experimental study of two saturated natural soils and their saturated remoulded soils under three consolidated undrained stress paths

Mingjing JIANG, Haijun HU, Jianbing PENG, Serge LEROUEIL

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 225-238 doi: 10.1007/s11709-011-0108-8

摘要: In this paper, an experimental investigation is conducted to study the mechanical behavior of saturated natural loess, saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests, namely, conventional triaxial compression test (CTC), triaxial compression test (TC) and reduced triaxial compression test (RTC). The test results show that stress-strain relation, i.e. strain-softening or strain-hardening, is remarkably influenced by the structure, void ratio, stress path and confining pressure. Natural structure, high void ratio, TC stress path, RTC stress path and low confining pressures are favorable factors leading to strain-softening. Excess pore pressure during shearing is significantly affected by stress path. The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior. The critical states in ′– space in CTC, TC and RTC tests almost lie on one line, which indicates that the critical state is independent of the above stress paths. As for remoulded loess or remoulded filling, the critical state line (CSL) and isotropic consolidation line (ICL) in -log ′ space are almost straight, while for natural loess or natural filling, in -log ′ space there is a turning point on the CSL, which is similar to the ICL.

关键词: stress paths     static liquefaction     natural soil     remoulded soil     loess     structure     total strength indices     excess pore pressure    

明挖法地下装配式结构接缝防水技术探讨

黄明利,杨泽,谭忠盛,王文正

《中国工程科学》 2017年 第19卷 第6期   页码 131-139 doi: 10.15302/J-SSCAE-2017.06.019

摘要:

装配式结构与传统的现浇结构相比具有节能、环保、节省模具、工期较短等特点,已在地上建筑中获得了飞速发展。由于地下环境复杂,地下装配式结构接头部位的防水处理成为难题,因此,地下装配式结构近几年在我国才刚刚起步。本文在分析地下装配式结构的接头形式和防水技术现状的基础上,提出了应用环氧灌浆料对预制装配式结构接头进行灌封,通过试验研究了环氧灌浆料本身及其黏接混凝土的力学性能。同时还针对明挖法修建的技术特点,介绍了基坑肥槽预拌固化土回填技术,阐述了预拌固化土对地下工程结构防水的作用,研究成果可供类似工程参考。

关键词: 预制装配式结构     地下结构接缝     环氧灌浆料     预拌固化土     防水技术    

标题 作者 时间 类型 操作

Machine learning-based seismic assessment of framed structures with soil-structure interaction

期刊论文

Nonlinear elastic model for compacted clay concrete interface

R. R. SHAKIR, Jungao ZHU

期刊论文

Shaking table testing of hard layered soil-pile-structure interaction system

LI Peizhen, REN Hongmei, LU Xilin, SONG Heping, CHEN Yueqing

期刊论文

HIGH QUALITY DEVELOPMENTAL APPROACH FOR SOIL AND WATER CONSERVATION AND ECOLOGICAL PROTECTION ON THE

期刊论文

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

期刊论文

Impacts of n-alkane concentration on soil bacterial community structure and alkane monooxygenase genes

Yueqiao Liu, Aizhong Ding, Yujiao Sun, Xuefeng Xia, Dayi Zhang

期刊论文

Structure creation in earthen construction materials: information from dry soil mixtures

Christopher BECKETT, Charles AUGARDE

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

土基海流耦合条件下海上风电场塔架支撑结构动力特性初探

严根华,古华,陆忠民,林毅峰

期刊论文

A simplified method for investigating the bending behavior of piles supporting embankments on soft ground

期刊论文

Behavior of compacted clay-concrete interface

R. R .SHAKIR, Jungao ZHU

期刊论文

近20年能源结构调整使我国土壤多环芳烃浓度下降

夏星辉, 刘亚男, 张真瑞, 席楠楠, 保嘉傲, 杨志峰

期刊论文

The effect of conservation tillage on crop yield in China

Hongwen LI,Jin HE,Huanwen GAO,Ying CHEN,Zhiqiang ZHANG

期刊论文

Experimental study of two saturated natural soils and their saturated remoulded soils under three consolidated undrained stress paths

Mingjing JIANG, Haijun HU, Jianbing PENG, Serge LEROUEIL

期刊论文

明挖法地下装配式结构接缝防水技术探讨

黄明利,杨泽,谭忠盛,王文正

期刊论文