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Reliability analysis of retaining walls with multiple failure modes

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Journal of Central South University 2013年第10期20卷 2879-2886页

作者：张道兵孙志彬朱川曲 School of Energy and Safety Engineering Hunan University of Science & Technology School of Civil Engineering Central South University

In order to reduce the errors of the reliability of the retaining wall structure in the establishment of function, in the estimation of parameter and algorithm, firstly, two new reliability and stability models of anti-slipping and anti-overturning based on the upper-bound theory of limit analysis were established, and two kinds of failure modes were regarded as a series of systems with multiple correlated failure modes. Then, statistical characteristics of parameters of the retaining wall structure were inferred by maximal entropy principle. At last, the structural reliabilities of single failure mode and multiple failure modes were calculated by Monte Carlo method in MATLAB and the results were compared and analyzed on the sensitivity. It indicates that this method, with a high precision, is not only easy to program and quick in calculation, but also without the limit of nonlinear functions and non-normal random variables. And the results calculated by this method which applies both the limit analysis theory, maximal entropy principle and Monte Carlo method into analyzing the reliability of the retaining wall structures is more scientific, accurate and reliable, in comparison with those calculated by traditional method.

关键词： retaining wall maximal entropy principle limit analysis Monte Carlo method multiple failure modes reliability

Model test on sand retaining wall reinforced with denti-strip inclusions

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Science China(Technological Sciences) 2008年第12期51卷 2259-2269页

作者： ZHANG MengXi1 & ZHOU Huai1,2 1 Department of Civil Engineering,Shanghai University,Shanghai 200072,China 2 Shanghai Chengtou City Land(Group) Corporation,Shanghai 200438,China Department of Civil Engineering Shanghai University Shanghai 200072 China Shanghai Chengtou City Land (Group) Corporation Shanghai 200438 China

In conventional reinforced soil structures,the reinforcements are often laid hori-zontally in the *** this paper,a new concept of soil reinforced with denti-strip inclusions was proposed and a series of laboratory model tests were carried out on sand retaining wall reinforced with denti-strip *** the horizontal displacements of the facing,the lateral earth pressures acting on vertical elements were measured.A microscopic measurement was performed to investigate the deformation and progressive failure of the sand within model retaining *** on the image analytical technique,the bearing capability and interaction mechanism of reinforced sand retaining wall were *** model of the initial shear failure and potential failure surface were also put *** the experimental results,it is shown that denti-strip inclusions can increase the bearing capability of retaining wall significantly and restrict the facing displacements efficiently,as compared with conventional horizontal reinforcement.

关键词： denti-strip inclusions reinforced sand retaining wall model test horizontal facing displacements lateral earth pressure on denti-elements failure surface

Seismic responses of the steel-strip reinforced soil retaining wall with full-height rigid facing from shaking table test

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Journal of Mountain Science 2018年第5期15卷 1137-1152页

作者： CAO Li-cong FU Xiao WANG Zhi-jia ZHOU Yong-yi LIU Fei-cheng ZHANG Jian-jing Key Laboratory of Transportation Tunnel Engineering Ministry of Education School of Civil Engineering Southwest Jiaotong University Department of Geotechnical Engineering School of Civil Engineering Southwest Jiaotong University Department of Civil Engineering and Architecture Hainan University

To investigate the seismic response of the steel-strip reinforced soil retaining wall with fullheight rigid facing in terms of the acceleration in the backfill, dynamic earth pressure in the backfill, the displacements on the facing and the dynamic reinforcement strain distribution under different peak acceleration, a large 1-g shaking table test was performed on a reduced-scale reinforced-earth retaining wall model. It was observed that the acceleration response in non-strip region is greater than that in potential fracture region which is similar with the stability region under small earthquake,while the acceleration response in potential fracture region is greater than that in stability region in middle-upper of the wall under moderately strong earthquakes. The potential failure model of the rigid wall is rotating around the wall toe. It also was discovered that the Fourier spectra produced by the inputting white noises after seismic wave presents double peaks, rather than original single peak, and the frequency of the second peak trends to increase with increasing the PGA(peak ground amplitude) of the excitation which is greater than 0.4 g. Additionally,the non-liner distribution of strip strain along the strips was observed, and the distribution trend was not constant in different row. Soil pressure peak value in stability region is larger than that in potential fracture region. The wall was effective under 0.1 g-0.3 g seismic wave according to the analyses of the facing displacement and relative density. Also, it was discovered that the potential failure surface is corresponds to that in design code, but the area is larger. The results from the study can provide guidance for a more rational design of reinforced earth retaining walls with full-height rigid facing in the earthquake zone.

关键词： Reinforced soil retaining walls Potentialfailure surface Full-height rigid facing Steel strip Seismic behaviors 1-g shaking table test

Control mechanism and technique of floor heave with reinforcing solid coal side and floor corner in gob-side coal entry retaining

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International Journal of Mining Science and Technology 2012年第6期22卷 832-836页

作者： Chen Yong Bai Jianbiao Yan Shuai Xu Ying Wang Xiangyu Ma Shuqi State Key Laboratory of Coal Resources and Mine Safety School of MinesChina University of Mining & Technology Faculty of Engineering University of Wollongong

Floor heave is the most common convergence in gob-side entry *** paper analyzes the form,process and characteristics of gob-side entry retaining with the comprehensive methods of theoretical analysis,numerical simulation and the field *** results present that bending and folding floor heave is the main factor in the stage of the first panel mining;squeezing and fluidity floor heave plays a great role in the stable stage of gob-side entry retaining;the combination of the former two factors affects mainly the stage of the second mining ahead;abutment pressure is a fundamental contribution to the serious floor heave of gob-side entry retaining,and sides corners of solid coal body are key part in the case of floor heave controlling of gob-side entry *** heave of gob-side entry retaining can be significantly controlled by reinforcing sides and corners of solid coal body,and influence rules on the floor heave of gob side entry retaining of sides supporting strength and the bottom bolt orientation in solid coal side are *** results have been successfully applied in gob-side entry retaining of G20-F23070 face haulage roadway in #2 coal mine of Pingmei Group,and the field observation shows that the proposed technique is an effective way in controlling the floor heave of gob-side entry retaining.

关键词： Gob-side entry retaining Abutment pressure Forms of floor heave Reinforcing sides of solid coal side Bolt in a floor corner

Supporting and retaining competent primary care workforce in low-resource settings:lessons learned from a prospective cohort study

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Family Medicine and Community Health 2023年第4期11卷 13-35页

作者： Mingyue Li Haoqing Tang Huixian Zheng Yiran Tian Xiaoran Cheng Haozhe Cheng Xiaotian Zhang Dan Hu Xiaoyun Liu School of Public Health Peking UniversityBeijingChina China Center for Health Development Studies Peking UniversityBeijingChina School of Health Policy and Management Nanjing Medical UniversityNanjingJiangsuChina

Objective Assess whether local health facilities can adequately support the performance of general practitioners(GPs)trained by China’s national compulsory services programme(CSP).Design Prospective cohort *** Health facilities in middle and western rural areas in China,2015–*** Cohorts of CSP graduates from 2015 to 2019 in four major medical *** outcomes Job performance measured by a 12-item Job Performance Scale;productivity measured by outpatient volume per day;turnover measured by ever changing jobs within the past *** 91.2%,92.0%and 90.5%GPs working in township health centres reported inadequate medication,equipment and external assistance from higher level hospitals,while CSP graduates working in secondary or tertiary hospitals reported a lower rate of less than 60%.The top three tests reported as lacking were blood gases(67.7%),microbiology(61.6%)and cancer biomarkers(49.7%);the top three lacked procedures were CT scan(64.8%),MRI scan(58.1%)and ambulatory BP monitoring(55.8%);and the top three lacked drugs were drugs for cardiovascular diseases(23.3%),systematic hormonal preparations(17.7%)and traditional Chinese medicines(13.0%).Multivariable analysis showed that facility support was positively associated with job performance—adequate medication increased job performance by 2.2 points(95%CI 0.7to 3.8),and adequate external assistance increased job performance by 3.3 points(95%CI 1.8to 4.8).Facility support was also positively associated with productivity—adequate medication increased outpatients seen per day by 20%(95%CI 0.1to 0.3),and adequate equipment increased outpatients seen per day by 12%(95%CI 0.0to 0.2).Facility support did not have significant impact on turnover,but GPs who changed jobs in the past year were 1.9–2.3 times more likely to report adequate facility *** GPs in township health centres experienced a high prevalence of shortage in facility *** identification of a positiv

关键词： retaining adequate facility

Comparison of Seismic Design Codes between China and the United States for Reinforced Soil retaining Walls

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Earthquake Research in China 2019年第1期33卷 147-152页

作者： XU Peng TIAN Hongcheng JIANG Guanlu WANG Zhimeng School of Civil Engineering Southwest Jiaotong University Key Laboratory of High-Speed Railway Engineering Ministry of Education China Railway Eryuan Engineering Group Co. Ltd.

Because of its excellent seismic performance, reinforced soil retaining walls are increasingly used in civil engineering. Although many countries have published corresponding design codes, the differences between them are still relatively large. Using the FHWA Code and the Code for Seismic Design of Railway Engineering(CSDRE), stability calculations of reinforced soil retaining walls were carried out and the similarities and differences between these two design codes were analyzed. According to the comparative analysis, the following conclusions are drawn: the inertia force, the earth pressure and the tensile force of reinforcements calculated from the CSDRE are less than those from the FHWA Code, and the safety factor calculated from the former is larger. Although the M-O method is recommended to calculate the dynamic earth pressure, the FHWA Code suggests a higher action point as compared to the CSDRE.

关键词： Seismic performance Reinforced soil retaining wall Inertia force Earth pressure Tensile force

Study on Ultimate Pullout Force of Grouting Anchors of the Anchor-Pull retaining Wall

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Journal of Geoscience and Environment Protection 2014年第5期2卷 32-37页

作者： Hongbo Zhang Yifan Yu Xiuguang Song Yingyong Li Jianqing Wu School of Civil Engineering Shandong University Jinan 250061 China Subgrade Security Engineering Research Center of Shandong Province Jinan 250061 China

Determination of the grouting anchor pullout force is a key step during the design of anchor-pull retaining wall, but it is mostly determined relied on empirical formula at present, and the rationality and the safety cannot be effectively guaranteed. Based on the engineering case of the gravity retaining wall of Qinglin Freeway, the model test was designed, and combined with the results of the ABAQUS finite element numerical analysis, it was analyzed that how the anchor axial pulling force distributes. The results showed that the force of the anchor near the wall bolt was large and which far from the wall was small and the ultimate pullout force was proportional to the length, diameter and shear strength. When the end tension of the anchor was small, the top load played a leading role on the anchor tension. This conclusion confirmed the calculation formula of ultimate pullout force was and provided a theoretical basis for anchor-pull retaining wall design and calculation.

关键词： Anchor-Pull retaining Wall Ultimate Pullout Force Lateral Earth Pressure Model Test Numerical Analysis

Analysis of the Factors for Displacement of Earth retaining Wall with Twin-Stepped Construction

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World Journal of Engineering and Technology 2019年第1期7卷 114-121页

作者： Seiya Sakuma Kazuki Maehara Takahiro Funatsu Akihiro Hamanaka Takashi Sasaoka Hideki Shimada Department of Earth Resources Engineering Faculty of Engineering Kyushu University Fukuoka Japan

The demand for specific earth retaining wall method is increasing, along with the advancement and overcrowding of underground space use, such as the?presence of close structures, in an urban area. The method is named stepped-twin?retaining wall. The feature of this method is to have inner and outer retaining walls and excavate the ground by two-step in order to minimize the effect of the excavation on neighboring existing structures. However, the design of the earth retaining wall is currently carried out by individual engineers based on their own experience. Therefore, it is crucial that the standard method of retaining wall using a two-step construction is established. As the first step toward the standardization, evaluation of factors affecting the ground behavior of the earth retaining wall was carried out. In particular, we picked up four major considerable factors, which are horizontal distance between the outer and inner walls, depth of outer wall embedment, mechanical properties of soil. The evaluation was done by using two dimensional FEM analysis and the results were summarized to make clear the effect of each factor.

关键词： Excavation Behavior Earth retaining Wall Finite Element Method

Lateral Earth Pressure Coefficient and Lateral Earth Pressure against retaining Walls

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Journal of Geological Resource and Engineering 2018年第6期6卷 251-260页

作者： Jose Medina Nicolas Sau Qutberto Acuna Department of Civil and Mining Engineering University of SonoraHermosilloSonora 83000México

According the Coulomb earth pressure theory,it is obtained that,for normally consolidated soils,the lateral pressure coefficient of a soil at rest is equal to 1,and it is independent of the soil type,either granular or cohesive;or that the material is in a loose or compact state;hard or a soft cohesive ***,a methodology to calculate the earth pressure for intermediate states between at rest condition and the active pressure is *** addition,a methodology to calculate the earth pressure for intermediate states between at rest condition and the passive pressure is *** practical examples are presented:one for a frictionless wall;and another for a coarse *** recommendations are given for the use of the lateral earth pressure coefficient for different applications.

关键词： Lateral earth pressure at rest retaining wall active thrust passive thrust Rankine Coulomb lateral earth pressure coefficient lateral earth pressure coefficient at rest