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Development of combined transitional pavement structure for urban tram track-road grade crossings

《结构与土木工程前沿（英文）》   页码 1199-1210 doi: 10.1007/s11709-023-0949-y

摘要： The grade crossings and adjacent pavements of urban trams are generally subjected to complex load conditions and are susceptible to damage. Therefore, in this study, a novel pavement structure between tram tracks and roads constructed using polyurethane (PU) elastic concrete and ultra-high-performance concrete (UHPC), referred to as a track-road transitional pavement (TRTP), is proposed. Subsequently, its performance and feasibility are evaluated using experimental and numerical methods. First, the mechanical properties of the PU elastic concrete are evaluated. The performance of the proposed structure is investigated using a three-dimensional finite element model, where vehicle-induced dynamic and static loads are considered. The results show that PU elastic concrete and the proposed combined TRTP are applicable and functioned as intended. Additionally, the PU elastic concrete achieved sufficient performance. The recommended width of the TRTP is approximately 50 mm. Meanwhile, the application of UHPC under a PU elastic concrete layer significantly reduces vertical deformation. Results of numerical calculations confirmed the high structural performance and feasibility of the proposed TRTP. Finally, material performance standards are recommended to provide guidance for pavement design and the construction of tram-grade crossings in the future.

关键词： urban tram track     grade crossing     combined track-road transitional pavement     polyurethane elastic concrete     finite element method    

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

《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    

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Application of Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to the guideline

null

《医学前沿（英文）》 2017年 第11卷 第4期   页码 590-594 doi: 10.1007/s11684-017-0537-4

摘要：

Grading of Recommendations Assessment, Development, and Evaluation (GRADE) offers a worldwide approach to guideline development for clinical practice. For the clinical practice of acupuncture therapy, 18 evidence-based guidelines have been developed in China using GRADE. In this study, we review the advantages and limitations of the GRADE approach in the guideline development for acupuncture and moxibustion and propose some solutions to these limitations. Scientific advantages of rating the quality of evidence, outcome-centric direction, overall progression to develop recommendations, and strength of recommendations providing specific clinical guidance are the advantages of GRADE. The limitations of GRADE in the development of guidelines for acupuncture and moxibustion include rating the quality of evidence for ancient literature and literature on famous traditional Chinese medicine experts’ experiences and specific guidelines for formulating recommendations from evidence. In the guideline development for clinical practice with acupuncture and moxibustion, we suggest that a specific method should be explored based on the GRADE approach and the characteristics of acupuncture therapy.

关键词： guideline     acupuncture     GRADE    

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Triage for management of cervical high-grade squamous intraepithelial lesion patients with positive margin

null

《医学前沿（英文）》 2017年 第11卷 第2期   页码 223-228 doi: 10.1007/s11684-017-0517-8

摘要：

The objective of this study is to guide a triage for the management of cervical high-grade squamous intraepithelial lesion (HSIL) patients with positive margin by conization. Clinico-pathological data of HSIL patients with positive margin by conization were retrospectively collected from January 2009 to December 2014. All patients underwent secondary conization or hysterectomy within 6 months. The rate of residual lesion was calculated, and the factors associated with residual lesion were analyzed by univariate and multivariate analyses. Among a total of 119 patients, 56 (47.06%) patients presented residual HSIL in their subsequent surgical specimens, including 4 cases of invasive cervical carcinoma (3 stage IA1 and 1 stage IA2 patients). Univariate analysis showed that patient age>35 years (P=0.005), menopausal period>5 years (P=0.0035), and multiple-quadrant involvement (P=0.001) were significantly correlated with residual disease; however, multivariate analysis revealed that multiple-quadrant involvement (P=0.001; OR, 3.701; 95%CI, 1.496–9.154) was an independent risk factor for residual disease. Nearly half of HSIL patients with positive margin by conization were disease-free in subsequent surgical specimens, and those with multiple positive margins may consider re-conization or re-assessment.

关键词： cervical high-grade squamous intraepithelial lesion     conization     positive surgical margin     hysterectomy    

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Grade 91钢抗蠕变性能的计算热力学研究 Article

Andrew Smith, Mohammad Asadikiya, Mei Yang, Jiuhua Chen, Yu Zhong

《工程（英文）》 2020年 第6卷 第6期   页码 644-652 doi: 10.1016/j.eng.2019.12.004

摘要：

本研究旨在了解在焊接Grade 91（Gr.91）钢时，热影响区（HAZ）内不同的临界温度与第二相的稳定性之间的关系。IV型开裂出现在Gr.91钢的焊接热影响区。

关键词： Grade 91钢     抗蠕变性能     铁素体-马素体钢     焊缝组织     计算热力学     第二相     合金成分    

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基于PFM的B级钢侧架耐久性分析

李伟,李强,王平

《中国工程科学》 2011年 第13卷 第1期   页码 56-61

摘要：

基于概率断裂力学对B级钢货车侧架的圆角细节进行了模拟耐久性试验研究，提出了一种新的通用当量初始缺陷尺寸分布的计算方法，建立了裂纹超越概率模型，从存活概率P, 应力水平σ, 裂纹形成时间t和经济维修极限ae 4个角度评估了结构的损伤度, 并结合实测的应力谱预测了其经济寿命。结果表明，裂纹萌生时间能很好地服从三参数Weibull分布，求得的通用EIFS分布参数通过了K—S检验，拟合效果很好。裂纹超越概率模型可以对结构产生的耐久性损伤进行定量度量，预测的经济寿命随裂纹穿越概率的增加呈现增长的趋势，验证了新的计算方法和概率模型的合理有效性。

关键词： 耐久性     疲劳     B级钢     裂纹    

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Silver-catalyzed bioleaching for raw low-grade copper sulphide ores

Tianlong DENG, Yafei GUO, Mengxia LIAO, Dongchan LI

《化学科学与工程前沿（英文）》 2009年 第3卷 第3期   页码 250-254 doi: 10.1007/s11705-009-0049-0

摘要： This research was conducted to investigate the biooxidation and copper dissolution from raw low-grade refractory copper sulphide ores located in the Xinjiang Autonomous Region of China using adapted bacteria. In order to accelerate the bioleaching rate, the adapted mixed bacteria and silver ion catalyst were tested in the leach columns at laboratory scale. The overall acid consumption was 4.3 kg sulphuric acid per kg of dissolved copper and was linearly related to the percent copper dissolution. The calculated copper dissolution rates obey the Shrinking Core Model. The relative activation energy of the whole biooxidative leaching stages was calculated to be 48.58 kJ/mol.

关键词： green process     biohydrometallurgy     bioleaching     reaction kinetics     sulphide ores    

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基于五品联动理论的品位效益优化决策研究

邵安林

《中国工程科学》 2014年 第16卷 第2期   页码 68-72

摘要：

本文以五品联动理论为研究背景，考虑到矿山工程中地质工程、采矿工程、配矿工程、选矿工程和冶炼工程5 个工程是相互联系的串联耦合工程，是矿山企业活动的主体，而与其相对应的地质品位、采出品位、入选品位、精矿品位和入炉品位对于矿山整体经济效益起到关键的控制作用。本文运用并拓展了“质量守恒”原理，利用“矿量守恒”和“金属量守恒”建立了品位经济效益模型，提出了五品联动品位—效益活跃指数，通过实例计算与分析，获得了某铁矿的品位优化数值，为进一步研究矿山企业工程管理模式奠定了基础。

关键词： 五品联动     品位—效益活跃指数     优化决策     矿冶工程    

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Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 998-1011 doi: 10.1007/s11709-020-0621-8

摘要： Urban tunnels crossing faults are always at the risk of severe damages. In this paper, the effects of a reverse and a normal fault movement on a transversely crossing shallow shotcreted tunnel are investigated by 3D finite difference analysis. After verifying the accuracy of the numerical simulation predictions with the centrifuge physical model results, a parametric study is then conducted. That is, the effects of various parameters such as the sprayed concrete thickness, the geo-mechanical properties of soil, the tunnel depth, and the fault plane dip angle are studied on the displacements of the ground surface and the tunnel structure, and on the plastic strains of the soil mass around tunnel. The results of each case of reverse and normal faulting are independently discussed and then compared with each other. It is obtained that deeper tunnels show greater displacements for both types of faulting.

关键词： urban tunnel     sprayed concrete     reverse fault     normal fault     finite difference analysis    

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高钢级钢管和高压输送：我国油气输送管道的重大技术进步

李鹤林,吉玲康,田伟

《中国工程科学》 2010年 第12卷 第5期   页码 84-90

摘要：

近年来，我国管道企业和相关科研院所联合攻关，取得了一批关键技术成果，这些成果包括：研制了X70，X80钢级高性能管线钢及焊管、管件；突破国际上螺旋缝埋弧焊管的使用禁区，确立了具有中国特色的“大口径高压输送主干线螺旋埋弧焊管与直缝埋弧焊管联合使用”的技术路线；在国内首次研究了高压输气管道动态断裂与止裂问题，采用Battelle双曲线模型预测了西气东输和西气东输二线等管道延性断裂的止裂韧性；在国内首次研究了油气管道基于应变的设计方法，解决了该设计方法及抗大变形管线钢管在强震区和活动断层管段应用的技术难题；解决了高强度焊管的腐蚀控制和应变时效控制等技术。

关键词： 油气管道     管线钢     螺旋缝埋弧焊管     止裂韧性     基于应变的设计    

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非爆炸且不可还原农用硝酸铵的热稳定性评估

汪旭光,沈立晋

《中国工程科学》 2004年 第6卷 第11期   页码 53-57

摘要：

绍了一种测试含能材料热稳定性的新方法——加速度量热仪，并用此法研究了硝酸铵和非爆炸且不可还原农用硝酸铵的热分解过程，得到了绝热分解温度与压力随时间的变化、自加热速率与分解压力随温度的变化曲线，计算了分解动力学参数表观活化能和指前因子，讨论了放热反应系统的热惰性因子对测试结果的影响，表明非爆炸且不可还原农用硝酸铵具有良好的热稳定性、安全性及其热稳定性的提高是爆炸特性得以消除的原因。

关键词： 农用硝酸铵     非爆炸性     不可还原性     加速度量热仪     热稳定性    

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Study of bond strength between various grade of Ordinary Portland Cement (OPC) and Portland Pozzolane

A D POFALE, S P WANJARI

《结构与土木工程前沿（英文）》 2013年 第7卷 第1期   页码 39-45 doi: 10.1007/s11709-013-0193-y

摘要： Since last two decades, the Portland Pozzolane Cement (PPC) is extensively used in structural concrete. But, till to date, a few literature is available on bond strength of concrete using PPC mixes. There are many literatures available on bond strength of concrete mixes using Ordinary Portland Cement (OPC). Hence, a comparative study was conducted on bond strength between OPC and PPC mixes. In the present investigation, total 24 samples consisting of M20, M35 and M50 grades of concrete and 16 and 25 mm diameter of TMT bar were tested for 7 and 28 days. The pullout bond test was conducted on each specimen as per IS: 2770-1967/1997 [1] and the results were observed at 0.25 mm slip at loaded end called as critical bond stress and at maximum bond load called as maximum bond stress. It was observed that the critical bond strength of PPC mixes is 10% higher than OPC mixes. Whereas, marginal improvement was noticed in maximum bond strength of PPC mixes. Hence, based on these findings, it could be concluded that development length for PPC mixes could be reduced by 10% as compared with same grade of OPC mixes.

关键词： bond strength     Portland Pozzolane Cement (PPC) concrete     Ordinary Portland Cement (OPC) concrete     bond between concrete and steel     pullout test     development length    

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切内里基线隧道——穿越瑞士阿尔卑斯山脉的平轨铁路线南段的施工经验 Article

Davide Merlini, Daniele Stocker, Matteo Falanesca, Roberto Schuerch

《工程（英文）》 2018年 第4卷 第2期   页码 235-248 doi: 10.1016/j.eng.2017.09.004

摘要：
本文总结了在修建15.4 km 长切内里基线隧道（CBT）期间获得的经验，这条隧道为从北向南跨越瑞士阿尔卑斯山脉的平轨铁路线的南段。该项目由直径为9 m 的双管组成，双管之间每隔325 m设置一个联络通道。在线路中部及其南端，应后勤和运营要求，开挖了大型洞室。总开挖长度大约为40 km。隧道穿越阿尔卑斯山处的岩层由各种岩石类型和若干断层带组成。最大埋深达850 m。主隧道和联络通道的开挖通过钻爆法（D&B）进行。支护由锚杆、钢筋网、纤维增强喷射混凝土和（必要时的）钢拱架构成。为开挖进口隧洞，使用了敞开式隧道掘进机（TBM）。大埋深导致岩石受到挤压，这种状况的特征为在穿越较弱岩层时产生较大的各向异性收敛。较弱岩层要求安装可变形支护。在北洞口，隧道（断面增大）穿过A2 高速公路（连接瑞士北部和南部的主要道路轴线）下方，此处埋深较小，且隧道通过的是软地层。为限制地表沉降，成功采用了垂直和近水平喷射灌浆与分部开挖相结合的方法。南洞门位于人口密集的市区。开挖自南洞门开始，包括一
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桥岛隧组合跨海通道的最新建设技术

葛耀君, 袁勇

《工程（英文）》 2019年 第5卷 第1期   页码 15-21 doi: 10.1016/j.eng.2019.01.003

关键词： 工程成就    

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Bioleaching of copper from pre and post thermally activated low grade chalcopyrite contained ball mill

Sandeep PANDA, Nilotpala PRADHAN, Umaballav MOHAPATRA, Sandeep K. PANDA, Swagat S. RATH, Danda S. RAO, Bansi D. NAYAK, Lala B. SUKLA, Barada K. MISHRA

《环境科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 281-293 doi: 10.1007/s11783-013-0484-5

摘要： Bioleaching of a low grade chalcopyrite (ball mill spillage material) was tested for copper recovery in shake flasks. The original samples (as received) were thermally activated (600°C, 30 min) to notice the change in physico-chemical and mineralogical characteristics of the host rock and subsequently its effect on copper recovery. A mixed culture of acidophilic chemolithotrophic bacterial consortium predominantly entailing strain was used for bioleaching studies and optimization of process parameters of both original and thermally activated samples. Mineralogical characterization studies indicated the presence of chalcopyrite, pyrite in the silicate matrix of the granitic rock. Field emission scanning electron microscopy coupled with Energy dispersive spectroscopy (FESEM-EDS) and X-ray Fluorescence (XRF) analysis indicated mostly SiO . With pH 2, pulp density 10% w/v, inoculum 10% v/v, temperature 30°C, 150 r·min , 49% copper could be recovered in 30 days from the finest particle size (-1+ 0.75 mm) of the original spillage sample. Under similar conditions 95% copper could be recovered from the thermally activated sample with the same size fraction in 10 days. The study revealed that thermal activation leads to volume expansion in the rock with the development of cracks, micro and macro pores on its surface, thereby enabling bacterial solution to penetrate more easily into the body, facilitating enhanced copper dissolution.

关键词： ball mill spillage     thermal activation     bioleaching     copper    

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标题 作者 时间 类型 操作

Development of combined transitional pavement structure for urban tram track-road grade crossings

期刊论文

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

期刊论文

Application of Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to the guideline

null

期刊论文

Triage for management of cervical high-grade squamous intraepithelial lesion patients with positive margin

null

期刊论文

Grade 91钢抗蠕变性能的计算热力学研究

Andrew Smith, Mohammad Asadikiya, Mei Yang, Jiuhua Chen, Yu Zhong

期刊论文

基于PFM的B级钢侧架耐久性分析

李伟,李强,王平

期刊论文

Silver-catalyzed bioleaching for raw low-grade copper sulphide ores

Tianlong DENG, Yafei GUO, Mengxia LIAO, Dongchan LI

期刊论文

基于五品联动理论的品位效益优化决策研究

邵安林

期刊论文

Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

期刊论文

高钢级钢管和高压输送：我国油气输送管道的重大技术进步

李鹤林,吉玲康,田伟

期刊论文

非爆炸且不可还原农用硝酸铵的热稳定性评估

汪旭光,沈立晋

期刊论文

Study of bond strength between various grade of Ordinary Portland Cement (OPC) and Portland Pozzolane

A D POFALE, S P WANJARI

期刊论文

切内里基线隧道——穿越瑞士阿尔卑斯山脉的平轨铁路线南段的施工经验

Davide Merlini, Daniele Stocker, Matteo Falanesca, Roberto Schuerch

期刊论文

桥岛隧组合跨海通道的最新建设技术

葛耀君, 袁勇

期刊论文

Bioleaching of copper from pre and post thermally activated low grade chalcopyrite contained ball mill

Sandeep PANDA, Nilotpala PRADHAN, Umaballav MOHAPATRA, Sandeep K. PANDA, Swagat S. RATH, Danda S. RAO, Bansi D. NAYAK, Lala B. SUKLA, Barada K. MISHRA

期刊论文