钢管混凝土柱受剪承载力试验

江棹荣　倪振华　谢壮宁
（汕头大学，广东汕头515063）

摘要：根据风洞试验同步多点压力扫描技术和本征正交分解方法重构作用于圆拱顶屋盖的脉动风力。对重构的脉动风荷载的时间历程曲线及其统计性质与实测风荷载进行比较。计算部分测压点上重构的风荷载的自功率谱、互功率谱及相干函数，并用实测荷载的功率谱作了检查。提出一种采用缩阶技术用完全二次型组合法计算大跨屋盖的风致响应的方法，这种方法利用少量本征模态计算缩阶的主坐标功率谱而得到脉动风荷载功率谱。为检验方法的效率，给出采用不同数目主坐标的圆拱顶屋盖部分节点竖向均方根位移的计算时间和计算误差，以及采用不同数目主坐标的缩阶技术得到的全部节点的竖向均方根位移响应的误差分布。
关键词：本征正交分解；圆拱顶屋盖；风致响应；功率谱计算

Application of POD to calculation of wind-induced response of large roofs

Jiang Zhaorong　Ni Zhenhua　Xie Zhuangning
(Shantou University，Shantou 515063，China)

Abstract: The fluctuating wind loads on a dome-like roof are reconstructed based on the synchronous multi-pressure scanning technique of wind tunnel tests and the proper orthogonal decomposition(POD)method. The time-history curve and the statistics of the reconstructed fluctuating wind loads are compared with those of the measured wind loads. The auto-spectra, cross-spectra and correlation of the reconstructed loads for some taps are computed and examined in comparison with those obtained from the measured loads. A reduced-order approach to calculating the wind-induced response of large roofs with complete quadratic combination is proposed. In this approach the spectra matrix of fluctuating wind loads is obtained through calculating the reduced spectra matrix of the principal coordinates with a few proper modes. To verify the efficiency of the approach, the computing time and error of the vertical RMS displacements of some nodes of the dome with different numbers of principal coordinates are presented. Moreover, the error distributions of the vertical RMS displacement response of all nodes using the reduced-order technique with different number of principal coordinates are illustrated.
Keywords: proper orthogonal decomposition; dome-like roof; wind-induced response; spectra calculation

E-mail: zhni@stu.edu.cn

CNP1000核电厂安全壳1:10模型拟动力试验

钱稼茹¹ 赵作周¹ 段 安¹ 夏祖讽² 王明弹²
(1.清华大学，北京100084；2.上海核工程研究设计院，上海200233)

摘要: 由半球形穹顶、筒体和2根扶壁柱组成的预应力混凝土安全壳是我国最新开发的CNP1000先进核电厂的标志建筑物。为验证其在峰值加速度为0.2 g的设计地震水平SL-2工况下的安全，为该安全壳的技术系统集成提供模型结构动态试验依据，完成了该安全壳一个1∶10预应力混凝土模型的单自由度拟动力试验。试验分两个阶段，加载方向分别与安全壳的扶壁柱连线垂直和一致；在有限元分析的基础上，确定了两个阶段试验单自由度体系的理论质量。采用人工波作为地震输入；每个阶段分别进行3个工况试验，地震峰值加速度分别为1 g、2 g和3 g，根据相似关系，对应于实体结构分别为0.1 g、0.2 g和0.3 g；模型结构阻尼比分别取为0.02、0.05和0.05。结果表明，在峰值加速度2 g地震作用下，筒体底部个别测点达到混凝土开裂应变，模型等效抗侧刚度降低仅5％；在峰值加速度3 g地震作用下，除筒体底部外的筒壁测点的应变都小于混凝土开裂应变，模型等效抗侧刚度降低约14％，结构处于弹性阶段。半球形穹顶安全壳具有大的抗震安全储备。
关键词：预应力混凝土安全壳；半球形穹顶；1∶10模型；拟动力试验；设计地震水平SL-2

Pseudo-dynamic tests of a 1∶10 model of pre-stressed concrete
containment vessel for CNP1000 nuclear power plant

Qian Jiaru¹ Zhao Zuozhou¹ Duan An¹ Xia Zufeng² Wang Mingdan²
（1.Tsinghua University, Beijing 100084, China;
2.Shanghai Nuclear Engineering Research and Design Institute, Shanghai 200233, China）

Abstract: CNP1000 is the latest developed nuclear power plant in China. The pre-stressed concrete containment vessel(PCCV), consisting of a semi-spherical dome, a cylinder and two buttresses, is a symbolic structure for CNP1000. In order to verify the seismic safety of this new type of PCCV under the design earthquake level of SL-2 (peak acceleration 0.2 g)and to provide the dynamic test data for earthquake resistant design of the structure and technical integration of the PCCV, a series of single-degree of freedom(SDOF)pseudo-dynamic tests of a 1∶10 model were carried out. Based on the loading direction, the test was carried out in two stages. For test stage 1, the loading was applied perpendicular to the connection line of the two buttresses, and for test stage 2 the loading was applied along the connection line of the two buttresses. Theoretical mass of the SDOF system for each test stage was determined based on finite element analysis of the test model. An artificial earthquake wave was employed as the input. There were three load cases for each test stage with the peak acceleration being 1 g, 2 g and 3 g, respectively, corresponding to 0.1 g, 0.2 g and 0.3 g for the prototype PCCV structure, and the corresponding damping ratio of the test model was assumed to be 0.02, 0.05 and 0.05, respectively. The test results indicate that under earthquake excitation of a peak acceleration 2 g(corresponding to design earthquake level SL-2), the tensile strain at some concrete monitoring points near the fixed bottom of the model reached cracking level. The equivalent lateral stiffness of the model is decreased by 5% of its initial value. When the peak acceleration was 3 g, the maximum principal tensile strains at monitoring points on the cylinder, except the monitoring points near the bottom, were less than the cracking strain. The equivalent lateral stiffness of the model is decreased by 14% of its initial value. The test PCCV model as a whole was within the elastic range. The PCCV with semi-spherical dome has sufficient seismic resisting safety.
Keywords: pre-stressed concrete containment vessel(PCCV); semi-spherical dome; 1∶10 model; pseudo-dynamic test; design earthquake level SL-2

E-mail: qianjr@mail.tsinghua.edu.cn

考虑土-结构动力相互作用的框架结构的参数识别研究

周　云　易伟建
（湖南大学，湖南长沙410082）

摘要：对一座采用柱下独立基础的钢筋混凝土4层框架结构进行了随着层数增加的4种工况模态实验，用脉冲锤击法测试得到了各种工况的整体模态频率和振型。考虑地基-基础-上部结构动力相互作用，上部框架结构采用缩聚得到的弯剪结构模型，下部基础利用Pais等人提出的弹性地基上埋置矩形板的地基阻抗函数进行简化处理得到的计算模型。在满足地基动剪模量和各层混凝土的弹性模量随框架层数的增加而增加的原则下，建立了4种工况下的多目标优化准则。将基于频率数据识别欠定问题的灵敏度方法进行了结构物理参数以及地基参数同时识别，识别得到的模态实验值与测试值符合良好。识别结果能够反应地基基础对结构的影响并为进一步损伤诊断提供了依据。
关键词：土-结构动力相互作用；框架结构；实验模态分析；多目标优化；灵敏度方法；参数识别

Parameter identification for frame structures considering dynamic soil-structure-interaction

Zhou Yun　Yi Weijian
(Hunan University，Changsha 410082，China)

Abstract:Four cases of experimental modal analyses, with variation of the number of stories, were conducted for a four-story reinforced concrete frame structure with independent footing under the columns. The hammer impulse method was employed to measure the global modal frequencies and the mode shapes of each case. Considering the dynamic interaction of the soil-base-structure, a shear-bending frame model is employed for the superstructure, and the simplified embedded square slab’s impedance function proposed by Pais et al. is employed as for the infrastructure. Using the criterion that the foundation’s dynamic shear modulus and story’s elastic modulus will increase with the increase in stories, a multi-objective optimization criterion is formulated. A sensitivity method for under-determined problems, using frequencies, is employed to identify the physical parameters and foundation parameters simultaneously. The identified modes match well with the measured ones. The identified parameters can reflect the influence of foundation on the structure and provide the basis for damage identification.
Keywords: soil-structure interaction; frame structure; experimental modal analysis; multi-objective optimization; sensitivity method; parameter identification

E-mail: zhouyun05@126.com

压电智能混凝土梁主动控制试验研究与有限元分析

薛伟辰 李 杰 杨 枫
（同济大学，上海200092）

摘要：基于8根压电智能混凝土梁的主动控制试验，较为系统地研究压电智能混凝土梁在静力荷载和压电驱动器产生的驱动力作用下的变形恢复能力、应变恢复特性和裂缝闭合特征，重点分析配筋率、跨高比和驱动器埋设位置等因素的影响。试验结果表明，通过对压电智能混凝土梁施加驱动力，可以有效地实现智能混凝土梁的应变、变形和裂缝的主动控制，其中应变恢复率达到30%左右，变形恢复百分比在21%~42%之间，裂缝宽度闭合程度大致在12%~15%之间。另外，基于非线性有限元原理，编制压电智能混凝土梁的分析程序，实现压电智能混凝土梁主动控制的全过程分析。
关键词：智能混凝土梁；压电驱动器；主动控制；变形恢复；应变恢复；裂缝闭合；非线性有限元分析

Active control test study and FEM analysis of piezoelectric smart concrete beams

Xue Weichen Li Jie Yang Feng
（Tongji University, Shanghai 200092, China）

Abstract: Based on the active-control experiments of eight piezoelectric smart beams, the strain and displacement restoring capacity and the characteristics of crack closing of smart beams, under static loads and actuating forces induced by piezoelectric actuators, are systematically studied. The influences of longitudinal reinforcement ratio, span-height ratio and locations of actuators are emphatically analyzed. Experimental results show that the control of piezoelectric smart beams is achieved well when the actuating force was applied to smart beams. Ratio of strain restoration is about 30%, ratio of displacement restoration about 21%~ 42% and ratio of crack closure gets to approximately 12%~15%. In addition, nonlinear FEM codes are developed for analysis of active control of piezoelectric smart concrete beams.
Keywords: smart concrete beam; piezoelectric actuator; active control; displacement restoring capacity; strain restoring capacity; crack closure; nonlinear FEM analysis

E-mail: xuewc@mail.tongji.edu.cn

碳纤维布加固钢筋混凝土板的耐火性能试验研究

吴　波　王军丽
(华南理工大学亚热带建筑科学国家重点实验室，广东广州510640)

摘要：在ISO834标准升温条件下，进行3块设置不同防火材料的碳纤维布加固钢筋混凝土板，以及1块未加固板的耐火性能对比试验。分析不同防火措施对高温下碳纤维布加固钢筋混凝土板的破坏形态、跨中挠度及耐火极限的影响。试验结果表明： （1）只要采取适当的防火措施，在使用荷载明显增大的情况下，碳纤维布加固钢筋混凝土板仍具有与未加固板大体相当甚至更长的耐火极限； （2）与薄型防火涂料相比，水泥砂浆的防火保护效果相对较弱； （3）厚度5 mm的薄型防火涂料的防火效果相对较好。为确保实际工程中碳纤维布加固钢筋混凝土板具有足够的耐火能力，科学合理地选择防火材料及其厚度是十分重要的。
关键词：碳纤维布；加固；钢筋混凝土板；耐火性能

Experimental study on reinforced concrete slabs strengthened with
carbon-fiber-sheets and subjected to high temperatures

Wu Bo Wang Junli
（State Key Laboratory of Subtropic Architecture Science，South China University of
Technology，Guangzhou 510640，China）

Abstract: The fire resistance performance of three reinforced concrete（RC）slabs strengthened with carbon-fiber-sheets and covered with different insulating materials are tested, following the ISO834 standard heating process, and the test results are compared with those of an unstrengthened RC slab. The influences of different insulating measures on the failure mode, deflection at mid-span, and fire resistance of the strengthened RC slabs are analyzed. The test results indicate that:（a）when insulating measures are adopted appropriately, even though the service loading is increased significantly, the fire resistance of the RC slabs strengthened with carbon-fiber-sheets may be approximately equal to or longer than that of the unstengthened slab;（b）the insulation effectiveness of cement mortar is weaker than that of scraping insulation materials; and（c）the insulation effectiveness of scraping insulation material with a thickness of 5mm is better than that of 3mm. In order to ensure that RC slabs strengthened with carbon-fiber-sheets possess sufficient fire resistance capacity, it is important to carefully choose the type and thickness of insulating materials.
Keywords: carbon-fiber-sheet; strengthen; reinforced concrete slab; fire resistance performance

E-mail: bowu@scut.edu.cn

四肢钢管混凝土格构柱极限承载力试验研究

陈宝春¹　欧智菁^{1, 2}
（1.福州大学，福建福州350002；2.福建工程学院，福建福州350007）

摘要：进行共计22根四肢钢管混凝土格构柱的极限承载力试验，试验参数为长细比和偏心率。介绍试验过程和试件的破坏形态，对试件的荷载-挠度曲线、极限承载力及组成构件的受力等进行了分析。试验结果表明，格构柱的柱肢以受压为主，缀管受力较小且处于弹性阶段。近载侧柱肢在试件进入非线性后紧箍效应开始发生作用且不断增大。格构柱破坏时有较明显的面内弯曲，属整体破坏。随着长细比和偏心率的增大，构件整体侧向挠度增大、极限承载力降低。长细比和偏心率对极限承载力的影响基本上是独立的，格构柱总体承载力的折减系数可采用分离的偏心率折减系数和长细比折减系数相乘来计算。研究结果表明，偏心率折减系数可采用与单圆管钢管混凝土偏压柱相似的公式计算；长细比折减系数计算中，换算长细比可应采用简化的放大系数法。
关键词：钢管混凝土；格构柱；长细比；偏心率；试验；极限承载力

Experimental study on the ultimate load carrying capacity of four-tube
concrete filled steel tubular laced columns

Chen Baochun¹　Ou Zhijing^{1, 2}
(1.Fuzhou University，Fuzhou 350002，China；
2.Fujian University of Technology，Fuzhou 350007，China)

Abstract: A total of 22 four-tube Concrete Filled Steel Tubular（CFST）laced columns are tested, with the experimental parameters being slenderness ratio and eccentricity. The process of the test and the failure of specimens are presented. The load-deflection curves, ultimate load carrying capacity and behavior of specimen components are analyzed. The test results indicate that compression force is dominant in longitudinal elements, the forces in the lacing tubes are small and the material is in elastic phase. The hoop function of steel tube to the concrete core in longitudinal elements in the load side takes effect and increases after the specimen enter nonlinear phase. The ultimate load carrying capability of specimens decreases with increasing slenderness ratio and eccentricity. The influences of slenderness ratio and eccentricity to ultimate load carrying capability are essentially independent. The global strength reduction of the laced column can be expressed as a product of the dependent reduction factor of slenderness ratio and that of eccentricity. The results indicate that the reduction factor of eccentricity can be calculated by a formula similar to that for a single eccentrically compressed circular CFST column. For the reduction factor of slenderness ratio, equivalent slenderness ratio can be calculated by using a simplified magnified parameter method.
Keywords: concrete-filled steel tube（CFST）; laced column; slenderness ratio; eccentricity; test; ultimate load carrying capacity

E-mail: baochunchen@fzu.edu.cn

正交异性闭口加劲板的承载力分析理论及试验研究

李立峰　邵旭东
(湖南大学，湖南长沙410082)

摘要：加劲板的局部稳定是正交异性扁平钢箱梁结构设计中的一个关键问题，我国桥梁设计规范没有这方面的规定。为了解决正交异性扁平钢箱梁结构中闭口加劲板的稳定极限承载力计算问题，以适应我国目前钢桥应用日益广泛的需要，在总结中外学者研究成果和国内外设计规范的基础上，提出一种计算闭口加劲板稳定承载力的计算理论，该理论计入材料非线性、几何非线性、初始几何缺陷、焊接残余应力等4种不利影响，并对加劲板结构的初始几何缺陷大小的取值以及残余应力分布模式进行讨论。为了验证理论的正确性、把握闭口加劲板结构的屈曲特性，设计3种不同结构布置的6块闭口加劲板结构进行稳定承载力模型试验，得到加劲板的破坏形态、极限荷载大小以及荷载-位移关系曲线。试验结果与理论分析结果吻合较好，这表明该理论可用于对闭口加劲板的极限承载力计算。
关键词：正交异性钢箱梁；闭口加劲板；稳定；承载力；非线性；模型试验

Theoretical study and model test on the capacity of orthotropic U-rib stiffened plates

Li Lifeng　Shao Xudong
(Hunan University，Changsha 410082，China)

Abstract: The local stability of stiffened plates is a key issue in the design of orthotropic steel box girders, which has not yet been included in the specifications of bridge design. A method of calculating the ultimate strength of U-rib stiffened plates is put forward on the basis of research and various design specifications both at home and abroad. Four aspects including material nonlinearity, geometric nonlinearity, initial geometric imperfection and residual stress are taken into consideration. The amplitude of initial geometric imperfection and the distribution pattern of residual stress are also discussed. Model tests for 6 pieces of stiffened plates with different structural arrangements are conducted to verify the proposed method and to understand the buckling characteristics of U-rib stiffened plates. The breaking mode, ultimate load and load-displacement curve are obtained, and the test results agree well with the theorical results.
Keywords: orthotropic steel box girder; U-rib stiffened plate; stability; capacity; nonlinear; model test

E-mail: hdllf@21cn.com

预应力锚索锚固段应力分布影响因素分析

战玉宝¹　毕宣可²　尤春安¹
（1.山东科技大学，山东青岛266510；2.山东科技大学泰安校区，山东泰安271019）

摘要：采用有限元法，研究预应力锚索锚固段应力分布的影响因素。讨论荷载作用下预应力锚索锚固段应力分布规律，分析荷载大小、被加固岩土体性质、锚固段长度、锚固体直径等因素对预应力锚索锚固段应力分布规律的影响。分析表明，预应力锚索锚固段应力分布非常不均匀；岩石越坚硬，锚固段应力分布越集中，岩石越松软，应力分布越均匀；锚固长度达到一定数值时，再增加锚固长度，只能导致锚索材料的浪费，而对承载能力的提高帮助不大；锚固体的直径越小，锚固段应力分布的峰值越大，应力分布越不均匀，锚固体的直径越大，应力的峰值越小，应力分布越均匀；锚固较硬的岩体，宜选用直径较粗锚固长度较短的锚索，而锚固较软的岩土体，宜选用直径较细锚固长度较大的锚索。
关键词：岩土工程；预应力锚索；应力分布；影响因素

Analysis of factors influencing the stress distribution in prestressed cables

Zhan Yubaosup>1　Bi Xuankesup>2　You Chun’ansup>1
(1.Shandong University of Science & Technology，Qingdao 266510，China；
2.Tai’an Campus，Shandong University of Science & Technology，Tai’an 271019，China)

Abstract: Factors influencing the stress distribution in prestressed cables were analyzed by using the finite element method. The distribution of the shear stress in the prestressed cables was discussed and analyzed for the following influencing factors: load, rock and soil property, anchorage length and diameter. The results indicate: the stress distribution in the anchorage section of the prestressed cable is non-uniform; the harder the rock, the more concentrated the stress distribution; the softer the rock, the more uniform the stress distribution; once the anchorage length reaches a certain value, further increase of length has little help to the improvement of bearing capacity; the smaller the diameter of the anchorage body is, the larger the peak stress in the anchorage section with more non-uniform stress distribution; and the larger the diameter of the anchorage body, the smaller the peak stress in the anchorage section with more uniform stress distribution. Shorter cables of larger diameters are better suited for anchoring in harder rock mass while longer anchors of smaller diameters are better suited for anchoring in softer rock mass.
Keywords: geotechnical engineering；prestressed cable；stress distribution；influencing factor

E-mail: zhanyubao@tom.com

条形荷载下加筋土边坡破坏机制的数值模拟

高文华¹　Richard J.Bathurst²
(1.湖南科技大学，湖南湘潭411201；
2.加拿大皇家军事学院（RMC），金斯敦安大略省，ON K7K 7B4)

摘要：为了克服模型的尺寸效用，获得加筋与不加筋边坡在条形荷载下的各种性状参数和边坡的破坏机制，建立用于分析和模拟3个大型室内足尺加筋与不加筋边坡破坏机制的数值计算模型。边坡回填材料采用级配较差的粗砂，土体的非线性弹性响应采用Duncan-Chang双曲线模型E-B模式加以描述，破坏准则采用Mohr-Coulomb屈服准则，并采用与屈服条件不相关联的流动法则。加筋材料采用两节点的弹塑性锚索结构单元进行模拟，并采用无厚度的弹簧-滑动系统来模拟筋土之间的相互作用和相对运动。数值计算采用基于有限差分的连续介质快速拉格朗日分析方法（FLAC），分别对与破坏面位置和形态密切相关的节点位移速度向量、塑性区和剪应变速率分布3个参数进行了计算，获得了3个边坡在条形极限荷载下的双楔体破坏机制和极限承载力，与试验结果吻合较好，验证了模型的可行性。在此基础上，对不同的条形荷载位置及不同填土材料强度下边坡破坏机制进行了数值模拟和分析。研究结果表明，无论加筋与不加筋边坡，当条形荷载位置距坡肩的距离减小时，边坡破坏面形态由双楔体过渡到圆弧形；当填土材料强度降低时，破裂面形态转化为圆弧形或对数螺线形。
关键词：边坡；破坏机制；土工格栅；条形荷载；FLAC

Numerical simulation of failure mechanism for reinforced and
unreinforced slopes under strip footing

Gao Wenhua¹　Richard J.Bathurst²
(1. 1.Hunan University of Science and Technology，Xiangtan 411201，China；
2.Royal Military College of Canada，Kingston，K7K 7B4，Canada)

Abstract: A numerical model is developed to simulate and analyze the failure mechanisms of three instrumented, full-scale, reinforced and unreinforced slopes under a strip footing. The backfill material of slopes is poorly graded sand, and it is modeled as a Duncan-Chang hyperbolic nonlinear elasto-plastic material with Mohr-Coulomb yield criterion and non-associated flow rule. The geogrids are modeled as elasto-plastic two-node cable elements. A spring-slider system without thickness is employed to model the interaction between sand and geogrids. The finite-difference-based Fast Lagrangian Analysis of Continua code, FLAC, is employed in the numerical analysis. The displacement, velocity, plasticity indicator and shear strain rate under strip footing are calculated. The ultimate bearing capacity and the dual-wedge failure mechanism of slopes thus obtained are in good agreement with the test results. On the basis of the above analysis, the failure mechanisms for different strip footing positions and different soil strengths are modeled and analyzed. The results indicate: the dual-wedge failure surface of slopes becomes a circular failure surface when the strip footing is near the crest of the slope; and the failure surface is transformed into a circular or logarithmic spiral when the strength of the soil decreases, whether the slope is reinforced or unreinforced.
Keywords:slope; failure mechanism; geogrid; strip footing; FLAC

E-mail: wenhuagao@163.com

管幕箱涵顶进施工中迎面土压力研究

万　敏¹　白　云²　陈文财³
（1.同济大学，上海200092；2.上海城建集团，上海200032；3.上海大学，上海200072 )

摘要：管幕法是在始发井与接受井之间，利用微型顶管技术在拟建的地下建筑物四周顶入钢管或其他材质的圆管，钢管之间采用锁口连接并注入防水材料而形成水密性地下空间，在此空间内采用开挖或箱涵顶进方案修建地下建筑物的一种新型暗挖技术。管幕箱涵顶进工法是管幕法与箱涵法的结合。上海市中环线虹许路—北虹路地下立交隧道工程是世界上首次在软土地区采用不加固软土方法进行管幕箱涵顶进施工的工程，由于该工程采用常规方法监测箱涵顶进前端迎面土压力非常困难，所以笔者将静力触探探头进行改装，水平固定于网格前端实测端阻力，并采用经典球孔扩张理论推导换算公式，用以计算迎面土压力。通过实测和计算分析，得到迎面土压力在箱涵侧壁和中隔墙附近较大，平均值接近被动土压力等规律。
关键词：管幕法；箱涵顶进；土压力；静力触探

A study on the front earth pressure during box culvert jacking within pipe-roof

Wan Min¹　Bai Yun²　Chen WenCai³
（1.Tongji University，Shanghai 200092，China；2.Shanghai Urban Construction Group,
Shanghai 200032，China；3.Shanghai University，Shanghai 200072，China)

Abstract: Pipe-roof method is an innovative excavation technique. Steel pipes or tubes of other materials are jacked into the soil between the starting shaft and the receiving shaft to form a type of closed underground space, within which the box culvert structure is constructed by jacking. It is the first time in the world that the pipe-roof culvert-box advancing scheme, without reinforcing the saturated soft soil to reduce cost, was adopted in the Shanghai Middle Ring Road subway project, crossing under the intersection of Hongxu Road and Beihong Road. In the project it is difficult to measure the pressure caused by the soil in front of the box culvert jacking if using the conventional method. The front earth pressure was measured by cone resistance of a CPT to the soil in front of the box culvert. Based on the theory of spherical cavity expansion, the conversion formula from cone resistance to earth pressure was introduced to calculate the front earth pressure. According to the calculation and analysis of the measured data, it is concluded that the front earth pressure of a box-culvert is larger than that in other areas and the average value is less than but close to that of passive earth pressure.
Keywords: pipe-roof method; box-culvert jacking method; earth pressure; cone penetration test

E-mail: wmhappy2000123@163.com

秦岭特长公路隧道火灾温度场的数值模拟

于 丽 王明年 郭 春
（西南交通大学，四川成都610031）

摘要：近年来世界各国的隧道火灾事故引发人们对隧道安全问题进行了广泛的探讨，尤其是对长大公路隧道的安全问题越发关注。由于隧道结构的特殊性，使得隧道内发生火灾时的状况格外复杂，其中烟流和温度扩散对隧道安全构成严重威胁，因此对隧道火灾温度场的深入研究将有利于隧道火灾预防及救援工作的展开。为了向秦岭特长公路隧道的防灾预案提供可靠依据，采用计算流体力学方法，利用商业CFD软件STAR-CD对秦岭特长公路隧道火灾温度场进行数值模拟，研究其纵、横断面的温度分布情况，数值模拟提供了较详细的数据和变化特征，为秦岭特长公路隧道的防灾救援提供了技术依据，也对认识其他长大公路隧道火灾灾变机理也有一定的参考作用。
关键词：流体力学；公路隧道；火灾；温度场

Numerical simulation of fire temperature field for the Qingling highway tunnel

Yu Li　Wang Mingnian　Guo Chun
(Southwest Jiaotong University， Chengdu 610031，China)

Abstract: Due to the particularity of tunnel structures, the situation inside a tunnel is very complex when under fire. Smoke flow and heat diffusion threaten tunnel safety. Study of tunnel fire temperature is helpful for fire prevention and rescue. To supply credible guide for fire prevention of the Qingling highway tunnel, numerical fluid mechanics is employed through the use of the commercial CFD software, STARCD, to simulate fire temperature, and distribution of temperature in cross and longitudinal tunnel sections are studied and detailed data provided. The results of numerical simulation agree well with existing model test.
Keywords: fluid mechanics； highway tunnel； fire； temperature field

E-mail: yuli_1026@163.com

隧道开挖条件下被动群桩遮拦效应分析

黄茂松　李　早　杨　超
（同济大学，上海200092）

摘要：隧道开挖不可避免地会引起周围土体位移，从而导致临近建筑物桩基础产生附加变形和内力，降低桩基承载力，引起上部结构失稳甚至破坏。如何分析隧道开挖对邻近群桩的影响成为岩土工程界所关心的问题，为此作者提出隧道开挖对群桩影响的两阶段分析方法：第一阶段采用Loganathan等（1998）提出的解析解计算隧道开挖引起的土体自由位移场；第二阶段基于Winkler地基模型将土体自由位移施加于桩分析桩基的力学反应，同时考虑桩基的遮拦效应分析隧道开挖对群桩的影响。采用三维整体数值分析方法分析隧道开挖对临近群桩的影响，并通过对比验证了简化解析方法的合理性，在此基础上分析隧道开挖条件下被动群桩的遮拦效应，分析表明： （1） 群桩遮拦效应随桩间距增大而减小； （2） 遮拦效应对前排桩影响小于对后排桩的影响，尤其是轴力； （3） 遮拦效应对位移的影响远小于对内力的影响，其中对水平位移的影响很小，可以忽略不计。
关键词：两阶段分析法；数值分析；被动群桩；遮拦效应

Analysis of the shielding effect of a pile group adjacent to tunneling

Huang Maosong　Li Zao　Yang Chao
（Tongji University， Shanghai 200092， China）

Abstract: The unavoidable ground movements caused by tunneling will induce additional displacements and internal forces of adjacent piles, which may have adverse effects on the bearing capacity of pile foundation. A simple analytical two-stage method is introduced for determining the response of a pile group to tunneling. First, the analytical solution proposed by Loganathan et al.(1998)is employed to estimate the free-field ground movement induced by tunneling. At second stage, the pile response is obtained by imposing the free-field ground movement on the piles through the use of Winkler model. The pile group responses to tunneling are obtained by considering the shielding effect of the pile group. A 3-D numerical method is employed to calculate the influence of tunneling on adjacent pile group. The results from numerical analysis are compared with those from a simple analytical method. The shielding effect of a pile group adjacent to tunneling is analyzed by using a simple analytical method.
Keywords: Two-stage method; numerical analysis; passive pile group; shielding effect

E-mail: mshuang@mail.tongji.edu.cn

浅埋暗挖隧道施工性态的数值模拟与分析

王绍君 刘宗仁 陶夏新
（哈尔滨工业大学，黑龙江哈尔滨150090）

摘要：地铁隧道施工中，隧道开挖程序、施作的步骤对隧道稳定性及地表沉降影响显著。北京地铁10号线某标段浅埋单洞双层隧道，是出入口通道与车站中洞、旁边单层侧洞相接的暗挖部分，单、双层转换，初支结构形式和施工都很复杂。目前国内外对单洞双层隧道分析较少，与车站和通道相连接的这种单洞双层隧道比较短，对它的分析往往被忽视。对采用3层6导洞的CRD工法施工的这种浅埋单洞双层隧道的施工性态进行数值模拟，分析该区域隧道施工引起的地表沉降，探索一次性开挖成洞及隧道分步开挖引起的地表沉降槽的变化形态，拱顶沉降及拱顶主应力的变化规律。数值分析表明：施工工序不同使隧道的偏挖引起的沉降槽向未开挖一侧偏移，此过程中地层最大沉降并不发生在隧道中线处，而是完成全部开挖，地层变形稳定后，其累计沉降最大值位于隧道中线处。隧道开挖衬砌完全施作后，地表沉降变化不大，但是后续开挖步引起的结构内力应予以重视，尤其对于中隔壁支撑及拱底衬砌的支护，要及时施作拱底二次衬砌。研究结果为单洞双层隧道分步施工控制地表变形和洞周位移提供参考依据。
关键词：浅埋暗挖隧道；单洞双层；施工性态；数值模拟；地表沉降

Numerical simulation and analysis of construction behavior of shallow tunneling by excavation

Wang Shaojun Liu Zongren Tao Xiaxin
(Harbin institute of technology，Harbin 150090，China)

Abstract: In the construction of subway tunnels, the process of tunnel excavation and construction procedure has a profound influence on the tunnel stability and subsidence of the ground surfaces. In Beijing Metro Line10, one section of the tunnel, connecting between the metro station and a side tunnel, has a single opening transformed from one passage to two. This in turn causes considerable complications in construction and the analyst has very little experience in dealing with such situation. In the present paper, numerical simulation was performed to investigate the construction behavior using a CRD method. The analyses included special features such as the ground subsidence resulting from tunnel construction, different forms of settlement trough caused by one-step or step-by-step tunneling method, settlement of the vault and change of the stress field in the vault. Numerical results indicate that the settlement trough tends to deflect sideway towards unexcavated areas due to different construction schedules. After all the excavation is completed and the ground settlement has become stabilized, the accumulated maximum subsidence occurs at the center line of the tunnel. There is only little movement to ground subsidence after all the liners are in place. However, special attention should be given to the stresses caused by subsequent excavation. In this case, secondary liners must be provided to support the mid-walls and vault bottoms. The study provides a reference to control the ground settlement and convergence of tunnel inner perimeter in contruction of tunnels composed of a single opening with two passages.
Keywords: shallow tunnel by excavation; single cavern and double layer tunnel; construction behavior; numerical simulation; ground subsidence

E-mail: wangshaojun@hit.edu.cn

考虑交叉口特性的疏散交通路线研究

高明霞　贺国光
（天津大学系统工程研究所，天津300072）

摘要：疏散是应急管理中的重要措施，在应急计划中有必要制定合理的疏散路线以确保疏散车辆尽快到达终点。以往有关最佳疏散交通路线的研究没有考虑交叉口延误和通行能力等因素，若疏散路线经过城市内拥挤路段，忽略交叉口的这些特性会导致结果不尽合理。将交叉口分方向延误和通行能力作为节点权重，建立了点权交通网络，通过在点权网络中求解最小费用流来优化事故地点至安全地点的最佳疏散交通路线及相应的疏散流量，设计了一种最小费用路算法求解该点权网络中的最小费用流。最后以一个数值算例说明了方法的应用，并对考虑和忽略交叉口特性２种情况下得出的路线进行了对比。结果表明该方法能很好地兼顾路网特点和疏散路线优化的要求；若执行忽略交叉口特性的疏散路线方案，极易造成交叉口的拥堵，延长车辆的走行时间。
关键词： 疏散路线；交叉口；点权交通网络；最小费用路算法

Optimization of evacuation routes considering movements at intersections

Gao Mingxia　He Guoguang
(Institute of System Engineering，Tianjin University，Tianjin 300072，China)

Abstract: Evacuation plays an important role in emergency management. Efficient tools are needed to produce evacuation route plans that identify routes of evacuation vehicles to minimize the time to evacuate people from affected sources to safety sites. Most research on the optimization of evacuation routes does not explicitly consider intersection movements. However, in congested street networks, turning movement delays traffic and capacity limitations at intersections may be significant, and thus ignoring them may lead to suboptimal or illogical routes. Considering the turning movement at intersections, a special network is constructed with the capacity and delay of intersection movements as the weights. Evacuation routes and the flow assigned to each route considering intersection movements can be obtained by searching the minimum cost flow in such network, with cost representing time. A successive shortest path algorithm is presented to find the minimum cost flow in such network. The validity of the method is demonstrated via a numerical example. The routes obtained for the example, when considering or ignoring intersection movements, are compared and analyzed, which indicates that congestion is quite likely to occur if executing a route plan that ignores movements at intersections.
Keywords: evacuation routes；intersection；network with node-weight；successive shortest path algorithm

E-mail: gaomingxia@eyou.com

交通网络旅行时间可靠度估计

唐小勇　王　炜　程　琳
(东南大学，江苏南京210096）

摘要：为了更精确地估计交通网络路段旅行时间可靠度，借助于Greenshilds速度密度模型和交通流三要素关系模型，假设路段故障率与交通流波动成正比关系而与时间无关，考虑影响路段可靠度３个方面因素：交通流波动、道路条件、出行者心理期望，通过理论推导，得到一个新的路段旅行时间可靠度估计模型。用matlab软件对模型进行模拟，分别得到可靠度与饱和度、道路故障率、出行者心理期望因子之间关系曲线。试验结果与真实情况较为吻合，模型较好地反映了３个因素对路段可靠度的影响。以路段可靠度为基础，计算OD对可靠度，并对其进行敏感性分析，提出路段单元可靠度对于OD对可靠度的敏感性可以归结为独立的两部分：本路径内其他路段影响和平行路径影响。在银川中心城区网络上对可靠度模型进行验证，讨论了其在交通运营管理和路网瓶颈识别中的应用。
关键词：交通网络；旅行时间可靠度；路段可靠度；敏感性分析

Travel time reliability assessment for traffic networks

Tang Xiaoyong　Wang Wei　Cheng Lin
(Southeast University，Nanjing 210096，China)

Abstract: To more precisely measure the reliability of link travel time, a new model is presented based on the assumption that the malfunction intensity of link is directly proportional to the fluctuation of traffic flow but independent of time. The model integrates three main influence factors of link travel time reliability: flow saturation, travelers’expectation and reliability of road condition. The model is theoretically derived from Greenshilds density-speed model and volume-speed-density model, and coded by using matlab. The relationships between link reliability and its three influencing factors are illustrated for different values of parameters. The simulation results are in good agreement with reality. Then reliability of OD(original and destination) pairs is computed by treating the OD sub-network as a system composed of links connecting in series and then in parallel. Through sensitivity analysis of OD reliability, it is found that the influence of link reliability to OD pair reliability could be categorized into two independent aspects: influence of other links within the same route and influence of other parallel routes. The model is tested for the road network of the central district in Yinchuan city，capital of Ningxia province in China, and the results indicate that the proposed model can reasonably estimate the reliability of link.
Keywords: traffic network; travel time reliability; link reliability; sensitivity analysis

E-mail: tangxiaoyong001@163.com

中国承包商国际化程度的一种评价指标体系

卜炜玮　朱宏亮
（清华大学，北京100084）

摘要：现有的企业国际化评价指标体系或因过于一般化不能反映工程承包商的特点，或因过于繁琐不适于大量企业的对比研究。作者提出一种包括海外收入系数、总收入系数、海外收入比、专业分布系数、业务国际化系数、组织国际化系数6项指标的承包商国际化程度评价指标体系，并用其对2006年入选《工程新闻纪录》（ENR）225强国际承包商的中国承包商进行了评价，对结果进行了分析。随后应用粗糙集理论与方法，对评价结果进行知识获取，得出结论：只需海外收入系数和业务国际化系数2个属性指标就可以有效区分评价对象；海外收入比虽然是判断企业国际化程度的重要指标，但对于企业的国际化指数却没有决定性的影响。对于中国承包商来说，增加海外经营收入和拓展业务地区范围是提高企业国际化程度的关键所在。
关键词：承包商；国际化；指标；粗糙集

An evaluation system for the internationalization of Chinese global contractors

Bu Weiwei　Zhu Hongliang
（Tsinghua University，Beijing 100084，China)

Abstract: A comprehensive system was provided to evaluate the degree of Chinese global contractors’internationalization. It includes 6 indicators, Oversea Revenue Coefficient, Overall Revenue Coefficient, Oversea Revenue Ratio, Specialized Field, Business Internationalization Coefficient and Organization Internationalization Coefficient, from which the Index of Internationalization can be obtained. With these indicators, a preliminary analysis is conducted of all the 46 Chinese global contractors listed in the Engineering News Record(ENR)Top 225 International Contractors 2006. Rough Set theory were applied in the process of knowledge acquisition of the result, and two conclusions are reached: only two indicators(Oversea Revenue Coefficient and Business Internationalization Coefficient)are necessary for distinguishing all these contractors; Oversea Revenue Ratio is not so important to the Index of Internationalization as we may usually think. Therefore, increasing oversea revenue and expanding market in different regions are key factors for those Chinese contractors eager to raise their degree of internationalization.
Keywords: contractor; internationalization; indicator; Rough Set

E-mail: buww03@mails.thu.edu.cn

路基土回弹模量应力依赖性分析及预估模型

陈声凯^1,2　凌建明¹　罗志刚¹
（1.同济大学，上海200092；２.上海市公路管理处，上海200063）

摘要：通过室内重复加载三轴试验研究4种常用路基土的回弹特性，分析回弹模量对体应力、侧向应力、偏应力的依赖关系。试验结果表明，回弹模量值是两个应力变量的函数，且当其中一个变量保持不变时，回弹模量值随另一变量呈非线性变化，函数关系应为幂函数形式。在此分析基础上，参考Uzan模型表达式，以偏应力和体应力为变量回归得出相应的路基土回弹模量预估模型，拟合结果良好。模型的建立，有利于更好地理解路基土的回弹特性，并为路基模量设计值的取用与路面结构力学响应计算提供可靠的技术依据。
关键词：路基土；回弹模量；重复加载三轴试验；应力依赖性；预估模型

Stress-dependent characteristics and prediction model of the resilient modulus of subgrade soils

Chen Sheng kai^1,2　Ling Jianming¹　Luo Zhigang¹
(１.Tongji University，Shanghai 200092，China；
２.Shanghai Highway Administration，Shanghai 200063，China )

Abstract: The dynamic resilient modulus of 4 subgrade soils were studied by using repeated loading triaxial test. The relationships between the resilient modulus, bulk stress, confining stress and deviation stress were analyzed. The result demonstrated that the resilient modulus is a function of two stress variables, and that when one stress variable is fixed, the relationship between the resilient modulus and the other stress variable is a power function. A prediction model which involves bulk stress and deviation stress was obtained from a stress-dependent analysis and the Uzan model.
Keywords: subgrade soils; resilient modulus; repeated loading triaxial test; stress-dependent; prediction model

E-mail：Kai13795427456@163.com

桥面沥青铺装层间应力分析简化模型

赵锋军^1,2　李宇峙²　易伟建¹
（1.湖南大学，湖南长沙410082；2.长沙理工大学，湖南长沙410076）

摘要：在分析总结桥面铺装结构承载特性的基础上，提出采用叠层梁作为桥面沥青铺装层间应力计算的简化模型。为避免梁端部层间应力的奇异性，假设钢板和沥青铺装层均满足平衡与变形协调条件，梁端部剪应力分布与梁中部一致，在此基础上推导简支叠层梁层间应力计算公式，最终得到桥面沥青铺装层间应力计算的实用公式，并根据圣维南原理说明了假设边界条件的合理性。利用所得实用公式分别计算分析钢桥面沥青铺装与混凝土桥面沥青铺装的层间应力，分析确定公式使用时的条件与参数取值。通过将公式计算结果与有限元计算结果相对比，验证公式的可用性与参数取值的合理性。通过对比钢桥面沥青铺装与混凝土桥面沥青铺装层间应力计算结果，得到钢桥面沥青铺装对防水黏结层材料具有更高的要求。
关键词：桥面沥青铺装；叠层梁；层间应力；防水黏结层

A simplified model for interlaminar stress analysis of bridge asphalt pavement

Zhao fengjun^1,2　Li yuzhi²　Yi weijian¹
(1.Hunan University，Changsha 410082，China；
2.Changsha University of Science Technology，Changsha 410076，China)

Abstract: Delaminating is one of the main fatigue damage modes of bridge asphalt pavement. Based on generalizing the structure characteristics of bridge asphalt pavement, the laminated beam model is developed as for bridge asphalt pavement. In order to avoid the singularity of interlaminar stress, it is assumed that the conditions of equilibrium and deformation compatibility of steel deck and asphalt pavement are similar. The distributions of shearing stress in the end and in the middle of the beam are consistent with each other, and thereupon, a formula for interlaminar stress in bridge asphalt pavement is derived. The rationale of the assumed boundary conditions is expounded by using the Saint Venant principle. The interlaminar stresses in steel bridge asphalt pavement and concrete bridge asphalt pavement are calculated by using this formula, and the results are in good agreement with those of FEM analysis. It is shown that the requirement on waterproof-bonding layer is stricter in steel bridge pavement than concrete bridge pavement.
Keywords: bridge asphalt pavement；laminated beam；interlaminar stress；waterproof-bonding layer

E-mail：zfj_007@tom.com

三峡工程二期深水围堰工程性状反分析研究

汪明元^1,2　程展林²　包承纲²　李青云²
（1.浙江大学，浙江杭州310027；2.长江科学院，湖北武汉430010）

摘要：三峡工程二期围堰是深水与复杂环境中土石坝工程建设的典范，设计阶段曾进行过大量研究，运行阶段进行了全过程监测，拆除时进行了调查和试验分析，发现围堰的实际性状与原来的研究成果存在一定的差异。在综合分析相关资料的基础上，以防渗墙的应力变形监测成果为基础，采用非线性有限元法对三峡工程二期深水围堰的实际工程性状进行了反分析，对防渗墙与堰体的相互作用采用基于多点约束的接触迭代算法模拟，得到了围堰各填料的参数。研究结果表明：对水下抛填料，应根据抛填的初始密度分层确定其变形参数；水下抛填砂砾石与风化砂对防渗墙的变形影响较大；上游侧堰体与防渗墙脱开的原因在于防渗墙上下游侧水位的升降；防渗墙侧的泥皮决定了接触面的力学特性并可改善墙体的应力状态，应力变形分析应考虑泥皮的影响；基于多点约束的接触算法能准确模拟防渗墙与堰体的相互作用，接触摩擦服从库仑定律；防渗墙顶与墙顶处堰体间发生冲切时，实际情况介于变形体间的接触与完全的未接触两种状态之间。
关键词：三峡工程；二期围堰；反分析；土石坝；防渗墙；风化砂

Back analysis of the stage Ⅱ cofferdam of the Three Gorges Project

Wang Mingyuan^1,2　Cheng Zhanlin²　Bao Chenggang²　Li Qingyun²
(1.Zhejiang University，Hangzhou 310027，China；
2.Yangze River Scientific Research Institute，Wuhan 430010，China)

Abstract: The stage Ⅱ cofferdam of the Three Gorges Project（TGP）is a paradigm of earth dams in deep water and complicated conditions. The key problems of the design plans have been studied, and field survey and monitoring have been performed in the service period. The test and investigation were implemented after the cofferdam was removed. Behavior of the cofferdam is back analyzed by using nonlinear FEM, based on the actual stress and deformation of the cut-off wall. The contact algorithm of multi-nodes restriction is adopted to model the interaction between the cofferdam and the cut-off wall. Parameters of the filling material are obtained based on the back analysis. The results indicates: properties of the throw-in material under water relies on its initial density; the throw-in gravel and weathered sands under water have obvious influence on the deformation of the cut-off wall; the water level rise upstream and drop downstream causes that separation of the cut-off from the filling material upstream. Moreover, the engineering characteristics of the interface between the fill and the cut-off wall are determined by parameters of the mud layer, therefore, the effect of the mud layer must be modeled in the stress and deformation analysis.
Keywords: Three Gorges Project（TGP）; stage Ⅱ cofferdam; back analysis; earth dam; cut-off wall; weathered sands

E-mail：wmy_90@163.com