2013 volumne 34卷 Issue 05
FENGHul,GAO Dan.yin91,LIUGuo-bin2,MA Xian—fen92
Abstract: Though simulating the excaVation process and stability fhilure of soft clay excavation whose depth was24m bycomplex geotechnical centrifuge,the stability factors,failure characteristics and symptoms were researched.Resultsdisplayedthat the embedded role on controlling the”skining”defb瑚ationwasvery favorable,also the case fbr excaVation stabilitywhen thewaUtoeinserted in hardpan,but whenwall toe reacheda cenain depth,the innuence wasunapparent as the insert depthincreasing.Forthe typical soft clay in Shanghai,critical insertion depthratio of retaining wall is 0.7.The failure symptomswere as follows:(1)The skirting deformation ofretaining wallwasobVious and its quantity valueis about 1/3 ofthemaximumhorizontal displacement ofthe wall.(2)Themasstransversal cracks arise whenthe surfacesubsidenceoutsideof excavation reached 1.38%日(日一excaVation depth).(3)The upheaval of bottom increases rapidly,the value reached 3.1~3.8%日,and near the retaining wall greater than the central.(4)Pit soilwasin the passive earth pres— sure limit state.The destruction slip surface characteristics were obtained byanalyzing failure phenomena.
LIN Hong-yu
Abstract: Pushovertheory has not only been widely used in elastic seismic analysis of the stlllcture,but also can accurately describe ultimate bearing capacity andfailure ofweak point of the stnIcture.According to the relationship betweenmoment—curvature of conerete filled steel tubular membersbased on the unified theory,the moment-rotation relationship in elastic-plastic state is deduced,and the calculation method of】Ⅵhinge and PMMhinge properties are put for’ward.Basedon the test results ofsimply—supported girder withconcrete filled steel tubulart11lss,the feasibility of proposed practical calculation method is verified.The comparison results showthat the calculation method to dete瑚ine plastic hinge properties of concrete filled steel tubularmembers is reasonable,and the analysis onthe ultimate bearing capacity of CFSTTrussGirder is credible,which pro— vides an ef耗ctive theoretical basis and research methods to grasp the large steel—concrete composite truss b而dge in elastic—plastic stage static anddynamic pe矗.o珊ance.
ZHANGJun,SHENJun—min,NIU Xi·rong
Abstract: Geogridcanimprove the tensile strength,shearstrength andoVemll stabilitysignificantly when it is used as reinforcementfor ground.Basedonthe discreteelementmethod software PFC2D,anumericalmodel is established to studythegeogrid reinforced soil.Compared with unreinforced soil,thefoUowing studies are ped.onned:the settlement of fbundation and the lateml and Vertical displacement distribution of soil with depth.Then,aparametric studyis carried outto investigate the bearingcapacity of fbundationandthe select— ed innuencing factors consist of the reinforced length,reinforced depth andthe number of reinforced layerS.Theresults show that the geogrid can reduce the foundation senlementandimprove tlle bearing capacity.It can restrict the ground horizontal and vertical displacement efkctiVely.The optimal pammeters of reinforced lengtII,reinforced depth andreinforced layers are 3曰、0.25曰and2 1ayers respectiVely.
LIU Yuan—wenl,LIU Yun—pen92
Abstract: The compatibility of mechanical properties betweencement and asphalt mortar and repair materials wasstudied by the fbur point bending method.With the help of finite element model,the eH.ect of difkrence in modulus of substrate mortar and repair mortar on the stress and strain distribution of composite sample was studied.Resultsindicated that difference in modulusof substrate monarandrepair mortardecided the loading transfer efficiency and failure mode,which mainly innuenced compatibility of mechanical properties.Accord.ing to the serVice state of CAM,fourpoint bending fatigue test wasemployed to identify the compatibility be.tweenCAMand repair mate“a1.
OU Yao.wenl一,ZHOUChao.yang
Abstract: To assess the 10adingquality of bridges,it is necessary to establish FEM,static loadingexperiment wasdesigned.Stress andstrain parameters such as themaximum horizontal thmst of arch feet(condition 1),the boom axial force(condition2),the b唔gest negatiVe momentof arch feet(condition3),themos卜positiVe bending moment of the main arch ring (condition 4) and longitudinal beam (condition 5) under diff色rent working conditionswere calculated by ANSYS;Modal and dynamicdenection were calculated by Midas.As an example,in the 16thacross,the surveyed vibrationf}equency of the bridge is 12%at aVerage higher than theoretical calculationone,namely the dynamicloading stiffness can’tmeet the design requirements.However,the reinforcementandthe maintenancemustbe put forwardinto.Threekinds ofmethodswerecompared at constmction dimculty,emciency.This mean can be used in similarlong-span bridges both home and abroad for testing and repai“ng reinforcement.
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