Research On Mechanical Properties And Retaining Effect Of Circular Diaphragm Wall

The research object of the thesis is the circular diaphragm wall which is theenclosure structure of Wuhan Parrot Cay Yangtze River Bridge’s north anchorfoundation engineering. The circular diaphragm wall is economic applicable anduniform stress, it has obvious advantages to ensure the safety of open caisson sinkingand reduce the impact of construction on the surrounding environment. By using thefinite element analysis software MIDAS-GTS to analysis the circular diaphragm wall,during the simulation, we select13key construction stages to make a systematicanalysis of the stress and strain of circular diaphragm wall. Comparison of calculatedand measured values indicates that the finite element model design used in this paperreasonably calculated correctly which can provide a numerical basis for the constructionprocess.For comprehensive analysis of retaining effect of circular diaphragm wall, thispaper pointed to establish three kind of simulation model: without the circulardiaphragm wall model, different thickness with the same depth model, different depthwith the same thickness model, which can take a systematic and comprehensive analysisof the retailing effect of the circular diaphragm wall under the same calculationconditions.The main results are as follows:(1) In the process of open caisson sinking, the calculation results show thecircular diaphragm wall stress is uniform, does not exist the phenomenon of stressconcentration;(2) The displacement of the top side wall gradually growth outward that is limited andcontrollable.(3) Comparing calculation values and the measured values of the settlement at themeasuring points, The error value between5%~15%and mainly in the range ofallowable in engineering, the model design is reasonable and reliable.(4) According to the research on retaining effect of circular diaphragm wall, if do not setthe wall, the measuring point on calculating settlement value are5to10times largerthan the measured settlement value; when changing wall thickness separately, thesettlement at the measuring point is not significant; when change alone the walldepth conditions, the settlement value is decrease with the increase of the wall depth,but the variation is little and the decrease trend is converge.