Research and Analysis of Steel Pipe Pile Cofferdam Structure Under Unbalanced Force Environment
Taking the P3 pier of the main bridge of the reconstruction and expansion project from Qihe to Jinan section of the Beijing-Taipei Expressway as the research background,the deep foundation excavation is located on the bank of the Yellow River.It has such characteristics as large backwater erosion in the downstream,being very close to the existing pier foundation,and bearing unbalanced water and soil pressure.The construction of cofferdams is difficult,which is likely to lead to the occurrence of safety problems such as excessive deformation of adjacent bridges and cofferdams.In view of the engineering example,combined with the characteristics of unbalanced force,the mechanism of steel pipe pile cofferdam support is explored.Through the finite element modeling analysis of the engineering example,the deformation and strength of the steel pipe pile cofferdam and the supporting structure are analyzed,and the influence of the adjacent existing bridge settlement is further analyzed.The finite element calculation results are compared with the actual monitoring data to verify the rationality of the finite element model.The results show that the deformation of the steel pipe pile cofferdam increases gradually with construction.The deformation is mainly concentrated at the water-soil boundary,and the deformation of the downstream face is greater than that of the upstream face.The maximum deformation is presented in the fifth analysis step(construction pile cap structure stage),and the deformation value is 30.40mm,which is located on the short side of the water surface.The support structure has obvious uneven stress on the left and right sides of the long side,especially in the second analysis step(the stage of installing the upper support structure).The maximum stress occurs in the fourth analysis step(the stage of soil excavation to the bottom of the foundation excavation),and the strength of the most unfavorable section is calculated to be 121.47MPa＜215MPa,which meets the requirements.The maximum settlement value and maximum inclination of the adjacent existing bridge meet the requirements of the specification.
foundation excavationsupportssteel pipe pilescofferdamfinite element analysisunbalanced forcedeformation
万方数据
维普
