Research On The Circumferential Stiffness And Mechanical Behavior Of Large Diaphragm Wall

Diaphragm wall is widely used in bridge engineering.Its performance affects the safety and economy of the foundation pit.At present,there are still many problems in the application of the diaphragm wall,such as slot joints,the influence of construction error on the circular stiffness of the wall because of empirical value,and the only calculationby finite element method.Moreover,the mechanical property of the diaphragm wall is not clear currently.This paper investigates the design method and mechanical property of the diaphragm wall of the long-span suspension bridge,which has obvious engineering practical significance and theoretical research value.Based on investigation on the available researches,the influence of construction error and joint mud cakeon circumferential stiffness of ground connection wall is studied systematically by using the experimental research,engineering instance data statistics and theoretical method.Furthermore,the calculation of the forces around the annular ground wall is obtained based on the energy method.The practical design solution for the gourd-shaped ground wall is then established.The main conclusions of this study are drawn as follows:(1)The test was carried out to investigate the influence of groove joint mud skin on the circumferential stiffness of the wall.The stress-strain curve of the joints was obtained through the test.An analytical model of three broken lines was proposed and a formula for calculating the correction coefficient of toroidal diaphragm wall's toroidal stiffness was derived.At the same time,considering the nonlinear stiffness effect of the joint clay skin,two calculation methods of the modified coefficient method and the series spring method,for the girder with vertical elastic foundation were proposed.(2)The influence of axial errors,thickness errors and inclination errors on the toroidal stiffness is studied within the allowable range of the construction specification,analyzed the influence of construction errors on the distribution law of the girth error,and found that the thickness errors and inclination errors obey the normal distribution.In order to control the influence of construction error on the connecting wall,the quality requirements of construction error control was put forward.It is suggested that construction error has little effect on the annular stiffness under the current construction technology level.(3)Based on the three-dimensional governing equation of the column shell under axial symmetric load,the method of deformation potential energy of the wall,lining elastic potential energy,horizontal soil pressure potential energy and elastic potential energy of the reaction force of the horizontal foundation of the annular underground continuous wall was obatained.In the light of the solution results,the functional solution of the wall displacement was derived.The Fourier series expression of the displacement trial function,combined with the boundary conditions,the variational principle to total differential of the undetermined parameters of trial function,the undetermined parameters of equations was adopted.Finally,the solution of the energy method to calculate the annular deformation of the diaphragm wall was obtained.It provides a simple and effective method for calculating the force of the circular underground diaphragm wall.(4)The theoretical method of mechanical properties of the gourd-shaped ground wall was established.The deformation and mechanical behavior of unlined,lined and complicated engineering hoist type ground wall were investigated in terms of the parametric analysis.The controlling of the horizontal displacement of the y-slot segment of the gourd-shaped earth connecting wall was suggested.Revealed the overall deformation law of the gourd-shaped ground connection wall.Moreover,the deformation and stress distribution of the middle partition wall,wall and lining were analyzed.The design method of the gourd-shaped ground connection wall were established,which providing a solid theoretical guarantee for the hang-rui high-speed dongting lake bridge anchorage foundation.