Finite Element Analysis And Comparison Of Supporting Structures Of Different Rows Of Piles In Deep Foundation Pits Based On ABAQUS

In our country,the theoretical research on excavation and support of various types of foundation pits lags behind engineering practice.At the same time,due to the lack of engineering experience,the construction team is limited,the support research is not perfect in theory and the construction management level is limited.As a result,many foundation pit engineering accidents have occurred in my country in recent years.Therefore,it is necessary to strengthen the theoretical research on foundation pit excavation and support.Based on the "nanjing G98 JML plot foundation pit supporting project",the city project as the background,through selecting single cantilever piles,pile in supporting type and three different pile with double-row piles supporting form as the research object,using the finite element analysis software of the three kinds of different pile supporting form modeling analysis,and through the control variable method,studied the change of some important parameters for the effects of the foundation pit supporting engineering draws the following conclusion:(1)Through the monitoring and analysis of the horizontal displacement and settlement of the foundation pit,it is proved that the supporting structure system of "bored pile+steel support" is reasonable and feasible.Compared with the actual monitoring data,the variation curves of pile horizontal displacement and ground settlement are more consistent,which verifies the feasibility of the finite element software ABAQUS simulation.(2)The structural deformation index of the internal supporting pile row is much smaller than that of other supporting structures.The internal support can significantly adj ust the stress of the pile body and effectively limit the deformation of the pile body.For the deep excavation of foundation pit and complicated geological conditions,the internal supporting row pile supporting structure should be preferred.Cantilever single row pile support structure is only suitable for shallow foundation pit and better soil foundation pit.If double row pile support structure is applied to deep foundation pit,it still needs to be combined-with other supporting systems.(3)When the spacing of piles is small,it has good integrity.Excessive increase of the row spacing of double row piles will gradually make the double row pile support structure no longer have the overall characteristics of portal frame system,and the deformation of front and rear row piles is quite different.In engineering,the row spacing of double row piles is of great significance to the supporting effect of deep foundation pit,and the row spacing of double row piles should be carefully considered.(4)In the internal supporting row pile supporting structure,increasing the stiffness of the internal support can improve the effect of the foundation pit support engineering to some extent.Excessive increase of the stiffness of the internal support is not reliable for improving the effect of the foundation pit support engineering.Changing the position of the internal support will have a greater impact on the internal force of the supporting structure,while the deformation of the foundation pit support engineering is relatively small.