Deformation Analysis Of Soil Nailing Supporting Foundation Pit Based On ABAQUS Secondary Development

The depth,difficulty and breadth of foundation pit engineering are increasing,the potential risk is also increasing,and the monitoring requirements for the construction process of foundation pit are gradually improved.With the development of finite element software such as ABAQUS and deep learning technology,simulation prediction has become an important method of engineering safety control.However,the modeling process of ABAQUS itself is more complex,which leads to the mismatch between the actual ability of the monitoring personnel and the operation requirements of the software.In the aspect of reducing the operation threshold of foundation pit deformation analysis through the secondary development of ABAQUS,a new research topic is proposed.Based on the foundation pit project of Guobinfu in Kaifeng City,the data of some monitoring points were selected and the time curve was drawn,and the soil deformation was summarized during excavation.The deformation was analyzed using two-dimensional numerical simulation of ABAQUS,and then the monitoring results and numerical simulation results were compared,and the factors that might affect the difference in data were analyzed.Based on python language,the scripting language of the earth nail support structure is written,and the GUI program is created using the RSG dialog constructor to achieve the goal of controlling the safety of the pit project.The main research content and results are as follows:(1)Three monitoring points at the top of slope and four monitoring points of surface subsidence are selected and time history curves are drawn respectively.The horizontal and vertical displacement of the slope top increases uniformly during excavation,and the change rate is slightly slowed down after the support structure is set.The settlement value of ground surface increases uniformly and the settlement value of overload area is larger than that of other areas.The deformation values will increase with the excavation of the foundation pit.After the support is completed,the data are basically stable.(2)The two-dimensional numerical simulation of typical section is carried out by ABAQUS.The comparison between the simulation results and the monitoring results shows that the development trend of the two data in the excavation process is basically the same,and the numerical value of the simulation results is slightly smaller than the monitoring data.Through the numerical simulation,it is found that the horizontal displacement increases along the slope depth;the vertical displacement of the slope top develops downward as a whole;the surface settlement around the foundation pit is larger in the overload area,and the settlement groove is formed in the area 2.0 ～ 10.0m away from the pit edge in the model.(3)Based on Python language,the script of two-dimensional simulation of soil nailing supporting foundation pit is compiled.By directly modifying the key parameters such as size,soil layer parameters,soil nailing parameters and concrete surface layer,the rapid modeling and calculation in batch is realized.And the post-processing instructions on the same screen are compiled.The horizontal displacement nephogram,vertical displacement nephogram,surface settlement curve and slope horizontal displacement curve are displayed on the operation interface.Using the built-in RSG dialog box builder of ABAQUS,the input boxes of various data are connected with the parameters in the script,and the GUI interactive interface is created.The modeling,calculation and analysis are integrated to avoid the mistakes of conventional operation.The parametric modeling can be realized only by changing the parameters,which simplifies the modeling procedure,and provides the basis for the application of ABAQUS numerical simulation in deformation analysis and early warning of foundation pit engineering.