| At present,with the gradual acceleration of China’s modernization process,people put forward higher requirements for daily life,and the development and utilization of underground space began to receive extensive attention.As a common construction method in underground engineering construction,pipe jacking method also began to get more applications.The pipe jacking method will disturb the soil during the construction process,resulting in the deformation of the nearby soil.When the degree is too large,it will lead to the collapse of the soil,which will pose a serious threat to the safety of the surrounding buildings and personnel.Therefore,it is necessary to reasonably predict,timely monitor and control the soil deformation caused by construction,in order to minimize the harm caused by construction.Based on the existing research,this paper uses the elastic theory and the establishment of MIDAS/GTS NX finite element model to study the law of soil deformation caused by steel pipe jacking construction in soft soil area,and analyzes the influence on surrounding buildings on the basis of the original model.At the same time,it changes the pipe jacking thrust,grouting pressure and soil elastic modulus to simulate the influence of different parameters on soil deformation.The main research results of this paper are as follows:(1)Based on the analysis of field monitoring data,the transverse and longitudinal deformation laws of soil during pipe jacking construction are preliminarily obtained.There is the maximum settlement of the transverse section directly above the pipe jacking axis,which gradually decreases symmetrically to both sides and finally tends to zero;The soil in front of the longitudinal excavation surface heaves and then settles,and the soil at and behind the excavation surface continues to settle.The change trend is to increase first and then decrease,and finally tend to be stable.(2)Combined with the stress characteristics of pipe jacking,the Mindlin elastic theory formula is deformed and integrated,and the soil deformation value under the combined action of jacking force and friction is calculated;Combined with the soil properties and relevant parameters,the sagaseta theoretical formula is modified to calculate the soil deformation value under the influence of soil loss,and the theoretical calculation value is superimposed and compared with the monitoring data value.It is concluded that the modified formula in this paper is closer to the measured data,which verifies the accuracy of the formula and provides a better elastic theoretical calculation method for the study of soil settlement in soft soil area.(3)By establishing the finite element calculation model of steel pipe jacking construction in soft soil area,the law of soil deformation is studied,the influence of pipe j acking construction on buildings is analyzed,and it is concluded that the buildings will tilt to the construction side.The relevant parameters such as jacking force,grouting pressure and elastic modulus are changed respectively to obtain the law of soil deformation under different parameters,which provides a good numerical simulation calculation method for studying the soil settlement caused by pipe jacking construction and a feasible idea for controlling soil settlement.(4)The monitoring data,theoretical data and simulation data are compared,and the causes of the error between the data are analyzed.At the same time,the application scope of the correction formula and numerical simulation is further analyzed,and the application scope of the two in theory is discussed. |
