Research On Force And Deformation Regularity Of Pile-anchor Supporting System In Deep Foundation Pit At Loess Area

Based on one deep foundation pit engineering at Xi·an, monitored the displacement andinternal force of pile-anchor supporting system at filed. According to the monitoring data, thefoundation pit deformation regularity and pile-anchor mechanics of pile-anchor supportingsystem was researched, back analyzed m·s values of different soil layers based on measuredvalues of support pile horizontal displacement and anchor stress of deep foundation pit pile-anchor supporting system, and then checked the deformation and stress of follow-up workingconditions. Results showed that:Deep foundation pit pile-anchor supporting system at loess area had obvious spatial effect,the most unfavorable section appeared at midpoint of foundation pit side wall, monitoringshould be enhanced in the process of practical monitoring.Based on the deep horizontaldisplacement curve of supporting pile, the paper analyzed synergistic reaction mechanism,researched the deformation compatibility of pile-anchor cooperative work, analyzeddeformation distribution and change law of supporting pile, found that there is a certaindifference between the pile deformation and soil behind the pile.Based on measured value ofpile steel stressometer, the paper analyzed the stress characteristic of support pile duringconstruction period, researched the mutual transformation and pile bending moment changelaw of compressive region and tensile region steel.Contrasted the value range and proposed value of different specifications, back analyzedvalue m based on measured values of support pile horizontal displacement and anchor stress,based on elastic foundation beam method and used static equilibrium to gain values of m ofdifferent soil layer.Analyzed the value law of m at loess area, combined with numericalcalculation of LiZheng and Midas, a good consistency was gained of3methods, and tested thecorrectness of the back analysis method adopted by the paper, analyzed the stress and deformation law of follow-up project after excavation of foundation pit based on the aboveconclusions, provided relatively correctly theoretical basis for design and deformation controlof later period foundation pit excavation.