Research On Deformation Law And Control Technology Of Deep Foundation Pit Support Structure Of Open-cut Tunnel In Soft Soil

With the rapid development of the city and the proposal of the national new and old kinetic energy conversion strategy,as well as the demolition of the old city and the expansion of the new city,the above-ground space resources have shrunk sharply,which has led to the rapid development of underground space construction.However,with deeper and larger underground foundation pits,as well as numerous water-rich soft soil qualities and complex engineering surrounding environment,the construction of soft soil deep foundation pits is becoming more and more difficult,which has caused many soft soils across China Accident of deep foundation pit instability and collapse.Therefore,this paper takes the Jinan Yellow River Tunnel as the engineering background,based on the combination of real-time monitoring and measurement data and numerical simulation software,the deformation and optimization of the structural excursion of the deep foundation pit of the soft soil open-cut tunnel during excavation and support In-depth research has been conducted on other issues.The content of this article is mainly as follows:(1)Based on the domestic and foreign soft soil deep foundation pit deformation references,the soft soil deep foundation pit support structure combined with internal support system support characteristics and deformation instability laws,analysis of the enclosure structure deformation mechanism,soil unloading layer deformation mechanism,foundation pit The surrounding subsidence mechanism,the deformation mechanism of the internal support instability,and the deformation mechanism of the bottom of the foundation pit,theoretically determine the factors affecting the deformation of the deep foundation pit in soft soil.(2)On-site monitoring measurement and theoretical calculation based on the deep foundation pit project of the open-cut yellow soft soil tunnel in Jinan,to study the law of displacement of the enclosing structure displacement,support internal force and surface settlement around the deep foundation pit,according to the real-time monitoring and measurement data on site Based on the theoretical calculation data of the deformation of the foundation pit,the time-varying curve of the displacement of the deep foundation pit is established,and the influencing factors of the deformation of the deep foundation pit in soft soil excavation are determined from the monitoring measurement.(3)The PLAXIS software was used to perform numerical simulation calculations on the deep foundation pits of open-cut soft tunnels in soft soil.To determine the influencing factors of deep excavation deformation in soft soil from the simulation calculation.(4)Based on the deformation law of deep foundation pits in soft soil open-cut tunnels,the instability deformation characteristics and failure forms of deep foundation pits in soft soil open-cut tunnels are analyzed,and soft soil open-cut tunnel excavation,steel support internal force changes,support structure parameter settings and surrounding surface Settlement and other control measures,through the test section to verify the deformation measures,to establish a deep excavation deformation control optimization displacement comparison curve,played a guiding role in the safe construction of deep foundation pits similar to soft soil.