Calculation On Bearing Capacity Of CFST Column Stiffened With PBL Under Axial Load

With the rise of the large-scale subway, tunnel and high-rise building, our countryappeared the foundation pit engineering more and more. The foundation pit engineeringinvolves geotechnical and structural engineering, in most cases, and belongs to a temporaryproject, the safety of foundation pit engineering has become the focus of attention in thedesign and construction of foundation pit. For the deep foundation pit of subway and high-risebuilding, China has accumulated calculation method for engineering design experience morerich and relatively mature structure, design and applied to the foundation pit engineering ofhighway tunnel. However, the highway tunnel excavation depth of foundation pit is mostlybelow13meters, a subway and high-rise building foundation is much more shallow, only torely on previous experience in engineering design is conservative, one-sided. In this paper,focusing on features of foundation pit engineering of highway tunnel structure, calculation ofthe structure commonly used in engineering and single row pile, steel sheet pile anddiaphragm wall support, its proven at different excavation depth and different geologicalconditions of the supporting structure of the work performance, in order to e nrich theexcavation of highway tunnel excavation engineering design experience, effectively improvethe construction technology.First of all, to study for foundation pit engineering of highway tunnel support structuredesign and analysis, including the calculation method of failure mode, the supportingstructure of the supporting structure of the basic assumptions and provide the research basis,numerical simulation for excavation.Secondly, according to the calculation principle of foundation pit supporting structure,establish the finite element model, the calculation of retaining structure of deep excavationprocess of the internal force and displacement are discussed, the geological conditions, thelateral support spacing, transverse strut channel number, slope height and the influence on thesupporting structure of the shadow, based on project needs, is improved to shorten theconstruction period of the construction process.Finally, the excavation depth maximum digging tunnel primary support scheme thatpump of single row pile and multi lateral bracing scheme is improved, and put forward a new kind of supporting scheme--the steel sheet pile prefabrication and Shuangpin I-steel asoblique supporting scheme, construction speed, mechanization degree is high, and thestructure calculation.In conclusion, this study found that: the single row piles supporting structure stability isaffected by the lateral support arrangement and pile embedded depth effect more obvious,continuous wall supporting structure stability by the embedded depth of the more obviouseffects, but by the change of the distance between the lateral support is relatively small; andput forward the typical construction process improvement. Pumping station foundation pitsupporting scheme, structure internal force value is basically the same with the original designscheme, in the process of excavation horizontal displacement is small, influence on theground settlement around deep excavation and building of small, due to the cancellation of thepost, to ensure sufficient construction machinery and the main structure of artificial reinforcedbanding operation space, is conducive to shorten the construction period.