Segmented Support of the Ultra-deep Bedrock Foundation Excavation and Anti-floating Control Technology of Bottom Plate
The ultra-deep bedrock foundation excavation has the characteristics of diverse rock layers,complex failure modes,and abundant fissure water.The depth of the ultra-deep bedrock foundation excavation of the south extension project of Qingdao International Academician Research Institute is 32.2 meters.The foundation excavation strata from top to bottom are composed of plain fill soil,silty clay,and strong,medium,and slightly weathered granite.The two support forms with cast-in-place pile+anchor rod and steel pipe pile+anchor rod were designed for the moderately weathered granite area.Using finite element software ABAQUS to simulate and analyze the difference in lateral stiffness between two types of support forms.Based on the analysis results,combined support scheme of composite soil nail walls,cast-in-place piles+anchor rods,and steel pipe piles+anchor rods was adopted for the on-site foundation excavation support.Considering the influence of rock fissure water,a combination of active and passive anti-floating scheme was designed for the structural bottom plate.The active anti-floating measures adopt the permanent drainage system when the fertilizer tank is backfilled,while the passive anti-floating measures adopt traditional anti-pull anchor rods,the effect is good.
foundation excavationultra-deep bedrockfissure watercombined supportsanti-floatingfinite element analysis