Abstract
Based on a deep excavation engineering in Qingdao, which is one of the largest or deepest soil-rock combination excavations in China, the design parameters and calculation results are given for excavation retaining and protection. The excavation on-site test data are provided, including the anchor axial force and pile top displacement, and a comprehensive analysis is carried out. Using numerical simulation, the distribution of anchor axial force is analyzed under different working conditions, as same as pile body deformation and slope body displacement are analyzed. Retaining and protection structure can be calculated in four stages by the elastic foundation beam method. Results: when the lower rock mass is calculated as soil by equivalent internal friction angle, the retaining and protection structure design parameters deviate from the actual needs with working conditions. The ratio of tested and designed axial force of anchor in soil layer is generally greater than the ratio in rock layer. Whether above the soil-rock interface or the pit base, the measured horizontal composite force of anchors is between the calculated active earth pressure and the static earth pressure. Anchorage section length is recommended 2.0 m in the medium or slightly weathered rock.
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Acknowledgments
This work was supported by China Academy of Building Research theoretical analysis research fund projects “Research on internal support technology of assembled large-span excavation” (No. 20141602330730035) and company’s self-financed research fund projects of CABR Foundation Engineering Co., Ltd. (20211602340730003).
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Zhang, W., Heng, C., Xu, C. et al. Research on Support Technology of a Soil-Rock Combination Deep Excavation in Qingdao. KSCE J Civ Eng (2024). https://doi.org/10.1007/s12205-024-2199-5
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DOI: https://doi.org/10.1007/s12205-024-2199-5