Research on the Stress and Deformation Characteristics of Vertical Shafts in Loess Paleosol Stratum
Research purposes:In order to accurately investigate the deformation characteristics of deep vertical shafts under loess paleosol geological conditions,a 53.5 m deep circular shaft was used as a support project to systematically monitor lateral soil pressure,deformation,structural internal force,and vertical and horizontal deformation of surrounding strata.Research conclusions:(1)During the excavation process of a deep vertical shaft,the overall deformation of the shaft wall structure is relatively small,with horizontal deformation"extruding first and then converging"and vertical deformation"sinking first and then uplifting".After the excavation of the vertical shaft reaches the design depth,it enters the stable stage after 15～30 days.(2)There are inflection points in the depth direction for the convergence deformation of the shaft wall,lateral soil pressure,and structural internal force,all of which occur at a depth of 0.5～0.7 times the design depth of the shaft.There is a good corresponding relationship between the stress deformation index and the soil properties.In the range of paleosol,the shaft wall deformation and soil pressure significantly decreased,about 40%～50%of the loess layer at the adjacent depth.The existence of paleosol significantly restricted the development of shaft deformation and soil pressure.(3)The lateral soil pressure of deep shaft lining structure in loess paleosol stratum is significantly different from the static soil pressure and active earth pressure.Within the depth range of 0～12 m,the lateral earth pressure is close to the static soil pressure;Within the range of 12～28 m,the lateral soil pressure is close to the active soil pressure;Within the range of 28～48 m,the lateral soil pressure is approximately 35%～65%of the active soil pressure.(4)The research result can provide a reference basis for calculating soil pressure and supporting structure design of vertical shafts under such geological conditions.
deep vertical shaftloess-paleosol structure profileon-site monitoringstress and deformation characteristics
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