Mechanical Characteristics Analysis Of Supporting Structure In Deep Foundation Pit Under The Condition Of Seepage

In the construction of riverside foundation pit, the river radial seepage caused byrainstorm will produce significant influence on the stability of foundation pit andsupporting structure. But currently, under the condition that water level suddenly rises, theresearch for influence of radial seepage on foundation pit character is rare. Therefore,studying the mechanical characteristics of riverside foundation pit and supportingstructure under seepage have important theoretical values and engineering significances.The main research are as follows:The paper takes the typical riverside deep foundation pit engineering in Qinhuangdaoas research object, based on the finite-difference universal calculation software FLAC3D,compiling calculation command, proceeding seepage analysis for dewatering infoundation pit engineering, and numerically simulating pile-anchor supporting system.Through dynamic process analysis for the stress and seepage field coupling, water levelrising effect on the mechanical characteristics of supporting structure in riversidefoundation pit engineering is discussed.The results of numerical analysis show that, at the initial water level, the effect ofseepage on soil horizontal stress and shear stress is less, but after water level rising, soilhorizontal stress at pit bottom significantly increases, stress concentration is outstanding atthe cornor of pit wall, while the largest value of soil shear stress appears at the bottom feetunder the excavation surface. The soil horizontal and vertical displacement aremonotonely increasing when the water level rises. When the water level rises for0.5m,pile moment and shear force have large increases, then get slowdowns in growth. To theupper and lower anchors, when water level rises for0.5m, axial force of free andanchorage section increase significantly. But when the water level rises from0.5m to2.0m,the increase is small. When water level rises for0.5m, Safety coefficient has a greatreduce. It has a linear relation decrease with small velocity afterwards.Comparing the numerical analysis results and monitoring alarm value, we can seethat, uplift of pit bottom and axial force of upper anchor reach the alarm value at the initiallevel, while the horizontal stress of soil, displacement of slope top, pile moment, and axial force of lower anchor reach it when the water level rises for0.5m. The influence of soilhorizontal displacement and pile-anchor supporting system on the stability of foundationpit is largest, which needs to focus on monitoring and prevention.The results of the study reveal that the seepage has laws on the deep foundation pitsoil and supporting structure, which provides theoretical guidance and technical supportfor engineering design, ensures the safety of riverside foundation pit engineering.