| In some northern cold area of foundation pit engineering,in some special weatherand engineering conditions, the freeze function to soil swelling, influence of frost heaveforce on the stability of supporting structure generation.The freeze function makes thesoil pressure of foundation pit wall in certain range effect becomes smaller, the dominantrole of frost heave effect.In the spring thaw season, if the support structure after soilwater content is larger, if the water can not be discharged in time, will be on supportingstructure have great soil pressure,at this point, the main load supporting structure for thesoil on the soil pressure of supporting structure of foundation pit deformation, will makea significant increase, caused by foundation pit supporting structure destruction andcollapse accident.In order to study the overwintering of foundation pit anchor supporting structure ofthe force and displacement variation of Baotou, according to a wintering foundation pitdisplacement monitoring and anchor axial force of change monitoring,In the south side ofthe layout of the seven pit displacement monitoring points on the first and second rowsrespectively installed anchor anchor dynamometer.By monitoring data collation andanalysis, the effects of winter frost heaving of the soil excavation pile anchor retainingstructure.On this basis, the simulation results with the measured data were compared andanalyzed,discusses the role of winter frost heaving pit supporting structure and theinfluence of the force deformation, draw some of the wintering pit engineering designand construction meaningful conclusions for future similar projects can provide areference.Through this work, the following conclusions can be drawn:（1）In some cold northern winter excavation areas during the project designshould fully consider the impact of frost and freezing and thawing of the soil foundationpit supporting structure stability.（2）Through establishing the mechanical model, get the relationship between thehorizontal frost heaving force and axial force of cable, can according to the soil frost heave rate of value added of horizontal frost heaving force, calculation of axial force ofcable.（3）Through the winter horizontal displacement of the pile monitoring found thatwinter displacement pit located south of the middle of the pile is larger than thedisplacement on both sides, after entering the winter period the top of the pile in theinitial period of horizontal displacement increased slightly but not significantly, analysisof the causes of possible although the outside temperature reached minus temperature,but did not reach the initial state of soil frost heave,a significant increase from thebeginning of the displacement in mid January, much larger than the displacement causedby frost heave displacement caused by excavation pit.（4）By piles of soil behind the settlement in wintering monitoring results show thatwintering supporting piles of soil behind the settlement amount because there is nomechanical perturbations small range of about1mm.（5）Through the winter pit anchor axial force change monitoring data shows thatthe first row of bolt axial force larger changes, an increase of64kN, located in the firstrow of anchor silt, this layer may be influenced by frost. The second row of anchorOwing to the sand layer, and a small amount of sand out of the pile after the bolt axialforce causes the second row of slow decline, but the decline is small.（6）Through the monitoring results Baotou anchor axial force of a winter pitstatistical variation analysis, the calculation of the axial force wintering anchor empiricalformula.（7）Seen from the result of finite element simulation, simulation support levelretaining pile top displacement and measured values of amplitude are consistent, the axialforce of the anchor value simulation changes in entering the wintering period showed thesame tendency with the measured values, so the simulation of rock bolt axial forcevariation has certain guiding significance for the project. |
PDF Full Text Request