Theoretical And Experimental Study On Vertical Compressive Bearing Capacity Of PHC Pipe Pile In Hefei Area

In Anhui City,Hefei province has weak expansive soil area,so it is suitable to popularize PHC pipe pile.In the determination of the bearing capacity of pile,there are some methods,such as empirical method,standard penetration method,static method,static load test and so on.Moreover,the ultimate bearing capacity of the pile is not applicable to the construction of the important buildings or the sensitive superstructure.Method for finding a feasible theory,this paper attempts to use the load through the settlement to determine the bearing capacity of the pile settlement curve,the load transfer mechanism of direct shear test,compression test,static load test of pile shaft three.The results show that the shear stress and displacement of the main clay layer around the pile are obtained by direct shear test,which is in accord with the ideal elastic-plastic model and the peak value of shear stress is about 54.1 kPa,and the relative displacement peak value is about 3.1mm.The shear stress increases approximately linearly with the increase of relative displacement,and then decreases with the peak value.Study on the influence to the pressure by applying different levels of depth effect,side resistance is not always increase linearly with depth,but changes with the variation of a specific factors,this variation can be used to describe the piecewise function.Three axial compression test was used to measure the stress and strain relationship of the strongly weathered argillaceous sandstone,which is also the ideal elastic-plastic model,and the stress peak value is 7.86MPa and the peak value of strain is 44.28%.The stress increases linearly with the strain,and the peak value decreases and fluctuates.According to the test results,the load transfer function of side resistance and end resistance is reduced to an ideal elastic-plastic model.Because of the little change of soil properties in this region,the silty clay layer is simplified into the main clay layer.Under this condition,the load settlement curve accords with the characteristics of the ideal load settlement curve.According to the elastic,elastic-plastic and fully plastic stage of the soil layer,the load value and the corresponding settlement value are calculated.The load settlement curve is obtained and compared with the measured curve.The fitting degree of the two curves is better,the theoretical value of elastic-plastic stage is slightly larger than the measured value,and the fitting degree is also high.Therefore,it is feasible to control the bearing capacity of pile by settlement.It can provide valuable reference for the design of pipe pile and bearing capacity determination...