Study On Bearing Capacity Of Grouting Support-plate Pile In Soft Soil Foundation

As a new type of pile foundation,the branch-disk pile is widely used in Bridge Foundation,Transmission Tower Foundation,underground parking lot foundation and high-rise building foundation.In recent years,with the rapid increase of the quantity and scale of civil engineering construction,it is gradually necessary to carry out engineering construction in the soft soil foundation area,and according to the current engineering technology is still difficult to solve the soft soil foundation of the poor characteristics.Therefore,based on the traditional branch-disk pile concept,combined with post-grouting technology,developed a grouting branch-disk pile.The feasibility and bearing capacity of the high-pressure grouting pipe embedded in the outer side of the reinforcing bar cage at the position of the supporting disc are studied by means of high-pressure grouting,and the complex is formed at the position of the supporting disc to act as the supporting disc:(1)Based on the literature at home and abroad,this paper analyzes and summarizes the characteristics,application scope and pile forming mechanism of the traditional pile with branches and plates,as well as the relevant theories of post-grouting technology,and introduces in detail the construction process of the pile with branches and plates with grouting,combined with the model test pile,the reasonable selection of the grouting pipe layout,grouting pressure and grouting quantity is made,and the state cause of the branch-disk complex is analyzed.(2)Through model test,the bearing capacity of cast-in-place pile and cast-in-place pile with branches and plates is studied and compared with traditional cast-in-place pile and squeezed branch and plates pile,the settlement curves of three pile types,namely,straight pile,cast-in-place pile and squeezed branch pile,are almost the same and relatively smooth.In the compression test,when the settlement reaches 4mm,the bearing capacity of the cast-in-place pile is about 600 N more than that of the straight pile,which accounts for about 60% of the ultimate load of the straight pile.In pull-out test,when the load exceeds 300 N step by step,the pull-out of the straight pile increases sharply,but the pull-out of the cast-in-place pile and the cast-in-place pile increases little.(3)Using ABAQUS numerical simulation to set up the numerical model under the condition of 20 mm,25mm,30 mm,35mm and 40 mm of the influence range of grouting around the pile,and uniformly add a single layer of mucky soft soil around the pile to extract the displacement field of the soil around the pile,through the analysis of the behavior of axial force transfer,the bearing characteristics of cast-in-place pile in soft soil foundation are obtained,which shows its feasibility and excellent bearing performance.