Experimental Research Towards The Effects Of Pore-forming Technology On The Pile Side Resistance Of Filling Pile

Pile foundation has the advantages of high bearing capacity, little deformation, and its bearing capacity is usually the the combined action of pile and soil in which the stress transfer mechanism and process is very complex. The pile side resistance which plays a very important role in the bearing capacity of pile functiongs before the pile end resistance does. Only in the way that choosing a reasonable value of pile side resistance can we make sure that the design of foundation is safe and economic. This paper focus on the effects of soil compaction technology on the side friction of filling piles.Test targets on the displacement pile and the none-displacement pile, additionally, it studies on the side frictions of piles as well as their influence factors using the method of model experiment and field test. Meanwhile we make expressions deduction of the calculation formula which is about the friction of cast-in-place pile.The foundation treatment can not only make the foundation soil compactness increase greatly but also make the friction resistance of filling pile greatly increased whose construction technology steps is compaction method in the first the grouting the pile secondly. In the field test we measured the pile side friction of the cast-in-place pile in which the foundation has been processed with Driving-Casting compaction and DDC compaction. Making a research that the effect on the pile side friction of non-displacement in the condition that the the foundation is processed by the two different ground treatment through the static load test of the compression pile and uplift pile.In the laboratory model tests we designed different density of foundation soil and different ways of pore forming to carry out the experiments. Different compactness represents varied degrees of density which is about the natural foundation soil and processed soil. The bore-making techniques include SDS pore-form. Driving-Casting pore-form and Dig pore-form which called non-displacement pile. On the basis of three kinds of pore forms, we study the effect on the pile lateral soil compactness because of the different bore-making techniques and the relationship between the compactness and the pile side friction. The test result shows that the pore forming way had a great influence on pile side resistance. For the same foundation condition the friction of displacement pile is greater than that in the non-displacement pile, especially the SDS pile; Pile resistance grows with the increase of compactness of foundation, but the increase rate is not same. The growth rate of the displacement pile is less than the non-displacement’s friction. The main factor which influence the pile side resistance is the compactness of soil,but neglect the methods of increasing the compactness because of its weak effect. Namely no matter when the soil get compaction, the same compactness will cause a similar friction. The research on the compaction effect after the foundation soil has been processed using the Driving-Casting compaction and SDS compaction indicate that the treated soil compactness which gradually decrease along the radial gradient, showing the distribution regularity of the power exponential function.Thus we can fit density distribution curve and the curve of pile side resistance and compactness.