Study On Horizontal Bearing Capacity Of Piles-Diaphragm Wall Anchor Arms Combined Foundation

The piles-diaphragm wall-anchor arms combined foundation is a new foundation to improve the horizontal bearing capacity.The the diaphragm wall and the anchor arms provides the horizontal resistance,the piles guarantees stability of combined foundation.The mechanism of action of this combined foundation is,the lateral deformation of combined foundation drives the relative displacement of anchor arms to soil,which in turn generates the anchor arms tension.The anchor arms tension cooperates with the passive earth pressurel,the skin friction and the horizontal resistance of piles,which in turn limits lateral deformation of combined foundation,and the piles-diaphragm wall-anchor arms-soil constitutes a interaction system to improves its horizontal bearing capacity.The horizontal bearing capacity of piles-diaphragm wall-anchor arms composite foundation is studied by the indoor model experiment and numerical simulation.The main conclusions are as follows:(1)Under lateral load,the failure modes of piles-diaphragm wall-anchor arms combined foundation are mainly divided into overthrow failure,sliding failure,diaphragm wall to anchor arms cracking failure and diaphragm wall to piles shear failure.Attention should be paid to the above strength verification when designing the piles-diaphragm wall-anchor arms combined foundation.(2)The bending moment variation of the piles-diaphragm wall-anchor arms combined foundation is proportional to increase of horizontal load.The bending moment of the wall is “convex”,at the same time,the absolute values of the maximum positive and negative bending moments are basically equal,except for the piles to wall diaphragm connection,the bending moment at the rest of piles is close to zero.(3)Under lateral load,lateral displacement of the top of pile-underground wall-anchor arms composite foundation is the largest,and the composite foundation shows a rotation trend around the back surface.When adjusting the parameters of the anchor arms,inclination rate can be controlled,under the same engineering condition,the horizontal displacement of pilesdiaphragm wall-anchor arms combined foundation is only 2/3 of that of pile-diaphragm wall composite foundations,so the piles-diaphragm wall-anchor arms combined foundation get a higher safety reserve.(4)Increasing the length and diameter of the anchor arms can increase the restrict to deformation of piles-diaphragm wall-anchor arms combined foundation,and make the bending moment of the wall more uniform,but when the length or the diameter attain to some value,increasing corresponding parameters has a lower efficiency in improving the horizontal bearing capacity.Therefore,increasing the length or diameter of the anchor arms can effectively improve the horizontal bearing capacity of the piles-diaphragm wall-anchor arms combined foundation within a certain range.(5)The horizontal load-bearing capacity of piles-underground wall-anchor arms composite foundation can be improved by uniformly setting the anchor arms on the wall,and after strengthening the soil around the piles-underground wall-anchor arms composite foundation,can increase synergistic effect between anchor arms bolts and the soil,thus the horizontal loadbearing capacity of piles-underground wall-anchor arms composite foundation can be improved.