The Full-scale Experimental Study On The Horizontal Bearing Capacity Of Pile Foundation

Pile foundation is a form that is commonly used in deep foundation, it can well adapt to various geological conditions and various load conditions, It has the advantages of high bearing capacity, good stability and low sedimentation, etc. At first, people consider pile foundation as a single compression member, ignoring its horizontal bearing capacity,mainly studying the vertical load-bearing characteristics. In the practical engineering, pile foundation sometimes suffer a large horizontal load,such as seismic load, wave load, wind load, etc. Japan's Niigata earthquake (1964, liquefied foundation) and miyagi earthquake (1984, liquefied foundation) earthquake damage investigations indicate that those buildings whose pile and the upper structur both damaged in earthquakes accounted for 2/3.So in those engineering practice in which pile foundation bears larger horizontal load, design staffers should consider the horizontal bearing capacity and shear properties besides the vertical bearing capacity of pile foundationFor studying the bearing capacity of single pile and pile double level for of pipe pile and the pile, this paper made the following work:(1) Reading extensively the characteristics of pile foundation under horizontal load data in the domestic and international, including the theoretical research method, model test and field test data;(2) Conducting the full-scale experimental study on the static load for single pipe pile and pipe pile double level,including three single pile and eight 1×2 pile double;(3)Conducting the full-scale experimental study on the static load for single bored pile and bored pile double level,including four single pile and eight 1×2 pile double;Based on the test and data analysis, get the following main conclusions:(1) Both single pile and pile double, the distance between the maximum position of the moment and the pile tip is 5-10 pile diameter, the distance between the reverse bend point position and the pile tip is 0.4-0.75 times of the pile length, and the position of the maximum bending moment will be down with the increase of the load;(2) The characteristic value of horizontal bearing capacity of piles should take smaller values for the load of the critical value of level load determined by H-?Y/?H and 10 mm displacement of pile top corresponds to the load;(3) The horizontal bearing capacity critical value and the ultimate value of single pile for the pile double foundation are larger than those values of single pile.(4) The critical value and the limit value of pile horizontal bearing capacity for r single pile and double piles are increased with the increase of pile diameter, but double pile bearing capacity range along with the change of pile diameter smaller than the extent of change as a single pile;before the critical load, the same load condition, the bending moment and displacemen of single pile decreases with the increase of pile diameter, pile double foundation pile top negative bending moment increases with the increase of pile diameter, while the most-positive bending moment value of pile and pile body displacement decreases with the increase of pile diameter;(5) The critical value and the limit value of double pile horizontal bearing capacity of the pile foundation increases with the increase of pile spacing; Before the critical load, the same load condition, the negative bending moment of pile top, the max bending moment of pile body, pile body displacement decreases with the increase of pile spacing; Position of maximum bending moment of pile and inflection point position and has little to do with pile spacing.(6). Under horizontal load, the front pile and the latter pile have different performance, pile cap negative bending moment and the pile body bending moment of the front pile are laeger than those of the latter;The same span ratio, the bigger the pile diameter, the differences is larger(7) For PHC pipe pile, mortar type connection method will reduce the critical value and the ultimate bearing capacity of pile; Mortar type connection method can effectively reduce the negative bending moment value of pile top or even eliminate negative bending of pile cap, but the most-positive bending moment value of pile body will increase at the same time.(8) For PHC pipe pile, the horizontal bearing capacity critical value and the limit value of double pile with vertical load pile are larger than those values of the pile without vertical load.(9) For PHC pipe pile, under the same load, pile body bending momen of the pile with vertical load is smaller than that of the pile without vertical load.(10) For piles, the same load condition, the horizontal bearing capacity critical value and the limit value of double pile which is embedded cap pile caps 12 cm are slightly larger than the horizontal bearing capacity critical value and the limit value of double pile which is embedded cap pile caps 6 cm.(11) The horizontal bearing capacity critical value and the limit value are similar for the pipe pile and bored pile with the diameter,but the bending capacity of bored pile is obviously better than that of pipe pile.