The Experimental Study On The Pile Foundation Friction Property For Zhanjiang Group Structural Clay

With the social and economic development, tall buildings in various regionsbecome more and more, which puts forward higher requirements to the foundation.Zhanjiang is located in the coastal areas of Guangdong Province, which is vastdistribution in structural clay, pile foundation has become widely used in the area. Theclay in Zhanjiang area has high natural water content, high compressibility, lowpermeability, and because of it’s remarkable structural property, the pile foundation inZhanjiang structural clay has its unique bearing character, the traditional experience isno longer applicable in the area. This paper researches on the grey structural clay inZhanjiang City, and through the comparison analysis between the single pile model fieldtest and prototype test, it’s able to explore the friction and bearing characters of pilefoundation in Zhanjiang group structural clay.In this paper, the main research work and conclusions are as follows:1. Considered the soil layer distribution situation in Zhanjiang and the local drillingdata, carried on the drilling experiment in the chosen approximate place and analysedthe experiment result, finally sought out the testing field for the model test.2. Discussed the current various materials and corresponding processingtechnology for the research of model piles, and selected seamless steel pipe and linecutting processing to accomplish the model test; designed and ultimately determined thetest data acquisition system and loading devices; discussed the slow sustaining loadmethod and the quick sustaining load method, which are the two kinds of commonlyused methods of test loading, and ultimately selected the former for this test.3. Demonstrated the specific data processing method for the model test result,according to the data obtained in the model test, painted the pile top load-displacementcurves, pile axial stress curves and pile side friction resistance curves, and obtained thedata of pile end resistance, studied the play mode of side friction and end resistance foreach single pile. The final conclusion is: under load, with the increase of the pile length,the model pile end resistance is reduced, and its commitment to the proportion of loadon pile top is reduced; the model pile side friction curve showed a parabola distribution and ultimate side friction stability is about40kPa.4. Through the data analysis of the prototype test and model test, the frictionproperty of the single pile in Zhanjiang group structural clay studied in more depth. Thefinal conclusion is: the end resistance of the prototype test pile is always small, in thepile foundation design process controlled by deformation, the effect of end resistancecan be ignored; the side friction of the prototype test pile bottom can not fully played, inthe pile foundation design process controlled by bearing capacity, the pile is too long.