The Experimental Research On The Determination Of The Ultimate Bearing Capacity And Its Influencing Factors Of Self-Balancing Test Pile

As a kind of foundation form,pile foundation is widely used now.It needs complicated construction procedure and technology.Besides that,it is easy to bring some quality problems in the process of construction, so the quality checking is very necessary,especially for the large-diameter piles. Traditional loading test method generally accepted as a most directly and reliable method for determining the bearing capacity of piles,but it will take more time and money, and require high condition for test field. As a new measuring technology,self-balance loading test method make up for those shortcomings effectivly because of its special advantages.At present, it has been appiled in many provinces.The actical firstly summarizes several traditional load testing methods used in the pouring piles which include static test method,dynamic test method and dynamic-static compound test method.Besides that,it analyzes the characteristics of these methods and make a contarst to them. It introduces the principle of of the self-balance loading test pile and the focal points of theoretical studies.Secondly,the text analyzes the loading mechanism of the compression pipes,uplift pipes and Self-balance loading pipes;it sums up two specific transfer ways for getting the ultimate bearing capacity-the simple method and the exact method and points the problems of them respectively.Besides that,the common questions between them-the K下,ξand K上, which will affect the accuracy of the calculation formula and the ultimate bearing capacity should be considered seriously.Through the Yilihe Lagre Brige self-balance loading test of three piles,the text presents the equipment,the process of the test and the course of calculation the ultimate capacity used two methods. Through the analysis results of the influence factor on the ultimate bearing capacity of self-balancing test pile by means of mumerical simulation and the results of this experiment,we get that the soil type isn't the only factor of the ultimate bearing capacity ultimate bearing,but also the drilling technology can not be ignored in certain engineering geological conditions.And then,the actical analyzes semi-quantitatively the degree of this influence.Thirdly, by taking a contrast the results of the experiment with a similar test,the text gets that the degree of loosening effect does indeed exist when caculating the ultimate bearing capacity in this geological conditions. It proposed several specific improvement measures to the simple conversion method,the exact conversion method and the coefficient of shaft resistance of upside pile.We expect these measures can offer some instructional advices for similar tests.Finally,it proposed some questions which are well worth studying through summarizing the whole text.