Research On Bearing Capacity Of Super-long Bored Pile

With the rapid development of chinese economic,large-span bridges construction is on the rise.though the large-diameter and super-long piles is often adopted by large-span bridge foundation at present,this type of pile design calculation is based on the current "Highway Bridge Design Code and basic foundation" which main outcome of the norms are for small and medium-sized diameter of the piles research,because its beating capacity calculating and system and deformation has no correlation and coordination with each other and the design calculation did not consider the pile - soil system interaction,also the norms did not take into account the specific circumstances of the differences,its disagrees with practical situation and the calculation does not apply to super-long and large-diameter bored piles.Therefore,in order to be able to give full play to the lead-bearing potential of the super-long and large-diameter piles in different kinds of geological condition and save project cost,it is necessary to study the loading-bearing properties under special geological conditions of the super-long and large-diameter bored piles which is needed for self-development of pile foundation theory and an urgent requirement for the engineering.This issue relies on the Yellow River Bridge which is on the expressway section between Baotou and Shulinzhao and adopts research technique which the laboratory test as well as the outdoor experiment unify to study the bearing properties of super-long and large-diameter bored piles under the Yellow River special geological.this article has done the following aspect work:1) engineering properties and parameters research of the bridge site's soil:according to sample drilling and the field and laboratory test,the bridge site of earth's physical characteristics and mechanical properties,such as compression strength and intensity has been studied.The lateral friction of piles and the end of pile resistance display data are obtained through the load experiment.2) research of the bridge site's soil influence to the pile foundation bearing capacity: Combined with the Bridge location geological of the actual situation - the geological and mechanical properties of layered,the Self-balancing test was carded out.And various soil layers friction and the end resistance are obtained to check preliminary pile foundation computation work and give a revised measure.The first measured data about lateral friction and the end resistance of the Yellow River special geological diameter bored piles was obtained through a series of studies and the side of the resistance and side stop playing loading of the transfer function are proposed,which can provide reference for the pile foundation design for the similar geological condition.The work puts forward the pile foundation design procedure and the value of design parameters and provide reference for the pile foundation design and construction design for the similar geological condition.According to the research results,the reliability of bored pile foundation design is increased.And the project investment is reduced as well as the project benefit is improved.