Bored Pile σ-y Settlement Curve Calculation Method And It's Application In Engineering

Being bored pile not only have high bearing capacity with small deformation, but also with the convenient for construction technique, and good applicability and so on advantages, thus highway engineering technical staff approve it and accept it rapidly, it has being the fiirst form for the foundation of highway and bridge. Along with the national economy continue rising, China highway and bridge have been developing rapidly, so the diameter is becoming larger and larger, and the demanding for the bearing capacity of foundation is stronger and stronger, which bring forward a higher demanding for the bored pile's theoretics and practical application.Under the vertical bearing capacity, although there are many methods to study the single-pile settlement theoretics, because of their calculated results with the majority are nonlinear with the actual pile, in "Bridge code", the bored pile's bearing capacity is not linked with the settlement calculation. Currently, the most accurate method of pile bearing capacity - settlement curve is static load test, but done a lot of static load test in advance is very difficult, so application in large scale is obviously unrealistic.This article relied on Hunan " No drilling for large diameter bored hollow pile " structure academic calculation and long analysis of SuTong Yangtze Bridge Pier 17 bored piles'test data, on the basis of concluding settlement curve calculation methods of various bored piles at home and abroad, continuously processed in analysis of results of the test pile in different parts of Chinese bored pile. The purpose is due to the different characteristics of the soil, and the differences in construction technique as well as the differences in the diameter and length of pile, makes settlement curve various, and extremely difficult to unify. After considering these factors, I will introduced stressσof pile top and relative settlement y of pile top to summarize molding. The author try to acquire the Rigid Coefficient of foundation in different soil layer in pile tip by compairing the actualσ-y settlement curve to calculatingσ-y settlement curve of these test piles, in order to supply the theories support of controlling bearing capacity by settlement.The existing foundation of highway bridge pile adopts bored pile,as given priority to pretecting the wall by slurry in the process of finishing hole, then there is inherent defects in construction technique( such as slurry proportion, the sediment in pile tip, the mudcake at pile side), resulting in piles tip and piles side resistance significantly reduced, regular using post-injecting grout to remedy. This article try to acquire the influence for bearing capacity of pile in different construction technique by the research forσ-y settlement curves of these test piles, In addition, we want to make use of the"σ-y settlement curve calculation method"to predict the load and settlement of bored pile, which can reduce some test piles. At last, we can also select a more reasonable, and safe and economic construction technique project by comparing the different bearing capacity of pile in differnt construction technique.