Matching And Analysis For Load-Settlement Curve Of Piles

The static load test is an accurate and reliable detection method to confirm ultimate bearing capacity of base pile. Testing data obtained by spent great amounts of manpower, funds and time not only provide accurate ultimate bearing capacity but also distribution of bearing capacity and quality of pile-forming. If the computer matching method is established on the basis of pile-soil physical mechanical models and combined with geological investigation information, not only ultimate bearing capacity can be gained but also the distribution of pile axial force and soil lateral friction are obtained, which has more practical value in confirmation of appropriate bearing layer at pile end, analysis of load transfer mechanism and guidance of pile design and test.In this paper, present research theory on pile-soil interaction mechanism are introduced. Double broken line loading model and three broken line unloading model are chosen to derive analytical recursion formula of pile load-settlement curve of layered soils. The curve matching program is programmed by VC++ language, matching ranges of soil lateral friction are limited by geological investigation information. Mechanics parameters of layered soil are inversed by simplex method. The distribution of pile axial force and soil lateral friction are calculated at the same time. The examples indicate that matching precision is higher, the soil parameters are quite reasonable, the results verity the feasibility and practicality of the program. Besides, the influence of pile-soil load transfer parameters to load-settlement curve is further analyzed. Pile-soil load transfer model is improved, sediment dirt under the pile and broken pile model is built, the analytic method of the defected pile load-settlement curve is deduced, and load-settlement curves of defect piles in different depth and degree are analyzed.