Method for determining ultimate bearing capacity of gravel pile

Abstract

A method for determining the ultimate bearing capacity of a gravel pile mainly comprises the steps that on the basis of the coulomb strength theory, the included angle between a fracture surface and the maximum principal stress acting direction is determined; and when the gravel pile is under the action of an upper load, the lateral confinement constraint force of foundation soil on the pile bodyis considered, the influence of pile body self-weight stress is also considered, the pile body stress is simplified to the direction of the inter-pile soil fracture surface, and a stress balance modelis established, so that the mutual relation between the gravel pile single-pile bearing capacity and foundation soil and the pile body self-weight stress is obtained, and then the more accurate gravel pile single-pile bearing capacity is obtained. The method is simple in calculation, more comprehensive in consideration of influence factors, and more in accordance with engineering practice in calculation result, provides accurate and reliable basis for engineering design and construction, and avoids waste.

Description

technical field [0001] The invention relates to a method for determining the ultimate bearing capacity of gravel piles. Background technique [0002] The composite foundation of crushed stone piles is composed of loose materials such as sand and gravel. After holes are formed in the weak foundation, these loose materials are filled into the soil in batches to form dense sand piles with a certain depth and larger diameter, which are similar to natural foundations. An improved artificial foundation is formed to solve the problem of insufficient bearing capacity of the foundation. Gravel piles are suitable for compacted and loose sandy soil, silt soil, plain fill and miscellaneous fill foundations. The mechanism is different with the different soil properties to be reinforced: it has displacement and compaction effect on sandy soil, silt and gravel soil; for clayey soil and filling soil, it is mainly displacement, with different degrees of compaction and promotion. The role o...

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Problems solved by technology

However, the four calculation models of single pile bearing capacity of gravel piles do not consider the effect of foundation soil self-weight and pile self-weight on the ultimate load. Although the passive earth pressure method considers the effect of soil weight, it does not consider the influence of pile self-weight.

As a result, the accuracy of each theoretical calculation is different, and the results are inconsistent. It is difficult to determine which calculation model is in line with the reality. It is quite different from the original test results on site, especially for gravel piles with a slightly larger diameter, which is even more different from the actual project.

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