Pile foundation flexible connection joint only used for pulling resistance and construction method

Abstract

The invention provides a method for realizing flexible connection of a joint of a pile and a raft foundation, which only provides uplift bearing capacity and rigidity and does not provide compression bearing capacity and rigidity, and a construction method for researching and developing the joint. According to the pile foundation flexible connection joint, a pile cap is formed at the top of a pile body of the pile foundation flexible connection joint through secondary pouring, the orthographic projection area of the pile cap is larger than that of the pile body, and a reinforcing mesh with a reinforcing function is preset in a raft foundation on the periphery of the pile cap; a flexible compressible plate is arranged between the top of the pile cap and the raft foundation, a protective plate for enclosing the pile body is arranged in a lower lying space of the pile body, the upper portion of the protective plate is in rigid contact with concrete at the bottom of the pile cap, and a joint filling material filling layer is arranged between the side face of the pile body and the protective plate; and a gap filling material filling layer is arranged between the side face of the pile cap and the raft foundation. In the dry season, an uplift pile is in a dormant state under the action of a vertical load; and in the wet season, the effect of the uplift pile is gradually exerted, and it is guaranteed that the whole structure and the local structure do not float upwards.

Description

technical field [0001] The invention relates to the technical field of pile foundation raft foundation. Background technique [0002] In recent years, due to the increase of extreme weather and the acceleration of the urban construction process, the urban groundwater level has shown a rising trend, and anti-floating stability safety accidents have occurred from time to time. In the anti-floating design of the raft foundation of building structures, it is often encountered that the groundwater level of the site is too high and the structure’s own weight alone cannot meet the anti-floating stability. Set three schemes of uplift piles to solve the design problem of anti-floating stability. [0003] For projects whose anti-floating grade is Class A, the new "Technical Standards for Anti-floating of Construction Engineering" increases the anti-floating stability coefficient to 1.1, and the anti-buoyancy combination coefficient of the upper part of the structure and the internal ...

AI Technical Summary

Problems solved by technology

Since the vertical stiffness of the pile foundation is much greater than that of the surrounding soil, when the structural pressure load causes the foundation to deform, the rigid connection between the pile and the raft foundation will cause the pile foundation to bear most of the vertical load first, resulting in the installation only according to the anti-floating requirements. The number of piles cannot meet the safety of the compressive bearing capacity (technical contradiction 2)

[0007] 3. For the case where anti-floating piles are only partially installed, due to the difference in settlement between the natural foundation part and the pile foundation part under compression and anti-floating conditions, the rigid connection between the pile and the raft foundation will greatly increase the stress on the raft foundation , leading to an increase in the thickness of the raft foundation and an increase in the reinforcement, increasing the difficulty of the design of the raft foundation (technical contradiction 3)

[0008] 4. At present, the usual design method is to make the pile foundation meet both the compressive bearing capacity and the uplift bearing capacity. The larger value of the two results in a waste of the number of pile foundations (technical contradiction 4); The piles are arranged concentratedly in the area where the vertical load is relatively concentrated, such as under the column. In this way, when the groundwater level rises, and the overall anti-floating bearing capacity provided by the pile foundation is sufficient, it will occur due to the unevenness of the pile foundation layout. As a result, the local anti-floating capacity of the waterproof board is insufficient, and the deformation is too large, which leads to the problem of cracking of the waterproof board

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