Composite foundation piles composed of steel pipe piles and cement-soil piles

Abstract

The invention discloses a combined foundation pile composed of steel pipe piles and cement-soil piles. The cement-soil piles are covered outside the steel pipe piles. The steel pipe piles include an upper pile, a lower pile and a round bottom pile. shaped truss, the diameter of the upper pile is smaller than the diameter of the lower pile, and the steel pipe pile also includes a steel connecting piece connecting the upper pile and the lower pile, and the steel connecting piece is a stepped cylinder with a small upper part and a larger lower part; There is a lubricating medium between the sleeve and the steel sleeve and the upper pile, and a flange is fixed on the outside of the bottom end of the steel sleeve. There is an elastic pad between the flange and the step surface of the large-diameter cylinder of the steel connector. A steel plate is fixed in the middle of the height of the pad, and the flange is connected to the steel plate in the elastic pad, and the steel plate in the elastic pad is connected to the steel connector; the upper edge of the outer side of the steel sleeve at the junction of the soft soil layer and the neutral soil layer There are many inverted L-shaped steel plates around the circumference. The combined foundation pile can fully increase the pile side friction resistance of the full pile length in each soil layer, thereby improving the bearing capacity of the foundation pile.

Description

technical field [0001] The invention relates to the technical field of pile foundation engineering, in particular to a composite foundation pile composed of steel pipe piles and cement-soil piles. Background technique [0002] With the rapid development of foundation engineering construction, the requirements for various types of foundation piles are becoming more and more extensive, and the requirements for the adaptability of foundation piles are also getting higher and higher. Different soil properties have different requirements: in some soft soil areas, the mechanical properties of shallow soil layers such as silty clay layers are poor, while deep soil layers such as silty clay layers or plastic clay layers have better mechanical properties. In this soft soil area, some large-scale machinery and equipment installed in industrial factories that have been built require composite foundation piles composed of steel pipe piles and cement-soil rotary grouting piles, referred ...

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Problems solved by technology

[0003] However, there is generally a technical deficiency in the combined foundation piles of the above prior art: since the top of the steel pipe pile is directly or indirectly fixed to the bottom of large mechanical equipment, the steel pipe pile is closely combined with the outer cement-soil pile from top to bottom. Extending, when large-scale mechanical equipment is working, the steel pipe pile transmits the upper load to the cement-soil pile through the bonding force between the cement-soil pile, and the cement-soil pile transmits the load to the cement-soil pile through the side friction resistance between the pile and the soil around the pile. The soil around the pile is used to complete the transmission of cyclic loads composed of vertical loads and horizontal loads generated during the operation of large mechanical equipment

However, because the ultimate pile lateral friction in shallow soft soil layers such as silty soil layers is small, shallow soils have limited bearing capacity for piles to resist uplift or compression, while the bearing capacity of deep soils is often too late. Therefore, the composite foundation pile will have a certain degree of settlement, which will cause the equipment fixed on the upper part of the composite foundation pile to be skewed and unstable.

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