Combined caisson and pile foundation for strengthening foundation and construction method thereof

Abstract

The invention discloses a caisson and pile combined foundation of consolidated subsoil and a construction method of the caisson and pile combined foundation. The caisson and pile combined foundation of the consolidated subsoil comprises the consolidated subsoil, a sand-gravel cushion, a caisson, bored piles, pile bottom grout, top seal concrete and scour protection. The main construction method comprises the following steps: consolidating the foundation with an underwater compaction sand pile or a deep-layer cement mixing pile; laying the sand-gravel cushion on the consolidated subsoil; sinking the caisson with a skirt, pile sinking guide holes and grouting reserved pipes on the sand-gravel cushion; after the caisson is located, constructing bored piles through the pile sinking guide holes; after construction of the bored piles, casting the top seal concrete at the bottom in the caisson; grouting the bottom of the caisson through the grouting reserved pipes at the bottom of the caisson, carrying out pile bottom grouting through grouting pipes in the pile, and at last casting the top plate of the caisson. In the construction process, the scour protection shall be performed around the caisson according to requirements. The caisson and pile combined foundation of the consolidated subsoil and the construction method of the caisson and pile combined foundation, disclosed by the invention, can effectively improve vertical and horizontal bearing capacity of the caisson, and control sedimentation and horizontal displacement of the caisson.

Description

technical field [0001] The invention belongs to the technical field of bridges, and in particular relates to a bridge caisson foundation on soft soil foundation and its foundation treatment technology, in particular to a caisson and pile combined foundation for strengthening the foundation and its construction method. Background technique [0002] As bridge construction moves from inland to the open sea, construction conditions such as deep water, soft foundation, strong wind, rapids, waves, and strong earthquakes become more complex. The foundations of cross-sea bridges are often located in deep water areas, and there are thick covering layers of soft soil, sandy soil, cohesive soil, and crushed (pebble) soil alternately, and there may be uneven soft (hard) interlayers in the covering layer; in addition, In addition to bearing huge vertical forces, it also bears horizontal loads such as wave forces, earthquake forces, and ship collision forces. The above-mentioned construc...

AI Technical Summary

Problems solved by technology

This patent has the following deficiencies: 1. There is no soft soil layer on the seabed, and the initial settlement of the caisson foundation is difficult to control, especially the simultaneous construction of bridge towers and pilings, which will lead to excessive settlement and inclination during the construction period Risk; 2. The construction space of steel pipe piles inside the caisson is narrow, and the construction of steel pipe piles is very difficult; 3. The patent does not specify the specific meaning of the sealing and waterproof device between the bottom of the caisson and the piles, which is relatively vague, and it is very difficult in actual construction. It is difficult to ensure complete water tightness; 4. Since there are no treatment measures on the seabed, for soft soil with poor permeability, it will be difficult to realize the joint force of caisson subsoil and pile foundation envisioned in this patent

Due to the limited bearing capacity of the base soft soil, in order to ensure the simultaneous construction of bridge towers and pile foundations, a large base area must be provided, resulting in waste of caisson materials

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