Structure of prefabricated pile-plate brackets for underpinning existing pile foundations through shield tunneling and construction method

Abstract

The invention relates to a structure of prefabricated pile-plate brackets for underpinning existing pile foundations through shield tunneling and a construction method. The structure of the prefabricated pile-plate brackets for underpinning the existing pile foundations through shield tunneling and the construction method are especially suitable for underpinning of the existing pile foundations low in foundation bearing capacity but high in requirement on deformation of upper structures. Prefabricated parts are adopted for piles in the structure, and therefore the construction period is greatly shortened, and the quality of the parts can be guaranteed.

Description

technical field [0001] The invention belongs to the technical field of geotechnical and underground engineering, and in particular relates to a prefabricated pile-slab underpinning structure and construction method in which a shield passes through an existing pile foundation, and is especially suitable for when the bearing capacity of the foundation is insufficient and the deformation of the superstructure is strictly required The existing pile foundation underpinning and its. Background technique [0002] The establishment of urban underground transportation system plays a vital role in alleviating the increasingly tense urban traffic congestion. In January 2015, the National Development and Reform Commission officially approved the short-term construction plan of Jinan's rail transit. So far, China has spent more than 50 years to make all municipalities and sub-provincial cities have a relationship with the subway. However, with the continuous improvement of the urban rai...

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Problems solved by technology

[0003] Chinese patent CN101936167B discloses a construction method for bridge underpinning combined with shield construction to pass through bridge pile foundations. Before shield tunnel crossing construction, the pile foundation of the bridge is replaced with an enlarged slab foundation, and the bottom plate of the enlarged foundation is The soil foundation has been reinforced. When the surrounding layer of the existing pile foundation is soft soil and the soft soil layer is thick, the depth of foundation reinforcement will inevitably increase, resulting in an increase in project cost, and the settlement of the new slab foundation cannot be effectively prevented.

[0004] Chinese patent CN101761068A discloses a box-raft pressure-bearing foundation underpinning and construction reinforcement method for the bridge pile foundation above the river where the tunnel crosses. The soil foundation below is reinforced by grouting. The soil foundation reinforcement and the reinforcement of the rotary grouting piles in this method will inevitably bring about a significant increase in cost.

[0005] Chinese patent CN102418531B has opened a kind of shield to directly cut off the overpass bridge pile group excavation construction method, and its method is by planting reinforcement on each bridge pile, and valve plate and grouting are jointly carried out pile foundation underpinning, and the valve plate foundation in its method is also It is not suitable for thick and soft soil strata and the risk of direct pile cutting by shield tunneling is high

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