Refined blast construction method for narrow deep foundation pit under complicated geological condition

Abstract

A refined blast construction method for a narrow deep foundation pit under a complicated geological condition comprises the following steps: step 1, flattening a field; step 2, excavating earth in a foundation pit area; step 3, carrying out trench blast construction and shallow hole step blast of a main blast area foundation pit; step 4, performing static breaking excavation on a diaphragm wall and rock in the area near latticed columns; and step 5, conducting waist beam and support construction, and then repeating construction in the steps 3-5 until the foundation pit is excavated. The methoddivides different blast areas, the refined combined blast excavation manner is adopted, and a convenient construction method is provided for excavation of the narrow rocky deep foundation pit. By arrangement of the protection scope of the latticed columns and diaphragm walls, the refined construction method combining trench blast, shallow hole step blast and static blast is adopted, and rapid breaking construction is performed on foundation pit rock. The arrangement of construction of edge expansion assisted holes fully utilizes the stress of rock, the excavation efficiency is improved, and the vibration damage of blast is reduced.

Description

technical field [0001] The invention relates to the technical field of blasting construction, and relates to a blasting construction method, in particular to a refined blasting construction method for narrow and deep foundation pits under complex geological conditions. Background technique [0002] With the continuous deepening of urban construction in our country, urban rail transit projects have developed rapidly, and there are more and more corresponding deep foundation pit projects. Usually, most of the subway lines pass through the central area of ​​the city, with dense buildings (structures), various pipelines criss-crossing, heavy traffic, and dense pedestrians, which increases the difficulty of subway construction, especially in the parts where deep foundation pit construction must be carried out, and the construction risk bigger. [0003] In most cities in China, excavation of deep foundation pits using excavators equipped with grabs or mechanical excavation with l...

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Problems solved by technology

Finally, the obvious disadvantage of patent 2 is that it is cumbersome to use the steel bar plus square wire device for setting and the rock mass crushing efficiency is not efficient

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