Construction method for plain concrete underground diaphragm wall of deep foundation pit

Abstract

The invention discloses a construction method for a plain concrete underground diaphragm wall of a deep foundation pit. The construction method comprises the following steps: (1) conducting framing adjustment on a designed plain concrete underground diaphragm wall into a first slotted section and a closed slot section which are arranged at an interval, wherein the width of the first slotted section equals to the maximum width of the working part of a slotting machine; (2) carrying out construction of the first slotted section, then lowering reinforcement cages, pouring concrete to a level being 2 meters higher than the bottom surface of a basement floor, and then pouring the mortar of which the label is M10 to the ground level; and (3) carrying out construction of the closed slot section, then pouring concrete to a level being 2 meters higher than the bottom surface of the basement floor, and backfilling plain soil to the ground level, so as to form an underground diaphragm wall. The construction method disclosed by the invention has the advantages that as the reinforcement cages are improved, the original underground diaphragm wall smooth slotting method is replaced by spaced slotting method, and the number of the reinforcement cages abutting, concrete consumption, and the chiseling off workload in follow-up project are reduced; the operation is simple; safety risks and construction costs can be reduced; and construction time can be shortened.

Description

technical field [0001] The invention relates to a construction method of a plain concrete underground diaphragm wall of a deep foundation pit, specifically a reasonable, safe and reliable construction method of a plain concrete diaphragm diaphragm wall of a deep foundation pit, and belongs to the field of building deep foundation pit engineering. This method is applicable to the construction of similar engineering plain concrete underground diaphragm walls. Background technique [0002] With the continuous development of my country's infrastructure construction, the number of underground rail transit and high-rise buildings is increasing, and the excavation depth of foundation pits is increasing, and the impact of pressurized water on the safety of foundation pits is also increasing. As an effective foundation pit support method, the underground diaphragm wall has the characteristics of high rigidity and good impermeability. [0003] In the shield shafts of subway stations ...

AI Technical Summary

Problems solved by technology

The effective length of plain concrete is from the bottom of the wall to the bottom of the large foundation pit. However, due to the fact that the existing trough-forming equipment cannot meet the requirements of accurate underwater construction, and the verticality of the I-beam at the joint of the trough section is high, it is often adopted. The plain concrete underground diaphragm wall is poured to the ground, and when the foundation pit is excavated, it is excavated and removed to the bottom of the large foundation pit, which not only wastes materials, but also increases the construction period and cost

[0004] Moreover, since the reinforcement cage of the plain concrete underground diaphragm wall is only composed of a small amount of structural steel bars such as longitudinal trusses and transverse trusses, and one-sided I-beam joints, the overall rigidity is small and easy to deform. The safety risk of hoisting is large and it cannot be hoisted as a whole. Separate hoisting I-beam needs to be butted, which takes a long time and the joints have been butted multiple times and the water-stop effect cannot be guaranteed

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