Top-down construction method for anchor rod and rotary jet grouting back cover deep foundation pit without precipitation operation

Abstract

The invention belongs to the technical field of civil engineering and particularly relates to a top-down construction method for an anchor rod and rotary jet grouting back cover deep foundation pit without precipitation operation. The top-down construction method for the anchor rod and rotary jet grouting back cover deep foundation pit without precipitation operation particularly comprises the steps of construction preparation, construction of a water stop curtain of a high-pressure rotary jet grouting pile of the side wall of the foundation pit, construction of a rotary jet grouting pile back cover, construction of an anti-floating anchor rod, and excavation of the foundation pit. The water stop curtain of the high-pressure rotary jet grouting pile of the side wall of the foundation pit is connected with the jet grouting pile back cover, and the anti-floating anchor rod is connected with the rotary jet grouting pile back cover of the anchor rod. According to the top-down construction method, it can be ensured that a side wall support is closely connected with the rotary jet grouting pile back cover while the requirements for strength, stability and impermeability from construction of the water stop curtain of the high-pressure rotary jet grouting pile of the side wall of the foundation pit, the jet grouting pile back cover and the anti-floating anchor rod are met, the external anchorage section of the anti-floating anchor rod is located in the rotary jet grouting pile back cover, an effective water stop system can be formed in the deep foundation pit, and influence on construction from the underground water level does not need to be controlled.

Description

technical field [0001] The invention belongs to the technical field of civil engineering, and in particular relates to an upside-down construction method for a bottom-sealing deep foundation pit by rotary grouting of bolts without precipitation. Background technique [0002] With the construction of large-scale transportation water conservancy projects, industrial buildings, high-rise and super high-rise buildings and urban underground projects, there will be a large number of deep foundation pits and ultra-deep foundation pit projects, and their safety will directly affect the surrounding buildings, pipe network and construction. safety. The dewatering construction of deep foundation pits not only changes the distribution of groundwater and seriously wastes groundwater resources, but also changes the mechanical properties of the original rock and soil layers, resulting in design failure of foundation pit support structures and deformation or even destruction of surrounding ...

AI Technical Summary

Problems solved by technology

The dewatering construction of deep foundation pits not only changes the distribution of groundwater and seriously wastes groundwater resources, but also changes the mechanical properties of the original rock and soil layers, resulting in design failure of foundation pit support structures and deformation or even destruction of surrounding structures.

In order to protect the groundwater resources and the mechanical properties of the original rock and soil layers, the existing construction methods cannot meet the requirements of energy conservation and environmental protection.

[0003] At present, the deep foundation pit dewatering operation is a necessary procedure for foundation pit excavation in the existing construction methods. The dewatering operation will lead to the exploitation of a large amount of groundwater, which will change the distribution law of groundwater and the mechanical properties of the original rock and soil layer. Serious accidents such as bottom sand gushing and foundation pit instability

The existing deep foundation pit construction methods are difficult to achieve in terms of protecting groundwater resources and not changing the mechanical properties of the original rock and soil layers.

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