Abnormal-shape double-row pile for supporting foundation pit side wall and construction method of abnormal-shape double-row pile

Abstract

The invention discloses a special-shaped double-row pile for supporting the side wall of a foundation pit and a construction method thereof. The special-shaped double-row pile includes a reinforced concrete pouring pile, a front row of pile crown beams, a cement-soil mixing wall, section steel, a rear wall crown beam and rigid piles. The top of the reinforced concrete pouring pile is connected with the front pile crown beam, and the reinforced concrete pouring pile is connected with the front row pile crown beam to form the front pile. The profiled steel with a predetermined length is inserted at intervals, the top of the cement-soil mixing wall is connected with the rear wall crown beam, and the cement-soil mixing wall is connected with the profiled steel and the rear wall crown beam to form a rear wall, The front row of piles is connected with the rear row of walls through the rigid frame beam to form a special-shaped double row of piles. The invention provides a special-shaped double-row pile for supporting the side wall of the foundation pit, which has simple structure, convenient construction, low cost, is not restricted by the red line of the construction site and the surrounding underground facilities of the foundation pit, and can combine the soil retaining effect of the foundation pit with the water stop The effect is combined into one.

Description

technical field [0001] The invention belongs to the technical field of foundation engineering, and in particular relates to a special-shaped double-row pile for supporting the side wall of a foundation pit and a construction method thereof. Background technique [0002] With the rapid development of urbanization and the vigorous promotion of urban integration, the construction of underground facilities such as underground parking lots, underground commercial plazas, and underground railways requires foundation pit support. These foundation pit projects often have the following characteristics: the outer wall of the basement is close to the building planning red line; there are a large number of underground facilities such as existing buildings and pipe networks around the foundation pit; the groundwater level is relatively high. As a result, the traditional foundation pit support technology has the following three serious problems: (1) The traditional soil nail support, comp...

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Problems solved by technology

As a result, the traditional foundation pit support technology has the following three serious problems: (1) The traditional soil nail support, composite soil nail support, and pile-anchor support technologies all require the construction of tens of meters long soil nails in the horizontal direction or anchor rods, which often exceed the red line of architectural planning, the basement line of existing buildings around, or are affected by underground pipe network and other facilities, so that the application of these support technologies is limited; (2) traditional cantilever pile support or internal support support technology Although there is no soil nail or anchor rod construction, construction can be carried out within the red line of the building plan, and will not be affected by the surrounding underground facilities, but the rigidity of the cantilever pile support technology is low, the depth of the foundation pit generally does not exceed 6 meters, and the deformation of the pile top is relatively large. Therefore, the engineering application is limited; and the internal support technology needs to construct a large number of reinforced concrete beams or steel structure support members within the plane range of foundation pit excavation, which not only affects earthwork excavation, underground foundation and building construction, but also affects large-scale For foundation pits, the installation and removal of a large number of supporting components not only prolongs the construction period but also increases the cost; (3) For foundation pits with groundwater, in order to reduce the impact of groundwater level on surrounding existing buildings and underground pipe network facilities, traditional foundation pit support Technology also requires the construction of a continuous cut-off curtain wall around the foundation pit to prevent groundwater outside the foundation pit from flowing into the foundation pit, and the construction of the cut-off curtain wall greatly prolongs the construction period and increases the project cost.

However, the existing double-row pile technology often constructs a water-cutting curtain wall outside the double-row pile or in the middle of the two rows of piles to intercept water in order to solve the problem of groundwater during excavation of the foundation pit, which has caused two serious problems: ( 1) When double-row piles are supported, the force of the rear row of piles is generally much smaller than that of the front row of piles, and it is obviously not economical and practical to use reinforced concrete piles for the rear row of piles; (2) the water-cutting curtain in the double-row piles The wall needs to be constructed separately. Generally, only its water-cutting function is considered, and its soil-retaining function is not considered. This not only wastes materials, increases the cost, but also prolongs the construction period.

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