Construction method of deep foundation pit bracing system

Abstract

The invention relates to a deep foundation pit bracing system and a construction method thereof. The deep foundation pit bracing system comprises a curtain which is arranged at the periphery of a deep foundation pit, and steel pipe concrete pouring piles are constructed in the curtain according to designed interval and specification before prehardening of the curtain. The construction method of the deep foundation pit bracing system comprises the following steps: drilling three unit grooves connected together at one time, wherein a drilling machine stops rotating when drilling to scheduled depth; and injecting cement paste into the bottoms of the unit grooves from bottom to top, wherein the drilling machine rotates reversely to upwards lift a drilling tool to form the curtain, the drilling tool is lifted out of the ground, the next groove section is constructed in sequence, and the groove sections are in occluded cutting and overlapped with one another, so that an integrated continuous seepage-proofing curtain can be formed by the continuous construction. The invention has the advantages that the manufacturing cost is very low, the construction period is short, wide promotion is suitable; the tensile and compressive strength can be greatly improved due to the adoption of the concrete, the use of a large amount of anchor bars can be reduced, and the safety during the construction is improved; and the working period is not occupied for the pile construction, the time can be shortened greatly, and the construction period can be brought forward.

Description

technical field [0001] The invention relates to the technical field of deep foundation pit support, in particular to a deep foundation pit support system and a construction method thereof. Background technique [0002] With the rapid development of the economy, buildings are gradually developing into high-rise and large-scale buildings, and the requirements for civil air defense facilities are becoming more and more stringent. Almost all high-rise buildings have basements, underground garages, etc., and construction in urban areas is affected by surrounding buildings, pipelines Most of them require vertical support. How to choose a safe, reliable, economical and reasonable support system is the goal that the geotechnical engineering field has been pursuing. [0003] Existing vertical support systems generally include diaphragm wall support system, row pile support system, cement-soil wall support system, etc. Diaphragm wall support system is safe and reliable, but the cos...

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Problems solved by technology

[0003] Existing vertical support systems generally include diaphragm wall support system, row pile support system, cement-soil wall support system, etc. Diaphragm wall support system is safe and reliable, but the cost is high; row pile support system, Although the general cost is low, but the discontinuity of the piles, it is generally necessary to add corresponding water-stop measures to ensure the safe use of the system, and the combination of the two has always had hidden dangers. The original process of adding a curtain behind the pile row, pile It is integrated with the curtain, and the force is not uniform. The crown and beam connection between the piles is required. When the curtain has a water leakage point behind the pile, it is not easy to detect and it is difficult to repair; although the cement-soil wall support system has good continuity, It can effectively stop water, but the strength of cement soil is very low, especially the tensile strength is extremely low, generally less than 0.1Mpa. In use, it is generally necessary to add a large amount of steel and a large number of anchor rods to make up for the lack of strength, which is not only economically wasteful , and a large number of anchor rods are constructed below the groundwater level, and there are certain safety hazards in the construction process. How can we combine the safety, economy, and continuity of cement and soil of row piles to design a support system, will be a very good and applicable support system

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