Supporting structure in PBA method pilot tunnel and construction method of supporting structure

Abstract

The invention relates to a PBA method pilot tunnel inner supporting structure and a construction method thereof, and belongs to the field of building construction, the supporting structure comprises a continuous wall body and a cast-in-situ bored pile, the cast-in-situ bored pile is a rigid recycled concrete pile body, and the continuous wall body is a continuous wall body formed by tough low-strength recycled concrete. According to the low-toughness and low-strength recycled concrete, synthetic fibers are replaced by additional components consisting of bentonite, fly ash and basalt fibers, and lime is added, so that the prepared concrete is low in compressive strength, slow in compressive strength increase, good in toughness, capable of generating large deformation without cracking under the action of water and soil pressure, and high in toughness. Coordinated deformation with surrounding soil bodies and meat piles with large rigidity can be achieved, and tight attachment is guaranteed. The water glass and the calcium chloride solution are used as additives, so that the impermeability of the concrete is improved. The supporting structure has the advantages of toughness, low strength, good waterproof performance and the like, is green, environment-friendly and low-carbon, and can be applied to waterproofing of underground engineering.

Description

Technical field [0001] The present invention belongs to the field of building construction, in particular a support structure in the PBA method and its construction method. Background technique [0002] The PBA method is also known as the cave pile method, which is to dig a small guiding hole. After the small guiding hole is applied, the beam column is completed, and then the top structure is applied, then subsequent construction is carried out under its protection. The PBA method is a retaining structure, which cannot stop water; in the case of groundwater, although the method of precipitation can be used, but the precipitation causes the waste of groundwater resources, the PBA method has been greatly underwater. limit. [0003] In recent years, some experts scholars have proposed the embedded water curtain of the biting pile to replace the pile, but there is a problem: [0004] 1) The difficulty of the pile is difficult, and it is extremely difficult to collapse during the dril...

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Problems solved by technology

[0004] 1) It is very difficult to form a hole in the pile, and it is easy to collapse the hole during the drilling process in the water-rich stratum, which brings great difficulties to the quality of the hole and the water-stop effect;

[0005] 2) It is difficult to coordinate the verticality of plain piles and meat piles of occlusal piles. Practice has proved that after reaching a certain depth, plain piles and meat piles are prone to bifurcation, especially in the sand and pebble layer. There are gaps, and the water-proof effect is difficult to guarantee

[0006] 3) The deformation of the plain concrete pile and the non-concrete pile is not coordinated, resulting in water leakage;

[0007] 4) The compressive strength of plain concrete piles increases with time, which makes it difficult to drill and cut in the later stage and is prone to fragmentation during drilling and cutting, resulting in water flow channels

[0008] 5) Plain concrete piles are prone to cracking after being stressed. Although synthetic fibers such as polypropylene fibers, polyester and polyacrylonitrile fibers are added, such synthetic fibers are not easy to diffuse, difficult to enhance toughness, and cannot be degraded to pollute the environment

[0009] 6) The concrete bleeding rate of the plain concrete pile is relatively high, and the water is easy to generate channels in the concrete during the floating process, thereby reducing the anti-penetration ability of the pile body

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