Construction method suitable for penetrating water supply pipe below tunnel in composite stratum with soft upper part and hard lower part

Abstract

The invention discloses a construction method suitable for penetrating a water supply pipe below a tunnel in a composite stratum with the soft upper part and the hard lower part, and belongs to the technical field of civil engineering. The construction method aims to strictly control tunnel arch settlement and prevent the situation that settlement overrun affects the water supply pipe to cause a structure (arch culvert) failure. By synthesizing the factors, the overall construction scheme is as follows: firstly, an advance support is constructed; after the design effect is achieved, the composite stratum with the soft upper part and the hard lower part is constructed through a three-step method, specifically, the upper step, namely the soft stratum is excavated through a mechanical method,the middle and lower steps, namely rock strata are excavated through a blasting method, and the circulation footage of a control area is one steel frame interval; manual work cooperates with mechanical excavation as far as possible, timely closure for ring forming is achieved, and arch sinking is inhibited; a secondary lining closely follows the excavation surface, and one-time pouring forming isachieved through a formwork trolley arch wall; and hole interior and ground surface settlement monitoring of the control area, as well as vibration speed monitoring within the blasting impact range are strengthened, and information is fed back in time to guide the design and construction.

Description

Technical field: [0001] The invention belongs to the technical field of civil engineering, and in particular relates to a construction method suitable for tunnels passing through water supply pipes in upper-soft and lower-hard composite strata. Background technique: [0002] At present, there are many excavation methods for shallow-buried long-span tunnels, and the double-side-wall pilot tunnel method is one of the methods that can strictly control the settlement. Although the double-side-wall pilot pit method can better control the deformation of the surrounding rock and ensure construction safety, due to many procedures and complicated construction, the overall construction period is very long and the cost is high. In the upper soft and lower hard formations, especially in the lower hard formations (moderately weathered and slightly weathered rocks), there are certain limitations in the use of double-side-wall pilot pit method in blasting construction. First, the blasting ...

AI Technical Summary

Problems solved by technology

[0003] When the tunnel passes through the water supply pipe, it is necessary to strictly control the subsidence of the tunnel and the ground surface to prevent the structure of the water supply pipe from being damaged. For large-span tunnels in the upper soft and lower hard strata, after the upper soft soil layer is excavated, the lower rock stratum is excavated by blasting. , due to the blasting vibration, the blasting operation of the rock mass in the lower part of the tunnel may cause impact damage to the vault structure, and even cause large-scale settlement in the tunnel and on the surface

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