Abstract
Regular safety inspections are an important guarantee to ensure the high-quality operation of concrete structures of tunnels. The Chinese West-east Gas Pipeline Project is large in scale and complex in construction environment. These tunnels are equipped with gas pipelines, and the concrete structural defects of the tunnels are continuously exacerbated during the long-term operation. There are few studies on the safety evaluation methods of concrete structures of gas tunnels. Based on the characteristics of the operation of the gas tunnels, this paper proposes the establishment of a structural safety comprehensive inspection system from the following seven aspects, that is, the void between the concrete lining and surrounding rock, the strength of the concrete lining, the thickness of the protective layer of the reinforced concrete lining, the carbonization depth of the concrete lining, the deformation of the tunnel section, the cracks in the concrete lining, and the auxiliary concrete structure of the tunnel. In addition, a corresponding quantitative determination method and safety level classification standard are established. Based on the fuzzy mathematics theory and a structural safety comprehensive inspection system, a five-level safety evaluation method for tunnel concrete structures is proposed. Finally, a comprehensive inspection and evaluation were carried out for a tunnel running across the mountain.
Highlights
Regular safety inspections are an important guarantee to ensure the high-quality operation of concrete structures of tunnels
A fuzzy comprehensive evaluation is an evaluation method based on fuzzy mathematics theory
The defects in the concrete structures are continuously exposed during the long-term operation of the tunnel, such as concrete lining cracks, separation, and water leakage, which severely affects the operation quality and safety of the tunnel
Summary
Regular safety inspections are an important guarantee to ensure the high-quality operation of concrete structures of tunnels. Its basic principle is to compare the relative importance of the factors to be evaluated and determine the weight for each factor.[9] A fuzzy comprehensive evaluation is an evaluation method based on fuzzy mathematics theory It evaluates the research object based on the known evaluation standards and actual measurement data of the related indicators, which have undergone a fuzzy transformation.[10] The researchers have applied the above two methods to carry out extensive studies on the evaluation of the operating conditions of highways and railway tunnels.[8,11,12,13] The concrete structures of a gas pipeline tunnel usually include concrete lining and auxiliary structures such as anchor piers and pipe buttresses. The following classifications of inspection methods are determined. (1) For the measurement of separation behind the concrete lining of tunnels in dry regions of waters and mountains, GPR, an impact imaging method, and a high-density surface wave method can be used. (2) For tunnels under a water sealing operation, the measurement for a
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