The water around thenear-sea tunnels is supplied infinitely, and mechanical characteristics of the lining and movement joint are inevitably affected by waterproof methods. The research on the mechanical characteristics of the waterproof system is immature. As a case study of the Gongbei tunnel, a scale model was established in this study, and the stratum, pipe curtain, grouting circle, lining, waterproof board, and movement joint were simulated based on the similarity theories. By changing the externally applied water pressure and drainage discharge, the variation and distribution of the water pressure and strain on the lining with the fully wrapped waterproof (FWW) method, the lining with the partially wrapped waterproof (PWW) method, and the movement joint were investigated. Furthermore, several suggestions on the selection of the waterproof method were presented. The results indicate that the PWW method can reduce the water pressure and strain on the lining under the drained state. Under the state of free drainage, the strain on the lining with the PWW method may get a discount of about 30%. More attention could be paid to the waterproof of the movement joints in the construction process, especially the invert. The research results may offer some valuable insights into the waterproof design of similar near-sea tunnels.
With the orderly promotion of the infrastructure construction in China, the number of coastal tunnels is increasing, but the coastal environment is accompanied by a large amount of groundwater and the designs of the waterproof and drainage system of coastal tunnels have always been a hot topic in the industry. If the waterproof and drainage system designs of the coastal tunnels are improper, the tunnel structure will easily be damaged and the stability and service life of the whole project will be affected. Based on the Gongbei tunnel project of the Hong Kong-Zhuhai-Macao Bridge, this paper discusses the designs of the waterproof and drainage system, and the waterproof detail structures of the Gongbei tunnel. Indoor similarity tests were carried out to study the law of the free water discharge of the tunnel under variable water heads, the relationship between the water pressure outside the lining and the water discharge, the relationship between the water pressure outside the pipe roof and the water discharge, and the distribution of water pressure around the tunnel. The reliability of the indoor similarity test was verified by the field test. The results show that the whole waterproof system should be adopted in the Gongbei tunnel, that is, grouting ring + pipe roof freezing ring + initial lining + waterproof board + tertiary lining. In a certain range, the greater the water head, the greater the free water discharge of the tunnel. When the water head is large, the free drainage tends to a fixed value. When the tunnel is completely plugged, the water pressure outside the tunnel is distributed from the hydrostatic pressure. When the tunnel adopts drainage measures, the water pressure outside the lining will be reduced to a certain extent even the water discharge is very small. The above research can provide a reference for the design of the waterproof and drainage system similar to the coastal tunnel in the future.
When a TBM carries out tunnelling in complex strata, there is often low tunnelling efficiency and an increase in tunnelling costs due to the improper selection of tunnelling parameters, the wrong estimation of geological conditions, or adverse geology, so it is necessary to evaluate the tunnelling adaptability of TBM construction. In this paper, based on hydraulic engineering in Xinjiang, 11 evaluation indexes of TBM tunnelling adaptability are determined by comprehensively considering the influence of tunnelling parameters, geological conditions, and adverse geological factors on TBM tunnelling adaptability. After that, the membership function of each evaluation index is determined by referring to the existing research results and fuzzy mathematics method, and the weight of each evaluation index is determined and adjusted by the analytic hierarchy process (AHP)–entropy weight (EW) method. Finally, the adaptability evaluation method and evaluation model of TBM tunnelling are put forward. The TBM tunnelling adaptability evaluation model proposed in this paper is verified by relying on the actual situation of three interval tunnels in the project, and good effects are obtained. This study can provide a reference for the evaluation of TBM tunnelling adaptability in similar strata.
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