土木工程外文翻譯---在不良地質(zhì)條件下的隧道掘進(jìn)-建筑結(jié)構(gòu)-文庫(kù)吧
2025-04-17 14:10 本頁(yè)面
【正文】 Norway, the world’s longest road tunnel. The 100m*m cross section tunnel is being excavation in a Precambrian gneiss, a very good and stable rock mass: the supports are on average only 78 rock bolts plus a 7cm thick shotcrete lining per meter of tunnel. The excavation is carried out by the drill and blast method, which been evaluated to be less expensive and more reliable than the 。use of alarge diameter TBM. The average progress rate is – km per year with two faces, against the km per year, estimated for a large –diameter TBM (Kovari et al., 1993) With this background in mind, this paper is intended to address the problem of TBM tunnelling in difficult ground conditions. Based on a few selected case examples, the discussion is centered upon the relatively more important or difficult ground conditions which can be listed as follows: borability limits。 instability of excavation walls。 instability of excavation face。 faut zones。 squeezing. ROCK TBM TUNNELLING The practically infinity number of binations rock, soil and environmental conditions which may be encountered during tunnel excavation has determined a great difference in the types and characteristics of the available TBM’s . There are many different schemes for the classification of tunnelling machines. For the example the AITES/ITA Working Group (Mechnisation of Excavation ) is currently working on the definition of an internationally acceptable classification of TBM’s with the purpose of establishing terminology and “terminology” for the optimum choice of the machine (Table 1). 西南交通大學(xué)本科 畢業(yè)設(shè)計(jì) 第 3 頁(yè) Rock tunnelling machine can be grouped in to three main categories (Table2): Unshielded TBM (. Open TBM), Single Shielded TBM which is the way of creating new types of TBM’s that are suitable for application over a wider range of geological conditions, even though the distinction between TBM for rock and TBM for soft ground remains. From the point of view of rock TBM dimensioning, it is necessary to point out that, although TBM’s of more than 10 m in excavation diameter have been constructed, it is always advisable to try to limit the maximum size of the tunnel and therefore that of the TBM. As easily perceived, the reasons for limiting the tunnel diameter are: ? the potential of a TBM in hard rock decreases with in increasing diameter (Kovari et al., 1993。 Bruland. 1998)。 ? There are technological limits for the maximum dimensions of some major TBM ponents, for example, the bearing and the head。 ? The intensities of both the instability phenomena and the induced convergence also increase with increasing diameter of the excavation (Tseng et al., 1998。 Barla G. and Barla M., 1998). There already exists a positive and consolidated experience in the use of TBM’s in
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