一、双緩隧道全断面开挖某隧道全长2379.41米,穿过版状頁岩,F=5～石6,岩层約成80°的傾角,与隧道中綫的夹角約为80°。岩的每层厚度0.5～1.0米,两层之間夹有薄层軟石。在个別地段有少量渗水。隧道曾采用过几种开挖方法。1959年按单綫施工时,开始是上下导坑先拱后牆;而后又改为先牆后拱;最后是全面开挖。1960年单綫改为双綫,首先考虑的問題是采用什么方法开挖。当时工期紧迫,木料、水泥都很紧张,又看到石质較好,再加上有些单綫全断面开挖的經驗,于是便采用了側中槽全断面开挖。 (1)側中槽全断面开挖簡介其施工順序如图1所示: 1.上导坑:断面为2.5×2.0m,頂部为弧形不做支撑。 2.拱部扩大:为了导坑出碴方便,扩大紧紧跟上,与上道坑保持3～4m距离。扩大分两层成台阶开挖,每层厚約1.25m,工作面长約6～10m。 3.挖側中梢:为了在起拱綫以上的拱部平台上鋪 First, the double slow tunnel full-face excavation of a tunnel full-length 2379.41 meters, through the plate-shaped shale, F = 5 ~ 6, rock formation of about 80 ° angle, and the tunnel center line angle of about 80 °. The thickness of each layer of rock 0.5 to 1.0 meters, sandwiched between two thin layers of soft rock. In some areas there is a small amount of water seepage. Several methods of excavation have been used in the tunnel. In 1959, according to the single-line construction, it began with the upper and lower pilot pit arch arch wall; and later changed to the first wall arch; Finally, full excavation. In 1960 the single line to double line, the first question to consider is what method of excavation. At that time, the construction period was tight. Both timber and cement were very tense, and they also saw that the stone quality was better. Coupled with the experience of some single-section full-face excavations, the full-face side excavation was adopted. (1) side of the groove full section excavation Brief introduction The construction sequence shown in Figure 1: 1. On the pilot pit: section 2.5 × 2.0m, the top of the arc do not do support. 2. Arch Department to expand: In order to guide the pit out of ballast easy to expand to keep up, and on the road to maintain a distance of 3 ~ 4m. Expansion in two steps into the excavation, each layer is about 1.25m thick, working surface length of about 6 ~ 10m. 3. dig side of the tip: in order to arch lines above arch platform on the shop