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高黎贡山越岭隧道是大理-瑞丽铁路建设中的关键性工程,位于印度板块与欧亚板块相碰撞的缝合带附近,即滇缅泰亚板块与腾中地块(又称腾冲褶皱带、腾冲微板块),穿跨其相互碰撞汇聚的怒江缝合带。由于工程地质条件复杂,为确保隧道设计的安全与合理性,采取水压致裂方法,对该线路深埋长隧道开展了两个阶段的地应力测量工作。第一阶段对三个选线方案进行了8个钻孔的测量;第二阶段进行了5个深钻孔的测量。三向主应力关系式基本为S_H≥S_v>S_h,地应力特征主要以水平构造应力为主,隧道硐身附近的最大水平主应力优势方向基本在北东至北东东变化。根据水压致裂法地应力测量结果,对高黎贡山越岭隧道轴线走向、隧道断面形状的选取进行了讨论,预测了隧道开挖过程中发生岩爆的可能性。
The Gaoligong Mountain Crossing Tunnel is a key project in the construction of the Dali-Ruili Railway. It is located near the suture zone where the Indian plate collides with the Eurasian Plate, that is, the Yunnan-Burma Tianya Plate and the Tengzhong Block (also known as the Tengchong Fold Belt, Tengchong microplate), wear across the collision of their Nujiang suture convergence. Due to the complexity of engineering geological conditions, to ensure the safety and rationality of the tunnel design, a hydraulic fracturing method was adopted to measure the geostress of two phases in the deep long tunnel of the railway line. In the first stage, eight borehole measurements were made for the three alignment options; in the second stage, five deep borehole measurements were made. The three-way principal stress relationship is basically S_H≥S_v> S_h. The main features of the geostress are horizontal tectonic stress. The dominant direction of the maximum horizontal stress around the tunnel body basically changes from North to East. According to the results of stress measurement by hydraulic fracturing method, the paper discusses the direction of the tunnel and the shape selection of the tunnel in the Gaoligong Mountains, and predicts the possibility of rock burst during tunnel excavation.