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以石质高陡边坡下修建富龙高速公路为例,分析了深挖路堑的劣势,提出并成功实施了柱式棚洞的变更方案;进而针对全断面开挖法,在对边坡自稳性分析的基础上,采用有限元法分别模拟了半暗挖地段采用与不采用联合支护(微型倾斜锚桩、锚杆、喷射混凝土的组合)时地层的受力及变形,定量分析了联合支护的效果,进行半暗部开挖后由于自重应力场导致的位移最大约2.1mm,而施做联合支护对降低位移作用微弱,反而提高了部分围岩区域的内部应力值,加剧了边墙围岩内部的应力集中,说明完整性、均质性较好的石质高陡边坡下采用联合支护对抑制地层变形、改善地层受力状况效果不明显。研究结果表明:富龙线石质高陡边坡下修建公路时优先采用棚洞方案是可行的,且在此条件下修建棚洞时可根据情况改进微型倾斜锚桩、锚杆、喷射混凝土的联合支护方式。
Taking the construction of Fulong Expressway under high and steep slopes as an example, this paper analyzes the disadvantage of digging the cutting and puts forward and successfully implements the change plan of column-type sheds. Then, according to the full-face excavation method, Based on the stability analysis, the finite element method is used to simulate the stress and deformation of the formation in the semi-submerged excavation with and without the combination of support (micro-inclined anchor pile, anchor bolt, shotcrete) The effect of joint support is that the displacement due to self-weight stress field is about 2.1mm after the excavation of the semi-dark section, but the joint support exerts a weak effect on reducing the displacement, but increases the internal stress value of part of the surrounding rock area, which aggravates The stress concentration in the surrounding rock of the side wall shows that the combined support under the high and steep slope with good integrity and homogeneity has no obvious effect on suppressing the deformation and improving the stress state of the formation. The results show that it is feasible to adopt the scheme of shed-hole preferentially when building the highway under the steep slope of Fulian line, and the improvement of the micro-inclined anchors, bolts and shotcrete Joint support mode.