深埋大跨度软岩硐室让压支护设计研究

Yield supporting design for deep and large-span soft rock caverns

针对金川三矿区破碎硐室进行了较系统的支护设计研究,得到了一些有价值的成果。首先根据工程地质和围岩自身的特点,在原设计方案的基础之上提出了三步开挖、二次支护和三次让压的总体计算方案,并采用三水平四因素的正交试验表设计了16个让压支护方案;然后,应用FLAC2D对这16个支护方案分别进行了计算,并采用文中所提出的优选评价指标Es进行了综合评定和分析,得到了最佳让压方案;最后,应用FLAC3D对最佳让压方案进行了24工序的三维开挖与支护计算,并提出了较为合理的开挖与支护建议。实际应用表明,优化后的方案有利于该深埋大跨度软岩硐室的长期稳定,该优化设计方法有一定的推广价值。

Systematic researches on the supporting design for the breaking cavern in No. 3 Mining District of Jinchuan are conducted, and some valuable achievements are obtained. At first, according to the characteristics of engineering geology and surrounding rock mass, the general computation scheme of three-step excavation, two-time supporting and three-time yield is put forward. Sixteen yielding supporting schemes are designed by the orthogonal test table of three levels and four factors. Then, the sixteen supporting schemes are computed and analyzed by use of the FLAC^2D software, and the optimization appraisal index E8 first put forward in the paper is applied to synthetically assess and analyze these schemes. The optimum yield scheme is got. Finally, the three-dimensional excavation and supporting computation of twenty-four working processes is implemented by use of FLAC^3D for the optimum scheme, and some reasonable advices are gained. The results of practical application indicate that the optimum supporting scheme is in favor of the long-term stabilization of the deep and large-span soft rock cavern, and that the optimum design method is worthy to be popularized.