岩石地铁工程的围岩分级方法研究

摘要

Based on the Standard for Engineering Classification of Rock Mass, a rock mass classification method considering the engineering span effect is put forward in this paper by combining diagram-based quantized contrast with metro engineering features. The method includes adjusting the existing qualitative feature classification of sur⁃rounding rock, improving BQ indexes so that the qualitative classification is consistent with the quantitative classifi⁃cation, giving the sub-classification and corresponding BQ indexes for the surrounding rock of running tunnels and station tunnels based on the rock mass quality and engineering span classification and quantifying rock mass self-stability. Based on research on the physical and mechanical parameters and classification of surrounding rock for Chongqing Metro Lines 1 and 6, it is determined that on the premise of construction safety, one third of sandy sur⁃rounding rock of gradeⅣcan be classified as that of gradeⅢby the above classification method regarding the run⁃ning tunnel, and the percentage is 80%for the station tunnel.%在国标《工程岩体分级标准》的岩体质量分级基础上，文章运用图解法量化对比围岩分级方法，并结合地铁工程特点提出了反映工程跨度影响的岩石地铁工程围岩分级方法，包括：改进与调整现有围岩分级中围岩定性特征分级，同时改进各级围岩基本质量指标BQ值，使定性分级和定量分级协调一致；依据岩体质量和工程跨度分级的思想，给出区间隧道与车站隧道的亚级分级及其相应的BQ值，量化岩石地铁工程围岩自稳能力。通过对重庆轨道交通1#、6#线的围岩物理力学参数和围岩分级的调研，在同样保证安全的前提下，与国标相比，采用本文提出的岩石地铁工程围岩分级方法，区间隧道砂质泥岩有1/3的Ⅳ级围岩可以提升为Ⅲ级围岩；车站隧道砂岩约有80%的Ⅳ级围岩可以提升为Ⅲ级围岩。