中文摘要：

松动圈是岩体地下硐室稳定性评价和设计的重要指标之一。地下硐室的几何特性对松动圈的范围有一定的影响。运用显式有限差分法，从地下硐室的断面积、高度和跨度以及断面形状等方面就地下硐室的几何性质对松动圈影响的问题进行了数值模拟研究。结果表明：随着断面面积的增大，松动圈范围扩大，扩展速度加快；随着断面跨高比的增大，松动圈范围增大；高跨比变化对松动圈范围的影响较小；断面形状对松动圈范围及扩展速度有很大影响。研究结果对地下硐室的开挖以及衬砌设计具有参考意义。

英文摘要：

Broken zone is one of important indices for stability evaluation and design of underground cavity. The underground cavity＇ s geometric properties have some influence on broken zones＇ range. This paper uses the numerical simulation based on the explicit finite difference method to analyze how these factors, such as the area, highspan ratio and cross-section shape of the underground cavity influence broken zones＇ range. The results show that with the increase of area, the range of broken zones expands and the pace of expansion becomes faster; broken zones＇ range also expands with the increase of high-span ratio, but the change of high-span ratio＇ s impact on the broken zones is small and the cross-section shape＇ s impact on the broken zones＇ range and the pace of expansion is large. The results of this paper can give a reference to underground cavity excavation and lining design.