60 m大跨度洞室最小矢跨比研究

大跨度洞室的最小矢跨比是大跨度洞室尺寸设计的重要参考依据,基于能够考虑岩体软化、剪胀、体胀、密度变化等开挖响应特征的Cavehoek本构模型和能够反映不同岩体质量、岩石单轴抗压强度条件下的极限应变标准,对不同地质强度指标GSI、埋深、侧压力系数、结构面等条件下的60 m大跨度洞室的最小矢跨比进行了研究.结果表明,GSI、侧压力系数、埋深3个因素中,GSI对大跨度洞室的最小矢跨比影响最大,侧压力系数和埋深次之;岩体质量越好,最小矢跨比越小,最小矢跨比与侧压力系数和埋深之间并非线性关系.结构面和岩石单轴抗压强度对大跨度洞室最小矢跨比有较大的影响,尤其是缓倾结构面非常不利于大跨度洞室成拱.

The research on the smallest rise-span ratio of large span cavern

The smallest rise-span ratio of large span cavern is an important reference to design the dimension of large span cavern. Based on both cavehoek constitutive model which can take some response characteristics during the excavation into consideration,such as the softening behavior of rock mass, dilation, volume expansion, density change, etc., and the critical strain which can reflect the influence of rock mass quality and UCS of the intact rock, the smallest rise-span ratio of 60 m long span caverns with different values of GSI, buried depth, lateral pressure coefficient of in-situ stress, structural planes, etc. were studied.The results show that: among the three factors of GSI value, lateral pressure coefficient and burial depth, the value of GSI has the biggest influence on the smallest rise-span ratio of large-span cavern, followed by the lateral pressure coefficient and burial depth. The better the rock mass, the smaller the ratio of smallest rise-span, and the minimum rise-span ratio is not linear with the lateral pressure coefficient and burial depth. The structure plane and UCS of intack rock also has great influence on the minimum rise-span ratio of large span cavern, especially the gently inclined structural plane which is not conducible to the arch forming of large-span caverns.