摘要
坝陵河大桥隧道锚洞工程周边围岩的岩溶较发育,勘察设计阶段确定其围岩级别为II～IV级。根据实际开挖所揭露的岩溶状况,需要调整超前支护和初期支护参数,以保证锚洞施工安全。在岩溶地质预报和一般地下工程岩体质量分级基础上,专门针对围岩为不同岩溶发育状态的岩体进行质量分级修正,建立锚洞岩溶围岩分级的物理模型和数学模型。根据岩体波速测试、岩体抗压强度以及岩溶发育程度修正系数等参数的确定,计算锚洞岩溶围岩级别主要为V级。事实上,在整个锚洞施工过程中,均采用超前小导管、超前锚杆、型钢拱架、挂网及喷射混凝土等强支护措施,锚洞开挖采用台阶法分步开挖。锚洞开挖完毕后对周边的破碎岩体及溶洞进行了注浆加固处理,也就是说,锚洞施工的超前支护和初期支护参数实际均按照V级围岩实施。实践表明,本工程岩溶围岩分级是合理的,对其他同类工程可提供借鉴。
Karst is fully developed in the surrounding rock of west anchor tunnel of Balinghe Bridge. The rock classification is considered as grades Ⅱ to Ⅳ during the survey. In accordance with the actual karst excavation, advanced and initial supporting parameters should be adjusted for construction safety of the anchor tunnel. On the basis of karst geological forecast and general underground engineering rock mass classification, the physical and mathematical models of karst rock classification for the anchor tunnel are established, aiming at amending rock mass classification for different kinds ofkarst rocks. According to the tests of rock velocity, rock strength, as well as the extent of karst correction factor and other parameters, the karst rock classification for this anchor tunnel is determined as grade V. In fact, throughout the construction process, these measures are adopted as strong support of the anchor tunnel, such as advanced small pipe, advanced anchoring, steel frame, steel wire, shotcrete, etc..And the bench cut method is also taken for the anchor tunnel excavation. In addition, the fractured rock and the surrounding cave are reinforced by grouting after the excavation of anchor tunnel. In other words, the parameters for initial support of the anchor-tunnel are taken by considering the rock mass as grade V. In practice, it indicates that the karst rock classification for this tunnel is reasonable, which can be taken as a reference for other similar projects.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2009年第6期1208-1212,共5页
Chinese Journal of Rock Mechanics and Engineering
关键词
岩石力学
岩溶
地质预报
围岩分级
rock mechanics
karst
geological forecast
surrounding rock classification
