摘要
针对近对称型节理发育的Ⅳ级围岩区段,建立二维离散元计算模型,分析公路隧道开挖时不同支护参数下围岩深部位移、锚杆轴力及初支内力的分布特征及变化规律,探究该类地质条件下锚喷支护的必要性,明确合理的支护形式及设计参数。分析表明:施作格栅拱架后,必须设置锁脚锚杆,以减小围岩受扰动程度,确保落底安全;设置锁脚锚杆后,再增设系统锚杆、局部锚杆,支护效果提升不明显,建议原设计方案优化为"喷射混凝土+格栅拱架+锁脚锚杆",现场监测数据验证了该方案的可行性。
A two-dimensional discrete element model of tunnel is established,located in Ⅳ rock with symmetrical joint nearly. The displacement of the rock,the bolt axial force and the internal force of the concrete are researched under different support parameters,so that we can determine the reasonable support designing parameters. The results show that the lock pin bolt should be set when the steel grid is installed to reduce rock loose range and ensure tunnel safety,the supporting effect of the additional bolt systems,local bolt is not obvious when the foot bolt lock is set. It is recommended that the original design change as ‘shotcrete ＋ steel grid ＋ bolt lock pin ＇,the feasibility of the scheme is verified by the monitoring data from the field.
出处
《施工技术》
CAS
北大核心
2017年第1期85-88,共4页
Construction Technology
基金
贵州省交通运输厅科技项目(2014-122-022)
