挤压性破碎软岩隧道大变形特征及机制研究

为了实现对埋深的模拟，考虑振动台的载重量，设计并制作了一套质量较轻的柔性伺服气压加载系统.分别开展了考虑和不考虑松动圈的振动台模型试验，同时建立了相应工况的隧道动力计算数值模型，将试验结果与数值计算结果进行了对比.模型试验数据与数值模拟结果规律较为一致，且反映了松动圈的动力响应影响，表明采用柔性加载来模拟埋深产生的地应力的方法是可行的.结果表明：在一定埋深条件下，隧道结构的自身振动特性表现不明显；松动圈的存在增大了隧道结构和周围岩体的加速度响应，从而使结构破坏程度更为严重；无论有无松动圈，结构整体的动力响应规律相似.松动圈对隧道结构地震动响应的不利影响可以归结为松动圈与围岩交界面发生地震波的折射和反射以及松动圈相比于围岩较软弱，地震时更容易发生局部变形这2个因素.

Simulating excavation damaged zone around a circular opening under hydro mechanical conditions

Considering the load capacity of the shaking table, a light-weighted servo-controlled flexible air bag loading system was designed and fabricated, which was used in shaking table model tests for load cases both setting and not setting a loosen-zone. Numerical models were also built for the same load cases. The results from model tests and numerical simulation were compared, showing consistence and the effects from the loosen-zone. It is then testified that the flexible loading system could be applied to dynamic tests on shaking tables. Results shows that the vibration feature of buried tunnel under certain depth itself is not obvious; acceleration responses of the tunnel structure and the surrounding rock is enlarged by the existence of a loosen-zone; with the loosen-zone, the damage of the structure is more serious; however, the loosen-zone does not change the strain response law of the tunnel structure. The adverse effects of the loosen-zone on the ground motion response of the tunnel structure can be concluded: 1) the refraction and reflection of the seismic wave occur at the interface between the loosen-zone and the surrounding rock; 2) the loosen-zone is weaker than the intact surrounding rock, and the local deformation is more likely to occur during the earthquake.