汶川地震公路隧道普通段震害分析及震害机制研究

Analysis of seismic damage and mechanism of general section of highway tunnel in Wenchuan earthquake

在汶川地震中隧道普通段出现了严重的震害,为了提高高烈度地震区隧道普通段的抗震性能,通过统计分析汶川地震公路隧道普通段震害调查资料,对隧道普通段进行了震害分析。结果表明,隧道普通段震害主要发生在软岩均一段、软硬围岩交接段软岩部分以及围岩缺陷段。通过三维有限差分数值模拟和现场典型震害分析,研究了公路隧道普通段的震害机制,探明了围岩均一普通段隧道震害机制,即硬岩隧道普通段基本无震害,软岩隧道普通段震害较严重,衬砌结构受地震惯性力影响较大,强制位移次之;探明了围岩软硬交接普通段隧道震害机制,即震害主要发生在软硬围岩交接段软岩部分,震害的主要影响因素为强制位移,地震惯性力次之;探明了围岩缺陷普通段隧道震害机制,即震害主要由地震惯性力造成强制位移影响很小。研究成果可为高烈度地震区公路隧道普通段的抗震设防提供参考。

For the tunnel general sections, seismic damage types appeared in Wenchuan earthquake. In order to improve aseismatic performance of tunnel general sections in high intensity earthquake area, by analyzing the seismic survey data of general sections of highway tunnel in Wenchuan earthquake, seismic damage analysis is concluded. The results show that the seismic damages of tunnel general sections occurred mainly in the soft rock of uniform section, the soft rock part of soft and hard surrounding rock and the defect section. Through three-dimensional finite difference numerical simulation and analysis of typical field damage, seismic damage mechanism of highway tunnel general section is studied. The seismic damage mechanism of surrounding rock uniform general section is understood; namely there is almost no seismic damage in the hard rock tunnel general section damage, while the seismic damage is more serious in the soft rock tunnel general section; lining structure is greatly influenced by the seismic inertia force, and forced displacement comes second. The seismic damage mechanism of the soft and hard surrounding rock general section is revealed, that is, the seismic damage occurs mainly in the soft rock part of soft and hard surrounding rock; the main influence factor is the forced displacement, closely followed by seismic inertia force. The seismic damage mechanism of the defect of general section is disclosed, namely the seismic damage is mainly caused by the seismic inertia force, and forced displacement has little effect. These research results can provide reference for the seismic fortification of highway tunnel general section in high intensity earthquake area.