土–结构动力相互作用分析打桩引起相邻隧道振动

Analysis of tunnel vibration due to pile driving under soil-structure dynamic interaction

某集装箱码头打桩施工紧邻拟建的大直径越江隧道,桩身长度达到50 m,隧道直径约18 m。为了分析打桩对该隧道可能产生的振动影响,采用有限元模拟打桩引起的隧道振动。该问题的本质是桩–土–隧道三者组成的体系在冲击荷载下的整体动力响应。桩与土、土与隧道之间的力学关系是这类问题的重点和难点。这种力学关系实质上是动荷载作用下的动力接触关系。利用ANSYS的瞬态分析和接触单元,通过对动力参数和接触参数进行合理设置,在验证了某工程实例的基础上,对该问题进行了有效的数值模拟,从而分析出隧道在打桩冲击荷载下的振动规律,为确定打桩间距、打桩深度以及打桩能量等重要参数提供参考。

The pile driving of a container terminal is close to the large-diameter tunnel to be built, with the length of pile being up to 55 m and the diameter of tunnel being about 18 m. To analyze the potential vibration of the tunnel affected by pile driving, the vibration was simulated with FEM. The problem was the dynamic reaction of the whole system consisting of piles, soil and tunnel under the impact load of pile driving. The mechanical relationship among piles, soil and tunnel was the key and difficulty for such kind of problem. In fact, it was the relationship of dynamic contact under dynamic load. According to the transient analysis and contact elements of ANSYS, and based on the verification of a practical project, the problem was successfully simulated by setting up dynamic and contact parameters reasonably, then the vibration of tunnel under the impact load of pile driving was analyzed. Important parameters including safe distance, pile length and energy of pile driving were provided for reference.