软土地基明挖矩形框架隧道动力响应及震陷加固分析

Study on Dynamic Response and Earthquake Subsidence Reinforcement of Open Cut Rectangular Frame Tunnel in Soft Foundation

为探明软土地基明挖矩形框架隧道动力响应特性及震陷加固效果,对某一裙边加固及桩基础加固的明挖隧道建立三维模型进行动力分析。研究结果表明:1)地震过程中软土地层随地震波振动的同时,逐渐下沉并发生震陷,且在软土区域中心沉降值最大;2)隧道顶板中心处受力最大,抗震设计中应重点考虑,底板及侧墙受力较小;3)桩基础及裙边加固能够显著降低隧道的动力响应及地表沉降,其中桩基础深度对加固效果有较大影响,加大桩基础深度并穿越软土地层可取得良好的加固效果,增加裙边加固深度对减轻震陷的作用不明显。

In order to study the dynamic response characteristics of open cut rectangular frame tunnel in soft soil foundation and the effect of earthquake subsidence reinforcement,a three-dimensional model was built for an open-cut tunnel with skirt reinforcement and pile foundation reinforcement for dynamic analysis.The results show that firstly the soft soil layer gradually sinks with the vibration of the seismic wave during the earthquake,and the central settlement in the soft soil region is the largest.Secondly,the stress at the center of the tunnel roof is the largest which should get more attention in seismic design,while the stress on the bottom plate and the side wall is small.Thirdly,pile foundation and skirt reinforcement can significantly reduce the dynamic response of tunnel and settlement of ground.The length of the pile foundation has great influence on the reinforcement effect,which means that good reinforcement effect can be obtained if the pile passes through soft soil layer.On the contrary,increasing the depth of the skirt reinforcement has very little effect.