复合断面隧道受侧方沉桩影响的模型试验研究

Model test study on the composite section tunnel influenced by lateral pile driving

打桩施工产生的冲击荷载和挤土效应可通过地层传递到隧道结构,需进行控制和监测来保证地铁隧道的正常运营。基于青岛地区的地层工况,采用室内模型试验研究复合断面隧道受旁侧沉桩施工的影响。试验中考虑了单桩、群桩、沉桩深度与桩隧间距等因素,研究沉桩对既有隧道附加弯矩和振动效应的影响。结果表明:随着桩隧间距的增大,隧道的附加弯矩逐渐减小,附加弯矩的分布形态基本呈现出了隧道顶部和底部远离中心点位、左右两端靠近中心点位的趋势。当沉桩深度超过某一定值时,沉桩深度和桩隧间距对隧道振速有明显的影响。模型试验揭示了复合地层中沉桩施工对临近既有隧道的受力变形和动力响应规律,研究成果可为类似工况下隧道监测提供参考。

The impact load and earth squeezing effect generated by piling construction can be transferred to the tunnel structure through the stratum,which needs to be controlled and monitored to ensure the normal operation of subway tunnel.Based on the stratum condition in Qingdao area,laboratory model test was conducted to study the influence of lateral pile driving construction on the composite section tunnel.In the test,factors such as single pile,group piles,the depth of pile driving and the distance between piles and tunnel are considered to study the influence of pile driving on the additional bending moment and vibration effect of existing tunnel.The results show that with the increase of the distance between piles and tunnel,the additional bending moment decreases gradually.The distribution pattern of the additional bending moment basically shows that the top and bottom of the tunnel are far away from the center point,and the left and right ends of the tunnel are close to the center point.When the depth of pile driving exceeds a certain value,the depth of pile driving and the distance between piles and tunnel have obvious influence on the tunnel vibration velocity.The stress deformation and dynamic response of pile driving construction to adjacent existing tunnel in composite stratum are revealed.The research results can provide a certain reference for tunnel monitoring under similar working conditions.