山岭隧道洞口段围岩注浆厚度对抗震效果的影响分析

Analysis of the Influence of Grouting Thickness of Surrounding Rock at the Entrance of Mountain Tunnel on Anti-Seismic Effect

以山岭隧道洞口段为研究对象,通过有限元数值模拟验证在不同注浆加固厚度下的加固效果,结果表明:注浆加固措施对拱顶沉降和最大加速度有一定的影响,随着注浆加固厚度的增大,隧道各个部位的拱顶沉降和最大加速度逐渐减小,最大位移降幅发生在拱顶,最小发生在仰拱;隧道左侧最大主应力整体大于右侧,最大值部位为左拱脚处,这与整个隧道洞口左侧处于浅埋偏压有关;注浆加固围岩能够减小隧道的应力,入射10%超越概率地震波时,除个别监测点外其余部位都有不同程度的降低,左隧道拱顶处降低幅度最大,右隧道为右拱腰处。入射2%超越概率地震波时,双侧隧道各部位都有一定程度的降低,左隧道降低幅度平均值约为15.5%,右隧道约为11.3%;虽然注浆加固措施对山岭隧道洞口段有一定的作用,但降低幅度有限,对于强震区应采用联合加固措施,以保证隧道的稳定性。

Taking the entrance section of mountain tunnel as the research object,the reinforcement effect under different grouting reinforcement thickness is verified by finite element numerical simulation.The test results indicated:grouting reinforcement measures have a certain impact on the peak vault settlement and maximum acceleration.With the increase of grouting reinforcement thickness,the vault settlement and maximum acceleration of each part of the tunnel gradually decrease,the maximum displacement reduction occurs in the arch crown,and the minimum occurs in the inverted arch.The peak value of the main stress on the left side of the tunnel is larger than that on the right side,and the maximum value is at the left arch foot,which is related to the shallow buried bias pressure on the left side of the tunnel entrance.Grouting reinforcement of surrounding rock can reduce the stress of the tunnel.When the incidence rate of 10%exceeds the probability of seismic wave,all the other parts have different degrees of reduction except some monitoring points.The reduction range is the largest at the left tunnel vault and the right tunnel is at the right arch waist.When the incident seismic wave of 2%exceeds the probability,each part of the tunnel on both sides has a certain reduction,the average reduction amplitude of the left tunnel is about 15.5%,and that of the right tunnel is about 11.3%.Although grouting reinforcement measures have a certain effect on the entrance section of mountain tunnel,the reduction range is limited.For the strong earthquake area,the joint reinforcement measures should be adopted to ensure the stability of the tunnel.