地下室基础预应力管桩施工对某既有隧道的影响研究

Research on Influence Distance of Prestressed Pipe Piles Construction for Basement Foundation in an Existing Tunnel

临近既有隧道进行挤土桩施工会对桩基周围的岩土体造成一定扰动,并对临近既有构筑物产生超净孔隙水压力和水平挤压力。以某建筑项目地下室基础预应力管桩临近既有隧道施工为例,利用小孔扩张理论计算出挤土桩的施工影响范围,通过分析计算影响范围及桩基与隧道的平面距离关系,发现该项目桩基施工对既有隧道的影响很小,提出将靠近既有隧道的两排预应力管桩改为非挤土桩等建议,从而使沉桩挤土效应的不良影响减到最小。

The construction of soil-displaced piles near the existing tunnels can cause certain disturbance to the surrounding rock and soil around the pile foundation,and generate super clean pore water pressure and horizontal compaction pressure on the adjacent existing structures.Taking the construction of a prestressed pipe pile for the basement foundation near an existing tunnel in a certain construction project as an example,the construction influence range of soil-displaced piles is calculated by using the theory of small hole expansion.By analyzing and calculating the influence range and the plane distance relationship between the pile foundation and the tunnel,it is found that the construction of the pile foundation in this project has little influence on the existing tunnel.Suggestions are put forward to change the two rows of prestressed pipe piles near the existing tunnel to non-soil-displaced piles,so as to minimize the adverse effects of pile sinking and soil displacement.