静压沉桩引起邻近隧道水平位移计算方法研究

A study on the calculation method of horizontal displacement of adjacent tunnels caused by static pressure sinking piles

静压沉桩过程中会产生强烈的挤土效应,使得桩周土及邻近的地下电缆隧道产生扰动变形,如果变形过大,可能破坏隧道的防水结构,造成隧道渗漏水,严重影响隧道的正常使用及安全。在圆柱孔扩张理论及基床系数法的基础上,研究了饱和软土地区静压沉桩作用下周边地层及邻近既有电缆隧道应力及水平位移的理论计算方法;考虑群桩效应,推导了单排群桩施工造成邻近既有电缆隧道水平位移的理论计算方法,并研究了群桩效应影响系数的取值范围;最后,开展了实际工程的理论计算和数值模拟。研究结果表明:提出的方法可方便计算出单桩及单排群桩施工造成的邻近既有电缆隧道的水平位移,计算结果与数值模拟结果吻合性良好。研究可为有邻近桩基施工时电缆隧道的扰动预测及保护提供参考。

In the process of static piling,there will be a strong soil squeezing effect,which will cause disturbance and deformation of the soil around the pile and the adjacent underground cable tunnel.If the deformation is too large,it may destroy the waterproof structure of the tunnel,causing leakage and seriously affecting the normal use and safety of the tunnel.Based on the theory of cylindrical hole expansion and the method of foundation bed coefficient,the theoretical calculation method of stress and horizontal displacement of surrounding strata and adjacent existing cable tunnels under the action of static piling in saturated soft soil areas are firstly studied.Secondly,considering the effect of group pile,the theoretical calculation method of horizontal displacement of adjacent existing cable tunnels caused by a single row of group piles construction is deduced,and the range of influence coefficient of group pile effect is studied.Finally,the theoretical calculation and numerical simulation of practical engineering problems are carried out.The results show that the method proposed in this paper can effectively calculate the horizontal displacement of adjacent existing cable tunnels,and the results are in good agreement with the numerical simulation results.The research can provide a reference for the prediction and protection of the disturbance to cable tunnels in the construction of adjacent pile foundations.