中文摘要：

地铁隧道往往不得不从既有结构基础附近穿过,隧道的施工会扰动周边地层,引起邻近基础及结构的沉降,甚至影响其安全或正常使用。为了预测并控制隧道开挖引起的结构沉降,就需要计算隧道开挖对地层的扰动程度。现有隧道开挖塑性区理论均以自由地层（地层中没有结构基础荷载作用）为前提假设,没有反映承载地层隧道开挖影响的特殊性。考虑均质各向同性理想弹塑性地层,利用自由地层隧道开挖影响的解析解和结构基础荷载影响的解析解,提出一个预测承载地层隧道开挖引起的地层二次应力及塑性区形状和范围的理论方法,并通过算例分析基础荷载形式、大小和位置对隧道开挖塑性区的影响。结果表明,达到一定量值的邻近基础荷载会使隧道开挖塑性区的形状和范围明显地不同于自由地层隧道开挖塑性区,具体与荷载的位置、大小及分布形式有关。

英文摘要：

It is often unavoidable for metro tunnels pass nearby existing structure foundations.Tunneling may disturb the surrounding ground and cause nearby structure foundation settlements and thereby adversely affect safety and serviceability.In order to predict and control tunneling induced structure settlement,it is necessary to calculate the degree and extent of tunneling disturbance to the ground,especially the shape and range of the potential plastic zone in tunneling-induced secondary stress field.Existing theories on tunneling-induced potential plastic zoning are all based upon the premise that the ground is free from structure foundation loadings.In the present study,assuming homogeneous isotropic ideal elasto-plastic ground,a theoretical method for predicting the secondary stress and potential plastic zone caused by tunneling in load-bearing ground is developed by superimposing the analytical solution for tunneling in green field with the analytical solution for structure foundation loading,and calculations are conducted to analyze the effects of the position,magnitude and pattern of foundation loadings on tunneling induced plastic zone.The results reveal that foundation loadings of sufficient magnitude may significantly alter the potential plastic zone caused by nearby tunneling.