在城市建设中，紧邻建筑物桩基进行基坑施工会引起桩基产生附加变形和附加 内力，进而会影响到上部建筑物的安全性与适用性． 关于该问题的理论研究，目前广泛采 用的弹性地基梁法将桩基视为 Winkler 地基或 Pasternak 地基中的 Euler-Bernoulli 梁，未考 虑桩基的剪切效应及基坑开挖扰动引起的地基参数沿桩基竖向的不均匀性． 文中将既有 桩基视为 Vlazov 地基中的 Timoshenko 梁，考虑桩基剪切效应及地基参数沿桩基竖向不均 匀分布的特性，建立了基坑开挖对邻近单桩力学行为影响分析的两阶段解析方法，与既有 研究成果及现场监测数据进行了对比验证，结果表明:该计算方法能够对基坑开挖影响下 邻近单桩的力学响应进行准确有效的分析． 同时，从地基模型的选择和桩基剪切效应的影 响两方面进行了讨论分析，分析表明: Vlazov 地基模型参数确定更具理论依据且该模型更 符合工程实际;随着桩径的增大桩基剪切效应对桩基内力的影响显著． 

 The construction of foundation pit adjacent to the pile foundation of a building will cause additional deformation and internal force of the pile foundation，which will affect the safety and applicability of the upper building． In view of the current theoretical research on this problem， the elastic foundation beam method is widely adopted，which simplified the pile as an Euler-Bernoulli beam resting on the Winkle foundation or Pasternak foundation． However， this method is unable to account for the shearing effect of the pile and the unevenness of the soil parameters along the pile caused by excavation． So an improved twostage analytical method was proposed，seeing existed piles as Timoshenko beams resting on the Vlazov foundation and considering both the bending and shearing effects． The results were compared with the existing research results and field monitoring data． The results show that the calculation method can accurately and effectively analyze the mechanical response of adjacent single pile under the influence of foundation pit excavation． At the same time，the selection of foundation model and the influence of shear effect of pile foundation are discussed and analyzed． It is concluded that the parameters determination of Vlazov foundation model has more theoretical basis and the model is more in line with engineering practice; and with the increase of pile diameter， the shear effect of pile foundation has a significant impact on the internal force of pile foundation．