中文摘要：

桩基负摩阻力是个复杂的问题，由于其与土力学诸多领域的理论问题都有关联，所以对桩基负摩阻力的研究必然可加深对其他相关理论问题的认识。到目前为止，与桩基负摩阻力直接相关的诸多理论问题，都还未能得出令人满意的解答。针对这一现状，选取桩基负摩阻力研究中凰待解决的3个基本理论问题（影响桩基负摩阻力的主导因素、负摩阻力的实质以及负摩阻力的动力来源）加以研究。基手现场试验资料，从中分析得出影响桩基负摩阻力的2个主导因素，并据此从理论上推导出了槛基负摩阻力的实质，即桩基负摩阻力可看作是桩周有效沉降土体的重力在土体抗剪强度的转化之下而产生的一种作用于桩身的力，最后建立一个说明桩基负摩阻力动力来源的理论模型。

英文摘要：

Investigation on negative skin friction（NSF） is complicated in the effort to connect with some other theoretical problems in soil mechanics field. Consequently, it could help to advance our understanding on these problems in soil mechanics field in the NSF.However, some theoretical problems of the NSF are not interpreted reasonably. In order to understand the problems three important theoretical problems of the NSF. the dominant influencing factors of the NSF, the relation betffeen NSF, and weight of the soil mass around pile and the power sources of the NSF are analyzed. Based on the in-situ data and theoretical analysis, two dominating factors, i.e., the effective weight of the soil mass above certain depth and the settlement of the soil mass around the pile at the certain depth, are discussed. Then on the basis of the two above-mentioned dominating factors, the NSF could be regarded as a.force acted on pile due to the lost gravitational potential energy of the subsiding soil mass, and as the force limited by shear strength of the soil mass. Finally, a theoretical model of power sources of NSF to illuminate the results is established.