【作者】 张景魁；

【导师】 吴培明；

【作者基本信息】 西南交通大学 ， 结构工程， 2003， 硕士

【摘要】 桩基做为一种最古老的基础工程形式，在现代化阶段得到迅速发展。随着桩基技术的发展和施工工艺的推陈出新，桩基础已经成为工程建设中应用最广泛的基础形式，桩基础在设计和施工中产生的负摩擦力也渐渐为人们所认识。鉴于负摩擦力对桩基础应用过程中的重要影响，桩基础的负摩擦力已经成为基础工程界的一个技术热点。 国内外一些实测资料表明桩基础在使用阶段负摩擦力可能产生非常大的下拉荷载和沉降，尤其产生的不均匀沉降对基础危害最大。在工程实践中，要在设计阶段即考虑可能出现的负摩擦力以保证基础的稳定性，在施工阶段要采取必要的措施避免出现负摩擦力，使用阶段出现的负摩擦力也要及时防治。 本文提出了在工程设计中如何处理桩基负摩擦力的方法，包括什么情况下考虑负摩擦力、负摩擦力中性点位置的确定、桩基下拉荷载的计算、负摩擦力的群桩效应、负摩擦力对桩基竖向承载力和沉降的影响、设计施工中如何避免出现负摩擦力以及对已经出现的负摩擦力如何根治。作者用该方法对一工程算例进行分析计算，评价其方法的可行性。 论文用手工、MATLAB和ANSYS三种方法分别计算负摩擦力对桩基的竖向承载力和沉降等参数产生的影响，并将计算结果和不考虑负摩擦力桩的设计进行比较，得出在工程设计中如何考虑负摩擦力，以及如何处理已经出现负摩擦力的桩基础。 研究结果表明： (1)在工程设计中，有些情况由于负摩擦力产生的下拉荷载数值相当大，在设计中应充分给予重视，以避免在使用中由于下拉荷载使桩的轴向荷载增加引起桩的沉降或不均匀沉降，而导致建筑物的破坏。 (2)在工程设计中，应当按本论文阐述的方法对桩的负摩擦力进行计算，验算桩基的竖向承载力和沉降等参数，保证工程设计的安全性。 (3)在施工中要防止负摩擦力产生，对已经产生负摩擦力的桩基础按本论文提到的方法及时救治。更多还原

【Abstract】 Pile foundation is one of the oldest foundation forms, and develop very rapidly in modernize era. Along with the piles technology’ s development and construct skill bring forth the fresh, pile has became the broadest foundation forms in project item. The negative friction in pile’ s designing and constructing is acquainted with for engineer. Due to the important infection in using foundation, the negative friction in pile has became one of the engineering skill focus.Many survey data refer to mortal down load and sedimentation be produced due to the negative friction in pile foundation. The inequable sedimentation endanger the pile foundation greatly. In engineering practice, negative friction must be considered to ensure the foundation stability. The measure to avoid the negative friction must be carry out in construction phase and to prevent the negative friction in using.This thesis put forward a systemic method to settle the negative friction in project design. It includes when the negative friction must be consider, the zero position decided, count the down load, the negative friction group pile, the infection on end-bearing and sedimentation and stability , how to deal with in design to avoid the negative friction and how to solve when the negative friction produced. In this thesis the author figure out a engineering project by the method and prove the method feasibility.In this thesis consider the negative friction’ s infection on the parameters of vertical weight and sedimentation by MATLAB and ANSYS, and compare the conclusion with the design without the negative friction. In this thesis summarize how to avoid and deal with the negative friction in designing and using.Researches indicate:(1) The negative friction in pile will lead to large number of down load in some designs. This friction must be considered in designto avoid the sedimentation and destroy in the building.(2) In project designing the negative friction must be calculate by the method in this thesis. Parameters of vertical weight and sedimentation must be checked to ensure the design security.(3) The negative friction must be avoid on construction . When the friction has been founded, people must deal with by the method in this thesis.更多还原