【作者】 程宝辉；

【导师】 夏元友；

【作者基本信息】 武汉理工大学 ， 岩土工程， 2003， 硕士

【摘要】 传统静载试验是公认的确定单桩承载力最直观、最可靠的方法，但由于必需专门的反力系统，试验费时、费力、费用高昂且对试验场地有着极高的要求，也因此不可能做到随机抽检及大量普查；特别是在某些恶劣的条件下，由于空间的限制甚至不可能进行静载试验。同时随着近年来桩基朝着高承载力、超长桩方向的不断发展，因试验吨位的加载难度已使得基桩的静载试验根本无法进行。作为一种新兴的单桩承载力测试技术——自平衡试桩法，其测试技术的优越性及其在经济上的巨大潜力，目前在北美已被公认为是进行基桩静荷载试验的首选方法，在我国的北京、江苏、甘肃的等地区也已经开始小范围地试用。 自平衡试桩法的最终目的是建立单桩桩顶的Q～S曲线，并据此判定单桩的极限承载力。但因加载方式与桩身实际受力状态的不同以及荷载传递机理的差异，使得测试结果与传统静载存在一定的误差。因此，如何根据自平衡加载方式下桩土相互作用机理建立合理的数理模型，并采取科学的数据转换方法，实现自平衡测试结果向传统静载的准确转换，已经成为自平衡试桩法应用于实际工程的瓶颈。 本文根据自平衡加载方式下桩身的实际受力状况、桩土间的相互作用机理以及单桩破坏机理，建立了单桩的离散元模型，采用ANSYS通用分析软件，选取合理的单元类型、材料特性等，数值分析了基桩在自平衡加载方式下上下桩段的相互关联、荷载传递机理以及与其它加载方式的区别，论证了采用自平衡试桩法测定单桩极限承载力的可行性。在此基础上，着重研究了自平衡测试结果的数据转换方法，并以荷载传递法为基础，提出了等值位移插值转换法、弹性压缩递推转换法及模拟静载迭代转换法等三种数据转换方法，编写了计算机分析计算程序。结合本文的研究成果，在实际工程中进行了自平衡试桩法与静载试验的对比试验。结果表明：自平 武汉理工大学硕士学位论文衡试桩法与传统静载试验具有较好的一致性;采用本文的提出的数据转换分析方法，转换曲线与传统静载曲线吻合性较好，极限承载力的判定误差在10%左右，能够满足工程精度的要求。 最后，在全面总结论文工作的基础上，提出了本课题尚有待进一步深入研究的一些问题。更多还原

【Abstract】 Traditional load test is generally accepted as a most directly and reliable method for determining the bearing capacity of piles. Because the method need special reaction system, it will take more time and money and require high condition for test field. So it cannot be done randomly and widely, and cannot be done under hardly conditions. Load test is difficult to be carried with the development of higher bearing capacity and long length. As a new measuring technology, self-balanced method has its advantage on technology and economy. At present it is first load test method in north American and it has been applied in some province in china.The final purpose of self-balanced method is to get top Q-S curve, and determine ultimate bearing capacity of single pile based on it. Because of the difference of loading way and load transfer mechanism, its transferred result has some deflection with traditional load test. So how to transfer scientifically self-balanced test data into top load curve according to its actual working behavior, become the obstacle of its practical application.In accordance with actual forcing behavior and reaction mechanism between pile and soil, The article analyzes the relation between top part and bottom part, load transferring mechanism and difference with other loading way by ANSYS program. So the reliability of determine bearing capacity by self-balance method has been proved. Based on above three methods of transferring self-balanced test data into top load data have been provided andrelative computer program has been edited. The contrast test between self-balance test and top load test has been done applying the research of the article, it shows that the transferred curves are well consistent with top load curves, so it can satisfy the engineering requirement and its accuracy can amount to about ninety percent.Finally, some problems deserving further study are suggested based on concluding the whole research.更多还原