A Novel Method of Analysis of Single Piles and Pile Groups Subjected to Lateral Loads

本项目将为横向荷载桩的分析和设计提供一种全新的方法。由于在解决层状弹性土中桩受侧向荷载问题的分析上取得了突破，这种新方法现在成为可能。对于桩头受力或力矩作用的问题，采用虚功原理、变分法和初始参数法求解。该方法将适用于具有任意土层数的土壤沉积物和单桩或桩群。在土的应力-应变响应中引入非线性将使分析更适合于解决实际工程问题。这种设计受风、地震、交通、波浪和土压力荷载影响的桩支撑结构的创新方法是基于弹性响应的封闭形式的解决方案，因此更容易使用，更容易与工程师联系起来（因为土壤应力-应变响应是通过工程师熟悉的参数在单元级别引入的）。它捕获了其他方法无法捕获的土与桩相互作用的各个方面，例如桩截面与周围土的三维相互作用以及土中和沿土-桩界面出现的剪应力。该方法还将提供桩周土体的位移场，并结合非线性应力-应变模型，合理地考虑土体的非线性。直接得到结构设计所需的桩身挠度、弯矩和剪力沿桩长曲线。广泛的验证计划通过现场和实验室实验方法（包括离心机测试和先进的x射线计算机断层扫描技术）和数值方法。为了促进工业采用这种新方法，将制定一项技术转让计划。还将制定一项教育计划，其中将包括为在职工程师、教育工作者和学生提供的短期课程和网络研讨会（少数民族教育工作者和学生参加短期课程将获得奖励）。该项目将与日本熊本大学和英国诺丁汉大学地质力学中心建立新的国际合作关系

PROJECT ABSTRACTIn this project, a completely new method for the analysis and design of laterally-loaded piles will be developed. The new method is now possible because of an analytical breakthrough in the solution of the problem of a pile subjected to lateral load in a layered elastic soil. The solution obtained for a pile loaded at its head by a force and/or a moment is based on the use of the principle of virtual work, the results of the calculus of variations and the method of initial parameters. The method will be applicable to soil deposits with an arbitrary number of soil layers and to single piles or pile groups. Introduction of non-linearity in the stress-strain response of the soil will make the analysis ideal to address realistic engineering problems.This innovative approach to the design of piles supporting structures subjected to wind, seismic, traffic, wave, and earth-pressure loads is based on a closed-form solution for elastic response, and is therefore simpler to use and easier for engineers to relate to (because the soil stress-strain response is introduced at the element level through parameters that are familiar to engineers). It captures aspects of the interaction of the soil and pile that other methods cannot capture, such as the 3D interaction of the pile cross-section with the surrounding soil and the shear stresses that appear in the soil and along the soil-pile interface. The proposed method will also provide the displacement field in the soil around the pile, allowing, by combination with a non-linear stress-strain model, the accounting of soil non-linearity in a rational way. The pile deflection, bending moment and shear force profiles along the pile length (needed for structural design) are directly obtained. Extensive validation is planned by field and laboratory experimental methods (including centrifuge tests and advanced X-Ray Computed Tomography technology) and by numerical methods.To facilitate adoption of this novel method by the industry, a technology transfer program will be developed. An educational program will also be developed, which will include short courses and webinars to be offered to practicing engineers, educators and students (incentives will be available for minority educators and students to attend the short courses). The project will allow establishment of new international collaborative ties with Kumamoto University in Japan and with the Centre for Geomechanics at the University of Nottingham in the U.K.