刚性—亚刚性桩复合地基抗震性能研究

发布时间：2018-01-11 17:16

本文关键词：刚性—亚刚性桩复合地基抗震性能研究　出处：《广州大学》2017年博士论文　论文类型：学位论文

【摘要】：刚性-亚刚性桩复合地基是一种新型的高强复合地基,近年来,在珠三角地区乃至全国得到了较多工程的应用。但从目前的研究成果来看,相关研究还大都局限在竖向承载力和沉降方面,对其抗震性能的研究较少,对其在动力荷载作用下,特别是地震激励下的动力响应研究相对匮乏。本文针对地震激励下,考虑刚性-亚刚性桩复合地基的加固体中桩土共同作用,设计和完成了刚性-亚刚性桩复合地基振动台模型试验,建立了相应的数值分析模型,对刚性-亚刚性桩复合地基抗震性能进行深入研究,分析了地震激励下的动力响应规律、动力和变形特性,研究了傅里叶谱频谱和能量分布特点等,为刚性准-亚刚性桩复合地基的抗震设计和工程实践提供试验和理论基础。主要研究内容如下:一、在查阅了国内外相关文献的基础上,介绍了国内外复合地基特别是刚-柔性桩复合地基的发展历程和复合地基的主要研究成果;归纳了刚性-亚刚性桩复合地基在我国工程实践和研究情况,介绍了目前国内外复合地基抗震性能的研究方法和成果。二、介绍了目前广泛采用的成层场地地震反应的时域和频域分析方法,通过分析,震波作为一种极其复杂的随机信号,其频率和幅值特性均随着时间发生较大的变化,地震波频率和幅值的时变性对岩土地震响应具有较大的影响。在建立概化分析模型的基础上,借助弹性波动理论和希尔伯特黄变换(HHT),以地震时频联合域为分析范畴,推导了考虑地震波时间-频率-幅值特性的成层地基地震响应时频计算方法,进而介绍了桩复合地基的地震响应分析方法。三、设计完成了刚性-亚刚性桩复合地基试验模型和试验方案,采用半刚性模型土箱完成了振动台模型试验,获取地震作用下场复合地基的动力特性及地震反应变化规律。根据试验结果,对刚性-亚刚性桩复合地基在不同水平地震(El Centro波,Kobe波和Taft波)激励下刚性桩、亚刚性桩及桩间土的加速度放大系数、位移、傅里叶谱和能量分布情况进行对比分析,对刚性桩和亚刚性桩的应变和弯矩包络图进行对比分析,对褥垫层的减震效果进行了分析。四、分析总结了ABAQUS有限元软件在岩土工程中的应用,以及对复合地基的动力反应求解过程,根据刚性-亚刚性桩复合地基振动台模型试验,进行适当的假设和简化,建立了有限元计算模型。通过数值计算,分析了刚性桩复合地基在水平地震荷载作用下刚性桩、亚刚性桩和桩间土的动应力、水平加速度时程曲线的特点,分析了桩身应力随深度的变化规律;分析三种地震激励下复合地基动力响应的特点和规律。五、通过数值计算,对三种地震波激励下的桩身剪应力和弯矩进行了分析;对振动台模型试验和数值模拟两种研究手段得到的弯矩和位移的包络图和变化规律进行对比,证实了得两种研究手段得到的弯矩和位移包络图和变化规律均较为接近,两者能相互验证、补充和完善。
[Abstract]:Subrigid rigid - pile composite foundation is a new type of high-strength composite foundation, in recent years, has been widely used in engineering of the Pearl River Delta region and the whole country. But judging from the current research results, related research is mostly confined in the vertical bearing capacity and settlement, the research on its seismic performance is less, the under dynamic loads, especially the dynamic earthquake response research is relatively scarce. According to seismic excitation, considering rigid sub rigid pile composite foundation reinforcement in pile-soil interaction, and completed the design of rigid sub - rigid pile composite ground shaking table model test, established the corresponding numerical model. The seismic performance of sub rigid pile composite foundation for in-depth study of rigid, analysis of dynamic response of seismic excitation, dynamic and deformation characteristics of Fourier spectrum and energy spectrum divided bout point, Rigid quasi - to provide a theoretical and experimental basis subrigid pile composite foundation for seismic design and engineering practice. The main contents are as follows: first, on the base of consulting relevant literatures at home and abroad, introduced the domestic and foreign composite foundation especially the development process of rigid flexible pile composite foundation and composite foundation, the main research results; summed up the rigid sub rigid pile composite foundation in our country's engineering practice and research, introduces the research methods and achievements at home and abroad of seismic behavior of composite foundation. In two, the time domain and frequency domain analysis methods of seismic response of a layer is widely used by analyzing the wave as a random signal is extremely complex the frequency and amplitude characteristics, along with the change of time, the time-varying seismic wave frequency and amplitude has a significant influence on the seismic response of rock and soil. In the establishment of generalizability analysis model The basis, by means of elastic wave theory and Hilbert Huang transform (HHT), the seismic joint time-frequency domain analysis category, deduced the calculation method considering the soil seismic response time - frequency seismic wave amplitude frequency characteristics, and then introduces the pile composite foundation to the seismic response analysis method. Three. Completed the design of rigid sub rigid pile composite foundation test model and test scheme, the shaking table model test using semi rigid model of soil box, get off the earthquake changes the dynamic characteristics and seismic response of composite foundation. According to the test results, the rigid sub rigid pile composite foundation under different levels of earthquake waves (El Centro, Kobe wave and Taft wave) under the excitation of the rigid pile, flexible pile and soil between piles and the acceleration amplification coefficient, displacement, Fourier spectrum and energy distribution were analyzed for rigid pile and sub rigid pile strain Comparative analysis and moment envelope diagram, the damping effect of the cushion is analyzed. Four, analyzed and summarized the application of ABAQUS finite element software in geotechnical engineering, and the composite foundation for solving dynamic response process, according to the rigid pile composite foundation subrigid shaking table model test, make appropriate assumptions and simplified finite element models are established. By numerical calculation, analysis of rigid in the horizontal seismic load of rigid pile composite foundation pile, sub rigid pile and soil dynamic stress, displacement curve characteristics of horizontal acceleration, analyzes the pile stress variation with depth analysis of the characteristics and rules; the dynamic response of composite foundation under seismic excitations is three. Five, through numerical calculation, analyzes the three kinds of incentive pile under seismic wave shear stress and bending moment; two methods of model tests and numerical simulation of shaking table The comparison between the envelope diagram and the change rule of the bending moment and displacement is obtained. It is confirmed that the moment and displacement envelope diagram and the variation rule obtained by the two methods are all close. The two can mutually verify, complement and perfect.

【学位授予单位】：广州大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TU473.1

【参考文献】