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本文介绍大连市引碧供水工程的大沙河倒虹吸地基中采用振冲碎石桩进行加固处理的工程实践。文中对振冲碎石桩的加固设计、施工和检测结果及其消除细、中砂地基论危险性的效果等作了重点的全面的评述和论证。工程实践的对比结果表明,在本工程中应用振碎石桩加固将是理想和经济的最佳选择。 相似文献
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以杭州秋涛路与钱塘江之间的一个住宅小区中的七层点式住宅为例,阐述了振冲碎石桩与饱合粉土地基形成复合地基后的共同工作状态及桩土应力比和面积置换率这二个参数的取值方法,从而说明了振冲碎石桩加固饱合粉土地基是可行的。 相似文献
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振冲碎石桩在地基处理中的应用 总被引:3,自引:0,他引:3
振冲碎石桩是近几年发展较快的软弱地基处理方法。通过对辽源污水处理厂A?/0反应池地基处理的应用,系统介绍了振冲碎石桩在施工过程中的机械及工艺流程。并就加固机理、施工方法以及实用效果几个方面进行了阐述。说明振冲碎石桩适用于松散砂土、粉土及淤泥质粉土地层,经过成孔、排污、清孔、填料、振密,最终控制成桩,可明显改善地基承载力,对软弱地基处理效果显著,具有一定的推广价值。 相似文献
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振冲碎石桩具有施工速度快、工艺简单、投资低、加固效果好的优点,被广泛应用于水利工程、道路修建、建筑工程等多个领域。在四川会理县黎溪镇大海子水库坝基处理工程中采用了振冲碎石桩技术。结合该工程实例,介绍了振冲碎石桩的施工原理、施工工艺、施工顺序、施工情况等,并对该工艺的实用价值和经济价值进行了评价。 相似文献
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针对工程实践中出现的问题,将打入桩的自由段简化为入土端嵌固、锤击端简支的压杆模型,建立桩的振动微分方程,研究锤击轴向力对桩振动频率的影响,并对比锤击初阶频率与桩振动基频的关系得出锤击作用引起柔性桩共振的规律,提出了避开共振影响范围,解决现场工程问题的方法. 相似文献
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粘弹性地基中有限长桩横向受迫振动问题解析解 总被引:5,自引:1,他引:5
基于动力Winkler模型(BDWF)对粘弹性地基中有限长桩的动力响应进行求解,得到了其在桩顶受水平循环荷载作用下的简单形式的时域解析解。通过迭加原理得到了半正弦激振条件下的瞬态解析解,经过简单的数学运算得到了桩头动力阻抗系数。通过对稳态激振时幅频曲线和相频曲线的分析,讨论了桩侧土阻尼系数和刚度系数对共振频率和共振峰值的影响规律。并讨论了桩底边界条件对水平动力响应的影响。本文为单桩的动力分析提供了一种简单的解析分析方法,可为工程设计提供初步参考。 相似文献
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饱和黏弹性地基土中管桩纵向振动研究 总被引:1,自引:0,他引:1
用解析方法在频率域内研究考虑质量耦合效应的饱和黏弹性地基土中管桩的纵向振动特性。基于Biot理论,采用薄层法,推导得到饱和黏弹性地基土的位移、应力等的表达式。将管桩等效为一维弹性杆件处理。根据界面连续性条件,给出饱和黏弹性地基土中管桩的纵向振动一般分析方法和桩顶动力复刚度的表达式。在该基础上,对比分析饱和地基土中实心桩和管桩纵向振动特性。通过算例分析,考察桩周土和桩芯土的力学参数对桩顶刚度因子和等效阻尼的影响。研究表明,饱和黏弹性地基土中实心桩和管桩的纵向振动有明显的差异。 相似文献
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西安地区旋挖钻孔灌注桩竖向承载力特性的试验研究 总被引:9,自引:3,他引:9
旋挖钻孔灌注桩是西安地区近年来广泛采用的一种灌注桩形式,通过对西安地区不同场地20余根旋挖钻孔灌注桩静载试验及桩身应力测试结果的分析,论述了黄土地基中旋挖钻孔灌注桩的荷载传递性状,经过与《建筑桩基技术规范》有关规定的比较,初步探讨了这种桩型单桩竖向极限承载力的特怀。 相似文献
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基于ANSYS软件模拟桩的挤入过程 总被引:2,自引:0,他引:2
基于ANSYS软件分析了桩土之间的相互作用,模拟了桩打入时土中的应力、应变情况。通过结合ANSYS中的接触分析和生死单元,以DP材料来模拟土体,采用循环命令的方式来分析桩土接触时复杂的应力状态。模拟结果得到了圆孔扩张理论和极限平衡法的验证。 相似文献
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土工格室广泛运用于道路或铁路路基的补强和病害整治,针对不同几何尺寸土工格室的整治效果不同,采用焊距为340、400、680 mm和高度为0.10、0.15、0.20 m组合的9种不同规格土工格室进行整治铁路基床下沉病害的现场试验,并与换砂法试验进行了对比,分析不同整治法的轨下动应力衰减规律。结果表明,格室每增高0.01 m,动应力衰减增加约0.6%~1%;焊距每增加100 mm,动应力衰减降低约5%;相比较于换砂法,土工格室法轨下动应力衰减快、分布均,路基强度高,表明换填厚度的大小与整治方法密切相关。在试验的基础上提出了换填厚度设计容许应力法,综合考虑了路基应力水平、格室与砂垫层动应力衰减性能以及路基基床土的容许承载力,为换填厚度设计提供了理论设计方法。 相似文献
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Stefan van Baars Baars 《Geotechnical and Geological Engineering》2004,22(3):391-400
In The Netherlands 70% of the steel sheet piles are installed with vibrators. This is because vibrators have a high production
rate and therefore a low installation cost. This method only works for soft peat and clay layers and saturated sand layers
which are not densely compacted. During pile installation several problems might occur. In this paper the attention is paid
to avoiding jamming of the pile before it has reached its planned depth. In most of these cases this is caused by a design
error which has let to a vibrator which is too light. Over the years different design tools, such as computer models, design
graphs and design equations, have been developed in order to predict the minimum required vibrator force. In this paper a
new design equation is presented, which consists of three parts: the mass of the sheet pile, the friction along the shaft
and the soil resistance at the tip of the pile based on the cone penetration resistance. This equation and several other design
tools for sheet pile installation, have been compared with 18 field tests. It was found that the general design graphs of
the Dutch Union of Foundation Contractors (NVAF), the design equation of the Dutch Civil Engineering Centre for Construction
Research and Design Rules (CUR) and the German design equation of the EAU1996 gave very poor results. The computer model Vibdrive
from Holeyman (1996), the design graphs for specific locations from the NVAF and the new presented design equation from the
author gave reasonable predictions. Since the computer program is, because of its complexity, not regarded as a design tool
for daily design work and the local design graphs only exist for a small number of locations in The Netherlands, the new design
equation is according to the field tests the best method for the calculation of the vibrator needed for sheet pile installation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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This paper mainly investigates the influences of compressible parameters on the vertical vibration of a pile embedded in layered poroelastic soil media. The pile is treated as a 1D elastic bar by the finite element method, and fundamental solutions for the layered poroelastic soils due to a vertical dynamic load are obtained by the analytical layer element method. Based on the compatibility conditions, the pile-soil dynamic interaction problem is solved. The numerical scheme has been compiled into a Fortran program for numerical calculation. Influences of the pile-soil stiffness ratio, compressible parameters, vibration frequency and the soil stratification are discussed. 相似文献
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The dynamic response of an end bearing pile embedded in a linear visco‐elastic soil layer with hysteretic type damping is theoretically investigated when the pile is subjected to a time‐harmonic vertical loading at the pile top. The soil is modeled as a three‐dimensional axisymmetric continuum in which both its radial and vertical displacements are taken into account. The pile is assumed to be vertical, elastic and of uniform circular cross section. By using two potential functions to decompose the displacements of the soil layer and utilizing the separation of variables technique, the dynamic equilibrium equation is uncoupled and solved. At the interface of soil‐pile system, the boundary conditions of displacement continuity and force equilibrium are invoked to derive a closed‐form solution of the vertical dynamic response of the pile in frequency domain. The corresponding inverted solutions in time domain for the velocity response of a pile subjected to a semi‐sine excitation force applied at the pile top are obtained by means of inverse Fourier transform and the convolution theorem. A comparison with two other simplified solutions has been performed to verify the more rigorous solutions presented in this paper. Using the developed solutions, a parametric study has also been conducted to investigate the influence of the major parameters of the soil‐pile system on the vertical vibration characteristics of the pile. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献