钻孔灌注桩后压浆技术机理的新认识   总被引：1，自引：0，他引：1       下载免费PDF全文

吴礼生  徐卫红  王爱平 《探矿工程》2001,(5):4-6

通过分析上海地区应用钻孔灌注桩后压浆技术的工程实例的试验结果，进一步认识后压浆技术提高钻孔灌注桩承载力的机理，在深入分析和总结的基础上，提出了合理应用后压浆技术的建议。  相似文献   

采用小径密抗桩一条龙抢治滑坡的方法及效果     

周颂杰  郭映忠 《四川地质学报》1993,(2)

以往整治滑坡,较多地使用大口径挖孔桩或钻孔灌注抗滑桩,周期长、成本高。川地208队在治理重庆制药五厂已处于危急态势的滑坡中,采用“天平式”控制、勘治结合、快速抢险,用三排小径密抗桩(300mm口径)整治,取得明显成效。实践表明:浅层滑坡采用较小口径的密抗桩,并辅以排水,能达到事半功倍的效果。  相似文献   

PHC管桩荷载传递的试验研究和数值分析   总被引：11，自引：5，他引：11  

律文田  王永和  冷伍明 《岩土力学》2006,27(3):466-470

通过在预应力高强混凝土管桩(PHC桩)的桩顶、桩端及桩周各主要土层的分界面埋设应变计的静荷载试验，研究了PHC管桩的荷载传递机理，分析了轴力和桩侧摩阻力的变化规律。并以工程中PHC管桩的竖向抗压静载试验为基础，运用有限单元法对软土地区的PHC管桩桩-土相互作用进行模拟，在分析中采用弹塑性模型，引入了非线性接触面单元，并且考虑了土体的材料非线性。分析结果表明，计算值和实测值有一定的差别，但是变化趋势基本一致。  相似文献   

钻孔灌注桩桩底沉渣压浆处理研究与应用     

赵佩胜  于亮  王为 《岩土工程技术》2007,21(4):214-216,F0003

对桩底沉渣产生的原因、沉渣对灌注桩承载能力的影响以及沉渣的处理作了简要分析,讨论了灌注桩桩底压浆工艺的作用机理。重点结合实际工程介绍了该技术,经检测表明,灌注桩桩底压浆技术的使用有效地处理了沉渣,提高了桩的承载能力。  相似文献   

挤土类桩的挤土效应及其防治方法     

陈锦麟 《中国煤田地质》2007,19(A01):59-60

挤土效应是所有挤土类桩面临的共同问题，它可能造成临近建筑物破坏，地下管线断裂，道路隆起以及工程质量事故。依据挤土类桩挤土效应的形成机理，结合工程实例，提出了减少挤土效应的措施，如预钻排水孔、开挖防挤沟、设置观测点、控制压桩速度等措施，并根据施工地区不同的环境条件提出了合理的压桩顺序。  相似文献   

P–Y Curves for Piles Under Seismic Lateral Loads     

M.P. Romo  E. Ovando-Shelley 《Geotechnical and Geological Engineering》1998,16(4):251-272

This paper describes an experimentally based procedure for building dynamic P–Y curves for clays from the Campeche sound in the Gulf of Mexico and for Mexico City clays. Cyclic triaxial and resonant column tests were used to derive hyperbolic stiffness–strain and damping–strain functions that depend on soil plasticity and on relative consistency. The dynamic P–Y curves incorporate these functions and also include hysteretical and geometrical damping characteristics of the pile–soil system; they can be used directly in dynamic interaction analyses of structure–pile–soil systems in the time or the frequency domains. Usual practice relies on pseudo static formulations and a simplified alternative to include P–Y curves in this kind of analysis is also proposed, which is essentially the same as the dynamic ones but does not include radiation or hysteretical damping.  相似文献   

武汉白沙洲长江大桥百米长桩成孔技术与施工实践          下载免费PDF全文

李世京  廖光华 《探矿工程》1998,(3):10-11

介绍了百米长桩的施工方法、施工设备、护孔技术,并就深孔实施泵吸反循环的可行性、主要技术措施以及强风化岩层的糊钻问题进行了分析。  相似文献   

Filamentary structures in planetary nebulae     

Hanna Dahlgren  Per Carlqvist  Gösta F. Gahm 《Astrophysics and Space Science》2007,310(1-2):65-72

We have studied small-scale, filamentary features in 14 planetary nebulae and found that some structures are recurrent and shaped like the letters V and Y, with the apex or stem pointing toward the central parts of the nebula. Two such filaments containing dust, one in NGC 3132 and one in NGC 7293, were investigated in more detail. The mass and density of the filaments were obtained from extinction measurements, and their physical properties were derived. We propose that the structures are confined by magnetic fields, and derive magnetic field strengths of about 10⁻⁸ T, in line with earlier estimates. We also estimate the magnitude of the electric currents that we expect are generated in these dynamic systems. We propose a theory where the magnetic fields control the sculpting and evolution of small-scale filaments. This theory demonstrates how the substructures may form magnetized flux ropes that are twisted around each other, in the shape of double helices. Similar structures, and with similar origin, are found in many other astrophysical environments.  相似文献   

Vertical amplitude reduction of Rayleigh waves by a row of piles in a poroelastic half‐space     

Yuan‐Qiang Cai  Guang‐Ya Ding  Chang‐Jie Xu  Jun Wang 《国际地质力学数值与分析法杂志》2009,33(16):1799-1821

A row of rigid piles is addressed as the countermeasures for isolating Rayleigh waves in a poroelastic half‐space. The complex characteristic equations for Rayleigh waves are derived via Biot's theory and their existence conditions are given. The piles are modeled as Euler–Bernoulli beams with longitudinal displacements and the diffracted field by each pile is constructed only with Rayleigh waves. Six infinite linear systems of algebraic equations are obtained in terms of the equilibrium of forces and continuity of displacements at the pile–soil interfaces. The systems are subsequently solved in the complex least‐squares sense. The influence of certain pile and soil characteristics such as the permeability of poroelastic soil, spacing between the piles and length of the piles on the isolating performance of a pile barrier is investigated. Computed results show that the permeability of poroelastic soil displays a significant effect on the vertical amplitude reduction of Rayleigh waves. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

高应变法在判定大直径灌注桩缺陷中的应用     

卢贤锥 《福建地质》2010,29(1):22-28

测试数据准确可靠的高应变法检测,能够定量分析基桩缺陷,准确判定缺陷位置。通过工程桩的低应变法和高应变法对桩身完整性判定分析的工程实例,结合钻芯法验证,总结高应变法在不同情况下对桩身完整性的评定。  相似文献