Construction technology on pile foundation of No. 6 main pier in Dashengguan Yangtze Bridge

Based on pile foundation construction of No. 6 main pier, deep mudstone geological foundation and deep-water construction in Nanjing-Dashengguan Yangtze Bridge, the method of super-large-diameter bored pile in deep water is studied. The spread drill, application of PHP mud, and choice of machine are solved by adopting two machines of KTY4000 and KPG300A. Besides, the airlift reversing circulation is selected in slag discharge. The results show that this method can ensure successfully the construction of pier foundation to satisfy the demands of codes. __________ Translated from Construction Technology, 2008, 37(7): 5–7 [译自:施工技术]     

沉降及承载力双控复合桩基研究

本文通过将桩土共同作用理论和变形控制理论进行结合 ,按照传统的桩基设计理论 ,在满足承载力的条件下 ,通过调整桩数和桩长来满足建筑物的稳定性要求 ,并且建立了沉降及承载力双控复合桩基的设计计算模式 ,编制了相应的计算软件 ,通过工程实例验证结果比较合理 ,具有较好的社会经济效益及工程应用价值     

Use of static probing to determine the resistance of piles of circular cross section with an open lower end

A method of evaluating the vertical-load resistance of circular piles with an open end from the results of static probing is cited. Limiting pile resistances, as determined by testing, are compared with consideration given to coefficients proposed by the author, which are given in Construction Rule and Regulation 2.02.03-85. The program “KOL'TsO”, which automates circulation of the bearing capacity of a circular pile from static-probe data, is developed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 6–10, July–August, 1994.     

立式钢制储罐基础设计

以某罐区立式钢制储罐基础设计为例,探讨预制桩、灌注桩和浅基础应用于储罐基础的设计方法。储罐基础设计可比拟为“板-柱结构”体系,借助pkpm结构软件分析两种桩型承载力、浅基础设计、场地条件影响及桩-土共同作用。储罐桩基设计应对水平承载力、竖向承载力和配筋量三控制设计,对于端承型桩基,一般情况下单桩水平承载力起控制作用。相同桩数时,采用方形布桩的边桩配筋比环形布桩的更易产生突变。应用于软土场地的砼预制桩不仅应进行桩基承载力计算,还应加强桩基配筋验算。     

Experimental investigations of pile loads and foundation settlements in tall large-panel buildings

Conclusions 1. During the process of settlement of pile foundations with and without gratings in the nine-story large-panel frameless buildings with transverse and longitudinal bearing walls, the loads were redistributed and equalized, which was a consequence of interaction between the relatively rigid building box and the pliant base of the foundation. 2. Field investigations of the actual pile loads in the foundations of the nine-story large-panel buildings made it possible to establish that the design pile loads exceeded the actual values by 12–16%. 3. The nature of the distribution of the forces in the elements of the pile foundations of the large-panel frameless buildings indicates the need for taking into account the pliancy of the soil base of the pile foundation and its joint operation with the constructional components of the building box for determining the pile loads and for designing the gratings as well as the wall panels with gratingless support. 4. In the pile foundations of the nine-story frameless large-panel buildings with load-bearing, frequently transverse walls of the type of Series 1-464D, with and without gratings on compressible soils, the loads in piles with equal rigidities of the soil bases can be assumed to act as uniformly distributed, as an approximation, in engineering analyses. In the case of different rigidities of the soil bases of the piles, the load on each pile can be determined as a force proportional to the corresponding rigidity. 5. The actual settlement of the pile foundation of the large-panel building on alluvial soils was greater by a factor of 5–6, and for the building on the clay soils of the Ufa floor it was greater by a factor of 15 in comparison with the settlement of a single pile constructed on the basis of the same static test results, under the same soil conditions, and for the same loads. Hence, the coefficient ζ recommended in the SNiP II-17-77 for transfer from settlements of individual piles in static tests to settlements of piles in foundations under long-term loading should be differentiated according to the soil type and state. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 8–10, March–April, 1982.     

二桩承台的有限元分析

利用三维有限元方法和规范方法分析了桩承台的受力和变形特点,运用有限元软件ANSYS的分析结果和规范结果进行对比分析,得出桩承台分析较为可靠的结果,为桩基和承台设计提供了理论基础和技术参数。     

Engineering method of analyzing the bearing capacity of horizontally loaded pile groups

An engineering method is presented for analysis of the bearing capacity of a horizontally loaded pile group on the basis of the resistance of a single pile with a free head; the method accounts for the interaction between piles in the foundation, and the rigid fixity of their heads in an undeformable grillage. Results of the analysis performed in accordance with the developed procedure are compared with data derived from field tests of pile foundations. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 7–11, March–April, 2000.     

深基坑开挖与不同支护方案的优选

以某深基坑工程为例,利用有限元方法对其进行了支护桩几何尺寸对支护效果影响程度的数值模拟,得出了支护桩的最优尺寸;在此基础上,对深基坑开挖和支护过程中经常采用的支护桩、桩锚结构和桩加内支撑结构三种形式根据不同方案进行了数值模拟,得出了锚杆和支撑施加的最佳部位;同时经对比分析各支护形式下最优方案的应力水平云图后发现桩加内支撑支护形式是最适合本基坑工程的支护形式。最终为同类地质条件下的相似基坑工程的优化设计提供了参考依据。     

Evaluation of Long-Term Displacements of Pile Foundation Using Coupled FEM and Centrifuge Model Test

Recently the introduction of performance-based design into infrastructure including pile foundation is on process. For performance-based design, it is necessary to develop a practical prediction method for long-term displacements of pile foundation. In this paper, soil-water coupled analyses with FEM-FDM method are conducted to evaluate the long-term displacements of pile foundation installed in soft clayey ground. The analytical target is the actual pile foundation of road viaduct planned to be constructed in Niigata Prefecture, Japan. As constitutive model for ground, subloading t_ij model is adopted, which is a simple elasto-plastic model for normally and over consolidated soils. Further more, centrifuge model tests are conducted to verify the validity of the numerical analyses. As the conclusion of a series of analyses and centrifuge model tests, following aspects are clarified; 1) the long-term behaviour of pile foundation; 2) the influence of the thickness of bearing layer to the behaviour; 3) the mechanism of pile-soil-pile system, especially about how the load is allotted to each pile, how the migration of excess pore water pressure occurs, migrates and dissipates, and how the uneven settlement is caused.     

浅析桩梁结构复合桩基的简化设计方法

就南京地区一幢住宅楼的复合桩基设计实例，根据复合桩基的设计理论，给出了桩梁结构复合桩基的简化设计方法。其主要设计思想是对大桩距低承台摩擦群桩中的单桩取极限承载力，形成桩-土共同作用并明确分担荷载的复合桩基。该设计方法简单而有效，取得了明显的经济效果，具有一定的工程应用价值。     

On the bearing capacity of sandy foundation beds

Results of analytical investigations using the software package “GEO-MIGG”, which establish the scale effect of a structure on the bearing capacity and settlement of the foundation bed, are presented. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 2–8, May–June, 2006. An erratum to this article is available at .     

基桩检测方法及静载试验加载量问题探讨

由于有关规范对基桩检测的规定不完全相同,容易造成混乱。对《建筑地基基础设计规范》(GB 50007-2011)、《建筑桩基技术规范》(JGJ 94-2008)、《建筑基桩检测技术规范》(JGJ 106-2014)中有关基桩检测规定进行比较,对高、低应变检测方法及其适用情况进行分析,对桩承载力计算方法进行归纳,对静载试验加载量及桩身纵筋配筋问题进行探讨。得出如下主要结论:建筑桩基设计等级为甲、乙级的基桩应进行试桩,丙级的基桩一般可不试桩;高应变法检测基桩承载力和低应变法检测基桩完整性有一定的局限性和适用范围;钻芯法钻取的混凝土芯样试件抗压强度一般低于混凝土的强度等级;基桩承载力静载试验检测的最大加载量在不同情况下取值不同;需考虑负摩阻力的基桩承载力静载试验检测的最大加载量应考虑中性点以上部分桩侧摩阻力的不利影响。     

深基坑桩墙支护结构数值分析实用方法

研究了将深基坑桩墙支护结构视为弹性地基梁的数值分析方法 ,推导了采用“混合结构力学法”求解该问题的基本力学方程 ,提出采用“荷载增量法”模拟深基坑开挖施工的全过程 ,简要介绍了笔者多年来开发应用的深基坑桩墙支护结构设计软件系统PW’98,并给出了工程应用实例     

桩基础的优化设计

针对工程优化设计中的离散变量，采用有限元分析软件建立有限元模型，根据整数梯度法原理编制离散变量的优化设计程序，对桩基础的桩间距进行优化，得到了桩间距的合理建议值，为桩基设计提供了合理的依据。     

Consideration of soil-failure zones beneath foundation edges in analyzing a “bed-foundation-structure” system

An engineering method is developed for determination of the depth of failure zones beneath the edges of a foundation on the basis of the soil-strength parameters c and φ in analyzing a “bed-foundation-structure” system (BFSS). The formation of these zones must be considered in order to obtain reliable values of internal forces within the foundation, and its tilts. It is recommended to conduct additional research to determine c and φ at a depth to 1/4 the width of the foundation along its periphery. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 5–10, January–February, 2009.     

Experimental study on pile-end post-grouting piles for superlarge bridge pile foundations

The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper. There are totally 21 test piles. The maximum pile diameter varies from 2.5 m to 3 m, and the maximum length is 125 m; the bearing capacity of the post-grouting piles is over ten thousands tons. Based on the test results, the bearing capacity, displacement, and bearing characteristics before and after grouting were analyzed. The results show that the bearing capacity of the piles is increased in different degrees after grouting although the technical parameters, including the patterns of grouting pipes, pressure, dosages of cement, duration of grouting lasting time, are different. However, the obtained values are very discrete. In addition, the calculation formula for the post-grouting piles under specified grouting condition was deduced based on the statistics analysis results of 57 test piles. The research results have been applied in the design of bridge foundation. __________ Translated from Journal of Southeast University (Natural Science Edition), 2007, 37(6): 1066–1070 [译自: 东南大学学报 (自然科学版)]     

嵌岩桩桩长计算中桩基承载力计算式的探讨

结合建筑桩基设计及桥梁施工实践，针对JTJ02485中的嵌岩桩承载力计算的局限性，介绍了更符合嵌岩桩实际受力模式的计算方法，并提出了应用中的注意问题，以提高桩基设计的可靠性和经济性。     

Finite-element analysis of tapered piles under combined vertical and horizontal loadings

A universal method of analyzing tapered piles under the combined action of a horizontal, vertical, and moment loading is developed using the finite-element method and with consideration of their bending stiffness. It is derived on the basis of experimental data that the coefficient of subgrade reaction varies as a function of the horizontal displacement of the pile and the depth of the layer under consideration. Procedures are proposed for determination of the coefficient of subgrade reaction on the basis of data from static probing and for consideration of the non-linearity of the deformation of the soil bed and pile material, which makes it possible to calculate the “load-displacement” curve. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 6–12, January–February, 2000.     

刚性桩复合地基理论及其在广东地区的应用

针对目前刚性桩复合地基现行设计方法的不足,根据刚性桩复合地基桩土的荷载分担情况,通过桩身刚度、桩间土的刚度及桩顶砂垫层厚度等影响因素的分析,提出一种既考虑力的平衡、又考虑变形协调的刚性桩复合地基设计新方法。该方法在广东地区几个项目的应用结果表明:所提出的计算方法是合理可行的。采用刚性复合地基的沉降量与通常桩基础比较没有明显的差别。     

广州美术学院030号楼桩基托换有限元分析

结合广州美术学院 0 3 0号楼桩基托换工程实践 ,利用工程计算软件对托换时的桩体及梁进行模拟和应力应变分析 ,指出其分析结果对设计和施工具有参考价值。