长短桩复合地基的理论与实践

长短桩复合地基可以充分发挥地基土的潜能,有效提高地基承载力和减少地基沉降。长短桩复合地基的形成条件是确保长桩、短桩和桩间土在建筑物工作阶段能同时直接承担荷载;长短桩复合地基特别适用于压缩土层较厚的地基。长短桩复合地基承载力特征值fspk可采用下式计算：fspk=m1Ra1/＋β2m2Ra2/Ap2＋β2（1-m1-m2）fsko,提出了长短桩复合地基总沉降量的计算方法和优化设计的方法。最后给出了长短桩复合地基的一个应用实例。     

福永高速公路带帽混凝土桩复合地基优化设计思路浅析

根据建筑地基处理技术规范中混凝土桩复合地基设计计算表达式,对带帽桩复合地基和无帽桩复合地基的承载力、总沉降量进行了分析对比,并以此为依据对福永高速公路南屿互通带帽混凝土桩复合地基沉降控制的优化设计思路进行了分析.     

CFG桩复合地基综述

本文从工程特性、承栽力、地基沉降和施工工艺几个方面对CFG桩复合地基进行了介绍。本文认为该种复合地基能有娩提高承载力,减小地基沉降量。     

CFG桩在公路工程中的应用

根据CFG桩复合地基工程特性,确定高速公路高填方路基CFG桩复合地基的设计原则,提出地基沉降计算以及复合地基承栽力的计算方法,以及在高速公路中的实际应用。     

加筋建筑垃圾土地基模型试验

为了探讨废旧轮胎和建筑垃圾用于加筋地基的可行性,通过不同工况下的地基模型试验,研究压实度、填料、筋材对地基荷载-沉降特性的影响,并从土表变形和土压力方面简要探讨了加筋地基的工作机理.试验结果表明:提高压实度,地基的承载力和初始刚度均增大,沉降减小,建筑垃圾土的荷载-沉降特性优于砂土;同等条件下,废旧轮胎的加筋效果比土工...     

软基上桩承加筋路基与桩基桥台的承载机理

采用ABAQUS有限元软件建立桩承加筋路基和桩基桥台模型,系统研究桩基桥台－路基－地基的相互作用性状,包括桥台桩基水平位移、桥头路面沉降、桥台桩弯矩等的变化规律,分析深厚软土地基的超孔压固结,并提出若干施工建议。     

CFG桩复合地基承载力试验研究

通过对新株洲站CFG桩的试验研究和静载检测及数据分析,介绍CFG桩复合地基承载力的静载试验检测方法;证明静载试验能够检测CFG桩复合地基的承载力.试验结果为完善CFG桩复合地基加固软土地基检测标准提供依据,为在高速铁路软土地基加固工程中推广应用提供指导.     

散体材料桩和水泥桩复合地基固结理论研究综述

复合地基在地基处理中具有十分重要的地位,其用于加固地基,增强地基承载力和减小地基沉降具有良好的效果,因而在工程中被广泛采用。由于研究复合地基的固结是研究复合地基加固机理的主要内容之一,土体的固结直接影响复合地基的变形和承载能力。因此,有必要对复合地基的固结理论进行全面、系统地认识。本文主要对散体材料桩和水泥桩复合地基的固结理论进行综述,阐述了复合地基固结理论研究的现状和取得的理论成果。     

加芯搅拌桩复合地基设计施工要点

加芯搅拌桩具有高承载力、低沉降、造价低、保护环境、应用范围广等特点。2001年11月作者在昆明吴井广发苑二期工程中设计加芯搅拌桩复合地基，是云南省建设工程中首次应用加芯搅拌桩技术，之后发起组建云南《加芯搅拌桩复合地基研究》科研项目组，任科研负责人、项目组组长。3年来云南省应用加芯搅拌桩地基处理建房约15万平米，本文依据作者加芯搅拌桩存在三种破坏状态、具有设计可调性论述，总结工程实践经验，结合专利《加混凝土芯水泥土搅拌桩》(ZL02275785．6)撰写，以满足教学、科学研究和专利实施工程应用需要。     

复合载体夯扩桩承载力研究分析

复合载体夯扩桩是一种地基处理的新工法,具有承载力高、变形小的特点。文章结合工程实际,介绍了该桩的施工工艺、承载特点及检测效果。实践证明,复合载体夯扩桩可大幅度提高桩基承载能力和减少地基沉降,具有明显的经济效益和广泛的应用前景,是一项值得大力推广的技术。     

Bearing capacity of thin-walled shallow foundations: an experimental and artificial intelligence-based study

Thin-walled spread foundations are used in coastal projects where the soil strength is relatively low. Developing a predictive model of bearing capacity for this kind of foundation is of interest due to the fact that the famous bearing capacity equations are proposed for conventional footings. Many studies underlined the applicability of artificial neural networks (ANNs) in predicting the bearing capacity of foundations. However, the majority of these models are built using conventional ANNs, which suffer from slow rate of learning as well as getting trapped in local minima. Moreover, they are mainly developed for conventional footings. The prime objective of this study is to propose an improved ANN-based predictive model of bearing capacity for thin-walled shallow foundations. In this regard, a relatively large dataset comprising 145 recorded cases of related footing load tests was compiled from the literature. The dataset includes bearing capacity (Q_u), friction angle, unit weight of sand, footing width, and thin-wall length to footing width ratio (L_w/B). Apart from Q_u, other parameters were set as model inputs. To enhance the diversity of the data, four more related laboratory footing load tests were conducted on the Johor Bahru sand, and results were added to the dataset. Experimental findings suggest an almost 0.5 times increase in the bearing capacity in loose and dense sands when L_w/B is increased from 0.5 to 1.12. Overall, findings show the feasibility of the ANN-based predictive model improved with particle swarm optimization (PSO). The correlation coefficient was 0.98 for testing data, suggesting that the model serves as a reliable tool in predicting the bearing capacity.     

Bearing Capacity and Technical Advantages of Composite Bucket Foundation of Offshore Wind Turbines

Based on mechanical characteristics such as large vertical load,large horizontal load,large bending moment and complex geological conditions,a large scale composite bucket foundation (CBF) is put forward.Both the theoretical analysis and numerical simulation are employed to study the bearing capacity of CBF and the relationship between loads and ground deformation.Furthermore,monopile,high-rise pile cap,tripod and CBF designs are compared to analyze the bearing capacity and ground deformation,with a 3-MW wind generator as an example.The results indicate that CBF can effectively bear horizontal load and large bending moment resulting from upper structures and environmental load.     

岩溶地区高层建筑的桩基设计与施工

以湖北省某岩溶场地的高层建筑工程为例,对岩溶地区高层建筑桩基础的设计与施工进行了探讨,分析了复杂岩溶地区高层建筑桩基础的设计过程、溶洞的处理方法及桩基施工要点。 经过对比分析表明,冲孔灌注桩适应性强、承载力高,能钻穿溶洞达到稳定持力层,建议作为岩溶地区高层建筑的首选桩基础形式。     

Design of offshore wind power foundation with multi-bucket

Three- and four-bucket offshore wind power foundations with a new form of force-transferring structure are proposed in this paper, and the integrated finite element model of foundation-soil-transition structure is established by using ABAQUS. The carrying capacity of the proposed foundations is studied under vertical load, horizontal load and bending moment. It can be seen that the vertical bearing capacity of multi-bucket foundation can be roughly estimated by the vertical bearing capacity of single-bucket; the horizontal bearing capacity of the three-bucket foundation scheme is controlled by displacement, while that of the four-bucket foundation scheme is controlled by the internal forces of soils. Moreover, the carrying capacity is provided by the overall structure formed by multi-bucket before soil failure. Compared with the conventional single-bucket foundation, there are mainly tension and pressure that are applied to the multi-bucket foundation, so that the carrying capacity of the foundation can be fully utilized. The probability of soil failure can be well reduced with the proposed multi-bucket foundation, and the stress transmission of force-transferring structure is more consistent through steel beams with variable cross-section.     

Design of suction foundations

Suction foundations have been deployed in the last three decades in a growing number of offshore developments, for bottom-fixed and floating structures, in shallow and deep waters, many of them successfully. Suction foundations, traditionally used as anchors and jacket foundations in the oil and gas industry, are now also used in the offshore renewable (wind) industry, e.g. for monopods, tripods, and jackets. When technically feasible, suction foundations are often cheaper than pile foundations. Additionally, their installation is relatively noise-free and, by applying overpressure, they can be removed during decommissioning. This paper focuses on the more complex design issues and some pitfalls related to suction foundation design. Additionally design practices and recommendations for suction caisson design, including installation and extraction feasibility, foundation resistance, settlements and response in sand, clay and layered soil profiles, will be presented for basic understanding.     

UHPC在混凝土梁的加固应用研究进展

超高性能混凝土(Ultra-High Performance Concrete,UHPC)已经在混凝土结构的加固中得到广泛的应用。对在役混凝土梁常见的病害及工程中常用加固方法的优缺点,以及UHPC应用于混凝土梁加固的技术可行性、优缺点、应用前景进行分析,并对既有的UHPC加固梁的施工工艺、受力性能及计算方法等进行综述。研究结果表明:与传统的加固方法相比,采用UHPC对钢筋混凝土梁进行加固,无论在技术可行性、结构耐久性和工程造价方面,均存在明显的优势;与未加固的混凝土梁相比,UHPC 加固梁的承载能力和刚度等力学性能均大幅提高,且对旧桥自重的影响有限;其加固施工工艺是影响增大截面加固效果的重要因素,需结合工程案例开展系统研究;由于加固结构大多已服役数年,在计算加固构件的承载力时,初始损伤对结构承载力的折减是今后需要重点研究的问题。     

Methods for Estimating the Ultimate Bearing Capacity of Layered Foundations

Thebearingcapacityoffoundationsmeanstheulti mateloadsthatcanbeappliedonthefoundations.Inconventionaltheoriesofgeotechnicalengineering ,manybearingcapacityequationshavebeenprovidedtopredicttheultimatebearingcapacityoffoundations.Butmostoftheequationsrefertothefoundationsonhomogeneoussoilsandcannotbeusedforinhomogeneoussoils.Inpractice,foundationsoftenconsistoflayeredsoils,espe ciallyinharborengineering .Sometimesthestrengthpa rametersofsoilsarequitedifferentfromeachother .Therefore,themechanis…     

浆固碎石桩法的作用机理及其应用探讨

着重对浆固碎石桩法处理软土地基的机理、施工工艺及地基承载力特征值设计进行了探讨,得到了一些有益的结论,为类似的工程提供了理论依据。同时,结合工程实例对浆固碎石桩法处理软土地基的效果进行了检验,结果表明,经过浆固碎石桩法处理的地基承载力提高系数为2．03,地基的沉降量减少了50％,说明用该法处理软土地基是合理有效的。     

小断面预制桩在岩溶地基处理中的应用

通过某一工程载荷试验和施工后的沉降观察证明，采用小断面静压预制桩作为高层或小高层建筑复合地基的加固体，对施工条件受周边建筑物限制的岩溶地区进行处理，具有对周边影响小、工效高、桩身质量可靠和承载力有保证等优点。     

基于差异沉降控制的桩基优化设计

为解决传统桩基承载力低的问题,基于差异沉降控制优化设计桩基。分析桩基设计存在的问题,主要包括:桩基支承刚度设定误差高、桩基差异沉降大、桩基结构设计不合理,通过设定桩基支承刚度,控制桩基差异沉降,采用桩基塌孔承桩断裂结构,实现对桩基的优化设计。设计实例分析,结果表明,设计的桩基承载力明显高于对照组,能够解决传统桩基承载力低的问题。