地基桩基检测技术的探索与应用

当前检测单位和相关工程检测管理人员必须以项目基本情况和地基桩基检测理论为基础,优化配置和整合地基桩基检测工程的人、财、物,进而合理科学控制自平衡法检测技术在地基桩基检测应用中的常见问题,并从根本上提升地基桩基检测中的自平衡法检测技术应用措施。

建筑工程地基桩基础处理对策

国民经济的快速发展为建筑行业提供了更大的发展空间,建筑行业的发展与进步也构成了支撑我国经济快速增长的有力一环。建筑工程地基桩基础的处理技术在建筑工程施工中发挥着举足轻重的作用,应用更加合理、更加科学的地基桩基处理技术能够有效缩短建筑工期,降低工程成本,做到施工效率与质量的兼顾。本文分析了目前施工中几种主流的地基桩基处理对策,并在此基础上分析了其各自的特点与适用性,旨在为工程施工的顺利进行奠定坚实的基础,并为相关的施工技术人员提供一定的参考。

建筑工程地基桩基础处理对策

地基建设是建筑工程的基础,地质的质量指标直接关系地上楼层的顺利建设。科学合理的地基桩基础处理方案是地基工程施工的核心。本文分析了建筑工程地基桩基础处理对策,主要包括换填料层法、碾压密实法、碱液法以及打桩法,以期为相关同仁提供些许借鉴。

固结灌浆及高压旋喷桩地基软基处理施工关键技术浅析

为了解决施工过程中软土地基施工难度较大的问题,本次研究重点针对固结灌浆及高压旋喷桩地基软基处理施工关键技术进行探讨分析,意在通过控制沉降、提高强度、加固覆盖层的方式优化施工强度,尽可能避免沉降问题的出现,从根本上保证软土地基结构的施工稳定性,提升地基强度的同时也保证施工安全性,希望为相关人员带来一些参考。

成层地基–桩基–结构动力相互作用体系的计算分析

以一个1∶2大比例模型结构–地基的动力相互作用模型试验为基础,结合通用有限元程序MSC.Marc,对成层地基–桩基–结构动力相互作用体系进行了三维有限元分析。计算中采用考虑土非线性特征改进的黏弹性人工边界模拟外部土域,利用考虑动力相互作用中桩土分离、滑移以及桩基提离效应的接触模型反映桩土接触界面特性,并引入阻尼项表征桩土动力作用中的能量损耗,土体采用等效线性模型。通过计算分析与试验的比较研究,验证了计算模型和分析方法的合理性,进行了地震动输入下的地震反应分析,为地基–结构动力相互作用的进一步研究奠定了基础。

桩基与地基质量检测中注意的几个问题

本文结合项目建设开展的过程中,对于桩基和地基的检测技术进行有效的探索,力求达到实践工作的有效性和保障作用。桩基和地基是整个工程安全的基础,必须结合先进的检测技术进行安全性能的鉴定,对于存在的问题以及安全隐患进行有效的排查,有效地避免大的安全事故的发生,促进安全生产的推进。

自重湿陷性黄土地基上渡槽桩基设计计算

以宁夏扶贫扬黄灌溉一期固海扩灌八干渠工程渡槽的基础处理为例 ,阐述了自重湿陷性黄土地基桩基设计原则依据 。

岩土工程中地基与桩基础处理技术

在岩土工程中,地基与桩基础处理是施工的重点与难点。地基与桩基础的重要性十分突出,是影响岩土工程整体质量的关键所在,因此针对地基与桩基础处理技术的研究很有必要。在岩土工程中应合理应用地基与桩基础处理技术,为岩土工程质量提供更为有力的保障。基于此,本文分析了岩土工程的特点,并就地基与桩基础处理技术的应用进行探究,仅供大家参考。

民用建筑地基和桩基施工技术及管理措施研究

新时期下,社会经济发展速度日益加快,民用建筑也逐渐朝着高层化的方向发展。因此,在这种背景下,人们对民用建筑地基和桩基的承载能力要求越来越高。所以,为了能够满足人们对建筑工程的具体要求,在实际的民用建筑工程建设过程中,一定要强化对各个环节的把控,加大管理力度。基于此,本文即对民用建筑地基和桩基施工技术展开了深入分析,并在结合工程具体现状的基础上,制定了相应的施工管理措施,以期相关人员能够参考。

CFG桩基复合地基处理在车辆段中的应用技术

CFG桩基复合地基早于1988年立项进行研究,并应用于工程实体实践。由于CFG桩在施工工艺上具有总体施工周期短,施工速度快、施工造价低、施工质量容易把控等优点,已成为最普遍的地基处理技术和应用措施。CFG桩基复合地基的特性为刚性桩复合地基,根据其自身的特点及原理,主要适用于处理各种复杂的地基,在确保原地质形变小的前提下大大提高了原地基的承载力,此阐述依托于地铁车辆段内对于设备基础、检修沟、检修坑、行车轨道下方等需要基础加固部位,从施工工艺和质量控制角度进行研究和总结。

桩基负摩阻力探讨

论述了负摩阻力的产生条件,通过总结以往研究负摩阻力的方法及现状,给出了计算负摩阻力以及中性点位置的简化计算程序,提出了消除负摩阻力的一些措施。

复合地基静载荷试验现场操作要点

复合地基承载力特征值最直接、最准确的确定方法就是复合地基静载荷试验,静载试验的测试结果对复合地基施工质量复核、拟建建筑层数、基础类型、结构类型、使用安全、工程投资等方面影响很大,因此要求复合地基静载荷试验结果必须准确、可靠。

高强度花岗岩中大直径钻孔灌注桩施工技术分析

本文在研究中以高强度花岗岩中大直径钻孔灌注桩施工技术为核心,列举某工程案例,分析基于标贯值的抗拔桩竖向承载力研究,优化高强度花岗岩中大直径钻孔灌注桩施工技术,加强桩基与地基处理施工管理,提高施工质量,并为相关研究人员提供一定的借鉴和帮助。

浅析复杂地基中桩基承载机理计算

复杂地基中桩基承载机理通过科学的计算,可以确定复杂地基中桩基的单桩承载性能,从而使复杂地基整体承载性能可以满足现代工程标准要求,对提高现代工程地基质量与整体工程质量有着重要的作用。复杂地基中桩基承载机理与承载力、沉降有着直接关系,但目前复杂地基中桩基承载机理计算只能求出极限承载力,而缺乏对复杂地基中桩基承载机理沉降量的有效计算,所以基于弹性理论法进行复杂地基中桩基承载机理进行计算,又可以有效计算出可靠的桩顶沉降量。本文就广义弹性理论法对复杂地基中桩基承载机理计算进行设计,探讨基于广义弹性理论法的单桩计算思路与方法。

高层建筑中土建施工技术的应用研究

本文重点分析高层建筑中土建施工技术在其中的应用,目前在高层建筑中,比较常见的土建施工技术包括地基桩基技术、基础开挖技术以及混凝土浇筑施工技术。基于此,为了保证土建施工技术的应用效果,要对现有设计方案进行仔细研究,对施工材料质量进行管理和控制,以此来为高层建筑施工质量提供保证。

Influence of water-rich tunnel by shield tunneling on existing bridge pile foundation in layered soils

At present,shield tunneling often needs to pass through a large number of bridge pile foundations.However,there are few studies on the influence of shield tunneling on adjacent pile foundations by combining with groundwater seepage.Based on Winkler model,the calculation equations of shield tunneling on vertical and horizontal displacement of adjacent bridge pile are derived.Meanwhile,full and part three-dimensional finite element models are established to analyze the trend of bridge pier settlement,ground surface settlement trough,vertical and horizontal displacement of the pile and pile stress under three calculation conditions,i.e.,not considering groundwater effect,considering stable groundwater effect and fluid-soil interaction.The results show that the calculated value is small when the effect of groundwater is not considered;the seepage velocity of the soil above the excavation face is faster than that of the surrounding soil under fluid-soil interaction,and after the shield passing,the groundwater on both sides shows a flow trend of“U”shape on the ground surface supplying to the upper part of the tunnel;the vertical displacement of the pile body is bounded by the horizontal position of the top of the tunnel,the upper pile body settles,and the lower pile body deforms upward.The horizontal displacement of pile body presents a continuous“S”shape distribution,causing stress concentration near the tunnel.The calculated results of fluid-soil interaction are in good agreement with the field measured data and accord with the actual situation.

Consolidation analysis of composite foundation with partially penetrated cement fly-ash gravel(CFG) piles under changing permeable boundary conditions

Based on the double-layered foundation theory, the composite ground with partially penetrated cement fly-ash gravel(CFG) piles was regarded as a double-layered foundation including the surface reinforced area and the underlying untreated stratum. Due to the changing permeability property of CFG piles, the whole consolidation process of the composite ground with CFG piles was divided into two stages, i.e., the early stage(permeable CFG pile bodies) and the later stage(impermeable pile bodies). Then, the consolidation equation of the composite foundation with CFG piles was established by using the Terzaghi one-dimensional consolidation theory. Consequently, the unified formula to calculate the excess pore water pressure was derived with the specific solutions for the consolidation degree of composite ground, reinforced area and underlying stratum under instant load obtained respectively. Finally, combined with a numerical example, influencing rules by main factors(including the replacement rate m, the treatment depth h1, the permeability coefficient Ks1, Kv2 and compression modulus Es1, Es2 of reinforced area and underlying stratum) on the consolidation property of composite ground with CFG piles were discussed in detail. The result shows that the consolidation velocity of underlying stratum is slower than that of the reinforced area. However, the consolidation velocity of underlying stratum is slow at first then fast as a result of the transferring of effective stress to the underlying stratum during the dissipating process of excess pore water pressure.

Three-dimensional displacement characteristics of adjacent pile induced by shield tunneling under influence of multiple factors

Shield tunneling inevitably passes through a large number of pile foundations in urban areas.Thus,an accurate assessment of tunneling-induced pile displacement and potential damage becomes a critical part of shield construction.This study presents a mechanism research of pile-soil-tunnel interaction through Pasternak-based two-stage analysis method.In the first stage,based on Mindlin’s solution,the soil displacement fields induced by shield thrust force,cutterhead frictions,shield shell frictions and grouting pressure are derived.The analytical solution of threedimensional soil displacement field is established by introducing Pinto’s three-dimensional volume loss formula,which solves the problems that shield construction factors are not taken into account in Loganathan’s formula and only twodimensional soil displacement field can be obtained.In the second stage,based on Pasternak’s two-parameter foundation model,the analytical solution of pile displacement induced by shield tunneling in layered soil is derived.A case was found in the project of interval tunnels from Wanjiali Square to Furong District Government of Changsha Metro Line 5,where the shield tunnels were constructed near viaduct piles.The reliability of the analytical solution proposed in this study is verified by comparing with the field measured data and the results of finite element method(FEM).In addition,the comparisons of longitudinal,horizontal and vertical displacements of soil and pile foundation analyzed by the analytical solution and FEM provide corresponding theoretical basis,which has significant engineering guidance for similar projects.

Non-probabilistic fuzzy reliability analysis of pile foundation stability by interval theory

Randomness and fuzziness are among the attributes of the influential factors for stability assessment of pile foundation. According to these two characteristics, the triangular fuzzy number analysis approach was introduced to determine the probability-distributed function of mechanical parameters. Then the functional function of reliability analysis was constructed based on the study of bearing mechanism of pile foundation, and the way to calculate interval values of the functional function was developed by using improved interval-truncation approach and operation rules of interval numbers. Afterwards, the non-probabilistic fuzzy reliability analysis method was applied to assessing the pile foundation, from which a method was presented for non- probabilistic fuzzy reliability analysis of pile foundation stability by interval theory. Finally, the probability distribution curve of non- probabilistic fuzzy reliability indexes of practical pile foundation was concluded. Its failure possibility is 0.91%, which shows that the pile foundation is stable and reliable.

Effect of cantilever soldier pile foundation excavation closing to an existing composite foundation

Adjacent high-rise building with CFG pile composite foundation was studied using model test method to investigate stress and displacement of the foundation pile retaining structure, the subsidence and transmogrification law of the composite foundation. Two different project cases with and without high-rise building adjacent to pile foundation were compared. The relationships of slope pile bending moment, earth pressure, pile top displacement and complex settlement with respect to time were obtained. 1) When there is no adjacent building, the displacement of supporting system caused by excavation is mainly in the horizontal direction; while when the adjacent building exists, the displacement of supporting system will be vertical. 2) When the excavation depth is less than or equal to the adjacent building's composite foundation depth, the force of supporting structure is uniform and has small value, at the same time, the pile strength is in fully use and the foundation is stable; while when the excavation depth is greater than the depth of adjacent building's composite foundation, the results will be opposite. 3) During the excavation process, the adjustment of the composite ground loads on the supporting structure is carried out downward and the force of the supporting structure is reduced through the deformation of the bearing layer.