低应变检测管桩论文

A foundation has the extensively applied realm, is key figures building, large bridge, deep wharf of water and sea the petroleum terrace main foundation form that etc. recent years, a 基 engineering quantity problem influence building structure of the case of the normal usage and safety is a lot construction of the stake have the concealment of the height and the construction quantity of the stakes contain a lot of indeterminations factor, seeing from the angle of a quantity of 基 examination, the method and meanses of the improvement examination, the credibility that the exaltation examination work quantity and examinations assess the result, have the important meaning towards the quantity and safeties that insure an engineering of 基s, is also a research heat of 基 realm to order it a. The low contingency reflect a function with main method is to examine a body structure integrity, if a body blemish position judgment, construction the stake grows to check to settle sex to estimate the etc. with the concrete strength grade, making use of to measure glint a curve signal rows to break a body quantity accurately, expeling the engineering 隐 to suffer from, carrying on the evaluation to the quantity of the stake of 基 . This text to the Kelvin not the glint a new method of low contingency of the flexible material a body of line complete sex examination carried on the research. Build up the new model of the Kelvin non- line flexible material an a 维 of the problem motion;Give square distance of the control dynamics of the body, make use of a 维 not the line flexibility originally 构 the relation deduce a stalk toward dint and stalks toward emergency relation, putting forward a 维 not the line flexibility undulates new calculate way of problem;Adopt the FORTRAN language establishment procedure, the number imitates a speed( or move, acceleration) to respond to a form of the timing curve;Exist an establishment of 基 of problem to rise various form database to the integrity finally, is hereafter used for a complete sex examination service. And low contingency glint a method;A body integrity examines 2 phrases

桩基础 has the widespread application domain, is the high-rise construction, the large-scale bridge, the deep water wharf as well as the marine petroleum platform and so on use main foundation form. In recent years, 桩基 the project quality question influence construction structure normal use and the safe instance were very many. The pile construction has the high hiding as well as the pile construction quality has very many not definite factor, looked from 基桩 the quality examination angle, the improvement examination method and the method, improve the examination work quality and the examination evaluates the result the reliability, to guarantees 基桩 the project quality and safely has the vital significance, also is 桩基 one of domain research hot low strain reflection method main function examines the pile body structure integrity, like the pile body flaw position judgement, 施工桩 long proofreading and the concrete intensity rank qualitative estimate and so on, the use obtains the reflected wave curve signal accurately to delimit breaks the pile body quality, removes the project hidden danger, to 基桩 the quality carries on the appraisal. This article has conducted the research to the Kelvin non-linearity elastic material 料桩 body integrity examination low strain reflected wave new method. Establishes the Kelvin non- line elastic material 料桩 question the unidimensional undulation new model; Produced has controlled the body the dynamic equation, the use unidimensional non-linear elasticity this construction relations infers the pile axial force and the axial strain relations, proposed the unidimensional non-linear elastic undulation question new algorithm; Uses the FORTRAN language coding, the value simulation 基桩 桩顶 speed (or displacement, acceleration) responds the time interval curve profile; Finally 基桩 builds each kind of profile storehouse to the complete existence question, will use in 基桩 the complete examination service for later. As well as low strain reflection method; The pile body integrity examines 2 words

为保证预应力混凝土管桩的承载能力，以力学为主线，分析了管桩桩身混凝土抗压强度、有效预应力和管身截面面积在预制混凝土管桩设计、生产、施工三阶段中的重要作用，强调了预应力混凝土管桩的应用需综合考虑符合设计、生产、施工等方面的要求，可为预应力混凝土管桩的可持续发展提供参考。关键词：预制混凝土管桩；承载力特征值；抗压强度；混凝土有效预应力；截面面积；可持续发展0 前言随着近几年新工艺、新装备的进步，预应力混凝土管桩（以下简称管桩）行业得到了快速发展，但厚壁管桩布料困难、液压锤锤击施工断桩率偏高、工地钻芯检测管桩桩身混凝土抗压强度偏差大等技术问题依旧存在。与此同时，在绿色发展的大背景下，管桩行业也面临着如产业工人减少、砂石原材料等资源短缺等挑战，这些因素都影响着管桩行业的可持续发展。本文着眼于技术层面，以力学为主线，分析管桩桩身混凝土抗压强度、有效预应力和管身截面面积三参数在管桩承载力计算中的重要作用。1 管桩轴心抗压承载力特征值Ra设计人员主要根据管桩桩身轴心抗压承载力和抗裂弯矩来进行管桩选型，管桩桩身轴心抗压承载力的计算公式主要有以下两类：式中：φc为综合折减系数，取； fc为混凝土抗压强度设计值；A为管桩截面面积。式中：σu为混凝土抗压强度；σce为混凝土有效预压应力；A为管桩截面面积。式（1）利用了混凝土抗压强度设计值和经验数据综合折减系数，计算过程简单；式（2）体现了管桩混凝土抗压强度、混凝土有效预压应力和截面面积与桩身轴心受压承载力Ra的关系，下文将结合设计、生产、施工过程进行详细分析。 混凝土抗压强度σu在管桩生产方面，混凝土抗压强度是管桩桩身轴心抗压承载力的重要影响因素，也是设计人员进行桩身承载力计算的主要依据，如何控制好混凝土的质量就显得尤为关键。近几年，布料新工艺采用了整体模具挡板布料的方式，解决了厚壁管桩混凝土料堆积困难的问题，降低了工人劳动强度的同时，还可兼顾混凝土质量；泵送新工艺的发展应用也解决了劳动力短缺的问题，实现了自动化生产，但混凝土强度的偏低，在管桩桩身上钻芯检测的混凝土抗压强度往往很难达到80 MPa以上，遇到地质情况较复杂的工地，锤击法施工时，管桩易破损；免蒸压或双免工艺也日趋成熟，但难以进行大批量规模化生产。同时，存在管模周转时间较长、场地要求较大等问题。在管桩施工方面，国内管桩施工常用方式是锤击式打入或者静压压入。锤击式打入法又分为柴油锤锤击法和液压锤锤击法两种。运用公式（2），计算得到PHC500（100）A和 PHC500（125）AB的轴心抗压承载力特征值分别为2 362 kN和2 718 kN。用KB-60型6 t锤施打，锤高落距 m，击打入3 cm收锤，即最后贯入度为30 mm/10击。