回弹法推定砌体中蒸压灰砂砖抗压强度研究

发布时间：2018-04-03 19:05

本文选题：回弹法　切入点：蒸压灰砂砖　出处：《湖南大学》2015年硕士论文

【摘要】：随着建筑节能环保、土地资源保护等科学发展理念的深入推广,非烧结砖的发展日益壮大,其中的蒸压灰砂砖已经广泛应用到各种建筑物的墙体上。它是一种具有发展前景,替代烧结粘土砖的新型墙体材料。作为广泛应用于非破损检测的方法,回弹法主要用来检测混凝土强度、砌体中块体材料以及砂浆的强度。这种方法不会影响结构本身的承载能力,其主要特点是检测面广、费用低廉、非破损性、操作简便、检测迅速等优点。回弹法是利用弹簧驱动弹击锤并通过弹击杆弹击试样表面所产生的瞬时弹性形变的恢复力,使锤带动指针弹回并指示出回弹距离,以回弹值作为试样的抗压强度相关指标之一,来推定试样的抗压强度的一种方法。目前国内关于回弹法评定混凝土、砂浆和烧结砖等强度的技术方法已经非常成熟,国内也制定了相关的标准。然而,在国内非烧结砖领域内,关于回弹法的相关标准尚属空白。为了非烧结砖在国内能够健康发展,有必要建立起关于砌体中蒸压灰砂砖的回弹测强公式。本文的研究属于《非烧结砖砌体现场检测技术规程》中蒸压灰砂砖回弹测强推荐公式的基础研究。本文通过相关试验和数据对比分析,ANSYS/LS-DYNA有限元分析软件模拟分析,运用统计学原理,建立了适用于砌体中蒸压灰砂砖的湖南地区的回弹测强曲线。本文所做工作如下:(1)介绍了国内外蒸压灰砂砖的特点和发展前景、目前国内外的检测标准和方法、回弹法测定砌体中蒸压灰砂砖抗压强度的原理和影响回弹值的主要因素。(2)通过湖南大学24个蒸压灰砂砖标准试件的回弹对比试验,对不同竖向压力、试验方法、含水率和碳化深度对于回弹值的影响机理进行了研究。(3)利用ANSYS/LS-DYNA有限元分析软件对回弹仪弹击蒸压灰砂砖进行模拟分析,并对蒸压灰砂砖施加不同竖向荷载,得到各种竖向荷载下蒸压灰砂砖的应力、应变云图和关键点的等效应变时程图。(4)采用ZC4型测砖回弹仪对湖南大学的48个蒸压灰砂砖标准试件进行回弹测试,然后将其制作为抗压强度试件并进行抗压强度试验,将试验得到的共480组回弹值—抗压强度数据进行分组,共得到26组回弹平均值-抗压强度平均值。利用Origin软件内置函数对这些数据进行回归分析和曲线拟合,得到以指数函数表达的回弹测强公式。验证性实验结果表明,本文所建立的砌体中蒸压灰砂砖回弹测强曲线精度较高,为行业标准《非烧结砖砌体现场检测技术规程》的编写提供了重要依据。
[Abstract]:With the development of building energy conservation and environmental protection, land resources protection and other scientific development concepts, the development of non-sintered brick is growing, and the autoclaved lime sand brick has been widely used in the wall of various buildings.It is a kind of new wall material which has the development prospect and replaces the sintered clay brick.As a widely used non-damage detection method, the springback method is mainly used to detect the strength of concrete, block material and mortar in masonry.This method does not affect the bearing capacity of the structure itself. The main features of the method are wide detection area, low cost, non-breakage, simple operation and rapid detection.The springback method is to use the spring to drive the hammer and the restoring force of the instantaneous elastic deformation produced by the spring rod to the surface of the specimen, so that the hammer drives the pointer to bounce back and indicates the springback distance. The springback value is regarded as one of the relative indexes of the compressive strength of the specimen.A method of estimating the compressive strength of a specimen.At present, the domestic technical methods for evaluating the strength of concrete, mortar and sintered brick by rebound method have been very mature, and some related standards have been established in our country.However, in the field of non-sintered brick in China, the relevant standard of rebound method is still blank.In order to develop unsintered brick healthily in our country, it is necessary to establish the rebound strength formula of autoclaved lime sand brick in masonry.The research in this paper belongs to the basic research of the recommended formula of resilience measurement of autoclaved lime-sand brick in "Technical Specification for On-site Detection of Non-Sintering Brick masonry".In this paper, by using ANSYS- / LS-DYNA finite element analysis software and statistical principle, the springback curve of Hunan area suitable for autoclaved lime sand brick in masonry is established.This paper introduces the characteristics and development prospects of autoclaved lime and sand bricks at home and abroad, and the current testing standards and methods at home and abroad.The principle of determining the compressive strength of autoclaved lime-sand brick in masonry by springback method and the main factors influencing the springback value. Based on the springback comparison tests of 24 standard specimens of autoclaved lime-sand brick in Hunan University, the test methods for different vertical pressures are studied.The influence mechanism of moisture content and carbonation depth on the springback value is studied. The simulation analysis of autoclaved lime sand brick with ANSYS/LS-DYNA finite element analysis software is carried out, and different vertical loads are applied to the autoclaved lime sand brick.The stress, strain cloud diagram and equivalent strain time chart of key points under various vertical loads are obtained. The springback test of 48 standard specimens of autoclaved lime-sand brick in Hunan University is carried out by using ZC4 type brick resilience instrument.Then it was made as a specimen of compressive strength and tested on compressive strength. The data of 480 groups of springback value and compressive strength were divided into two groups, and 26 groups of average value of springback and average value of compressive strength were obtained.The regression analysis and curve fitting of these data are carried out by using the built-in function of Origin software, and the springback strength formula expressed by exponential function is obtained.The experimental results show that the resilience curve of autoclaved lime-sand brick established in this paper has a high precision, which provides an important basis for the compilation of the industry standard "Technical specification for on-site detection of non-sintered brick masonry".
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU522.1

【参考文献】