共查询到19条相似文献,搜索用时 218 毫秒
1.
2.
3.
4.
为建立科学、准确的喷射混凝土早龄期抗压强度专用测强曲线,基于以贯入法测试喷射混凝土的贯入深度为自变量和同时测试的混凝土抗压强度为因变量建立的实测关系曲线,分析了不少于3种拟合函数的回归曲线与实测关系曲线符合程度和偏差情况,最终确定符合程度较高的专用测强曲线拟合函数。结果表明:专用测强曲线应优先采用分段拟合,且宜以24 h龄期作为专用测强曲线分段的临界点;回归函数中三次函数分段拟合后相关系数均≥0.990,其抗压强度计算值与实测值的偏差值符合TB10426—2019《铁路工程结构混凝土强度检测规程》中±12%的规定。 相似文献
5.
混凝土强度检测用专用或地区测强曲线(1) 总被引:2,自引:0,他引:2
现行的《超声回弹综合法检测混凝土强度技术规程》CECS 02:2005规定,结构或构件中测区的混凝土抗压强度换算值优先采用专用测强曲线或地区测强曲线换算而得。当缺少专用或地区测强曲线时,可采用规程规定的全国统一测强曲线,但使用前应进行验证。《回弹法检测混凝土抗压强度技术 相似文献
6.
为准确测定长龄期混凝土强度,合理评估在役混凝土结构性能,分别采用超声回弹综合法与钻芯取样法对一既有钢筋混凝土栈桥进行了现场强度检测。以钻芯法测强值为基准,以幂函数为拟合方程,建立了西北地区长龄期混凝土超声回弹综合法分区测强曲线。将该测强曲线应用于工程实际,结果表明该测强曲线较通用测强曲线精度高,离散性小,可用于采用超声回弹综合法对长龄期混凝土强度值的推演。 相似文献
7.
某大厦混凝土回弹专用测强曲线的建立 总被引:1,自引:0,他引:1
谢卫兵 《华南建设学院西院学报》1999,(3)
本文通过对用回弹法测试某大厦结构混凝土强度的数据进行回归分析,建立了该大厦混凝土回弹专用测强曲线.该曲线不同于全国统一测强曲线,说明深圳市需要建立本地区的测强曲线以提高混凝土强度检测的准确性. 相似文献
8.
9.
10.
11.
12.
13.
14.
15.
16.
AutoCAD辅助施工测量放线 总被引:1,自引:0,他引:1
在大面积地下室工程轴线和圆弧曲线的测量控制中使用了AutoCAD绘图软件,简化工程测量内业翻样,将繁复的计算转换为直观的“图解法”,数据直接从图上量出,使测量放线变得快速、准确。 相似文献
17.
A new testing method for investigating the loading rate dependency of peak and residual rock strength 总被引:1,自引:0,他引:1
K. Hashiba S. Okubo K. Fukui 《International Journal of Rock Mechanics and Mining Sciences》2006,43(6):894-904
One of the important methods for investigating viscoelasticity is to measure the loading-rate dependency of peak strength; however, no experimental method has been established for accurately measuring the loading-rate dependency of peak strength from a small number of samples. In this study we propose such a method. A single sample is loaded at alternating strain rates to obtain stress–strain curves for both strain rates. The loading-rate dependency of peak strength obtained via this method was compared with the findings of conventional methods. The loading-rate dependency indicated for Tage tuff, Sanjome andesite and Akiyoshi marble was nearly identical to previous results obtained using conventional methods, including results obtained under confining pressure. The loading-rate dependency of peak strength in these experiments shows a close relation with the creep stress-dependency of creep life. We also investigated the loading-rate dependency of the stress–strain curve for the post-failure region for which few results have been published. Under confining pressure, the corrected stress–strain curve, obtained by multiplying the stress of the complete stress–strain curve obtained at the fast strain rate by a constant determined by the ratio between the fast strain rate and slow strain rate, is nearly coincident with the stress–strain curve for the slow strain rate. This is an interesting result and represents new knowledge that may help elucidate failure mechanisms in the post-failure region. The loading-rate dependency of stress in the alternating strain rate experiment proposed here was most clearly observed when the stress–strain curve becomes flat, parallel to the strain axis. Some improvements to the proposed method are required to enable accurate investigations of loading-rate dependency during low stresses immediately after initiation of loading or during the abrupt decreases in stress that occur following peak strength. 相似文献
18.
19.
水利工程中尚没有专用于实体结构砂浆强度的测试方法,通常参考建筑行业方法标准。本研究采用本地常用的原材料制作砌石墙体,预留标准养护和同条件养护试块,并用贯入法和冲击筛分法对实体砂浆强度进行检测和对比分析。研究发现,冲击筛分法可在一定强度范围内对砌石砂浆强度进行检测,而贯入法需结合水利工程中砌块特性,配制强度范围更宽的砂浆进行试验研究,以获得准确的砌石砂浆强度回归曲线用于实体检测。 相似文献