小样本条件下混凝土强度代表值的确定

Determination of Concrete Strength Based on Small Sampling Data with Information Diffusion Theory

针对小样本混凝土强度代表值确定时不能利用数理统计模型的问题,引入了信息扩散原理,提出了小样本条件下混凝土强度代表值确定的实用计算模型。2个混凝土强度检测案例的计算结果表明,利用《公路工程质量检验评定标准》(JTJ071-98)进行灌注桩芯样混凝土强度代表值确定,得到的代表值保证率在95%左右波动,具有不确定性;利用《超声回弹综合法检测混凝土强度技术规程》(CECS 02:88)进行单一构件混凝土强度推定,推定值的保证率小于95%,对结构的可靠性鉴定而言是偏于不安全的,应引起试验检测人员的充分重视。

It is well known that the statistical model can＇t be utilized in the determination of concrete strength from incomplete sampling data. Therefore a practical calculating model to solve the problem encountered is presented by use of the information diffusion theory. With the calculation of two practical examples, the results show that the guarantee rate of concrete core strength central value from cast-in-situ concrete pile based on Quality Inspection and Evaluation Standards for Highway Engineering （JTJ071-98） is fluctuating around 95%. Additionally, the guarantee rate of the extrapolated value of the conerete compression strength for single structural member based on Technical Specification for Detecting Strength of Concrete by Ultransonic-rebound Combined Method （CECS 02：88）, is less than 95 %, which is unsafe for structural reliability appraisal.