古建筑木材内部腐朽状况阻力仪检测结果的定量分析

Quantitative analysis on the detected results by resistograph on inside wood decay of ancient architecture.

为了探讨应用阻力仪检测方法定量评估古建筑木材材质状况的方法和途径,该文以故宫武英殿维修时替换下来的局部腐朽的5根落叶松旧木构件加工的319个试件为材料,用目测法将试件划分为未腐朽及4个腐朽等级,共5个等级,测定了试件的气干密度、抗弯强度和顺纹抗压强度,并对抗弯强度试件进行了阻力仪检测.应用统计学方法分析了阻力仪检测值与气干密度、抗弯强度和顺纹抗压强度之间的相关关系,用其中的284组数据建立了阻力仪检测值与木材物理力学性质间的线性回归分析模型,并用剩余的35个样本的检测值进行了模型验证.结果表明,随着腐朽程度的加深,木材密度、抗弯强度、顺纹抗压强度及阻力仪检测值均显著降低,5个腐朽等级间差异显著;木材达到"3"级腐朽时,4项指标分别降低为未腐朽材的24%、42%、76%和71%.阻力仪检测值与气干密度、抗弯强度和顺纹抗压强度之间均在0.01水平表现为极显著的线性相关关系,其中与密度的相关关系最大.对建立的线性回归模型进行的模型验证结果表明,模型预测值与实测值具有高度的一致性,两者在0.05和0.01水平上差异均不显著.

Five replaced partially-decayed Larix spp.timber frames from the Hall of Military Prowess,the Palace Museum,were collected and visually graded into five levels of decay to study the relations between resistance value measured by resistograph and air-dried density,bending strength and compressive strength parallel to grain respectively.The regression models were established and proved for different decay levels with 319-group samples.The results showed that wood density,bending strength,compressive strength parallel to grain and resistance values decreased evidently with the increase of decay degree,and there existed significant differences among four decay levels.The remaining value percentage of four indices at the third decay level were 24%,42%,76% and 71%,respectively.Significant linear correlation existed between resistance values and the other three indices at 0.01 level,and the correlation coefficient（r） presented the biggest value between resistance values and density.The regression model between resistance values and physi-machanical properties was established by 284-group data,and it was proved with 35-group samples of different decay levels.The results show that there are no significant differences between the predicted values by the regression model and the real values at both 0.05 and 0.01 levels.