电阻断层成像、应力波及阻抗仪3种无损检测方法对活立木腐朽程度的定量检测
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摘要
【目的】应用电阻断层成像法、应力波断层成像法和阻抗仪法对活立木树干腐朽程度进行检测和定量表征,判断3种方法的可靠性,为野外立木健康情况检测提供基础数据和理论依据。【方法】在黑龙江省哈尔滨市东北林业大学试验林场内,选取水曲柳和北京杨各25株(15株腐朽,10株健康)共50株100个截面,采用PICUS Tree Tronic型树木电阻断层成像仪、Arbotom应力波断层成像系统和Resistograph针式阻抗仪检测及木芯质量损失率估测4种方法对断面腐朽程度进行检测和定量表征。以木芯质量损失率计算的样木腐朽程度(E_s)为真值,利用最小二乘法分别建立电阻测定的腐朽程度(E_d)、应力波测定的腐朽程度(E_y)及阻抗仪测定的腐朽程度(E_z)与真值(E_s)之间的线性关系。【结果】电阻断层成像、应力波和阻抗仪3种无损检测方法能在不同腐朽程度上表征活立木木材质量损失率;从整体上来看,电阻检测和应力波检测结果与腐朽程度真值的拟合程度低于阻抗仪检测结果与腐朽程度真值的拟合程度;从不同腐朽阶段来看,在E_s<30%时,E_d和E_s的相关系数最高(R=0.823,P<0.01);在30%≤E_s<50%时,E_y和E_s的相关系数最高(R=0.658,P<0.01);在E_s≥50%时,E_z和E_s的相关系数最高(R=0.914,P<0.01)。【结论】电阻断层成像法对木材早期腐朽的检测比较敏感,而应力波断层成像法则相对在木材腐朽稍严重时更准确,阻抗仪法在腐朽各个阶段的检测结果都较为准确,且在腐朽严重时最准确,但会对木材造成微损伤。3种无损检测方法均能有效检测活立木腐朽,并有各自的特点,在实际腐朽检测中应根据实际检测需要来选择。
【Objective】Electric resistance tomography,stress wave imaging and resistograph were employed to detect and quantitatively characterize the internal decay for standing trees,then these three NDT(nondestructive testing)techniques were made comparisons in order to find out the appropriate technique matched with specific condition of standing trees in the forest field.【Method】An investigation about the accuracy of different NDT methods was carried out in the experiment forest of Northeast Forestry University in Harbin,Heilongjiang Province. 100 cross-sections of Fraxinus mandshurica and Populus × beijingensis standing trees were tested by four methods: electric resistance tomography,stress wave tomography,resistograph and estimation weight loss ratios of wooden increment cores. Taking wood core samples as research objects,testing results of three other kinds of NDT methods were compared. E_sdetermined by estimating weight loss ratios of wooden cores was regarded as the truth value of decay extent. Using ordinary least square regression to analyze the relationship between E_sand E_d(degree of decay determined by electric resistance tomography),E_sand E_y(degree of decay determined by stress wave),E_sand E_z(degree of decay determined by resistograph). 【Result】Resultsshowed that three NDT methods were able to estimate the different degree of decay for Fraxinus mandshurica and Populus × beijingensis standing trees; A s a whole,the fitting degree of E_dand E_s,E_yand E_swere both lower than that of E_zand E_s. In different decay degree,when E_s< 30%,E_dhad a strong positive correlation with E_s(R = 0. 823,P <0. 01),while when 30% ≤ E_s< 50%,E_yhave a significant positive correlation relationship with E_s(R = 0. 658,P <0. 01),electric resistance tomography had more sensitively reflect in incipient decay of standing trees,and stress wave had more accurate diagnosis on detecting middle decay of standing tress. E_zhad a strong positive correlation relationship with E_s,and when E_s≥ 50%,E_zhave a more positive correlation relationship with E_s(R = 0. 914,P < 0. 01).【Conclusion】Electric resistance tomography showed better diagnosis than the other two methods for incipient decay of standing trees,while stress wave imaging method used in the middle stage of decay testing was best,and resistograph can be used in the different stages of decay. It was suggested that each technique could be employed in the practical internal decay testing for standing trees according to the decay stage and operational conditions.
【Objective】Electric resistance tomography,stress wave imaging and resistograph were employed to detect and quantitatively characterize the internal decay for standing trees,then these three NDT(nondestructive testing)techniques were made comparisons in order to find out the appropriate technique matched with specific condition of standing trees in the forest field.【Method】An investigation about the accuracy of different NDT methods was carried out in the experiment forest of Northeast Forestry University in Harbin,Heilongjiang Province. 100 cross-sections of Fraxinus mandshurica and Populus × beijingensis standing trees were tested by four methods: electric resistance tomography,stress wave tomography,resistograph and estimation weight loss ratios of wooden increment cores. Taking wood core samples as research objects,testing results of three other kinds of NDT methods were compared. E_sdetermined by estimating weight loss ratios of wooden cores was regarded as the truth value of decay extent. Using ordinary least square regression to analyze the relationship between E_sand E_d(degree of decay determined by electric resistance tomography),E_sand E_y(degree of decay determined by stress wave),E_sand E_z(degree of decay determined by resistograph). 【Result】Resultsshowed that three NDT methods were able to estimate the different degree of decay for Fraxinus mandshurica and Populus × beijingensis standing trees; A s a whole,the fitting degree of E_dand E_s,E_yand E_swere both lower than that of E_zand E_s. In different decay degree,when E_s< 30%,E_dhad a strong positive correlation with E_s(R = 0. 823,P <0. 01),while when 30% ≤ E_s< 50%,E_yhave a significant positive correlation relationship with E_s(R = 0. 658,P <0. 01),electric resistance tomography had more sensitively reflect in incipient decay of standing trees,and stress wave had more accurate diagnosis on detecting middle decay of standing tress. E_zhad a strong positive correlation relationship with E_s,and when E_s≥ 50%,E_zhave a more positive correlation relationship with E_s(R = 0. 914,P < 0. 01).【Conclusion】Electric resistance tomography showed better diagnosis than the other two methods for incipient decay of standing trees,while stress wave imaging method used in the middle stage of decay testing was best,and resistograph can be used in the different stages of decay. It was suggested that each technique could be employed in the practical internal decay testing for standing trees according to the decay stage and operational conditions.
引文
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鲍震宇,邸向辉,王立海,等.2013a.小兴安岭天然林中冷杉立木含水率对应力波传播速度的影响.林业科技,38(1):22-24.(Bao Z Y,Di X H,Wang L H,et al.2013a.Effects of moisture content on propagation velocity of stress wave in Abies fabric standing trees in Xiaoxing’anling nature forest.Forestry Science&Technology,38(1):22-24.[in Chinese])
鲍震宇,王立海.2013b.电阻测试法在立木腐朽检测中的应用研究进展.森林工程,29(6):47-51.(Bao Z Y,Wang L Y.2013b.Application of electrical resistance testing method in detection of decay in standing trees.Forest Engineering,29(6):47-51.[in Chinese])
池玉杰.2002.木材腐朽与木材腐朽菌.北京:科学出版社.(Chi Y J.2002.Wood decay and wood decay fungi.Beijing:Science Press.[in Chinese])
高珊,王立海,王洋.2013.东北林区十个树种冻结活立木中应力波传播速度试验研究.森林工程,29(4):47-52.(Gao S,Wang L H,Wang Y.2013.Experimental study on stress wave propagation velocity in frozen standing trees of 10 species in northeast China.Forest Engineering,29(4):47-52.[in Chinese])
葛晓雯,王立海,孙天用,等.2014.基于应力波和阻抗仪技术的旱柳内部腐朽定量检测.林业科技开发,28(5):87-91.(Ge X W,W L H,Sun T Y,et al.2014.Quantitative detection of Salix matsudana inner decay based on stress wave and resistograph techniques.China Forestry Science and Technology,28(5):87-91.[in Chinese])
黄荣凤,王晓欢,李华,等.2007.古建筑木材内部腐朽状况阻力仪检测结果的定量分析.北京林业大学学报,29(6):167-171.(Huang R F,Wang X H,Li H,et al.2007.Quantitative analysis on the detected results by resisto-graph on inside wood decay of ancient architecture.Journal of Beijing Forestry University,29(6):167-171.[in Chinese])
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李文彬.2008.第15届国际木材无损检测会议.国际学术动态,(4):41-42.(Li W B.2008.15thInternational symposium on nondestructive testing of wood.International Academic Developments,(4):41-42.[in Chinese])
林文树,杨慧敏,王立海.2005.超声波与应力波在木材内部缺陷检测中的对比研究.林业科技,30(2):39-41.(Lin W S,Yang H M,Wang L H.2005.Comparative study on ultrasonic and stress wave for nondestructive test of wood defects.Forestry Science&Technology,30(2):39-41.[in Chinese])
刘泽旭,邸向辉,王立海,等.2014.检测角对健康立木中应力波传播速度的影响.东北林业大学学报,42(4):105-108.(Liu Z X,Di X H,Wang L H,et al.2014.Effect of different detection angle on propagation velocity of stress wave in health standing trees.Journal of Northeast Forestry University,42(4):105-108.[in Chinese])
孙天用,王立海,徐华东,等.2014.小兴安岭土壤化学性质对红松活立木树干腐朽的影响.北京林业大学学报,36(2):30-37.(Sun T Y,Wang L H,Xu H D,et al.2014.Effects of soil chemical properties on trunk decay of Korean pine standing trees in Xiaoxing’an Mountains of northeastern China.Journal of Beijing Forestry University,36(2):30-37.[in Chinese])
孙天用,王立海,孙墨珑.2013.小兴安岭红松活立木树干腐朽与立地土壤理化特性的关系.应用生态学报,24(7):1837-1842.(Sun T Y,Wang L H,Sun M L.2013.Correlations between standing trees trunk decay degree and soil physical-chemical properties in Korean pine-broadleaved mixed forest in Xiaoxing’an Mountains of northeast China.Chinese Journal of Applied Ecology,24(7):1837-1842.[in Chinese])
王朝志,张厚江.2006.应力波用于木材和活立木无损检测的研究进展.林业机械与木工设备,34(3):9-13.(Wang C Z,Zhang H J.2006.The research progress in wood and standing tree based on stress wave method.Forestry Machinery&Woodworking Equipment,34(3):9-13.[in Chinese])
王立海,杨学春,徐凯宏.2001.木材无损检测技术的研究现状与进展.森林工程,17(6):1-3.(Wang L H,Yang X C,Xu K H.2001.The present situation and advance in development of wood non-destructive testing techniques.Forest Engineering,17(6):1-3.[in Chinese])
王立海,徐华东,闫在兴,等.2008.传感器的数量与分布对应力波检测原木缺陷效果的影响.林业科学,44(55):115-121.(Wang L H,Xu H D,Yan Z X,et al.2008.Effects of sensor quantity and planar distribution on testing results of log defects based on stress wave.Scientia Silvae Sinicae,44(5):115-121.[in Chinese])
吴华桥,周启友,刘汉乐.2008.树干水分分布及运移的高密度电阻率成像法时空监测.地球物理学进展,23(4):1310-1316.(Wu H Q,Zhou Q Y,Liu H L.2008.Temporal and spatial monitorin of water distribution and migration in a tree trunk using electrica resistivity tomography.Progress in Geophysics,23(4):1310-1316.[in Chinese])
徐华东,王立海,游祥飞,等.2010.应力波在旱柳立木内的传播规律分析及其安全评价.林业科学,46(8):145-150.(Xu H D,Wang L H,You X F.2010.Analysis of stress wav propagation in hankow willow standing trees and stabilit assessment.Scientia Silvae Sinicae,46(8):145-150.[in Chinese])
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