腐朽虫蛀木构件的耐久性预测模型研究进展

Review of the Prediction Model for Durability of Structural Wood under Decay and Termite Attack

对木结构进行剩余寿命预测需要从材料层面考虑木材的腐朽、虫蛀、干缩裂缝和持续荷载对木材长期抗力的影响。木构件腐朽深度的增大和木材强度的降低是腐朽引起木材长期抗力降低的主要原因,构件中的虫洞数量和虫洞深度减小了构件的有效横截面积是虫蛀对木材长期抗力降低的主要影响。因此,本文从木材腐朽和虫蛀的角度,分析总结了木构件耐久性预测模型研究进展,包括地面木构件腐蚀随时间变化的模型,与土壤接触的地面木构件的腐朽模型,地下木桩的腐蚀模型和虫蛀的可靠度模型等。并在此基础上,指出腐朽机理的研究,考虑各种环境因素建立更加合理的腐朽规律和虫蛀规律是有待解决的关键问题。

Themechanical properties of the structural wood are affected by its surroundingsuch as shrinkage cracks, decay fungi, termite attack and duration of loadeffect. It is necessary to study how these factors affect the resistance of thewood member during service life in order to predict the residual life of timberstructure. Decay fungi induce the depth of decay increasing as time and thetermite attack makes the wood have more pinholes. Both of them will greatlyreduce the effective area of the wood member and meanwhile decay fungi decreasethe strength properties in wood. In this paper the research development andachievement of the prediction model for durability of structural wood underdecay and termite attack are reviewed in detail including decay model ofin-ground timber, exposed timber in ground contact, above-ground exposedtimber, protected timber and a reliability model under termite attack, and thenit is concluded that it is the key problem and main future research to study onthe mechanics of timber decay and to develop the quantitative prediction modelunder decay and termite attack considering various environmental factors.