为了明确正交胶合木（CLT）横向层断裂演化机制，本项目主要以国产锯材为研究对象，通过不同树种正交胶合木的制备、力学实验、横向层破坏演化、断裂力学计算和微观结构力学表征等实验，着重研究以下2个科学问题：弯曲应力作用下横向层锯材、胶层之间的交互作用与破坏演化问题；横向层锯材微观构造、横向层微观力学对其宏观断裂和裂纹扩展的影响。通过实验获得CLT断裂位置应力演变过程以及破坏发展过程，总结不同位置胶层破坏的应力、破坏时间、破坏规律以及横向层破坏应力、破坏时间、破坏规律，明确胶层破坏与横向层锯材破坏对于CLT横向层失效的交互作用。探究不同树种横向层破坏规律，分析锯材微观力学性能对裂纹扩展的影响，细化木材微观力学对于横向层破坏的影响。为CLT横向层断裂韧性合理计算，提高CLT横向层抗剪性能提供可靠的理论基础、科学依据和技术数据。

In order to clarify the fracture evolution mechanism of transverse layers of cross laminated timber (CLT),In this project, mechanical experiments were carried out on CLT prepared from domestic sawn timber, and transverse layer failure was completely recorded and fracture evolution of CLT was characterized by microstructure mechanics and fracture mechanics. The following two scientific questions were focused on: (1) The interaction between transverse sawn timber and adhesive layer and the failure evolution of transverse layer under bending stress. (2) Effects of microstructure and micromechanics of transverse layer on macroscopic fracture and crack propagation of transverse layer sawn timber. The stress evolution process and failure development process of CLT fracture location were obtained through experiments。The stress, failure time and failure rule of adhesive layer failure at different locations, as well as the failure stress, failure time and failure rule of transverse layer sawn timber were summarized. The interaction between adhesive layer failure and transverse layer sawn timber failure on the failure of CLT transverse layer was clarified. Explore the transverse layer failure rules of different tree species。The influence of microscopic mechanical properties of sawn timber on crack propagation and the influence of wood micromechanics on transverse layer failure was analyzed.