钢纤维混凝土裂缝扩展的双K准则研究  

Double-K fracture parameters of steel fiber reinforced concrete

作　　者：张井财 薛启超[1] 何建[1] 

机构地区：[1]哈尔滨工程大学航天与建筑工程学院,黑龙江哈尔滨150001

出　　处：《混凝土》2016年第9期16-20,共5页Concrete

基　　金：国家自然科学基金资助项目(51409056);黑龙江省自然科学基金(E2015047);哈尔滨工程大学自由探索计划(HEUCF150202)

摘　　要：钢纤维混凝土的裂缝扩展过程仍然可以划分为裂缝不扩展、稳定扩展以及失稳扩展三个阶段,因此基于素混凝土提出的双K断裂准则仍然适用;按照线性渐进叠加假定推导了钢纤维混凝土的裂缝尖端净强度因子和桥连韧度的计算公式,给出了针对钢纤维混凝土的临界裂缝的解析解算法和便于实际应用的近似算法并在此基础上给出了双K参数的计算方法。分析讨论了钢纤维混凝土裂缝扩展抗力的来源,该抗力理论是基于混凝土黏聚力和钢纤维桥连应力共同作用得到的,已公开发表文献数据与之符合较好。开展了钢纤维混凝土的三点弯曲试验,结果显示其起裂韧度总体增长但不成线性关系,而失稳韧度与纤维的体积掺量成近似线性增长关系,符合本研究理论。Double-K fracture parameters can also describle the cracking process of steel fiber reinforced concrete well since the crack go through three stages,the stage of crack arises,expand stage,break stage.Stress intensity factor cased by bridging stress and the net stress intensity factor were given based on the hypothesis of linear asymptotic superposition.Analytical expression and a approximation algorit-hm for double-K fracture parameters was given as well as the crack length at a critical situation.According to the formulas offered,a new crack extension resistance theory were proposed.In the new theory,both of the cohesive force and the bridging stress were taken inio account.The theory agrees with data from published.Three-point bending experimental studies were carried out.Results show that nearly for increases in volume ratio,but it not occurred to the.The result was in good agreement with theory.

关 键 词：钢纤维混凝土 断裂 裂缝扩展抗力 双K断裂准则 起裂韧度:失稳韧度 

分 类 号：TU528.01[建筑科学—建筑技术科学]