摘要
混凝土的裂缝断裂问题是评定混凝土结构工程安全的关键问题.结合起裂韧度准则和黏聚力模型,提出了一种混凝土裂缝断裂分析的简化预测方法.通过给定裂缝黏聚力的分布形式,推导了裂缝张开位移、外荷载的表达式,结合拉伸软化曲线给出了相应的求解方程和求解步骤,获得了裂缝起裂至扩展的全过程曲线.其中,裂缝扩展基于起裂韧度准则,黏聚力产生的应力强度因子和位移采用权函数方法进行计算.利用不同尺寸的楔入劈拉试件对断裂全过程进行了计算,结合现有的混凝土断裂试验成果对本文方法进行了验证.结果表明采用本方法可完整的计算裂缝断裂全过程并准确的预测带裂缝构件的极限承载力,从而验证了本文方法的有效性和合理性.
Cracks are the key issue for the safety of concrete structure. A simplified method for predicting concrete fracture was proposed in this paper on the basis of the initial fracture toughness criterion and the cohesive stress model. The expressions of crack opening displacement and load were derived by assuming the distribution of the cohesive stresses. Based on the tensile softening curve, the governing equations for concrete fracture were obtained, and the whole fracture process curves from the crack initiation state to the propagation state were calculated. In this method, the initial fracture toughness criterion was adopted as crack propagation criterion, and the stress intensity factor and the crack opening displacement were calculated by weight function. The proposed method was used to calculate the whole fracture processes of wedge splitting specimens with different sizes, and the results were compared with existing test results. The results demonstrated that the whole process of fracture can be accurately calculated and the ultimate bearing capacity of the specimen can be predicted. The reasonability of the proposed method was thus verified.
出处
《河北工业大学学报》
CAS
2015年第1期89-95,共7页
Journal of Hebei University of Technology
基金
国家自然科学基金(51309073)
河北省自然科学基金(E2014202257)
高等学校博士学科点专项科研基金(20131317120012)
清华大学水沙科学与水利水电工程国家重点实验室开放基金(sklhse-2014-C-02)
关键词
混凝土
裂缝
断裂
起裂韧度
黏聚力
concrete
crack
fracture
initial fracture toughness
cohesive stress
