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本文将混凝土视为粘弹性材料,同时考虑外界载荷持续作用下发生的蠕变变形和温度变化引起的应力松弛共同对裂纹扩展过程的影响.根据柘溪大坝的各项实测资料,按照文献[1、2],进行了平面应变的有限元计算,其结果与实测值基本一致. 计算结果表明,柘溪大坝坝墩存在着因水泥水化热及气温变化而造成的迎水面垂直初始表面裂纹,其深度达70—80cm,在1969年元月份的温度应力和水载荷共同作用下,裂纹进一步扩展,当水沿新张开的裂纹渗入到180—240cm时,裂纹扩展的深度达270—294cm.俟后,由于气温和水位的下降,小于330cm深度以内的裂纹停止扩展,到1969年6月份水位回升到164cm高程,在温度应力与水载荷共同作用下,深度达275—282cm以上的裂纹发生失稳扩展.
In this paper, the concrete is regarded as viscoelastic material, considering the creep deformation caused by the continuous load of external load and the stress relaxation caused by temperature change, which affect the crack propagation process.According to the measured data of Baoxi Dam, 1,2], the plane strain of the finite element calculation, the results and the measured values are basically the same.The calculation results show that there is a dam abutment due to the cement hydration heat and temperature changes caused by the vertical surface of the water surface Cracks, the depth of 70-80cm, in January 1969 the temperature stress and water load together, the crack further expanded, when the water along the newly opened cracks infiltrated to 180-240cm, the crack propagation depth of 270- 294cm. After 俟, the cracks within the depth of less than 330cm ceased to expand due to the decrease of air temperature and water level. By June 1969, the water level rose to a height of 164cm. Under the joint action of temperature stress and water load, cracks of depth 275-282cm Unstable expansion occurred.