The traditional non-destructive method of pipe piles and concrete plates is impact-echo technique based on one-dimensionalstress wave theory, and it can detect the big defects.
It indicates that stress state affects the close ways of voids and three-dimensional compressive stress state is the best one for healing the internal voids of object.
条件表明应力状态影响空洞的闭合方式,三向压应力是修复空洞缺陷的最佳应力状态。
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And then, by using the stress strength interference theory to calculate fracture probability is converted to resolve a onedimensional integral.