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考虑冻土的非线性断裂力学特征,基于现有J积分测试方法,提出了一种新的冻土非线性断裂韧度的测试方法——修正因子法。在传统方法中J积分可以写成如下表达:J=Je+Jp,其中Je为J积分的线弹性分量,Jp为J积分的塑性分量。Je的计算相对简单;但计算Jp相对困难,原因是其中的参数Up难于确定。为了使计算简单,可将塑性分量改写为Jp=qJe,J积分则改写为J=(1+q)Je,q称为塑性修正因子。该方法通过循环加、卸载试验得到非线性载荷-位移曲线(P-Δ曲线),并由载荷与位移的增量确定修正因子,在获得线弹性分量Je基础上,获得冻土非线性断裂韧度。采用该方法进行了冻土非线性断裂韧度测试,并将测试结果与相关文献结果进行比较,证明了该方法的合理性和有效性。
Considering the nonlinear fracture mechanics characteristics of frozen soil, a new method of testing the nonlinear fracture toughness of frozen soil - correction factor method is proposed based on the existing J integral test method. In the traditional method, J integral can be written as follows: J = Je + Jp, where Je is the linear elastic component of J integral and Jp is the plastic integral of J integral. Je’s calculation is relatively simple; however, it is relatively difficult to calculate Jp because the parameter Up in it is difficult to determine. In order to make the calculation simple, the plastic component can be rewritten as Jp = qJe, J integral rewritten as J = (1 + q) Je, q is called the plastic correction factor. In this method, the nonlinear load-displacement curve (P-Δ curve) is obtained through cyclic loading and unloading tests, and the correction factor is determined by the increment of load and displacement. On the basis of obtaining the linear elastic component Je, the nonlinear fracture toughness degree. This method is used to test the nonlinear fracture toughness of frozen soil. The test results are compared with the related literatures, which proves the rationality and effectiveness of the method.