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本文探讨了5种常用线性及非线性破裂准则方程在深层砂岩、页岩及硬石膏泥岩中的力学强度响应变化过程及预测精度.根据σ1-σ3变化样式将其划分为:连续上凸型、连续上凹型及离散型3种类型,类型划分与岩石内部颗粒分布状态、接触形式、脆度及蠕变性有关,与组分含量无关.同时采用AAE、RMSE及COV等指标对各准则条件下岩石C0及σ1预测精度进行了对比,结果表明:AAE、RMSE及R2之间有时会因出现较大的MAE值而发生不对应;COV能将精度放大;岩石C0预测效果与σ1-σ3变化样式具有较好对应关系;对于σ1的预测,当σ1-σ3为连续上凸样式时,一般Sheory、Bieniawski及H-B准则预测效果较好;当为连续上凹样式时,Sheory准则预测效果最好;当为离散样式时,较高的精度可能来源于线性准则或非线性准则.对于C0的预测,非线性Sheory、Bieniawski及H-B准则预测效果较好.最后对σ1离散值进行了定义,按文中方法去除离散值后能显著提高预测效果.
In this paper, the mechanical strength responses of five common linear and nonlinear fracture criterion equations in deep sandstone, shale and anhydrite mudstone are discussed and the prediction accuracy is discussed.According to the variation of σ1-σ3, they are divided into continuous convex, There are three types of continuous concave and discrete types, which are related to the particle distribution, contact form, brittleness and creep of rock, and have nothing to do with the content of the components.At the same time, using AAE, RMSE and COV, The prediction accuracy of rock C0 and σ1 are compared. The results show that there are some discrepancies between AAE, RMSE and R2 due to the large MAE value; COV can amplify the accuracy; the prediction results of rock C0 and the variation of σ1-σ3 For the prediction of σ1, the general Sheory, Bieniawski and HB criterion predict better when σ1-σ3 are continuous convex modes; Sheory’s criterion has the best prediction effect when the continuous concave mode is adopted; when For the discrete pattern, the higher accuracy may come from the linear criterion or the nonlinear criterion.For the prediction of C0, the nonlinear Sheory, Bieniawski and HB criterion predict better.Finally, the discrete value of σ1 After removal of discrete values according to the proposed method can significantly improve the prediction results.