岩石的非线性统一强度准则

Hoek-Brown强度准则在岩石工程中被广泛采用，但由于它没有考虑中间主应力效应，因而在理论和实际应用上都存在不足之处，综合统一强度理论和Hoek-Brown强度准则的优点，提出一个适用于岩石的非线性统一强度准则，这一准则既考虑岩石拉压强度相差较大的特点，又考虑了中间主应力效应及其区间性。Hoek-Brown强度准则和非线性双剪强度准则在π平面上构成了岩石屈服破坏面的内边界和外边界，它们均为所提准则的特例。岩石的非线性统一强度准则，其子午线是非线性的，其参数与Hoek-Brown准则的参数一致，可以用岩石的常规三轴试验结果按Hoek-Brown提出的回归公式得出，完整岩石能够从常规三轴试验数据预测出不同应力角的破坏极限线，与国内4个单位6种岩石20余组岩石真三轴实验结果对比表明，该准则与实验结果吻合良好，这一准则也可以推广到岩体或节理化岩体。

NONLINEAR UNIFIED STRENGTH CRITERION OF ROCK

Nonlinear unified strength criterion is presented and Hoek-Brown criterion is modified by the unified strength theory. The characteristics of rock and the effect of intermediate principle stress on rock strength is taken into account. Hoek-Brown criterion and nonlinear twin-shear strength criterion are two special cases of the nonlinear unified strength criterion. The limit loci on p plane of Hoek-Brown criterion and the nonlinear twin-shear strength criterion formulate inner and outer bounds. The parameters of the nonlinear unified strength criterion are the same as those of Hoek-Brown criterion obtained from normal triaxial test for rock block. The failure loci at defferent stress angle can be estimated from the nonlinear unified strength criterion. The comparison of the nonlinear unified strength criterion with the experimental data of six sets of true triaxial test for rocks shows the good agreements. This method can be generalized to rockmasses or jointed rockmasses.