基于SMP准则的破裂岩统计损伤软化模型及其应用研究

STATISTICAL DAMAGE SOFTENING MODEL OF FRACTURED ROCK BASED ON SMP FAILURE CRITERION AND ITS APPLICATION

岩石材料是一种非均质材料,而破裂岩是指岩体内部含有大量的裂隙、空洞、界面等缺陷,在荷载作用下其微元体破坏更具有随机性。在损伤理论的基础上,从微元体的强度随机分布的角度出发,在微元体强度度量方法上考虑损伤阈值的影响,假设破裂岩的微元体强度服从Weibull分布,结合考虑中主应力的SMP准则,建立破裂岩统计损伤软化本构模型,运用多种计算方法对模型参数m和F0进行确定。通过对小官庄铁矿2种破裂岩闪长玢岩以及矽卡岩的验证表明:在不同围压下,全应力–应变试验曲线与预测曲线吻合良好,能够反映损伤阈值的影响,且在较低围压下更为理想。同时,此模型能够反映随着围压的增加岩石的峰值强度增加而延性增大的性质,进一步验证模型的适用性及较强的应用价值。

The rock material is a kind of non-homogeneous material and there are a large number of defects such as fissures,voids,interfaces in the broken rock. Its micro units damage more randomness under the loads. Starting from micro units strength are random distribution on the basis of damage theory,a method for measuring microcosmic element strength of rock is presented with consideration of damage threshold. Assuming the micro units strength of broken rock obey Weibull distribution,combined with the SMP criterion,which considers the intermediate principal stress,the statistical damage softening constitutive model is built. And the model parameters m and F0 are computed using some methods. Through the calculation results of two kinds of broken rock in Xiaoguanzhuang indicate that:the predicted stress-strain curves under different confining pressures agree well with the test data,and it can reflect not only the influence of damage threshold but also more desirable in the lower confining pressures. At the same time,this model can reflect the characteristic that the peak strength increases and ductility increases with the confining pressure increase,which further shows that the applicability of the model and a strong application value.