不同强度准则对预测岩石抗拉强度的适用性  

Applicability of Different Strength Criteria for Forecasting Tensile Strength of Rocks

作　　者：杨烜宇 YANG Xuan-yu(Shanxi Transportation Technology Research&Development Co.,Ltd.,Taigyuan,Shanxi 030032,China)

机构地区：[1]山西省交通科技研发有限公司,山西太原030032 [2]山西省智慧交通研究院有限公司,山西太原030032

出　　处：《山西交通科技》2022年第3期42-46,50,共6页Shanxi Science & Technology of Transportation

摘　　要：巴西劈裂法广泛应用于测试岩石抗拉强度,利用弹性力学方法计算圆盘应力特征,可以间接得到岩石的抗拉强度。考虑了不同的破坏形态,对传统抗拉强度计算方法加以改进,并分别利用几种常见强度准则预测了岩石的抗拉强度:Mohr-Coulomb准则(M-C)、Griffith准则、Lade-Duncan准则(L-D)和Hoek-Brown准则(H-B)。研究发现:a)巴西劈裂试验一般会出现3种形式的破裂迹线:非贯通迹线、直线型贯通迹线、非直线型贯通迹线,造成这种现象的主要原因是岩石自身的横观各向同性;b)圆盘的抗拉强度沿着水平方向自圆心向两侧逐渐降低,表现为非中心起裂的试样抗拉强度较低;c)由于H-B准则是基于试验数据提出的经验准则,因此其计算结果与试验结果误差最小;Griffith准则作为一种针对抗拉强度提出的准则,其计算结果与试验结果误差较小;L-D准则适用于真三轴应力状态,在不考虑中间主应力情况下,其结果偏差较大;M-C准则更多考虑试样的剪切破坏,因此在计算抗拉强度时误差很大。The Brazilian split test is widely used to test the tensile strength of rock. Calculating the stress characteristics of the disk by elastic mechanics method to indirectly obtain the tensile strength of rock.Considering different failure modes, the conventional calculation method of tensile strength is improved, and the tensile strength of rock is forecast by using common strength criteria which are Mohr-Coulomb(M-C), Griffith,Lade-Duncan(L-D), and Hoek-Brown(H-B). The results show that there are three kinds of fracture traces in the Brazilian split test, mainly caused by the transverse isotropy of the rock itself. The tensile strength of the disk gradually decreases from the center of the circle to both sides in the horizontal direction, reflected by the low tensile strength of the specimen with an off-center crack. H-B criterion is an empirical criterion based on experimental data, so the error between calculation results and experimental results is minimal, and the Griffith criterion, as a criterion for tensile strength, has a small error. L-D criterion is suitable for a true triaxial stress state and has a large deviation when the intermediate principal stress is not considered. The M-C criterion considers more shear failure of specimens, so there is a large error in calculating tensile strength.

关 键 词：巴西劈裂 强度准则 抗拉强度 

分 类 号：TU452[建筑科学—岩土工程]