针对著名断裂教授 sin 提出的著名[S]<sub>min</sub>准则中所存在的若干缺陷,作者曾利用宏微观相结合的方法在文献[1,2]中提出了三个三维裂纹的起裂准则并很成功地解决了三维表面裂纹问题。本文的主要贡献在于:1 针对平面...针对著名断裂教授 sin 提出的著名[S]<sub>min</sub>准则中所存在的若干缺陷,作者曾利用宏微观相结合的方法在文献[1,2]中提出了三个三维裂纹的起裂准则并很成功地解决了三维表面裂纹问题。本文的主要贡献在于:1 针对平面裂纹的特殊个性,对文献[1,2]的假定作了更符合实际的改变,提出了二维裂纹的[U<sub>v</sub>]<sub>max</sub>、[σ<sub>α</sub>]<sub>max</sub>和[γ<sub>p</sub>]<sub>min</sub>准则。2 推出了平面裂纹起裂角和载荷的一般方程。3 求出了Ⅰ型和Ⅱ型裂纹的起裂角θ<sup>*</sup>和相应的 K<sub>Ⅲc</sub>/K<sub>Ⅰc</sub>值,这些值和实验结果比较表明本文所提准则较其它准则更佳。4 讨论了 Possion（泊松）比 v 和应力状态对θ<sup>*</sup>和 K<sub>Ⅱc</sub>/K<sub>Ⅰc</sub>值的影响,得出了 v 和应力状态对θ<sup>*</sup>几乎无影响而对 K<sub>Ⅱc</sub>/K<sub>Ⅰc</sub>有较大影响这一令人满意和从未有过的新发现。给出了三准则适用条件。展开更多
The complexity of a rock masses structure can lead to high uncertainties and risk during underground engineering construction.Laboratory tests on fractured rock-like materials containing a tunnel were conducted,and tw...The complexity of a rock masses structure can lead to high uncertainties and risk during underground engineering construction.Laboratory tests on fractured rock-like materials containing a tunnel were conducted,and twodimensional particle flow models were established.The principal stress and principal strain distributions surrounding the four-arc-shaped and inverted U-shaped tunnels were investigated,respectively.Numerical results indicated that the dip angle combination of preexisting fractures directly affects the principal stress,principal strain distribution and the failure characteristics around the tunnel.The larger the absolute value of the preexisting fracture inclination angle,the higher the crushing degree of compression splitting near the hance and the larger the V-shaped failure zone.With a decrease in the absolute value of the preexisting fracture inclination angle,the compressive stress concentration of the sidewall with preexisting fractures gradually increases.The types of cracks initiated around the four-arc-shaped tunnel and the inverted U-shape tunnel are different.When the fractures are almost vertical,they have a significant influence on the stress of the sidewall force of the four-arc-shaped tunnel.When the fractures are almost horizontal,they have a significant influence on the stress of the sidewall of the inverted U-shaped tunnel.The findings provide a theoretical support for the local strengthening design of the tunnel supporting structure.展开更多
文摘针对著名断裂教授 sin 提出的著名[S]<sub>min</sub>准则中所存在的若干缺陷,作者曾利用宏微观相结合的方法在文献[1,2]中提出了三个三维裂纹的起裂准则并很成功地解决了三维表面裂纹问题。本文的主要贡献在于:1 针对平面裂纹的特殊个性,对文献[1,2]的假定作了更符合实际的改变,提出了二维裂纹的[U<sub>v</sub>]<sub>max</sub>、[σ<sub>α</sub>]<sub>max</sub>和[γ<sub>p</sub>]<sub>min</sub>准则。2 推出了平面裂纹起裂角和载荷的一般方程。3 求出了Ⅰ型和Ⅱ型裂纹的起裂角θ<sup>*</sup>和相应的 K<sub>Ⅲc</sub>/K<sub>Ⅰc</sub>值,这些值和实验结果比较表明本文所提准则较其它准则更佳。4 讨论了 Possion（泊松）比 v 和应力状态对θ<sup>*</sup>和 K<sub>Ⅱc</sub>/K<sub>Ⅰc</sub>值的影响,得出了 v 和应力状态对θ<sup>*</sup>几乎无影响而对 K<sub>Ⅱc</sub>/K<sub>Ⅰc</sub>有较大影响这一令人满意和从未有过的新发现。给出了三准则适用条件。
基金Project(41807241) supported by the National Natural Science Foundation of ChinaProject(2021M693544) supported by China Postdoctoral Science FoundationProject(2022JM-160) supported by the Natural Science Basic Research Program of Shaanxi,China。
文摘The complexity of a rock masses structure can lead to high uncertainties and risk during underground engineering construction.Laboratory tests on fractured rock-like materials containing a tunnel were conducted,and twodimensional particle flow models were established.The principal stress and principal strain distributions surrounding the four-arc-shaped and inverted U-shaped tunnels were investigated,respectively.Numerical results indicated that the dip angle combination of preexisting fractures directly affects the principal stress,principal strain distribution and the failure characteristics around the tunnel.The larger the absolute value of the preexisting fracture inclination angle,the higher the crushing degree of compression splitting near the hance and the larger the V-shaped failure zone.With a decrease in the absolute value of the preexisting fracture inclination angle,the compressive stress concentration of the sidewall with preexisting fractures gradually increases.The types of cracks initiated around the four-arc-shaped tunnel and the inverted U-shape tunnel are different.When the fractures are almost vertical,they have a significant influence on the stress of the sidewall force of the four-arc-shaped tunnel.When the fractures are almost horizontal,they have a significant influence on the stress of the sidewall of the inverted U-shaped tunnel.The findings provide a theoretical support for the local strengthening design of the tunnel supporting structure.
