岩石力学第二份试卷
Section A Term Explaination术语解释
1.Brittle of rock 岩石的脆性
2.Shear strength of rock 岩石的剪切强度
3.In-situ stress 原(就)地应力
4.Fracture pressure破裂压力
5.Yoang’s modulus 杨氏模量
6.Principal stress主应力
Section B Brief Description简要描述
1.Describe the effective stress principle描述有效应力原理
2.Describe the influence of confining pressure on the deformation
and strength characters of rock mechanics描述围压对岩石变形和强度特征的影响
3.Briefly describe the shear strength criterion of Coulomb-Vavier
简要介绍Coulomb-Vavier抗剪强度准则
4.Describe Brazilian test steps and how to obtain the tensile
strength of rock with it 描述巴西实验的步骤,以及如何用它获得岩石抗拉强度
Section C calculations计算题
1.In order to study the strength feature of an sandstone ,we select
two samples to do the uniaxial compressive strength test .The test results are as follows: the uniaxial compressive strength is 60MPa, the peak strength is 120MPa with the confining pressure of 20MPa.
Assuming the shear strength is agreed with Coulomb-Vavier
criterion
Determine the cohesion and internal friction angle of the rock with Mohr’s circle method.
为了研究砂岩的强度特性, 我们选择两个样本做单轴抗压强度试验。

测试结果如下:单轴抗压强度是60 MPa、峰值强度是120 MPa，围压20 MPa。

假设抗剪强度符合Coulomb-Vavier准则, 用莫尔圆方法确定内聚力和岩石
的内摩擦角
2.In an oil field ,well depth is 1000m, sandstone strength confirms
to Mohre-Coulomb criterion. Its cohesion is 6.0MPa, its angle of internal friction is 45º, Poisson ratio is 0.25, uniaxial tensile strength is 2MPa. Overburden is 22.6MPa , minimum horizontal in-situ stress is 17MPa , maxmum horizontal in-situ stress is
23MPa , pore pressure is 12MPa .
Calculate the collapse pressure and fracture pressure , then determine the reasonal mud density window to open this formation . Notice: effective stress coefficient α=0.5.
一个油田,井深度为1000米,砂岩强度符合Mohre-Coulomb（摩尔-库仑）准则。

其内聚力是6.0MPa, 其内摩擦角是45º, 泊松比为0.25,单轴抗拉强度是2MPa。

上覆压力是22.6 MPa、最小水平地应力是17 MPa, 最大水平地应力是23 MPa，孔隙压力是12 MPa。

计算坍塌压力和破裂压力, 然后确定合理的泥浆密度窗口以钻进这套地层。

注:有效应力系数α= 0.5。