岩石力学试卷

岩石力学试卷

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.

为了研究强度特性的砂岩,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 gradient 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。其凝聚力是6.0MPa,其内摩擦角是45º,泊松比为0.25,单轴抗拉强度是2 mpa。上覆压力梯度是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来打开这个构造。

注:有效应力系数α= 0.5。