The image above represents horizontal stress.

To compute for horizontal stress, two essential parameters are needed and these parameters are **Poisson’s ratio (v) **and **vertical stress (σ _{v}).**

The formula for calculating the horizontal stress:

σ_{H} = ^{vσv} / _{1 – v}

Where;

σ_{H} = Horizontal Stress

v = Poisson’s Ratio

σ_{v} = Vertical Stress

Let’s solve an example;

Find the horizontal stress when the Poisson’s ratio is 24 and the vertical stress is 28.

This implies that;

v = Poisson’s Ratio = 24

σ_{v} = Vertical Stress = 28

σ_{H} = ^{vσv} / _{1 – v}

σ_{H} = ^{24(28)} / _{(1 – 24)}

σ_{H} = 672 / _{-23}

σ_{H} = -29.217

Therefore, the **horizontal stress **is **29.217.**

**Calculating the Poisson’s Ratio when the Horizontal Stress and Vertical stress is Given.**

v = ^{σH} / _{σ}_{v} + σ_{H}

Where;

v = Poisson’s Ratio

σ_{H} = Horizontal Stress

σ_{v} = Vertical Stress

Let’s solve an example;

Find the Poisson’s ratio when the horizontal stress is 12 and the vertical stress is 16.

This implies that;

σ_{H} = Horizontal Stress = 12

σ_{v} = Vertical Stress = 16

v = ^{σH} / _{σ}_{v} + σ_{H}

v = ^{12} / _{16 + 12}

v = ^{12} / _{28}

v = ^{12} / _{28}

v = 0.428

Therefore, the **Poisson’s ratio **is **0.428.**

Continue reading How to Calculate and Solve for Horizontal Stress | Rock Mechanics