Join 60,000+ competitive exam aspirants
If Cross Slope of a country is up to 10% the terrain is classified as
Plain
Rolling
Mountainous
Steep
Plain
Terrain classification in highway engineering is determined by the cross-slope of the ground. According to the Indian Roads Congress (IRC) standards, land with a cross-slope up to 10% is classified as 'Plain' terrain.
Terrain classification in highway engineering is determined by the cross-slope of the ground. According to the Indian Roads Congress (IRC) standards, land with a cross-slope up to 10% is classified as 'Plain' terrain.
Cross┬аSlope=RunRiseтАЛ├Ч100% тАФ Used to determine terrain category by measuring transverse gradient.
The classification is based on the ease of road construction and earthwork requirements. In plain terrain, the ground slope is gentle, minimizing the need for heavy cutting or filling, which directly influences the design speed and horizontal alignment geometry.
Terrain classification dictates design standards for curves, gradients, and sight distances.
IRC: 73-1980 specifies these categories for geometric design of rural highways.
Plain terrain allows for higher design speeds due to flatter profiles.
Higher terrain categories (Mountainous/Steep) increase construction costs significantly.
Simplifies geometric design selection.
Optimizes earthwork estimation.
Does not account for soil properties.
May require local adjustments for complex topographies.
Highway alignment planning.
Road design speed selection.
Estimation of project cost based on volume of excavation.
| Feature | Plain | Rolling |
|---|---|---|
Cross Slope Range | 0 - 10% | 10тИТ25% |
Rolling terrain (10тБ╗┬▓тБ╡%) implies undulating ground where some earthwork is required.
Mountainous terrain (25-60%) involves significant cross-slope variations requiring steep gradients.
Steep terrain (>60%) often necessitates specific engineering solutions like tunnels or bridges.
A is correct тАФ Terrain with a cross-slope up to 10% is classified as Plain because it provides a relatively flat surface with minimal requirements for significant earthwork.
Remember that while cross-slope defines terrain, the 'ruling gradient' varies inversely with the severity of the terrain classification.