Which of the following statement is wrong?a)Threshold condition is the...
Explanation:
The correct statement among the given options is option 'C', which states that the critical tractive force approach helps in designing unstable channels in alluviums. This statement is incorrect. Let's discuss each statement to understand why option 'C' is wrong.
a) Threshold condition is the one in which a few particles on the bed will just start moving:
This statement is true. The threshold condition refers to the minimum shear stress required to initiate sediment motion. When the shear stress acting on the bed exceeds the threshold shear stress, a few particles on the bed will start moving.
b) Knowledge of critical velocity helps in designing stable non-scouring channels:
This statement is true. Critical velocity is the flow velocity at which sediment particles start moving and the channel bed becomes susceptible to erosion. By designing channels with velocities below the critical value, it is possible to prevent scouring and maintain a stable channel.
c) The critical tractive force approach helps in designing unstable channels in alluviums:
This statement is incorrect. The critical tractive force approach is used to design stable channels in alluviums. The approach involves determining the critical tractive force required to initiate sediment motion and comparing it with the available tractive force in the channel. If the available tractive force is less than the critical tractive force, the channel is considered stable.
d) The knowledge of threshold condition is required for the computation of sediment load:
This statement is true. The threshold condition is essential for determining the sediment load in a channel. It helps in estimating the amount of sediment that will be transported by the flow based on the shear stress exerted on the bed.
To summarize, option 'C' is the incorrect statement among the given options. The critical tractive force approach is used to design stable channels in alluviums, not unstable channels.
Which of the following statement is wrong?a)Threshold condition is the...
Shield was the first person to analyze the experimental data on incipient motion condition using the critical tractive force approach. The assumption of the entry of clean and clear water in the channel is used to develop non-scouring highest possible flow velocity at the peak flow.