Sequentially arrange the steps involved in laying a sewer line:
A. Transferring the center line of the sewer to the bottom of the trench.
B. Setting sight rails over the trench.
C. Driving pegs to the level of the invert line of the sewer.
D. Placing the sewer in the trench.
Choose the most appropriate answer from the options given below:
Step 1: Setting sight rails.
The first step is to establish reference sight rails above the trench (B).
Step 2: Driving pegs.
Next, pegs are driven to the level of the invert line of the sewer (C).
Step 3: Transferring center line.
The sewer's center line is then transferred to the bottom of the trench (A).
Step 4: Placing sewer.
Finally, the sewer is placed in the trench (D).
Step 5: Conclusion.
Thus, the correct sequential order is B → C → A → D. Hence, the correct answer is (D).